Sikorsky SB-1 flies for first time [Archive]

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chopper2004

21st Mar 2019, 21:43

Many congratulations to Sikorsky

https://news.lockheedmartin.com/2019-03-21-Sikorsky-Boeing-SB-1-DEFIANT-TM-Helicopter-Achieves-First-Flight

cheers

IFMU

21st Mar 2019, 22:10

Awesome! Looks great!
https://youtu.be/Sm-N7trI0sw

The Sultan

21st Mar 2019, 22:56

They had to get it into the air or risk it being a symbol of a dead end failed concept. How bad is it that even after being two years late it was too dangerous to do an in ground effect hover until now. Bell is planning to suspend funding of the 280 as it has met its goals and obtained all of the data needed to elimate the risk of a production design. At the same time senior LM management must be wondering how much more money to sink into a program that has showed no return.

pants on fire...

21st Mar 2019, 23:44

heli1

22nd Mar 2019, 04:08

No info n duration of first flight ....joy selected video clips and no engagement of the pusher pro pulsed .Looks like still a way to go.

Bell_ringer

22nd Mar 2019, 06:08

Mostly underwhelming.
You can almost hear the accountants working out how deep the hole is going to be on this one.

IFMU

22nd Mar 2019, 10:57

No info n duration of first flight ....joy selected video clips and no engagement of the pusher pro pulsed .Looks like still a way to go.
First flight of the X2 was less than 30 minutes. Knowing Sikorsky test they have a build up plan and they will follow it. I don't think Sultana's jibes will change the pace at all. X2 flew 3 or 4 flights without the prop.
At least they didn't have any of that silly animation that some Sikorsky people seem so fond of.

Lonewolf_50

22nd Mar 2019, 12:18

Sultan, what do you mean by this?
Bell is planning to suspend funding of the 280 as it has met its goals and obtained all of the data needed to elimate the risk of a production design. Are you suggesting that Bell is currently in a position to go into the LRIP stage?

CTR

22nd Mar 2019, 14:21

IFMU

22nd Mar 2019, 21:32

Nice note from Bell Flight congratulating the Defiant team on LinkedIn. Interesting that one of the Bell Flight guys is trashing the Valor and saying Defiant is the way to go. What is up with that?

SASless

23rd Mar 2019, 00:45

CTR

23rd Mar 2019, 01:15

PlasticCabDriver

23rd Mar 2019, 09:23

Is it just me of does it remind anyone else of Toothless from How to Train Your Dragon?

https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/1117x629/8e7c8963_ec17_42e1_86e0_54834cb844fd_8a9f7c969e798bfd4fc0967 d551ff4aa6453990d.jpeg

CTR

23rd Mar 2019, 16:09

It is not just you!
https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/1334x750/2e5795f6_e3a6_4333_9f2b_88473b3b2a92_1173413d866cd16f0ad151a dbea4f625e2393c4a.png

Bell_ringer

23rd Mar 2019, 16:24

It is not just you!

You are both wrong, it's the hunt for red October.

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/1224x1035/6903c60c_b631_48cc_b239_7a0c2da115c9_4b0cf50947689b48afa4127 faac470c6416bbc75.jpeg

SplineDrive

23rd Mar 2019, 16:47

Sultan has not had the experience of working for multiple competitors in his career. Having worked for the big three plus multiple suppliers I developed an understanding that we are all kindred engineers. I never want anyone to lose a contract. Since it inevitably means someone will lose their job.

I'm with you... worked for several OEMs and closely with engineers from all three large US OEMs and some non-US helo OEMs. My primary takeaway from my career is all vertical take off aircraft are pretty terrible in some way :-) There's no perfect solution that works for every mission. So I'm not surprised some Bell Flight staff might think the "grass is greener" on SB>1 vs V-280. Some Sikorsky staff might say the same thing, based on the details they know about their solution and perhaps somewhat ignorant of what they don't know about the other.

SASless

23rd Mar 2019, 18:32

Did Sikorsky hire some British Aeronautical Design Engineers to work on this project?:}

CTR

23rd Mar 2019, 19:08

Nice note from Bell Flight congratulating the Defiant team on LinkedIn. Interesting that one of the Bell Flight guys is trashing the Valor and saying Defiant is the way to go. What is up with that?

I don’t use LinkedIn since it turned into another Facebook. Which I don’t bother with either.

But it I seriously doubt the post was from a Bell employee. How would you ever validate the individual’s claim? Any real employee could lose their job posting any information about the V-280, regardless if it was good or bad.

My guess is the post is from an old V-22 Osprey naysayer who has problems accepting the aircraft’s success.

Besides, currently how could anyone claim which aircraft is better? The Defiant has barely flown, and the Radier hasn’t completed as much envelope as the Valor. Not much information to base claims of superiority on for either aircraft. Other than maturity of tilt rotor technology and lower risk of development.

Evalu8ter

23rd Mar 2019, 21:45

CTR - well said. I thought it was classy from Bell to congratulate their competitors. Vertical lift is hard to do - we in the industry "get" that. Bell and Sikorsky/Boeing have taken contrasting views of how to approach the Army's Cap Set 3. Sikorsky built on the "what could have been" ABC, whereas Bell have leveraged their XV-15 / V-22 experience for the V-280. The latter seems to be going well; Defiant has a lot of work to do to catch up, but a few months should mean nothing to the US Army for a platform that will be decades in service. Inevitably, a loss will effect the losing team in terms of jobs and investment. Perhaps FARA opens up the chances of "everyone winning"; V-280 replacing UH-60 and a derivative of the S-92 Raider fulfilling FARA - effectively replacing the loss of the OH-58 and the missed opportunity of the RAH-66.

IFMU

24th Mar 2019, 14:19

I don’t use LinkedIn since it turned into another Facebook. Which I don’t bother with either.
But it I seriously doubt the post was from a Bell employee. How would you ever validate the individual’s claim? Any real employee could lose their job posting any information about the V-280, regardless if it was good or bad.
My guess is the post is from an old V-22 Osprey naysayer who has problems accepting the aircraft’s success.
Besides, currently how could anyone claim which aircraft is better? The Defiant has barely flown, and the Raider hasn’t completed as much envelope as the Valor. Not much information to base claims of superiority on for either aircraft. Other than maturity of tilt rotor technology and lower risk of development.
Apparently he is a disgruntled ex-employee of Bell. So, he has an axe to grind.
I've never been on facebook but I joined LinkedIn when Sikorsky closed Schweizer and I had to decide where I was going next. I agree a lot of it is non-professional.

IFMU

24th Mar 2019, 14:23

Commando Cody

27th Mar 2019, 21:19

I think back to the days of the Sikorsky ABC and XV-15 competition back in the 1980's.....each outfit had a lot to win or lose upon how the competition turned out.

Odd that Sultan continues bashing anything/everything Sikorsky but then we are used to his standard of posts.

A note: There was no competition between Sikorsky's S-69/XH-59 (ABC craft) and the XV-15. They were separate NASA research programs investigating new technologies for powered lift flight. As NASA programs, they weren't intended to lead to an operational aircraft. The XH-59 flew 106 hours between 1973 and 1981 and wasn't very successful. In 1982 it was proposed to modify the aircraft with new rotors, new engines and a pusher prop in a shared cost program with Sikorsky, but Sikorsky wasn't willing to put any of its own money into that,

The XV-15 first flew in 1977. It was much more successful, and was even flown at the Paris Air show. At the end of the planned tests, NASA planned to decommission it, but Bell leased it back and at their own expense flew it to expand the envelope, update some of the materials and components and demonstrate it to various military and civil agencies. This included a number of "guest" crew including military and civil pilots, personnel from various agencies and even members of Congress. It was also used to support procedures development for the V-22. Eventually, the airframe ran out of flight hours and was flown to the Smithsonian where it's now on display

CTR

27th Mar 2019, 22:40

The XV-15 first flew in 1977. It was much more successful, and was even flown at the Paris Air show. ...,,,,, Eventually, the airframe ran out of flight hours and was flown to the Smithsonian where it's now on display

I actually knew the Bell mechanics who accompanied the XV-15 to DC to decommission it. Drain fluids, remove pyrotechnics, etc. The aircraft structures and drivetrains still had life left. It was the rotor blades that were at the end of their life.

One interesting side story on the decommissioning of the aircraft occurred after all the ceremonies were over. As part of the ceremony to inaugurate the aircraft into the museum, the museum had a group of key pilots and engineers from NASA and Bell sign the nose of the aircraft. The new Bell president nicknamed “Red”, who had only been at Bell a few months, and never worked for NASA or Bell took the liberty to sign his name on the nose of the aircraft in big letters. The man had literally nothing to do with the development of the XV-15, but he felt the need to add his name next to all those deserving people for posterity.

Of course when the aircraft was decommissioned the mechanics “accidentally” spilled solvent over just his signature and needed to wipe it off

SASless

28th Mar 2019, 03:33

Cody,

The aircraft went to Fort Rucker and were "compared" even if not a formal competition but you know that those controlling purse strings and procurements were watching closely.

IFMU

28th Mar 2019, 22:40

One interesting side story on the decommissioning of the aircraft occurred after all the ceremonies were over. As part of the ceremony to inaugurate the aircraft into the museum, the museum had a group of key pilots and engineers from NASA and Bell sign the nose of the aircraft. The new Bell president nicknamed “Red”, who had only been at Bell a few months, and never worked for NASA or Bell took the liberty to sign his name on the nose of the aircraft in big letters. The man had literally nothing to do with the development of the XV-15, but he felt the need to add his name next to all those deserving people for posterity.

Of course when the aircraft was decommissioned the mechanics “accidentally” spilled solvent over just his signature and needed to wipe it off
Here is an X2 story on signed panels. At the end of the Elmira flight test program at Schweizer, the Florida guys were packing up the aircraft to take it south to do the envelope expansion. The Sikorsky crew chief was having all the Schweizer folks who worked the program sign one of the panels on the inside. I took my oldest over to show him the aircraft before it left. They gave me the sharpie so I could sign then they handed it to my 8 year old to sign it also. He didn't actually work on it at all though I did. Those signatures are in the Smithsonian now. The X2 is parked right next to the XV-15.

Commando Cody

29th Mar 2019, 02:47

I actually knew the Bell mechanics who accompanied the XV-15 to DC to decommission it. Drain fluids, remove pyrotechnics, etc. The aircraft structures and drivetrains still had life left. It was the rotor blades that were at the end of their life.

One interesting side story on the decommissioning of the aircraft occurred after all the ceremonies were over. As part of the ceremony to inaugurate the aircraft into the museum, the museum had a group of key pilots and engineers from NASA and Bell sign the nose of the aircraft. The new Bell president nicknamed “Red”, who had only been at Bell a few months, and never worked for NASA or Bell took the liberty to sign his name on the nose of the aircraft in big letters. The man had literally nothing to do with the development of the XV-15, but he felt the need to add his name next to all those deserving people for posterity.

Of course when the aircraft was decommissioned the mechanics “accidentally” spilled solvent over just his signature and needed to wipe it off

Touche. I forgot it was actually the proprotor blades.

Commando Cody

29th Mar 2019, 03:14

Sultan, what do you mean by this?
Are you suggesting that Bell is currently in a position to go into the LRIP stage?

If I may venture a reply:

Bell had always said that they were building their JMR-TD demonstrator in such a way that they could go in a rapid manner to production if they weren't bound by the Army's glacial FVL-M schedule. Back in 2017 they were saying they could deliver (I can't remember if it was initial production or IOC) by 2024. Keep in mind that JMR-TD was not meant to result in a production contract.

Originally, both the demonstrators were to fly in 2017 and a one year demonstration phase was to follow. This phase was to be funded partly by the Government, but mostly by the manufacturers, with the carrot being that the manufacturers who flew in JMR-TD could be expected to have a leg up when the actual FVL-M competition started years later. Then next phase, starting in 2019 would be the Army spending a few years analyzing the JMR-TD results of the two concepts. Of courses ince Sikorsky's SB>1 was, as were all previous X2s, way late getting in the air that didn't happen.

In 2018 Bell basically accomplished all that was to demonstrated in JMR-TD. As late as December they were offering to take the V-280 beyond what was required for the TD phase and expand the envelope and produce more data, albeit with financial participation by the Army. In addition, they were talking about taking the V-280 at their own expense on a demonstration tour, similar to what was done with the XV-15.

I suspect that what's happening is that while there was much hoopla about the Army pressing forward with FVL-M which had the interest of all the services plus potential foreign sales, it seems lately that what the Army really wants to fund is FVL-Light, their latest attempt to replace the OH-58, a craft primarily of interest only to them. The requirements for this craft don't require anywhere near the advance that FVL-M does. Bell is saying that they can't ask their shareholders to keep funding an aircraft for a market that, no matter how successful, for which the Government is not all that anxious to develop. So, Bell is saying that without further government interest in moving on, since they've met the requirements for JMR-TD, they're going to stop flying the V-280 and put their money on something where there's a chance of a production contract in the foreseeable future. We may see Sikorsky fly the SB>1 the minimum they can just so people will not dismiss the technology out of hand and follow Bell's lead of going where the money is.

This would be too bad, and a great loss to the country.

IMO

Commando Cody

29th Mar 2019, 06:50

Now there can finally be a competition between FVL demonstrators. Sultan exaggerated the Defiant schedule delay. First Flight was per DOD contract supposed to occur in the fall of 2017. So the Defiant is approximately 16 months late.

The hurdle for the SB>1 team now is completing all the FVL Key Performance Parameters by the end of this year, as required in the DOD contract. Based on the Sikorsky Raider still not having completed it’s flight test goals, there may not be adequate time for the Defiant. Especially if any more unpredicted problems occur.

Of of course the Army can always change the rules of the competition to give the Defiant a chance to catch up. Not very fair to the people at Bell and suppliers that busted their tails to keep their promises.

I predict a government announcement in the next couple months stating the Defiant will be given additional time to catch up with the Valor. The only question is how much time.

If I can be permitted to drone on:

There's no actual competition between these two demonstrators. Right now
they are part of the Joint MultiRole-Technology Demonstrator program.
That's a program to demonstrate advanced powered lift technologies
which could be used for a future program to actually produce an
operational aircraft. In the actual governmentspeak of the Army, "JMR-TD
is a demonstration of transformational vertical lift capabilities to
prepare the DoD for decisions regarding the replacement of the current
vertical lift fleet". It was going to require "Significant investment
by industry". Army looked at proposals from AVX, Bell Karem and
Sikosrky-Boeing and in 2013 chose the V-280 and SB>1 to proceed to the
demonstrator stage, while AVX and Karem received smaller contracts to
keep developing their technologies in the lab. Originally there were to
be two phases, one would be the air vehicle demo and the other would be
work to prepare to demonstrate missions system architecture. When the
actual competition took place, the winning air vehicle would be expected to
use whatever mission system won that competition,. I don't know if
they're following through with the Phase II demo.

Although the V-280 and SB>1 proposals were selected for JMR-TD flight
test, Army says what actually comes from the Future Vertical Lift-Medium
(FVL-M or FVL Capability Set 3) competition will not necessarily be
production versions of them. Frankly, though, it's thought they will
have a big advantage. Since FVL CS# is intended to replace at least the
UH-60, UH-1, AH-1 and maybe the AH-64, along with exports, that big a
potnetial market made industry willing to put up a lot of their own
money.

More governmentspeak: "The FVL acquisition program of record for
Capability Set 3 is utilizing the JMR TD knowledge base robustly in the
Analysis of Alternatives and acquisition planning". Bear with me, I'll
probably be a bit off in the following dates. The original plan was that
both demonstrators would fly in 2017. 2018 would see both aircraft
demonstrating their technology's capabilities, help Army determine how to
use aircraft with these advanced capabilities, what to look for in
an operational aircraft and develop datasets that wold be used in the
future FVL-M competition. 2019 and 2020 would be used to analyze the
data. Around 2020 an actual RFP for FVL-M is hoped to be issued refining the RFI
that was issued in 2016 based on what was learned in JMR-TD. That would
be the actual competition. There would expected to be a flyoff looking
to a contract award somewhere around 2024. Then would follow a prolonged
EMD period of eight years or so, culminating in an IOC somewhere between
2032-34, depending on who you ask and when.

There is some concern that with a schedule that long, other fiefdoms
will try and grab some of the FVL-M money for their own pet projects.
Also, with all the Congressional and Presidential elections before
IOC, it'll be hard to keep political support focused given that
politicians voting the money won't be able to point at something for which
they can claim credit in the next election for quite a while. OTOH,
the interest shown in FVL-M by all the services and potential foreign
operators will be a big help.

That plan, though, has been knocked a bit off course. Sikorsky's
repeated inability to get SB>1 into the air will at best force a delay
in the whole process, unless Army was willing to write the technology
off, and there would be too much lobbying going on that would prevent
that.

A bigger potential problem for FLRAA (Future Long Range Assault
Aircraft), Army's new name for FVL-M comes from the Army itself. In
recent times they've started beating the drums for and elevating the
priority for FARA (Future Attack Reconnaissance Aircraft), the new name
for FVL-Light. This will be the fifth attempt to field a replacement for the
OH-58, a requirement unique to the Army and which will not advance
capability or the technology nearly as much as FLRAA. An initial RFP has
already been issued, and up to six contracts are to be issued for the
next development stage in June. In March 2020 this will be cut down to
two bidders to participate in a flyoff in 2023. A contract award for a
program of record is planned for 2024, with IOC in 2028. Nowadays
that's blazing speed, and it's interesting how some of those dates
parallel what was originally hoped for for FLRAA. Where the money is
going to come from to support both programs without stretching one out
(guess which) is an unanswered question.

Hope I haven't bored everyone too much.

The Sultan

29th Mar 2019, 15:39

From R&W:

The U.S. Army is itching to leave the demonstration phase and in 2019 launch its official competition for a high-speed, long-range Black Hawk replacement, according to service aviation officials.

If all goes as planned, 2019 could be the year Army aviation zeroes in on a future long-range assault aircraft (FLRAA) that eventually will replace the Black Hawk and see service with both the Navy and Marine Corps as well.

If true, it looks like the Army is returning to the original time line which makes the SB-1 of little relevance except to flag the ABC concept as higher risk with lower performance than realized by a tilt rotor design.. If the Navy and Marines really have input into the plan the final requirements will be heavily influenced by the V-280 test results which will exclude the ABC.

CTR

29th Mar 2019, 17:59

If I can be permitted to drone on:

There's no actual competition between these two demonstrators. .

The only disagreement I have these thoughts is with the word “actual”. A better word might be “formal”.

Today’s article in Breaking Defense explains this better than I could. Comments at the end are interesting also.

https://breakingdefense.com/2019/03/fvl-announcements-on-black-hawk-shadow-replacements-in-weeks/

Commando Cody

30th Mar 2019, 04:33

The only disagreement I have these thoughts is with the word “actual”. A better word might be “formal”.

Today’s article in Breaking Defense explains this better than I could. Comments at the end are interesting also.

https://breakingdefense.com/2019/03/fvl-announcements-on-black-hawk-shadow-replacements-in-weeks/

I did read that article before my lengthy post. The key points here are that this is another RFI. RFIs are put out all the time. Army has put out multiple RFIs on FLRAA already, but there is still no identified date for an actual RFP. An RFP is where there's a real request for bids to produce/buy something real and where there's identified money. Also note that when and if there's an actual RFP, they want other companies involved, they specifically mention Karem. This indicates that there is a competition to come, not restricted to the JMR candidates. This is what Army always said would be the case. Still, the two JMR craft might be expected to have the inside track when and if a real compensation takes place. Got to love that govenmentspeak: "... the rest is really things that are pre-decisional that we have to socialize at echelon to make sure the team is ready to move forward.” In other words, 'We're not really doing anything yet, but we hope to".

I do find the statement, " “We know a lot about that lift-offset compound design already and it doesn’t necessarily need to fly as much...", quite interesting. X2 may be a great thing. But so far, all the vehicles for the last 40 years have been late, missed multiple announced deadlines, haven't flown all that much (example, either XV-15 30-40 years ago flew more hours that all the X2s combined. So have the AW609s) and except for showing that they can fly fast in a straight line, what of their promised performance breakthroughs have been shown? My point being not that X2 is bad, just that it's hard to say we know a lot about it. Possibly Army doesn't want to be perceived as limiting "competition", plus there are a lot of lobbyists who will go into overdrive if Army says, we want a variant of a technology with a lot of demonstrated applicability. This would mean Bell, with their Tilt-Rotors, Karem who is working on a variant of Tit-Rotor technology and AVX which is championing a coaxial compound that is much close to Kamov's concept, but more advanced.

My big worry remains that FLRAA will fade away as Army gets excited about their "proprietary" FARA. FARA actually has a real schedule, including a real RFP and identified money.

I do find the comments interesting and agree with most of them.

CTR

30th Mar 2019, 10:56

SASless

30th Mar 2019, 11:45

But just like some of those unofficial races that have a very nice wager to collect upon winning the competition!

Commando Cody

31st Mar 2019, 07:17

No disputes on the contract definition. Just describing how the development of the two aircraft plays out to the public. As is noted in the Breaking Defense article.

“Officially, what’s happening now is a technology demonstration (https://breakingdefense.com/tag/jmr-td/), not a competition to see who builds an operational aircraft. But de facto, the Valor and Defiant have become dueling prototypes for the Black Hawk replacement. Rugen wants to officially start a competition.”

Sort of like two cars at a stop light reving their engines. Not really an official race.

What Rugen is describing is pretty much what was always planned for FVL-M. His statement about, " We know a lot about that lift-offset compound already..." doesn't make a lot of sense given X2's track record (or lack thereof) so far. We know a lot about what Sikorsky has been promising, but not much at all about whether they can actually do it. Given that all the X2s were late, only flew a few hours and have yet to demonstrate much except being quick on a straight course, it would be incredibly risky to think we know enough about X2 to compete now. That extra $20 million is nice, but Bell would probably use their share to take V-280 beyond what was required for JMR-TD (Bell offered to do that in late 2018-early 2019, while Sikorsky would use the money to attempt to get up to the JMR-TD requirements. Of course the gov't money already supplied was supposed to cover that.

It's sort of like two cars at a stop light, but one of them has repeatedly run the race before, while the other one has trouble keeping the engine running and has two flat tires.

Commando Cody

31st Mar 2019, 07:19

But just like some of those unofficial races that have a very nice wager to collect upon winning the competition!

Again, given that Army is all hot to go with FARA, the old staying applies, "Show me the money".

Lonewolf_50

1st Apr 2019, 00:30

@Commander Cody: thanks for that.
and as for this
There is some concern that with a schedule that long, other fiefdoms will try and grab some of the FVL-M money for their own pet projects. Also, with all the Congressional and Presidential elections before IOC, it'll be hard to keep political support focused given that politicians voting the money won't be able to point at something for which they can claim credit in the next election for quite a while. OTOH, the interest shown in FVL-M by all the services and potential foreign operators will be a big help. Yeah, funding grabs and Congressional "wisdom" like what brought us F-35. :mad: Part of the terrain, I guess. But it still grates on the nerves.

The Sultan

5th Apr 2019, 17:11

/ (https://www.flightglobal.com/news/articles/us-army-details-future-long-range-assault-aircraft-457256/)From Flight International:

The service is perhaps willing to pay more for its next rotorcraft because it is asking for a significantly higher level of performance. For example, the UH-60M has a maximum cruise speed of 151kt (280km/h), while the US Army wants its next utility rotorcraft to have a maximum cruise speed of 280kt (519km/h).

The US Army wants FLRAA to have an unrefueled combat radius of 300nm (556km) and a one-way unrefueled range of at least 2,440nm (4,519km).

These requirements along with a selection in two years pretty much eliminates the SB-1’s concept as it will never cruise at 280 knots, let alone the Marines wanting 330 knots, with all that drag. I also assume only a tilt rotor will mate the range requirement.

Full article:

https://www.flightglobal.com/news/articles/us-army-details-future-long-range-assault-aircraft-457256/

PastTense

5th Apr 2019, 17:25

Several companies are developing helicopters that could replace the U.S. Army’s aging Black Hawk fleet (https://www.cnet.com/news/how-the-helicopters-of-the-future-are-shaping-up/) in the coming decades. One of those futuristic aircrafts, Sikorsky-Boeing’s Defiant (https://en.wikipedia.org/wiki/Sikorsky%E2%80%93Boeing_SB-1_Defiant), took its first test flight (https://breakingdefense.com/2019/03/sb1-defiant-takes-flight-can-it-catch-bell/)two weeks ago.

The Defiant is based on Sikorsky’s experimental X2 technology, which holds the record for being the fastest helicopter technology (https://spectrum.ieee.org/aerospace/aviation/the-fastest-helicopter-on-earth) in the world. A demonstration craft reached 435 km/h in 2010, beating the 1986 record of 400 km/h by the Fédération Aéronautique Internationale (https://www.fai.org/).

“The Defiant design represents a leap forward in vertical lift technology,” says Boeing (https://www.boeing.com/) spokesperson Randy Rotte. “While it can fly at nearly twice the speed and has twice the range of conventional helicopters, it retains the very best, if not better low-speed and hover performance of conventional helicopters.” The Black Hawk has a top speed of about 290 km/h and combat range of 580 km.The craft’s unconventional design consists of dual coaxial main rotors—two rigid rotors that spin around the same axis in opposite directions—and a push propeller in the rear.
https://spectrum.ieee.org/tech-talk/aerospace/military/sikorsky-boeings-defiant-helicopter-first-flight

MPN11

5th Apr 2019, 19:19

But ... does it have MCAS?

The Sultan

8th Apr 2019, 10:46

MPN

The S-97 had something like MCAS which apparently took control from the pilot resulting in a busted aircraft.

The Sultan

18th Apr 2019, 04:17

Only two flights in a month. Not an impressive demonstration pace.

This guy is struggling to make the program sound viable. Really not enthusiastic about what he is spinning.

Boeing Defiant Interview

IFMU

18th Apr 2019, 14:35

Thanks for the link! I hadn't heard they had a second flight. Not sure I agree that he was struggling to make the program sound viable, but I don't think he is very knowledgeable about the technology.

Jack Carson

18th Apr 2019, 20:32

I had an opportunity to fly the X-59 with the two J60 engines (3000 lbs. thrust each) installed in March of 1983. It was a short 45 minute flight that began with a short running takeoff followed by what would be categorized as a maximum performance climb at 45 degrees pitch up. Once leveled off we made a level speed run at just under 250 KIAS. As we rotated during the take off roll the torque from the PT-6 twinpac (1800 ESHP) reduced to 0%. The rotor system operated as an autogyro from takeoff rotation until we slowed for our descent to approach for landing. The PT-6s smoothly re-engaged providing power for hover and landing. The short end of the story is, the X-59 flew more than 100 hours and achieved a pretty significant flight envelope 36 years ago. It required a combined 6000 lbs. of thrust from the two J-60’s to push this little 11,000 lb. aircraft out to a maximum of 263KIAS. I have to believe that the SB-1 Defiant will require more than a T-55 engine to meet its goals. To say that the vibrations during my flight were significant would be an understatement.

The Sultan

19th Apr 2019, 00:37

JC

From Bell site:

Bell Helicopter's compound research helicopter, a highly modified Bell UH-1, attains a speed of 316 mph in level flight. This is an unofficial speed record and has remained unchallenged.

That is 275 kts which indicates with enough thrust even a conventional helicopter can get to high speeds. Like the -59 this test bed had no range and shook like hell.

IFMU

19th Apr 2019, 03:26

I had an opportunity to fly the X-59...
Jack,
When I was recruited to design and build the X2 FBW I spent a lot of time studying the ABC and talking to the old timers. Everything you say about the ABC is true. The X2 and its successors are different in two respects. The blade planform is a leap way beyond what you had on the ABC. The drag is way lower even without the nifty inter-rotor fairing. Also due to the driveline, speed of the main rotor is controllable. It doesn't autorotate away like the ABC, even at flat pitch. The ABC was a cool aircraft, and it advanced the state of the art of blade construction, but still seemed to be designed around hover. You probably remember the twist of the blades. What is good for low speed is bad for high speed, and visa versa. Time will tell for the Defiant, numbers don't lie.
Bryan Cotton

Commando Cody

19th Apr 2019, 06:23

JC

From Bell site:

That is 275 kts which indicates with enough thrust even a conventional helicopter can get to high speeds. Like the -59 this test bed had no range and shook like hell.

There used to be a saying that the F-4 proved that with enough thrust, even a barn door will fly.

Jack Carson

19th Apr 2019, 15:49

IFMU
There are always compromises. Having enough blade twist to a achieve hot high hover capabilities while achieving reasonable cruise speeds and range is challenging.

SplineDrive

19th Apr 2019, 21:40

What Rugen is describing is pretty much what was always planned for FVL-M. His statement about, " We know a lot about that lift-offset compound already..." doesn't make a lot of sense given X2's track record (or lack thereof) so far.

What the Army may well know is that a flatwise rigid rotor will have very significant levels of vibratory hub moments and vertical shears unless the number of blades +/- 1 is higher than any significant harmonic air loads in the blades. With 3 blades, the XH-59A had blade 2P, 3P, and 4P translating into vibe hub loads and blade 2P is always quite high leading to epic levels of vibration. A four bladed rotor avoids that 2P generating vibe hub loads, but 3P, 4P, 5P are still reasonably large and it's nearly impossible to not have a flatwise blade mode in that region, amplifying one or more of those air loads. The 4 bladed X-2 rotors will have less-than-epic, but still incredibly high levels of vibratory hub loads.

The aerodynamic benefits of the ABC rotor are significant but they come at considerable cost.

IFMU

19th Apr 2019, 22:27

IFMU
There are always compromises. Having enough blade twist to a achieve hot high hover capabilities while achieving reasonable cruise speeds and range is challenging.
If you look at the installed power required for high speed flight, you are more than covered. Also with 8 blades there is enough solidity to absorb the power required for high/hot even without all the twist.

IFMU

19th Apr 2019, 22:33

The 4 bladed X-2 rotors will have less-than-epic, but still incredibly high levels of vibratory hub loads.
They certainly can, but we were balancing the X2 using conventional techniques. Then vibes were cleaned up with AVC. The predominant harmonics are not exactly as you say but not sure if that info was published.

SplineDrive

19th Apr 2019, 22:56

They certainly can, but we were balancing the X2 using conventional techniques. Then vibes were cleaned up with AVC. The predominant harmonics are not exactly as you say but not sure if that info was published.

Right, I'm speaking from a "first principles" textbook point of view, the full problem is certainly more complex, but unlikely in a positive way. Question is, can that AVC clean up the vibes to a production level across an entire flight envelope? I'm sure the Army will be interested in that answer.

IFMU

19th Apr 2019, 23:08

Right, I'm speaking from a "first principles" textbook point of view, the full problem is certainly more complex, but unlikely in a positive way. Question is, can that AVC clean up the vibes to a production level across an entire flight envelope? I'm sure the Army will be interested in that answer.
We did it on the X2. Not just AVC, you need to balance too. Most likely the Raider and Defiant guys have gotten further as management during X2 didn't allow as much dedicated vibe work as we would have liked.

CTR

20th Apr 2019, 14:49

I have been wondering for a while. Is the AVC system on the Defiant and Raider considered a flight critical system? By that I mean, is it like a flyby wire flight control system where redundancy is required and complete system failure can result in loss of the aircraft?

IFMU

20th Apr 2019, 18:11

Definitely not for the X2. I can't imagine it is flight critical for its progeny.

CTR

20th Apr 2019, 19:12

Definitely not for the X2. I can't imagine it is flight critical for its progeny.

Has enough flight envelope on any X-2 been expanded enough to be remotely sure?

IFMU

20th Apr 2019, 20:10

Has enough flight envelope on any X-2 been expanded enough to be remotely sure?
Yep. 252 kts level flight for the X2 and something like 262 in a shallow dive.

SplineDrive

21st Apr 2019, 23:36

Yep. 252 kts level flight for the X2 and something like 262 in a shallow dive.

There is far more to a full flight spectrum than straight and level flight, even high speed flight, nor is it a forgone conclusion that high speed flight is the worst regime from a vibration control standpoint. From released videos and statements, it appears the S-97 has performed a wider variety of maneuvers, Nz levels, etc. than the X-2 demonstrator did, even without yet hitting its top line speed goal. Sikorsky has been publicly pretty mum on what is has learned about vibration control on that aircraft, so it's hard to project much to SB>1.

However, that said, if vibrations on a rigid rotor can be significant, and I believe math and available evidence says they can be, then an AVC system has to be suitably powerful. An active system capable of (nearly) canceling large vibrations is technically capable of nearly doubling them with incorrect system operation. It might not need to be strictly flight critical, but it could well be mission critical.

CTR

22nd Apr 2019, 02:11

It might not need to be strictly flight critical, but it could well be mission critical.

From what I have been told, PIO from severe vibration can be a concern. At least with FBW with notch filters this can be addressed. This may allow AVC loss to be only mission critical.

SplineDrive

22nd Apr 2019, 21:15

Yup. I’m sure cribbing S-97 line drawings generated some laughter at Bell.

PAXboy

6th May 2019, 22:21

As a rank outsider who knows nothing about Helis and had never heard of this machine until deciding to browse this forum:

Looking at the machine, I have to ask, why would anyone do that? As far as I am aware, the Osprey is not a runaway success and this machine looks like it's trying to tackle the same problem from a slightly different angle.

Lonewolf_50

7th May 2019, 14:01

the Osprey is not a runaway success
Actually, it is quite successful and doing well. I invite you to check the calendar. The year is 2019, not 1999. They've gotten through that rough bit (which had some dark times) about introducing new tech. I also suggest you look at V-280 Valor and think about how the future looks for tilt rotor. (Looks pretty good ...)

The coaxial rotor design concept isn't all that new. Kamov had two maritime helicopters that were serviceable (Helix/Hormone) but the trick they are going for in SB1 is to add the high speed flight end of the game to that basic idea. As noted above, that was tried 40 years ago with varying issues arising.
With a lot of new tech available, they can try again with greater hopes for success. They are also doing the crawl, walk, run thing: X2, S-97, now SB1.

The Sultan

7th May 2019, 14:28

Pax,

Marines continue to set the pace.

US Marine Corps (USMC) Lieutenant General Steven Rudder, deputy commandant for aviation, is confident that a tiltrotor can meet the service’s minimum cruise speed goal of 270kt (500km/h) for its Future Long Range Assault Aircraft (FLRAA).

The USMC plans to piggyback on the US Army-run FLRAA programme, though it wants a next-generation utility rotorcraft with even more capability than the US Army is asking, in particular the ability to cruise at least 270kt, which is the cruise speed of the Bell Boeing V-22.

CTR

10th Jun 2019, 13:14

Almost three months have past since the Defiant’s First Flight. Any flight test updates? Not unusual for a new aircraft to be down for a month following First Flight. But three months?

SansAnhedral

12th Jun 2019, 14:34

Almost three months have past since the Defiant’s First Flight. Any flight test updates? Not unusual for a new aircraft to be down for a month following First Flight. But three months?

As with Raider, flight test is progressing glacially. As of a couple weeks ago, supposedly SB-1 had completed its 3rd flight , hovering to 150 ft and 10 kts air taxi.

Raider has actually been flying since mid last year, demoing in secret at the request of the Army while also testing numerous desperate attempts to fix its gargantuan vibration issues. SB1 may be going down the same path as it (amazingly) did not incorporate many lessons learned from S-97.

etudiant

12th Jun 2019, 18:10

Have to wonder, is there a plan B for Lockheed/ Sikorsky? If the coax rotor does not scale as expected, what is their fallback?

SansAnhedral

12th Jun 2019, 19:21

Have to wonder, is there a plan B for Lockheed/ Sikorsky? If the coax rotor does not scale as expected, what is their fallback?

I would imagine a much more vocal propaganda push about how ITEP will make UH-60 and AH-64 perfectly suitable moving forward, and that FVL is an expensive wholly unnecessary endeavour.

CTR

13th Jun 2019, 02:08

Have to wonder, is there a plan B for Lockheed/ Sikorsky? If the coax rotor does not scale as expected, what is their fallback?

Make Textron a impossible to turn down offer for Bell. Before Boeing beats them to it.

The Sultan

16th Jun 2019, 21:32

From FG:

The compound co-axial rotor design flew for the first time in March, and has since made just two additional sorties, putting it well behind the rival Bell V-280 tiltrotor, which took to the air in December 2017.

From Sikorsky:

"We were hoping that we would be flying more," says Dan Schultz, president of Sikorsky.

Initial delays were caused by a third party that is producing a gearbox component, and the airframer is now working to catch up on the schedule slip.

Controls, transmission and rotor design have been validated by the flights so far, says Schultz, with "minimal vibration" detected.

So only three flights in three months confirmed. Appears they haven’t done anything beyond hover and very low speed. If this is the case nothing of the design has been validated and the vibration claim is no better than saying it is smooth while being towed. These kind of statements are the type made trying to keep LM from pulling the plug on funding. (Remember LM is on the V-280 where they have already seen the full capabilities of the aircraft and their products demonstrated to a timeline set back in 2015.)

SansAnhedral

21st Aug 2019, 16:13

So, another couple months and more deafening silence from the Defiant team. Has anyone heard any news?

Upon successful PSTB endurance envelop expansion, we expect to be positioned to quickly expand the aircraft flight envelope later this summer

Only 4 weeks of summer left...

SplineDrive

21st Aug 2019, 21:08

So, another couple months and more deafening silence from the Defiant team. Has anyone heard any news?

Only 4 weeks of summer left...

Perhaps the prop hasn’t been engaged to full power yet... when it does, you’ll hear that beast in the next state 🤣

SansAnhedral

22nd Aug 2019, 15:23

Perhaps the prop hasn’t been engaged to full power yet... when it does, you’ll hear that beast in the next state 🤣

According to a member of their design team I spoke with, the tail pusher is the 2nd most powerful single propeller assembly ever put on an aircraft.

The Sultan

8th Sep 2019, 23:52

SplineDrive

9th Sep 2019, 04:25

A good measure of the program is posed by the question of where the SB-1 was as hurricane Dorian was being projected to hit its base at Jupiter, Florida?

1. Did they fly it out? It has been five months since first flight and, by Sikorsky’s statements, well into envelope expansion by August.
2. Trucked it out? Embarrassing but may have been necessary if still not safe to fly.
3. Left in hanger, or maybe on ramp, in hopes of a direct hit which would allow them to end the program without more data to reinforce the obvious fact that the concept is a bust?

The facility isn’t close enough to the ocean for a storm surge to cause a loss, but high winds and a hanger door left open could generate an insurance check... not a great return on investment but better than nothing 🤣 In any case, the storm veered northward and wasn’t an issue.

CTR

9th Sep 2019, 15:35

No one out there with any intel on they can share on SB-1 flight test status?

I would assume any aircraft flights into FAA controlled air space would be public knowledge. Does lack of any information on flights into public air space infer that there have been no flights other than low level hovering within airport property?

IFMU

9th Sep 2019, 20:00

I would assume any aircraft flights into FAA controlled air space would be public knowledge.

Why would you assume that? They have their own radar feed, their own chase aircraft, and for VFR flights are not required to file a flight plan.

CTR

9th Sep 2019, 20:52

Why would you assume that? They have their own radar feed, their own chase aircraft, and for VFR flights are not required to file a flight plan.

ADS-B. The V-280 and it’s chase aircraft were required to carry ADS-B. Plus both the SB-1 and V-280 aircraft required FAA registration and FAA safety of flight clearance.

SansAnhedral

16th Sep 2019, 20:11

ADS-B. The V-280 and it’s chase aircraft were required to carry ADS-B. Plus both the SB-1 and V-280 aircraft required FAA registration and FAA safety of flight clearance.

Indeed, N100FV's Mode-S 24 bit address code is A00545

The Sultan

20th Sep 2019, 17:27

From Flightglobal:

The US Marine Corps issued a request for information for its Attack Utility Replacement Aircraft (AURA) programme, formally launching its search for a rotorcraft to succeed the Vietnam War-era Bell UH-1 utility and AH-1 attack helicopters.

The requirements are for a 295 kts cruise with a combat radius of over 400 miles which exceeds the latest FLRAA spec. Submission of responses are by Jan 2020. The question is will Boeing stick with the SB-1 (which by Sikorsky’s last press release has yet to reach 15 kts), make an independent response, or beg Bell to let them partner on Bell’s 280 based response?

Would expect some indication by AUSA in mid-October.

Lonewolf_50

20th Sep 2019, 18:23

That's a pretty weird article, about these *Vietnam War-era Bell UH-1 utility and AH-1 attack helicopters*
The AH-1W was, for example, hardly "Viet Nam era" given it's two T-700 engines and improved weapons systems.

The Marines now have the UH-1Y and AH-1Z that are not "Viet Nam Era" - they reflect a considerable improvement to the state of the art of the Huey/Cobra line.

Granted, the Marines looking long term at the next big change in attack helicopter capability to match their Ospreys makes sense, in terms of being able to keep up with the V-22's.

riff_raff

22nd Sep 2019, 03:36

SplineDrive

22nd Sep 2019, 15:48

Haven't seen the actual RFI document yet. Responses to some sections are due Nov. 22 and responses to other sections are due Jan. 1. Be interesting to see if they get any proposals for innovative propulsion/aero concepts that meet their objectives and truly merit funding. Giving serious funding to small companies to rapidly develop innovative concepts applicable to AURA objectives is also a good way to keep the existing JMR/FVL teams on their toes.

The requirements, of course, are key. If the Marines want something too different than either FARA or FLRAA, the industry is looking at yet another rapid development program of an advanced VTOL craft... which is exciting, but I think the industry is getting a little tired. One of these programs needs to become a fully funded program of record and not a one-off cost share project.

After being in this business for a couple of decades, I can tell you that if the 295+ knot speed is firm, it won't be an edgewise flow rotor. It's possible to hit those speeds, but not efficient enough to have good range and be a balanced platform. The shipboard compatibility requirements and exactly which hangers it needs to fit in will also heavily drive the design for AURA.

CTR

22nd Sep 2019, 23:10

I think the industry is getting a little tired. One of these programs needs to become a fully funded program of record and not a one-off cost share project. .

Not just the primes, component suppliers are also about to call it quits on investing on new DOD programs with high risk of no future contracts.

SansAnhedral

23rd Sep 2019, 20:27

Upon successful PSTB endurance envelop expansion, we expect to be positioned to quickly expand the aircraft flight envelope later this summer

Today is the first day of fall. And yet again, Sikorsky misses another milestone with this program. Literally every single date, whether it was contractually driven or self-imposed, has been missed or slipped by both the Defiant and Raider teams. It's simply mind boggling.

I have been following these programs for going on 10 years now, and have been suspicious of most of the claims from a technical standpoint nearly the entire time (hell just look at my post history). I cannot fathom how there has been almost zero pressing done by the aerospace and defense community and media journalists regarding the repeated failures, complete opacity, and outright lying that has come from Sikorsky throughout.

Nearly weekly there are news stories regarding FVL with headlining pictures displaying Defiant and breathless commentary about how its a leading contender for FLRAA. Does anyone else feel like they are taking crazy pills reading these pieces year in and year out? Will Defiant even fly again by year end now? Even the laughable historical lifetime combined flight rate for all ABC aircraft of 1 hour / month far exceeds what Defiant has achieved thus far.

etudiant

23rd Sep 2019, 23:10

Today is the first day of fall. And yet again, Sikorsky misses another milestone with this program. Literally every single date, whether it was contractually driven or self-imposed, has been missed or slipped by both the Defiant and Raider teams. It's simply mind boggling.

I have been following these programs for going on 10 years now, and have been suspicious of most of the claims from a technical standpoint nearly the entire time (hell just look at my post history). I cannot fathom how there has been almost zero pressing done by the aerospace and defense community and media journalists regarding the repeated failures, complete opacity, and outright lying that has come from Sikorsky throughout.

Nearly weekly there are news stories regarding FVL with headlining pictures displaying Defiant and breathless commentary about how its a leading contender for FLRAA. Does anyone else feel like they are taking crazy pills reading these pieces year in and year out? Will Defiant even fly again by year end now? Even the laughable historical lifetime combined flight rate for all ABC aircraft of 1 hour / month far exceeds what Defiant has achieved thus far.

There are so few remaining suppliers in the sector that a publication would be courting suicide to alienate any of them.
Hence all news reports are slightly massaged press releases, rather than independent opinions.
Bad for the industry and bad for the tax payer, but short term profitable.
Imho, the relevant precedent is the pre WW2 French defense industry, it produced some truly superb gear such as the Char 2bis, was hugely profitable and an abject failure from a national perspective.

The Sultan

24th Sep 2019, 00:30

Sept 2019 was suppose to be the conclusion of the FVL assault tech demo phase. It looks like the Marines are sticking to that with their AURA schedule of having RFI response in by Jan 2020. Defiant will obviously have no positive influence on whatever Boeing submits.

Meanwhile the V-280 is racking up flights doing demo’s or training with a lot of low altitude fully converted high speed passes and helicopter mode agility maneuvers. Quite impressive relative to speed, low acoustic signature, and looks.

SansAnhedral

10th Oct 2019, 15:38

Interesting article regarding recent SB1 model wind tunnel testing

NFAC tests next-generation military helicopter | Aerotech News & Review (http://www.aerotechnews.com/blog/2019/10/09/nfac-tests-next-generation-military-helicopter/)

“From the NFAC perspective, the wind tunnel test was successful,” Wang said.

One wonders if a seemingly unnecessary qualifying statement like that has some implications.

The Sultan

10th Oct 2019, 20:18

2019 is a little late to do wind tunnel testing on a design done in 2015. It would appear these tests were trying to determine how to fix the problems uncovered on the S-97 and carried over to the Defiant which has limited it to basically 200 kts (60 kts short of the X-2). We should know at AUSA in four days if they are making design mods to the Defiant to get closer to the 280 kt cruise required or scrapping the program outright.

etudiant

11th Oct 2019, 00:39

Interesting article regarding recent SB1 model wind tunnel testing

NFAC tests next-generation military helicopter | Aerotech News & Review (http://www.aerotechnews.com/blog/2019/10/09/nfac-tests-next-generation-military-helicopter/)

One wonders if a seemingly unnecessary qualifying statement like that has some implications.

The phrasing certainly leaves open the possibility that although the tests were successfully completed, the results were disappointing.
Stuff like that happens in the VTOL business.
I remember the Rockwell XV-12, a design based on the concept that a jet flux could entrain considerable ambient air, enough to add about 20% to the lift produced.
It worked fine in scale models, but not when scaled up to full size. Perhaps something similar is happening here.

The Sultan

16th Oct 2019, 11:56

From the second day AUSA press release:

The SB>1 Defiant (https://breakingdefense.com/2019/04/baby-steps-for-defiant-as-army-accelerates-fvl/) is back in the air, reaching speeds of 20 knots on its fourth test flight. It should reach the Army-mandated minimum speed of 230 knots by the end of March, “if we have no other significant things we learn along the way,” Boeing program manager Ken Eland said here this morning.

I guess this might be considered progress. A good PR headline would have been “SB-1 Doubles Flight Envelope in One Leap.” So six months to get to 20 knots and another 4 to 6 weeks before they will attempt a fifth flight. They also state they will reach 230 kts plus by March, but hedge by not saying what year.

SplineDrive

16th Oct 2019, 12:23

From the second day AUSA press release:

I guess this might be considered progress. A good PR headline would have been “SB-1 Doubles Flight Envelope in One Leap.” So six months to get to 20 knots and another 4 to 6 weeks before they will attempt a fifth flight. They also state they will reach 230 kts plus by March, but hedge by saying what year.

And no commitment to reach the SB>1 design speed at all.

SansAnhedral

16th Oct 2019, 14:56

From the second day AUSA press release:

I guess this might be considered progress. A good PR headline would have been “SB-1 Doubles Flight Envelope in One Leap.” So six months to get to 20 knots and another 4 to 6 weeks before they will attempt a fifth flight. They also state they will reach 230 kts plus by March, but hedge by not saying what year.

20 kts!!!

https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/480x167/giphy_23ba91d82e83dcf3d68da6a4ee8fbdaa81d63247.gif

The Sultan

17th Oct 2019, 04:00

Just think someone at Sikorsky/Boeing is congratulating themselves with getting this info in the press:

https://breakingdefense.com/2019/10/4-flights-3-hours-20-knots-boeings-defiant-inches-ahead/

They seem to think their continued “development” of the Defiant until the end of 2020 will be beneficial to the programs it was applicable to. Problem is the Marines want responses on their program no later than January and the Army in the first quarter of 2020 while they will still be struggling to get above 120 knots.

Got to wonder if the Marines/Army will say enough and save a billion dollars or so by selecting the V-280 derived offering from Bell and fast track development and fielding.

SansAnhedral

17th Oct 2019, 13:58

https://www.youtube.com/watch?v=CRE6ZtaxSnw

https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/300x300/thumb_hold_on_to_your_butts_when_your_mom_tells_you_43849949 _f7456e8cc60b8337f7d7a5bde1f0f476eb5eed9c.png

CTR

15th Nov 2019, 10:54

Any new Sikorsky Defiant flight test status news? It has been a month with no press releases or leaked intel.

Just curious, not trolling or looking to rehash history.

SplineDrive

15th Nov 2019, 14:58

Any new Sikorsky Defiant flight test status news? It has been a month with no press releases or leaked intel.

Just curious, not trolling or looking to rehash history.

There was another video posted a few days ago on YouTube showing Defiant doing low speed flights with some truly "beast mode" rotor head fairings installed. No word on if this was a check flight for the fairings or the 40 knot expansion mentioned in the media around AUSA.

SB>1 Fairing Flight Video

The Sultan

15th Nov 2019, 17:58

Fairings look more like they will add drag.

IFMU

16th Nov 2019, 12:40

Fairings look more like they will add drag.
That's why they don't make decisions based on looks! This cracks me up.

The Sultan

16th Nov 2019, 14:43

IFMU

Did the fairings on the S-97 work out as expected? The 97 is 50+ knots short of design speed not due to its horrendous vibration, but because of drag. As referenced elsewhere Sikorsky was back in the wind tunnel this year trying to come up with a solution. As the SB-1 fairings look even worse than the 97 it appears that testing was a bust. Will be surprised if they make it much past 200 knots, which is now 80 knots short of the new minimum cruise for the FLRAA.

CTR

16th Nov 2019, 15:47

Splinedrive,

Thanks for the link to the video. It didn’t come up on my usual searches.

Sultan, I believe the 280 KT requirement is a USMC AURA spec, not currently a US Army spec.

It would be a shame however if the Army for a second time opted out of a Tiltrotor aircraft.

SplineDrive

16th Nov 2019, 17:07

Fairings can be pretty large and bluff body looking and still reduce drag, so I’m confident that SB>1’s rotor fairings will be an improvement over the comparatively inelegant metal structure that are the rotor hubs. Raider’s hubs are a different structural solution and fair more compactly.

I don’t think Raider is 50+ knots off it’s target speed... it was never advertised to hit the speeds of the X-2 Demonstrator. And I can think of ways that vibration can limit top speeds if the high 4P vibes leak into the drivetrain or other components that have loads that directly scale with speed. So it’s performance miss could be both drag and vibration limited. That said, it’s still a sleek airframe with one of the slickest engine installations I’ve ever seen.

SplineDrive

16th Nov 2019, 17:10

If the Army opts out of a tilt rotor then they’ll be settling for an ITE upgraded Blackhawk or somehow decide an S-92 variant is what they wanted all along.

The Sultan

16th Nov 2019, 21:01

CTR

From a synopsis of the FLRAA requirements:

The Army wants the FLRAA to have a top speed of 250 knots, or more than 285 miles per hour, and potentially up to 280 knots, or more than 320 miles per hour. The maximum speed of the Army’s latest iteration of the Black Hawk, the UH-60M, is still under 200 miles per hour.

So minimum to be considered is 250 with desired 280. The Marines minimum is 280 with desired 320 kts.

The Sultan

16th Nov 2019, 21:18

henra

17th Nov 2019, 08:27

Fairings look more like they will add drag.
Find the error....

Aerodynamics by looking at pictures.
Scrap all CFD and wind tunnel....

Folks never cease to amaze me.

Bell_ringer

17th Nov 2019, 09:52

Whilst aerodynamics is a complex subject well above the pay grade of most mere mortals, you don’t need a wind tunnel to determine a brick is aerodynamically challenged :}

henra

17th Nov 2019, 10:10

Whilst aerodynamics is a complex subject well above the pay grade of most mere mortals, you don’t need a wind tunnel to determine a brick is aerodynamically challenged :}

That actually depends quite a bit on flow direction and Reynolds number :E

SplineDrive

17th Nov 2019, 15:45

Spline

All of the attention the Army has given the V-280 indicates they are ready for a tilt rotor. Add to that that the Marines spec for a new medium can only be met by a tilt rotor the Army will not want to cede leadership of the program.

As for the 92: the last military variant worked out to $200M apiece, far above the $42m target FLRAA unit cost.

On the 97 the max speed was suppose to be 240 knots which in the commercial world requires you to demo 267 knots (+11%). The 97 struggles to get above 180kts and the refined scout/attack derivative is now billed as having only a 205 kt top speed. So I stand by the 50 kts short.

Oh, I agree that the Army is ready for a tilt rotor and that such an aircraft is the right technical solution for long range assault... I'm just suggesting what Sikorsky's next strategy might be.

As for speed, I see how you got 50 knots short now... it has definitely missed the target very significantly. The Raider-X has grown in gross weight and drag more than horsepower, so I fully expect a slower cruise and top speed. So much so that the complexity of the configuration isn't worth the cost and payload hit if a slick and optimized conventional helicopter can achieve similar speed targets.

Defiant might have enough installed power to make its targets... let's see if it has the funding and patience also required.

CTR

17th Nov 2019, 23:47

Defiant might have enough installed power to make its targets... let's see if it has the funding and patience also required.

The problem with using excessive power to achieve speed and payload is that there is always a price. SFC (fuel consumption) always suffers. This is one of the limitations of X-2 technology. It is hard to beat getting on wing (as on a Tiltrotor) for maximum range.

The Sultan

11th Dec 2019, 01:04

How much did Sikorsky pay for this?

https://m.youtube.com/watch?v=YK26VfUyMlc

From this week, but same old video. Apparently no real progress in 9 months of flight testing.

Lonewolf_50

11th Dec 2019, 14:11

How much did Sikorsky pay for this? https://m.youtube.com/watch?v=YK26VfUyMlc
From this week, but same old video. Apparently no real progress in 9 months of flight testing. Popular Science: what credibility do you give to that mag?

CTR

11th Dec 2019, 16:19

Anticipation is making me wait. It’s keeping me waiting....

With all respects to Carly Simon ;-)

Landing gear still down and pusher prop still not turning.

The Sultan

12th Dec 2019, 00:14

Popular Science: what credibility do you give to that mag?

Lone,

None, but it appears the best Sikorsky can pay to publish bogus feel good stories.

SplineDrive

12th Dec 2019, 12:47

Landing gear still down and pusher prop still not turning.

I wonder how that propellor gearbox likes sitting stationary in a vibrating environment? In a non-rotating state, some of the gear mesh and bearing rolling element contacts are direct metal-metal with no fluid film separating the surfaces. Could eventually get fretting damage. Presumably they’re doing something to keep the transmission at a reasonable operating temperature when it’s not spinning so when power is quickly clutched in, the system isn’t cold.

The Sultan

12th Dec 2019, 15:15

I wonder how that propellor gearbox likes sitting stationary in a vibrating environment? In a non-rotating state, some of the gear mesh and bearing rolling element contacts are direct metal-metal with no fluid film separating the surfaces. Could eventually get fretting damage. Presumably they’re doing something to keep the transmission at a reasonable operating temperature when it’s not spinning so when power is quickly clutched in, the system isn’t cold.

Good point. Another design flaw to add to the list. I have seen a bearing which had Brinelling (subtle impact damage to balls and races due to installation or handling errors) which spalled at locations around the circumference of the races at ball spacing intervals well before the overhaul/inspection interval. We have also seen what happens to an Airbus 225 when a transmission is dropped during shipping and the bearings not replaced (not proven, but a leading contender to have resulted in separation of the rotor).

The tail is a severe vibratory environment on any rotorcraft. More so on an ABC type with inherently brutal vibration levels. As all this is common knowledge, you would think Sikorsky would run the tail at no thrust while they expand their hover envelope if they could. Points to a serious drive system issue.

SplineDrive

12th Dec 2019, 15:24

The tail is a severe vibratory environment on any rotorcraft. More so on an ABC type with inherently brutal vibration levels. As all this is common knowledge, you would think Sikorsky would run the tail at no thrust while they expand their hover envelope if they could. Points to a serious drive system issue.

Perhaps they designed in a mitigation and are just testing it as they intend to fly. In any case, there’s probably some learning that will happen at the rear end of the aircraft. Hope they publish some papers!

IFMU

12th Dec 2019, 16:57

SplineDrive

12th Dec 2019, 17:02

The X2 vibe levels were not brutal, and in fact were most benign at hover. This is when you would not be spinning the rear gearbox.

Please name one gearbox where the oil is warmed up prior to running it up. I've never seen that in any helicopter or car. One of my friends flew hueys in Antarctica and they would drain the oil out of the gearbox and engine so they could bring it inside overnight, but other than that I think you guys just like making things up!

A transmission isn’t usually hit with MCP torque 15 seconds after it starts the first rotation. If the clutching process is going to take a few minutes (same as starting turbines, going to flight idle, checking the lists, ready for take off, go) well, sure. But I imagine that the desire is to clutch the prop in at a much faster rate than that.

IFMU

13th Dec 2019, 03:26

A transmission isn’t usually hit with MCP torque 15 seconds after it starts the first rotation. If the clutching process is going to take a few minutes (same as starting turbines, going to flight idle, checking the lists, ready for take off, go) well, sure. But I imagine that the desire is to clutch the prop in at a much faster rate than that.
We didn't have a clutch on the X2. But you would clutch up the prop at flat pitch, not MCP. Once it was clutched up you would roll in the prop pitch and start ramping up the power. I am not sure I see a valid concern.

Nige321

13th Dec 2019, 15:34

Good point. Another design flaw to add to the list. I have seen a bearing which had Brinelling (subtle impact damage to balls and races due to installation or handling errors) which spalled at locations around the circumference of the races at ball spacing intervals well before the overhaul/inspection interval. We have also seen what happens to an Airbus 225 when a transmission is dropped during shipping and the bearings not replaced (not proven, but a leading contender to have resulted in separation of the rotor).

The tail is a severe vibratory environment on any rotorcraft. More so on an ABC type with inherently brutal vibration levels. As all this is common knowledge, you would think Sikorsky would run the tail at no thrust while they expand their hover envelope if they could. Points to a serious drive system issue.
Talk about an armchair expert...
Words fail me...

CTR

13th Dec 2019, 16:44

For the purpose of safety my group designed a concept for de clutching a conventional anti torque tail rotor on the ground. Of course unlike the X-2 concept we needed to re engage the tail rotor prior to take off.

There was never a concern on bearing fretting when de clutched. We didn’t brake to halt rotation, we used max pitch to dissipate inertia. Therefore there was always go to be creep from clutch drag and external forces. This was actually a concern to some, but we didn’t want the added weight and complexity of a brake.

Our tail gearbox was splash lube. Getting to an acceptable operating temperature came quickly after less than a couple minutes. Less than the time to complete preflight. On the X-2 they can engage after take off and wait a bit if required before increasing pitch.

We never got beyond the test bench stage. No technology issues. Just cost and weight impacts were unacceptable.

The Sultan

13th Dec 2019, 18:43

We never got beyond the test bench stage. No technology issues. Just cost and weight impacts were unacceptable.

CTR,

So you don’t know if Brinelling would be an issue as bench test would never yield the aircraft vibratory environment (the whole bolted to Mother Earth thing).

The Sultan

13th Dec 2019, 18:54

Nige wrote:

Talk about an armchair expert...
Words fail me...

Even the S-97 had the tail running on initial tests. So after 9 months Sikorsky would have the tail prop turning if they could. The fact they don’t proves my point.

https://m.youtube.com/watch?v=jX3flLU9Wac

SplineDrive

13th Dec 2019, 20:27

Nite wrote:

Even the S-97 had the tail running on initial tests. So after 9 months Sikorsky would have the tail prop turning if they could. The fact they don’t proves my point.

https://m.youtube.com/watch?v=jX3flLU9Wac

The S-97 has never not had a spinning prop shown during any kind of operation... could have a different clutch type (wet vs dry) and thus not be a direct comparison to SB>1. Given the close proximity of the prop to the exhaust, a wet clutch that always had some viscous drag and thus some prop rotation on Raider makes some sense.

The Sultan

14th Dec 2019, 03:56

Spline,

Maybe someone who knows can clarify. Until then, as the S-97 is a prototype for the following designs you would expect a similar layout. Also we have seen no evidence that confirms the SB-1’s pusher is even connected to the drive system. If not connected after a year+ of running it points to a major problem they are having to address.

CTR

14th Dec 2019, 05:32

CTR,

So you don’t know if Brinelling would be an issue as bench test would never yield the aircraft vibratory environment (the whole bolted to Mother Earth thing).

Sultan,

As you probably are aware, rolling element bearing Brinelling is caused by excessive static load and fretting is caused by oscillating motion less than a full bearing rotation from vibration (even under no load).

So if the rotor can freewheel even a couple degrees in flight and the loads are low, both fretting and Brinelling are addressed. Having designed large pitch trim actuators including the C-17, I am intimately familiar with these bearing concerns.

The Sultan

14th Dec 2019, 10:11

CTR,

In none of the videos of the SB-1 have I seen the tail prop rotate even a few degrees. You may or may not know that in ground shake tests of helicopters/tilt rotors the gearboxes are routinely replaced with non-flight components prior to start of the tests to insure the bearings on flight hardware are not damaged. The vibration levels components are exposed to during these tests are, in most cases, less than or equal to those exhibited on the basic aircraft during operations.

CTR

15th Dec 2019, 07:14

In none of the videos of the SB-1 have I seen the tail prop rotate even a few degrees. You may or may not know that in ground shake tests of helicopters/tilt rotors the gearboxes are routinely replaced with non-flight components prior to start of the tests to insure the bearings on flight hardware are not damaged.

The one question I cannot answer is if the SB>1 of the S-97 have a dedicated brake for their tail rotor. I am curious to know.

As far as ground shake testing on helicopters and Tiltrotors, I have supported both.

The key differences in shake testing performed on the ground versus flight is that the rotors are intentionally locked for ground testing, and the gearboxes are not designed for this environmental condition. Additionally, gearboxes used for ground testing are almost always not acceptable for flight before any testing is conducted due to design and manufacturing deviations.

Finally, remember that the pylon conversion actuators on Tiltrotors are gearbox driven ball screws. They spend long periods stationary, under load, and in a high vibration environment. The key difference is they are designed from the beginning to operate in this environment.

So the question is not if gearboxes can survive this environment, it is if they were designed to survive this environment.

The Sultan

15th Dec 2019, 13:42

The Sultan

15th Dec 2019, 14:10

CTR

15th Dec 2019, 16:56

CTR

One thing you missed on actuators is they don’t rotate continuously at 600 to 24000 rpm under load like gearbox components and associated bearings and therefore not relevant to the discussion of gearboxes not operating for extended periods in high vibratory environments.

Actually, as one example the V-22 conversion actuator gearbox input speed is approximately 6,000 RPM, an output of approximately 600 RPM, and continuous bearing contact stresses higher than in high speed gearboxes (which I have also designed parts for). Actuator gears and bearings on the V-22 actuators also experience full load reversal and impact loads from emergency stop braking. With the exception of high temperature run dry requirements, the V-22 conversion actuators are subjected to a more severe environment than a typical tail rotor gearbox.

This is not to say the X-2 gearboxes are properly designed to deal with the environment. Only that the technology to design gearboxes to withstand the environment is not new or unique.

IFMU

16th Dec 2019, 15:01

IFMU

Some of the highest vibration in helicopters occurs in the rotor transverse flow range which is the 20 to 40 knot range. These vibration levels often exceed cruise flight levels and do seem to be the speeds the SB-1 is still trying to achieve.

Additionally, as you know, the X-2 relied on an active vibration suppression system to make the vibration in the cockpit tolerable. Unlike rotor or transmission mounted devices this system has only an affect on the area in proximity of the device and can significantly increase the vibration in other areas of the fuselage. A cockpit mounted AVS could easily double tail vibration over a not having one.
The translational airspeed region was not as challenging as high speed flight in the X2. In fact for most of the lower speed region the X2 vibes could be managed without AVC using only classical methods to balance the rotors.
When I was a younger man I also thought AVC would make vibes better in some areas but worse in others. Makes sense from what we learned in freshman level physics. On an S92 with cabin mounted force generators (FGs) surveys showed that vibe levels pretty much decreased everywhere though pilot and passenger were the focus. So reality and theory diverge here.
The X2 FGs were not cabin mounted but were on the structure as close to the dynamic system as possible. This reduced the vibes before it got to the cabin. The result was not merely tolerable, but the IPS at 250kts was lower than a UH60 at cruise. That is exceptional!

The Sultan

14th Jan 2020, 07:43

Comments made by senior govt officials indicate that the SB-1 has run out of time without doing much more than hover. Quote from Defense News:

While the SB-1 logged much less in flight time than the V-280, the Army has determined it has enough data to move forward on its FLRAA program rather than extend the JMR TD to wait for the Sikorsky-Boeing team to log equivalent hours to its competitor Bell.

As there have been no reports that the SB-1 has exceeded even 20 kts at the end of the JMR-TD the data the Army has gathered supports a conclusion that the tilt rotor can meet or exceed all program goals while the ABC concept is plagued with multiple limitations that will keep it from being a viable platform.

Full Article:

https://www.defensenews.com/land/2020/01/13/congressional-budget-add-for-armys-long-range-assault-aircraft-aims-to-drive-down-risk/

Nige321

14th Jan 2020, 08:30

Comments made by senior govt officials indicate that the SB-1 has run out of time without doing much more than hover. Quote from Defense News:

As there have been no reports that the SB-1 has exceeded even 20 kts at the end of the JMR-TD the data the Army has gathered supports a conclusion that the tilt rotor can meet or exceed all program goals while the ABC concept is plagued with multiple limitations that will keep it from being a viable platform.

Full Article:

https://www.defensenews.com/land/2020/01/13/congressional-budget-add-for-armys-long-range-assault-aircraft-aims-to-drive-down-risk/

That isn't what the article says.
There will “always be a disparity between where particular vendors are, but that does not mean they’re not ready to compete,”
Nice try though... :yuk:

CTR

14th Jan 2020, 12:58

Sultan has yet to realize that in the US Army and DOD in general, political motives almost always trump technological realities.

Sikorsky from the start of the FVL technology demonstrator selection was favored by the US Army to be the ultimate supplier for the UH-60 replacement. With all the resources of Sikorsky and Boeing combined, how could they fail? Then Bell all alone, using advanced design tools and proven tilt rotor technology, screwed that all up and succeeded beyond expectations. Does anyone think that if the situation was reversed, and Bell was two years behind schedule, that the US Army would select Bell to proceed to the next stage and build a prototype? Of course not. If Bell had failed as badly in producing a demonstrator aircraft as Sikorsky and Boeing have done, the competition would be over and the SB>1 Defiant would be moving forward in development all alone.

Sultan, what is just, fair and technically correct has no place in the administration of the FVL contracts.

SansAnhedral

14th Jan 2020, 13:50

Its downright laughable how much tapdancing the defense media does when it comes to reporting on SB1 in order not to potentially upset LockMart.

I've now read I think 4 different articles regarding the comments by the Army on the FLRAA timeline, and not a single one of them gives any attention to the fact that SB1 only managed to fly for less than 5 hours in almost a full calendar year, nor the fact it hasn't demonstrated anything appreciably more than daylight under its wheels. They seem to be more focused on the BS excuses about rotor blade manufacturing....something that had zero to do with it staying on the ground after the blades were delivered (presumably....unless the blades are actually not holding up in PTSB runs, which would be even more of a disaster).

Similarly, all the same reporters have displayed some considerable collective amnesia on the craft that was intended to serve as risk reduction to Defiant - the S97. With 5 full years since first flight under its belt, why hasn't there been any Army pilots in that thing? Why has it not even approached its target max speeds, or displayed any of the fancy maneuverability Sikorsky loves to show off in their computer generated movies?

Literally nobody is calling out the elephant in the room on this tech, Many people in the industry have been saying for years the ABC concept is flawed, doesn't scale, and has immense fundamental issues. If the abject failure of the SB1 demonstrator program and the lack of any real progress with the S97 over half a decade doesn't make that case, its hard to imagine what would. The silence on this outside of aviation forums and defense article comment sections is deafening.

The Sultan

14th Jan 2020, 15:33

Nige wrote:

That isn't what the article says.

The purpose of 280 and Defiant programs was to demonstrate the concepts which could meet the anticipated FLRAA requirements. Data from these programs would be used to refine the final spec ahead of a development competition and fly-off. Now that the JMR-TD phase has not been extended and the Army will soon be releasing the requirements for the production FLRAA effort the SB-1 is irrelevant with respect to the next phase (except for further demonstrating that the ABC is not a viable contender). So the Army statements are basically that they have seen enough and are moving on.

If the final spec comes out with a max speed range of 20 to 300 kts, max altitude of 10 feet to 20k feet, and a range of 100 feet to 700+ miles I will concede that I was wrong and the SB-1 is not a failure.

Moving forward it will be interesting to see what Boeing proposes as I do not see them not trying to compete for FLRAA.

CTR

14th Jan 2020, 16:24

Sultan,

In a fair and just world he would be correct. But I believe the US Army will give Sikorsky as many bites of the apple as possible to try to get it right.

In the meantime, as a program becomes delayed by over a decade, Sikorsky will continue to make money on Blackhawks.

SansAnhedral

14th Jan 2020, 18:02

In the meantime, as a program becomes delayed by over a decade, Sikorsky will continue to make money on Blackhawks.

https://www.pprune.org/showthread.php?p=10492312

I expect this effort will soon begin in earnest.

SplineDrive

14th Jan 2020, 21:48

Its downright laughable how much tapdancing the defense media does when it comes to reporting on SB1 in order not to potentially upset LockMart.
...
Literally nobody is calling out the elephant in the room on this tech, Many people in the industry have been saying for years the ABC concept is flawed, doesn't scale, and has immense fundamental issues. If the abject failure of the SB1 demonstrator program and the lack of any real progress with the S97 over half a decade doesn't make that case, its hard to imagine what would. The silence on this outside of aviation forums and defense article comment sections is deafening.

Got some savage comments here, lol.

The Sultan

14th Jan 2020, 23:11

CTR,

From the reported govt comments the general impression I got was the FLRAA will be accelerated to pick two to continue soon with down select in 2022/23 rather than 2025. If this ends up being the case I don’t see how anyone but Bell can get something in the air and demoed with the required flight spectrum (if a flight evaluation is even still going to be a requirement). If this is the case I expect to see Boeing banging on Bell’s door asking/demanding to be a partner and LM saying doing the avionics is good enough.

etudiant

15th Jan 2020, 00:01

rotormatic

17th Jan 2020, 21:11

https://www.verticalmag.com/news/sikorsky-boeing-sb1-defiant-100-knots/

Ascend Charlie

17th Jan 2020, 23:47

For 100kt, the fuselage angle is noticeably nose-down - what will it look like at 280kt?

The Sultan

18th Jan 2020, 00:10

Wow. . . .100 knots. The fuselage angle indicates the tail prop is probably generating little or no thrust which means the fuselage has to tilt to get any non vertical thrust. A shame the program it was developed for completed last month.

Copter Appreciator00

25th Jan 2020, 19:52

Good afternoon, folks. I'm a semi-new member. It seems that there is a bit of anti-SB-1 sentiment, and i'll rant my ideas on it. ALot of us want to see Bell Helicop-- er, Bell Flight, prevail in the FVL FLRAA or whatever it's called now. They're kind of an underdog i.e. they've had their machines in various entries over the years, and lost out to the AH-64 and UH-60 i.e. bid programs for Turkey, Taiwan, South Korea, Greece, etc, other countries, and the dominance of the AW139 in civil and militaries, the seeing the dead end of the ARH-70 bid, the Bell 210/412 not being picked over the Lakota UH-72... It would be great to see Bell prevail, especially as the Navy went with the AW-119 for the TH-57 replacement despite the idea of replacing a Bell 206 with a 407 seemed like a sure bet. Seems like Leonardo is winning everything these days!! I also secretly kick my table leg when I see on heli Hub that some other county Air ambulance replaces their Bell 412 with a $&@ Airbus H135/145 or Leo-Agusta Westland-Boeing whatever AW139. If only the Bell 525 had been ready in time for the UH-1N replacement... grrr.
It's good to see the AH-1Z get some foreign interest, like the Czech Republic's order and Bahrain' s pending sale, with Morocco and Romania showing interest. bell was able to make a sale to pakistan - but the AH-1Zs are currently in storage due to political order.
I believe the winged and plane-propped V-280 will have the range and speed advantage, and will be agile enough at the X. I simply don't see the SB>1 being as fuel efficient with the twin rotors and pusher prop, but may be nearly as fast as Valor due to raw power, but if Raider S-97 and Raider X are examples, it will be very agile at the X. We have to be aware that Sikorsky has a strong contender in the SB-1. However, I am sure Bell has their cards lined up for the FVL, with the V-280 building on the V-22 to make a strong case for tilt-rotors, and their B360 Invictus has the least complex approach to FARA, which may be a good thing. Go Bell Flight!

SplineDrive

26th Jan 2020, 15:38

For 100kt, the fuselage angle is noticeably nose-down - what will it look like at 280kt?

It would be near level body to minimize drag at speeds greater than ~180-200 knots. Looks like at least several of the shots had the aircraft flying in "helicopter mode" with the main rotor producing horizontal force and the prop freewheeling. The earlier XH-59A, with it's comparatively poor rotor aerodynamics, and limited power/weight ratio compared to some modern X-2 aircraft, could do 156 knots as a pure helicopter. Given the advancements and installed power in the more recent aircraft, they should have an even larger "helicopter mode" flight envelope to work in before prop thrust "airplane mode" flight is required. So if the prop driveline of SB>1 isn't ready yet, they still have plenty of flight envelope to explore.

IFMU

26th Jan 2020, 16:48

Because it is in flight test, they will be doing flights at many different power settings on the rotor, prop, plus horizontal tail position. Each one will give a different attitude for a given airspeed. There is no reason it won't fly level body throughout the envelope once they have it mapped out.

Lonewolf_50

26th Jan 2020, 16:53

IFMU: gee, what's with the common sense and rational thought in a post?
Are you sure you are in the right place? :E

SansAnhedral

27th Jan 2020, 16:40

if Raider S-97 and Raider X are examples, it will be very agile at the X.

Sikorsky's marketing team is certainly earning their paychecks....I'm still at a loss with regards to these repeated sentiments from people.

40 years after XH-59, 10 years after X2, and 5 years after first flight on S-97 and the most extreme maneuvering we have seen is footage of Raider plodding around lazy strafing circles played back at 1.5X speed on Sikorsky youtube videos.

I simply don't see the SB>1 being as fuel efficient with the twin rotors and pusher prop, but may be nearly as fast as Valor due to raw power

The fastest hot-rod, all-engine X2 squeaked past 260 kt in a shallow dive. The V-280 has reportedly flown in excess of 310 kt (and recall the XV-15 reached 345 kt in a shallow dive). The odds an edgewise-rotor-flight ship even sniffs the speeds of a tiltrotor flying on a wing with remotely the same installed power is essentially zero.

The Sultan

27th Jan 2020, 20:47

SplineDrive

27th Jan 2020, 21:02

If the Army specs a high rate roll reversal at high speed (low rotor rpm) to simulate SAM avoidance the ABC concept is finished. The S-97 crash at full rpm showed how even moderate roll rates will cause the rotors to collide.

The crash was a result of the wrong set of control laws being active, not the rate of input... the crash isn’t representative of how well the aircraft will maneuver. Most rotary wing platforms are capable of blade to “something” strikes if control laws drive the aircraft to a bad state.

Lonewolf_50

28th Jan 2020, 12:57

If the Army specs a high rate roll reversal at high speed (low rotor rpm) to simulate SAM avoidance the ABC concept is finished. The S-97 crash at full rpm showed how even moderate roll rates will cause the rotors to collide. My instructors at Fallon and Nellis, regarding SAM evasion by helicopters, would be laughing pretty hard at your understanding of how slow aircraft deal in modern SAM avoidance.
high rate roll reversal at high speed (low rotor rpm) to simulate SAM avoidance
And that was with tech that is about 30 years old.
Missile seeker heads have not gotten worse in the interim.

The Sultan

28th Jan 2020, 15:12

My instructors at Fallon and Nellis, regarding SAM evasion by helicopters, would be laughing pretty hard at your understanding of how slow aircraft deal in modern SAM avoidance.

Lone

The FLRAA is a 280+ Kt aircraft and not a 30 yr old 120 kt or slower design. I believe the avoidance technique is still to pop chaff and flares and then be somewhere else when the missile arrives. Kind of defeats the purpose to fly straight and level after deploying countermeasures.

From a countermeasures description:

Once the presence of a "live" IR missile is indicated, flares are released by the aircraft in an attempt to decoy (https://en.m.wikipedia.org/wiki/Decoy) the missile; some systems are automatic, while others require manual jettisoning of the flares.

The aircraft would then pull away at a sharp angle from the flare (and the terminal trajectory of the missile) and reduce engine power in attempt to cool the thermal signature. Optimally, the missile's seeker head is then confused by this change in temperature and flurry of new signatures, and therefore follows the flare(s) rather than the aircraft.=13.33px

Lonewolf_50

28th Jan 2020, 15:31

Lone

The FLRAA is a 280+ Kt aircraft and not a 30 yr old 120 kt or slower design.
Sorry, 280 knots is still slow.
There is a rate change that takes a lot more speed to make a difference to a seeker head with tech that is two generations older than what is available now.
What feels like a radical maneuver in that cockpit looks pathetic to the seeker head.
(Granted, I am sure that old OV-10 Bronco hands may have a tew things to say about this).
I believe the avoidance technique is still to pop chaff and flares and then be somewhere else when the missile arrives.
I expect that's still true. Without various countermeasures and a change in all three axes, evasion isn't even a useful term.

The Sultan

28th Jan 2020, 16:19

The crash was a result of the wrong set of control laws being active, not the rate of input... the crash isn’t representative of how well the aircraft will maneuver. Most rotary wing platforms are capable of blade to “something” strikes if control laws drive the aircraft to a bad state.

From my reading of the accident report the wrong set of control laws increased the roll input to cyclic command by a factor of 2.5 which led to over control resulting in a couple of roll reversals causing the blades to collide. The “instantaneous” roll rates achieved during the event were never higher than would be expected in aggressive flight maneuvers. One selling point of the ABC was the rotors were so stiff it would be impossible for them to deflect enough to collide even in the most severe maneuvers. The 97 accident shows this is not true and will be a governing constraint limiting the agility of an aircraft billed as being highly maneuverable.

SansAnhedral

28th Jan 2020, 16:22

Lone,

To be fair, it was the Army themselves (and Sikorsky over the years with their presumed greater hover maneuverability) who had been touting the value of exceeding ADS-33 requirements and the (preposterous) idea of dodging threats from slow speed/hover.

It was always the knock against tiltrotors, hence why the V280 added massive amount of flapping to address the V22's relative sluggishness. Bell always argued the survivability was not from dancing around a seeker, but flying high above the threat, faster, and eliminating the time time on station. The Army should really have recalled the AH-64 fights in Najaf to remember why the doctrine immediately changed from lobbing munitions from a stand off hover to constant high speed strafing attacks.

noneofyourbusiness

21st Feb 2020, 00:03

Update today. Sikorsky sounds nervous. Go to breakingdefense.com

“We’re flying it before we’re buying it,” McCarthy said this morning. “There’s nothing better than putting hours against the platform and learning.”"The SB>1 Defiant compound helicopter has only 11 hours of flight testing, versus over 160 for Bell’s V-280 Valor""But what has the actual aircraft done in flight? Fell said that Defiant has flown backwards, sideways, banked at a 45-degree angle, and flown forward in level flight as fast as 150 mph (130 knots).

"But that’s not halfway to the 322 mph (280 knots) that the Army wants. Even the Army’s minimum requirement for top speed is 265 mph (230 knots).

"When will the Defiant fly at its top speed? “A few months,” Fell said. That’s a remarkably short timespan compared to how long it’s taken to get it this point."

The Sultan

21st Feb 2020, 02:22

The aforementioned article:

https://breakingdefense.com/2020/02/weve-got-enough-data-on-defiant-sikorsky-boeing/

The Sultan

21st Feb 2020, 11:36

Another article.

https://www.verticalmag.com/news/sikorsky-boeing-defiant-helicopter-tail-rotor/

I like this part:

If the tail boom, which includes no hydraulics, took a direct hit and literally fell off, the aircraft would still be able to operate as a helicopter. All control surfaces aft of the engine outlet are controlled by electronic actuators.

So advanced it doesn’t have a CG! What a joke, Hope they briefed the DOD with more accurate info. This thing would back flip like anything else. Even if you only lost tail thrust good luck making it back to base at 90 or so knots.

Lonewolf_50

21st Feb 2020, 13:06

The Army should really have recalled the AH-64 fights in Najaf to remember why the doctrine immediately changed from lobbing munitions from a stand off hover to constant high speed strafing attacks. Heh, are you referring to the 2003 raid by 11th Aviation Regiment, or a different fight?
The Army requirements for Comanche had some very tough to meet lateral movement numbers. I'll offer that "shoot it from a hover" was being been abandoned in the midl to late 90's in at least a part of the Army's recon / attack community.

chopper2004

16th Mar 2020, 23:15

https://www.lockheedmartin.com/en-us/news/features/2020/sb1-defiant-moves-forward-for-future-vertical-lift-fvl.html?utm_source=facebook&utm_medium=social&utm_campaign=fvl&Campaign+Term=RMS---Future-Vertical-Lift,RMS---Defiant&Campaign+Content+=100001183036889&linkId=100000011212635

”The U.S. Army announced that the Sikorsky-Boeing team has been selected to move forward in the Future Long-Range Assault Aircraft’s Competitive Demonstration and Risk Reduction Program (CD&RR) program.”

Ascend Charlie

17th Mar 2020, 07:01

...is that the sound of Sultan choking on his hat?

The Sultan

17th Mar 2020, 11:01

AC

I never really thought the Army would do the smart thing and sole source this phase of FLRAA (it is the Army after all). If the performance specification hasn’t been scaled back from a min cruise speed of 250 kts and a real target of 280 kts the SB offering is there only to blunt program delaying protests as it will never meet this requirement.

SplineDrive

17th Mar 2020, 12:42

...is that the sound of Sultan choking on his hat?

https://www.verticalmag.com/news/bell-valor-boeing-sikorsky-defiant-flraa-selection/

Bell, of course, got a CD&RR OTA contract as well.

I love how the Sikorsky press release talks about their “proven” configuration. They have another couple of weeks to make their 230 knots in March commitment... and there’s far more to proving a platform than flying straight and level at far less than your design speed.

Evalu8ter

17th Mar 2020, 12:46

Not really surprising that both JMR-TD aircraft are getting CDRR contracts. It buys the Army some time to see if the Defiant can deliver anything like its promise and to work out how the metrics look when combined with FARA. There will be political pressure to ensure the same company doesn't win both to help maintain the industrial base and the Pork Barrel. My money is still firmly on Bell for FLRAA - it's still way ahead in terms of maturity and reduced risk. When the Army announce the 2 development contracts for FARA we'll have a clearer picture.

CTR

17th Mar 2020, 12:56

Reading the more detailed Vertical article, this award is only for a two year design study, not the expected contract to build EMD representative aircraft for a fly off competition.

This is a disappointment for Bell and a life line for Sikorsky/Boeing. Fair? No. But this is a DOD contract.

“These competitively awarded OTA agreements consist of risk reduction activities that combine government research with input from industry partners to inform the future development and procurement of the FLRAA weapons system, according to a copy of the public announcement obtained by Vertical.

Under the agreements, each company will produce initial conceptual designs, requirements feasibility, and trade studies using model based systems engineering. These CD&RR agreements will extend over two years, informing the final Army requirements and the program of record planned for competition in 2022.”

https://www.verticalmag.com/news/bell-valor-boeing-sikorsky-defiant-flraa-selection/

CTR

13th May 2020, 12:53

Don’t blink the video is only 15 seconds long.

https://defence-blog.com/army/sikorsky-boeing-team-releases-new-video-of-its-sb1-defiant-helicopter.html

SplineDrive

13th May 2020, 13:43

Don’t blink the video is only 15 seconds long.

https://defence-blog.com/army/sikorsky-boeing-team-releases-new-video-of-its-sb1-defiant-helicopter.html

Depending on the maneuver, that may be a meaningful amount of fatigue life 😜.

Ah, I jest. Just hope they’re being safe when expanding the flight envelope.

SansAnhedral

13th May 2020, 15:11

Don’t blink the video is only 15 seconds long.

https://defence-blog.com/army/sikorsky-boeing-team-releases-new-video-of-its-sb1-defiant-helicopter.html

That entire montage makes the Defiant look wholly sluggish and ungainly, particularly in contrast to the videos of the V-280 performing low speed agility maneuvers. It's amazing that Sik/Boeing publish these as advertisements of its supposed performance attributes.

The aircraft should reach maximum speed capability of roughly 250 knots within the next few months

-Bill Fell 2/20/20

Still doesn't look remotely close to 250 kt.

Nige321

17th Jun 2020, 10:16

205 knots...

On June 9th, 2020, the #SB1Defiant (https://www.youtube.com/results?search_query=%23SB1Defiant) continued its test regiment and expanded the flight envelope, achieving 205 knots, surpassing the top speed of the legendary Black Hawk. Sikorsky Chief Test Pilot, Bill Fell remarked that this milestone is just the beginning and that the #SB1Defiant (https://www.youtube.com/results?search_query=%23SB1Defiant) has “got a lot more in it.”

https://www.youtube.com/watch?v=6WDYUaFOIqM

The Sultan

17th Jun 2020, 20:28

From an article on Breakingdefense.com:

“There are probably 50 different configurations” being looked at for the final design, added Randy Rotte, who’s Boeing’s marketing director for FVL. All the different variations would probably look identical to the layperson, but in one iteration, the design team may try to squeeze out every possible knot of speed, in another they may prioritize fuel efficiency and long range, and in yet another they may aim for minimum cost, working through hundreds of highly technical tradeoffs trade-offs.=13.33px

In the next anticipated battle space (the Pacific) both high speed and long range with full payload will be required. That is the purpose of the FLRAA program (hint LR means long range). By stating the secret parts out loud SB is admitting their design can’t do both. This is very bad for their prospects when their highest possible speed or longest possible range are woefully short of the V-280’s demonstrated capabilities.

SansAnhedral

17th Jun 2020, 21:15

Defiant can expect to hit 200 knots within six months after initial flight
-Ken Eland 10/09/18

The Defiant is back in the air, reaching speeds of 20 knots on its fourth test flight. The goal is that Defiant will hit triple digit speeds by the end of this year. It should reach the Army-mandated minimum speed of 230 knots by the end of March if we have no other significant things we learn along the way
-Ken Eland 10/15/19

The aircraft should reach maximum speed capability of roughly 250 knots within the next few months
-Bill Fell 2/20/20

The program will need a few more months to reach maximum speed, whatever that might be
-Bill Fell 6/16/20

SplineDrive

17th Aug 2020, 14:41

It’s been “a few months” again... any news on progress?

etudiant

18th Aug 2020, 01:34

One has to wonder whether the SB1 is simply getting used as a prop, to allow the Army to document that it had an open competition, even though the decisions have already been made.
At least, I do not recall any competition where the gap in aero performance was so large between the competitors. What am I missing?

Commando Cody

19th Aug 2020, 02:38

It’s been “a few months” again... any news on progress?

The SB>1 finally broke 200 knots on June 9. You'll note that some time back Sikorsky Boeing stopped predicting when they would achieve certain goals except to say "Real Soon Now".

Sorta like what started happening on the S-97. I read somewhere that Sikorsky has implied that the S-97 will not achieve its design speed. Can anyone confirm?

SansAnhedral

19th Aug 2020, 14:57

I read somewhere that Sikorsky has implied that the S-97 will not achieve its design speed. Can anyone confirm?

Seems Sikorsky's own demonstration flights have implied that. After reaching barely over 200 kt in Sept 2018, they subsequently have flown progressively slower in their big-to-do demo flights - only reaching 190 kt in July 2019 and then 180 kt in Feb 2020. And of course, nothing since then at all.

So in the 2 years since the maximum achievement of 20% below design speed, they have regressed a further 10% in demonstrated performance.

Plus, don't forget even Sikorsky has been stating that Raider-X will be slower then S-97.

SansAnhedral

28th Aug 2020, 15:27

Hey look, another 180 kt flight.

https://www.youtube.com/watch?v=mUKEOfa8RQcRaider And Defiant Fly Together For First TimeGraham Warwick (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fauthor%2Fgraham-warwick&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074559460&sdata=cdutlQ%2FV9EucZBen3JncBO520wuue%2BbbBR23I6S3ZXE%3D&reserved=0) August 28, 2020

In late July, two sleek rotorcraft raced together over the cypress wetlands of southern Florida, the pair exceeding 180 kt. as the Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074569451&sdata=cIwSqgTRdgE7GGPSdcx98rZl9uN8XdteiiOlAImGD7o%3D&reserved=0) S-97 Raider and Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074569451&sdata=cIwSqgTRdgE7GGPSdcx98rZl9uN8XdteiiOlAImGD7o%3D&reserved=0)-Boeing (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F12083&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074579440&sdata=33B8qzPBVs4HCfKhjsIP5LGm0yR%2BoJ0Z95gXaiWalVk%3D&reserved=0) SB-1 Defiant high-speed helicopters flew together for the first time.

The flight over Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074599430&sdata=4Vp33%2B7vtptPHxlWluovq4Hva7UdHbXPAzDzxCSzzE0%3D&reserved=0)’s West Palm Beach development flight center was staged for U.S. Army (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F13989&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074599430&sdata=ldRNsTM52PhKNtaI3lI7H0i2lxPwdz5HsmkFzL12tyU%3D&reserved=0) acquisition chief Bruce Jette. The Raider and Defiant are competing for two of the Army’s top modernization priorities: the Future Attack Reconnaissance Aircraft (FARA) and Future Long-Range Assault Aircraft (FLRAA), respectively.

For Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074609426&sdata=bsMrDRhCpPWYpOJg3%2BXF2Nw9iEXq0QQtA%2B%2BKivMPO3I%3D&reserved=0), now a Lockheed Martin (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F27191&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074609426&sdata=D7ZdWrJNhI6T1FUEJBShy8yhfNpNj487mtA8%2FfMJR7Q%3D&reserved=0) company, the formation flight held added significance because it came almost 10 years after its company-funded X2 technology demonstrator had set an unofficial speed record for helicopters of 250 kt. in level flight. Both the Raider and Defiant use the X2 coaxial rigid-rotor compound helicopter configuration.

Together, the X2, Raider and Defiant demonstrators represent a $1 billion investment by Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074619425&sdata=xCnp%2FSQgpRebgj847k9ulB0ABDPJ%2B4QvGzIPNWpkois%3D&reserved=0) and its industry partners, now targeted squarely at winning the FARA and FLRAA.

In 2005, flush with cash from producing H-60-series helicopters for the U.S. military and export customers, Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074619425&sdata=xCnp%2FSQgpRebgj847k9ulB0ABDPJ%2B4QvGzIPNWpkois%3D&reserved=0) launched the X2 program. Looking to guarantee its future with a new generation of helicopters, the company studied a wide range of designs, including tiltrotors, before deciding to revisit the coaxial rigid-rotor compound configuration it pioneered with the XH-59A Advancing Blade Concept demonstrator.

First flown in 1973, the XH-59A was fast, reaching a maximum level speed of 238 kt. But it was complex, with high fuel consumption, noise and vibration. Operating the four engines—two turboshafts for the rotors and two turbojets for propulsion—required a two-person crew.

Taking advantage of advances in technology during the intervening decades, Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074629415&sdata=PuPqosJUJcfSizXXflhULdxr1h8daAY6PBVvbd047fk%3D&reserved=0) simplified the concept to produce the X2: a single-seat, single-engine rotorcraft with fly-by-wire flight control, composite blades and airframe as well as active vibration control. The X2 demonstrator flew in 2008.

In 2010, after the X2 reached 250 kt., Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074629415&sdata=PuPqosJUJcfSizXXflhULdxr1h8daAY6PBVvbd047fk%3D&reserved=0) launched an industry-funded program to build two S-97 Raider light tactical helicopter prototypes using the configuration. Aircraft 1 flew in May 2015 and logged about 20 hr. before suffering damage during a hard landing caused by a flight-control software flaw. Aircraft 2 has now logged almost 69 hr., reaching a maximum speed of 207 kt. and angle of bank of 60 deg.

Flight testing of the S-97 is now dedicated to optimizing Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074639407&sdata=2XYaPTKEeqpvhBYzW6k3cvRRB8tUvHn2UFcWYfy3uqM%3D&reserved=0)’s Raider X design for FARA, focused on tweaks to minimize drag at high speed. “Those flight hours mean someone had a question,” says Jay Macklin, Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074639407&sdata=2XYaPTKEeqpvhBYzW6k3cvRRB8tUvHn2UFcWYfy3uqM%3D&reserved=0) director of Future Vertical Lift (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fprogram%2F40259 5&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074649398&sdata=%2FtW7u%2BuA9KTT1LtQOEudsFZo82vlpUel2N1NRkUdjF8%3D&reserved=0) (FVL) business development. And while the S-97 is flying, Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074649398&sdata=2H6osdjOiVE%2BvEYGe86s%2B0nIyMX2zhVZqOgBXx6sO18%3D&reserved=0) is making progress with the Raider X prototype. “The build is on,” he says.

The Defiant, meanwhile, has logged 20 hr. of flying since taking to the air for the first time in March 2019 and has exceeded 200 kt. and a 30-deg. angle of bank. Whereas the single-engine Raider was designed for 220 kt., the twin-turboshaft Defiant is designed for 230 kt. but with a speed goal “closer to 250 kt.,” says Bill Fell, Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074659398&sdata=koqOR3w2aKh%2FI4c5aiHluIHRVMVrVOf7lkduA6FmmHM%3D&reserved=0)’s chief test pilot. A flight to achieve that speed goal is imminent, the team indicates.

Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074659398&sdata=koqOR3w2aKh%2FI4c5aiHluIHRVMVrVOf7lkduA6FmmHM%3D&reserved=0) and FLRAA teammate Boeing (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F12083&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074669396&sdata=MpTAouEo3SjOktdNKdrMP4ybv9cPK51yIDRTRIB8d0w%3D&reserved=0) emphasize that both the Raider and Defiant combine high speed and maneuverability with the low-speed agility of a conventional helicopter. There are differences, however. The Raider and Defiant have no tail rotor; instead, differential torque on the coaxial rotors is used to turn at low speed. The yaw rates generated are the same and can be tailored to the mission requirement, test pilot Christian Corry says.

Both machines can fly like a helicopter at speeds of up to 150-160 kt. using conventional collective and cyclic control, Fell says. But when the tail-mounted propeller is engaged to provide propulsion, the coaxial rotors become rotating wings, Corry says, and collective pitch is automated to maximize lift and minimize drag at high speed.

Airspeed is controlled through the prop pitch, using the throttle, and flight control relies on rudders and elevators on the tail. “It’s more of an airplane than a helicopter,” Corry says. Unlike a conventional helicopter, whose nose must be pointed down or pulled up, the propulsor enables level-attitude acceleration and deceleration.

Reversing prop pitch “is like throwing a parachute out there,” Fell says. “It acts like a big brake.” This procedure is used routinely to maximize test time. Fell describes approaching the airfield in the Defiant at 180 kt., then reversing the prop and slowing rapidly while the nose stayed pointed down at the landing zone. “I was able to see everything the entire time during the approach, which you cannot do in a helicopter,” he says.

On the formation demo, the two rotorcraft stopped in about the same distance, despite the Defiant’s larger size, notes Randy Rotte, Boeing (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F12083&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074669396&sdata=MpTAouEo3SjOktdNKdrMP4ybv9cPK51yIDRTRIB8d0w%3D&reserved=0) director of global sales and marketing for FVL, cargo and utility. The Defiant so far is cleared to use only half the negative prop-pitch range, Fell adds. Once the full range is cleared, “we will see much more rapid deceleration,” he says.

And whereas a tail rotor is required for control throughout the flight envelope of a conventional helicopter, on the Defiant—as on the Raider—the propulsor can be disengaged, reducing the acoustic signature and improving survivability.

High speed, not hover, drives the power requirement in both aircraft. Powered by two 4,000-shp-class Honeywell (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F22311&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074679393&sdata=vyfKOc05YMep3k71HPDM96wpNqVsD9n5Oiim6c3%2BANc%3D&reserved=0) T55s, the Defiant is “loafing” at 180 kt. on less than 50% power, Fell says. “At the weights we are flying, we have hover power on one engine. That means contingency and high-hot capability,” he adds.

Even the single-engine Raider has “excess power you don’t see in a conventional helicopter,” Corry says. The competing FARA prototypes will both be powered by the 3,000-shp-class General Electric (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F31624&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074679393&sdata=ErCeBLRvSoafAVpto%2Fptx4TwbiLtdUEf6K8eeEmBKbI%3D&reserved=0) T901, a new engine that is expected to increase in power output over time. “Counter-rotating rigid versus fully articulated [rotor] provides growth potential,” Macklin says. “We can add power to the engine, and the design can take it.”

The coaxial rigid rotors also provide high control responsiveness. The 30,000-lb. Defiant “flies like a 20,000-lb. machine,” Fell says. “The crisp response from the rotors shrinks the machine.” The 11,000-lb. Raider “is more compact. It has that small, agile scout feel.” But both rotorcraft “fly the same” despite the difference in size.

“It is the entire integrated weapon system that creates survivability, but it starts with the speed, maneuverability and agility of the aircraft,” Macklin says. “It’s the packaging that provides the transformational capability,” Rotte notes. “It fundamentally changes the way you can fight—range, speed and maneuverability translate into survivability in a contested environment.”

Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074679393&sdata=x61Y3QV3b4MFRoUoPZgqLXqIopK0QR4alvfsV8nlj1k%3D&reserved=0) and Boeing (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F12083&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074689381&sdata=si4o3q2awg6Z8baNG%2B43ql2VMhx%2FgCcjrWXI40qLj%2B4%3D&reserved=0) are locked in competition with Bell for the FARA and FLRAA that will play out over the next three years. But for Sikorsky (https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Faviationweek.com%2Fawin%2Fcompany%2F15306&data=02%7C01%7Ccfoskey%40bellflight.com%7Cc79cf6cbc3154d3bc4 d008d84b61e321%7C2d5b202c8c074168a55166f570d429b3%7C0%7C0%7C 637342231074689381&sdata=Csxtk%2BlPSJZLEHZOzw5sCBq4W19QY4tH9GnzxZwPxQc%3D&reserved=0), more than a decade after betting its future on the X2 configuration, flying the Raider and Defiant together was a milestone—and a glimpse of how the Army could use them together in multidomain operations. “Seeing them in formation seemed like a natural evolution,” Macklin says.

Lets update the quote list!

Defiant can expect to hit 200 knots within six months after initial flight
-Ken Eland 10/09/18

The Defiant is back in the air, reaching speeds of 20 knots on its fourth test flight. The goal is that Defiant will hit triple digit speeds by the end of this year. It should reach the Army-mandated minimum speed of 230 knots by the end of March if we have no other significant things we learn along the way
-Ken Eland 10/15/19

The aircraft should reach maximum speed capability of roughly 250 knots within the next few months
-Bill Fell 2/20/20

The program will need a few more months to reach maximum speed, whatever that might be
-Bill Fell 6/16/20

A flight to achieve that speed goal is imminent
- Defiant Team 8/27/20

SplineDrive

29th Aug 2020, 22:34

"A flight to achieve that speed goal is imminent" - Defiant Team 8/27/2020

Which speed goal? The bare-minimum Army requirement of 230 knots? Or the current speed goal of "closer to 250 knots" (so I guess 241 knots qualifies)? Or SB>1's actual design speed?

ShyTorque

29th Aug 2020, 22:55

I wonder which one of the formation was slowing them down, and for what reason.

It’s a lot of effort to get to a speed not much faster than helicopters already in service. Just saying...

EvaDestruction

30th Aug 2020, 19:11

Such a beautiful machine! As one who learned in a Huey, that is a gorgeous machine and fine application of the coaxial design and all it's advantages.

It would be cool to see video of when they engage the propeller. Totally awesome.

SplineDrive

31st Aug 2020, 02:49

Such a beautiful machine! As one who learned in a Huey, that is a gorgeous machine and fine application of the coaxial design and all it's advantages.

I guess beauty is in the eye of the beholder... took another look through patents and found what looks like the application for the SB>1 rotor hub. Compare the patent art with the first flight image without rotor fairings. Figure 3 looks like the bottom main rotor head.

US Patent Application showing what looks like SB>1 main rotor system (https://patentimages.storage.googleapis.com/5e/d3/73/2437510c64ed32/US20190276143A1.pdf)

High resolution first flight image showing bare rotor system (https://prnewswire2-a.akamaihd.net/p/1893751/sp/189375100/thumbnail/entry_id/1_a42v3xvp/def_height/1800/def_width/2700/version/100011/type/1)

Since you have experience in the Huey, you’ll appreciate the evolution of rotor head technology from greased steel bearings to... steel bearings and TT straps. All metal construction, highly loaded oscillating steel bearings, and even the blade lugs look like they have doublers bolted on. Speaks to the load magnitudes involved on a rigid rotor head of this size. Doesn’t look light or prone to long bearing lives.

EvaDestruction

31st Aug 2020, 14:37

Thanks for the drawings and picture.

Yes, beauty is in the eye of the beholder! LOL

Two's in

31st Aug 2020, 21:33

SansAnhedral

1st Sep 2020, 14:47

That MR head is mighty complicated. It all undoubtedly works

Until they achieve and demonstrate a single promised performance metric, or even allow a non-company pilot in the thing to objectively assess the vibration, I would say the jury is still firmly out on that one.

CTR

1st Sep 2020, 18:33

Until they achieve and demonstrate a single promised performance metric, or even allow a non-company pilot in the thing to objectively assess the vibration, I would say the jury is still firmly out on that one.

Still no customer pilot has flown the Defiant?

Unbelievable that the US Army can be so patient.

SplineDrive

1st Sep 2020, 19:17

Still no customer pilot has flown the Defiant?

Unbelievable that the US Army can be so patient.

Maybe the U.S. Army doesn’t have a good dental plan for their pilots.

EvaDestruction

1st Sep 2020, 21:30

That MR head is mighty complicated. It all undoubtedly works, but what is the real % gain over a conventional helicopter in terms of cost/maintenance/operational benefit? It seems a lot like an idea looking for a requirement at the moment, I was at West Palm Beach when the Comanche was canned...

I fly out of Fort Pierce and managed a glimpse of the Comanche many years ago, a cool machine.

As for the coaxial design, the obvious gain is no tail rotor and assorted systems and penalties. Whether that outweighs the complexity of 2 rotor heads I have no idea, but the Russians have been using them for years.

Ascend Charlie

2nd Sep 2020, 11:42

but what is the real % gain over a conventional helicopter

The advantage is not having to rely on getting any lift from the retreating side of the disks.

Sure, in a one-disk system, the advancing blade can generate a lot of lift, but it has to throw most of it away, because it can only provide the dismal amount of lift that the struggling, half-stalled retreating blade provides. Otherwise, the sides are not balanced. The advancing side, at top speed, could provide around 7 times more lift than it is allowed to generate. But use a coaxial system, and there is an advancing blade on both sides, forget the retreating blade, and now because all that lift can be used, the diameter can be smaller. Simples. Tccchhhk.

SplineDrive

2nd Sep 2020, 13:34

The advantage is not having to rely on getting any lift from the retreating side of the disks.

Sure, in a one-disk system, the advancing blade can generate a lot of lift, but it has to throw most of it away, because it can only provide the dismal amount of lift that the struggling, half-stalled retreating blade provides. Otherwise, the sides are not balanced. The advancing side, at top speed, could provide around 7 times more lift than it is allowed to generate. But use a coaxial system, and there is an advancing blade on both sides, forget the retreating blade, and now because all that lift can be used, the diameter can be smaller. Simples. Tccchhhk.

To get most of that advancing blade benefit, though, simply being a coaxial rotor system isn’t enough. You have to be able to carry large moments across the hub and hold what would normally be an unusual rotor trim on each rotor so the center of lift on each rotor is offset from the rotor shaft. The Kamov style coaxial rotor systems don’t do this, so they don’t get an advancing blade benefit. Only relatively rigid rotor systems can. Unfortunately, the ability to carry large 1P moments in a rotor also means you carry large 2P, 3P, 4P, 5P, etc. moments as well. This is where the real problems begin. While 1P moments are very large (and generally commanded), 2P moments are also quite large (and unhelpful). 3/4/5P harmonic blade loads are smaller (still unhelpful), but also significant. In a flapping rotor hub, you have some design freedom to select the number of blades and blade tuning to choose how to minimize the impact of these harmonic loads, and with enough blades, rotors can fly quite smoothly. In a rigid coaxial rotor, the same problem exists, but there are more design constraints. If the rotors have more than 3 blades, the large 2P loads will generally cancel out at the hub, hence the 4 bladed designs on the current ABC aircraft. A 4 bladed rotor will interact with 3/4/5P harmonic blade loads. Those harmonic blade loads WILL end up as vibratory hub loads that must be mitigated somehow. Studying a helicopter dynamics textbook will show that. It’s not just a matter of “poor blade tuning” these aircraft struggle with, it’s the intersection of concept and physics.

Maybe Sikorsky finally gets a really excellent anti-vibration control system working for all flight conditions. Maybe they lose both FVL contracts. We’ll see.

IFMU

3rd Sep 2020, 02:55

A 4 bladed rotor will interact with 3/4/5P harmonic blade loads. Those harmonic blade loads WILL end up as vibratory hub loads that must be mitigated somehow. Studying a helicopter dynamics textbook will show that. It’s not just a matter of “poor blade tuning” these aircraft struggle with, it’s the intersection of concept and physics.
I used to be a Sikorsky/X2 guy. I'm probably not at liberty to say the particulars but I'll say you have your harmonics wrong with respect to what was creating vibes and what wasn't.

Maybe Sikorsky finally gets a really excellent anti-vibration control system working for all flight conditions. Maybe they lose both FVL contracts. We’ll see.
I have no knowledge of Raider or Defiant, but they got it working for X2. I personally don't see any reason why it wouldn't work for the new aircraft. They have excellent dynamics people, not just in theory but supporting the aircraft in the field and in the air.

IFMU

3rd Sep 2020, 02:58

That MR head is mighty complicated. It all undoubtedly works, but what is the real % gain over a conventional helicopter in terms of cost/maintenance/operational benefit? It seems a lot like an idea looking for a requirement at the moment, I was at West Palm Beach when the Comanche was canned...
I'd say the rotor is less complicated - it lacks a lead/lag hinge. It does have twice as many rotors, if that is what you mean as complicated. And, I'd also give you the fact the upper pushrods go up through the main rotor shaft, like on an Enstrom. Is an Enstrom complicated?

SplineDrive

3rd Sep 2020, 04:20

I used to be a Sikorsky/X2 guy. I'm probably not at liberty to say the particulars but I'll say you have your harmonics wrong with respect to what was creating vibes and what wasn't.

For a 4 bladed rotor system, 4P blade loads create 4P vertical shears at the hub. 3P and 5P blade loads get converted to 4P vibratory moments in the fixed system. Depending on where particular blade natural frequencies lay, you can somewhat minimize some of these responses at the expense of increasing others. I, personally, would rather deal with a pure 4P vertical shear from the hub than 4P pitch or roll moments in the fixed system. 2P vibes should be low but can exist if there are tracking or stiffness differences between the blades.

Pretty sure I have the above general statements correct since they would apply to any 4 bladed rotor (and ignoring higher harmonics). The X-2D, S-97 Raider, and SB>1 all have different hub and blade configurations. It’s not a given that the tuning and harmonic airloads across all three ships are identical, despite being 4 blades each. In fact, looking at the respective hub designs in patent art, I’m pretty sure they’re not identical. So the X-2D experience might not entirely translate to the larger ships.

The Sultan

3rd Sep 2020, 04:45

Ifmu Wrote:

I have no knowledge of Raider or Defiant, but they got it working for X2. I personally don't see any reason why it wouldn't work for the new aircraft. They have excellent dynamics people, not just in theory but supporting the aircraft in the field and in the air.

The X-2 was a tiny concept demonstrator with an occupied area of around 5 feet on the center line. It is simplistic to get that small of an area smooth in only one direction and at one frequency such as N/rev. The problem becomes significantly harder trying to suppress vibration over a large three dimensional space, which the last S-97 pilot report I saw says they have failed at. In fact the pilot quotes indicated the vibration (and loads?) were so bad that the crew were reluctant (note I didn’t say scared) to go above 180 knots once it became obvious the latest cure for vibration being tested did not meet expectations. As the 97 still appears to be restricted to 180 knots for even high profile demos they apparently failed to overcome the issue.

IFMU

3rd Sep 2020, 17:32

Until they achieve and demonstrate a single promised performance metric, or even allow a non-company pilot in the thing to objectively assess the vibration, I would say the jury is still firmly out on that one.

https://www.verticalmag.com/news/army-pilot-flies-sikorsky-s97-raider/?utm_source=vertical-daily-news-top-story&utm_campaign=vertical-daily-news&utm_medium=email&utm_term=top-story&utm_content=V1

SplineDrive

3rd Sep 2020, 19:07

https://www.verticalmag.com/news/army-pilot-flies-sikorsky-s97-raider/?utm_source=vertical-daily-news-top-story&utm_campaign=vertical-daily-news&utm_medium=email&utm_term=top-story&utm_content=V1

53 knots below Raider’s target speed w/o pylons/weapons installed, but an important milestone for Sikorsky. Thanks for the link.

CTR

3rd Sep 2020, 21:09

When I first saw the article, I was expecting that a customer pilot was finally flying the SB>1 Defiant. I can’t quite understand all the hype for an Army customer Pilot flying the S 97. I would’ve expected this to have already occurred years ago.

The article did note that an Army customer Pilot flew the V-280 back in February 2018. Would have enjoyed reading an article comparing the handling qualities of the two aircraft by the same pilot.

The Sultan

4th Sep 2020, 14:22

From Sans earlier:

Seems Sikorsky's own demonstration flights have implied that. After reaching barely over 200 kt in Sept 2018, they subsequently have flown progressively slower in their big-to-do demo flights - only reaching 190 kt in July 2019 and then 180 kt in Feb 2020. And of course, nothing since then at all.[/color]
]

From above article:
Raider achieved 187 knots, well in excess of the Army’s threshold speed for FARA.

Unless I missed a revision, the FARA min max speed was 180 knots. In what fuzzy world is 187 knots (+4%) considered well in excess of that requirement? In my world that difference is considered barely outside allowed measurement error. I know the commercial requirement is to demonstrate 10% margin to an never exceed airspeed limit, so they are (in their world) grossly short of the 198 knots required to get credit for being able to do 180 knots.

Sikorsky really needs better PR people. The speed thing is bad enough, the I not letting the Army sit at the real controls (paraphrasing) is worse. Implies that the 97 is not the easiest thing to fly. Wonder if their scared the Army pilot be slightly aggressive on the controls ending up in another collision between the rotors.

SansAnhedral

8th Sep 2020, 15:48

https://www.verticalmag.com/news/army-pilot-flies-sikorsky-s97-raider/?utm_source=vertical-daily-news-top-story&utm_campaign=vertical-daily-news&utm_medium=email&utm_term=top-story&utm_content=V1

Firstly, that was not a flight of (an actual FVL aircraft) Defiant. Secondly, I must have missed the part in there where Charlie was permitted to make a single comment about the Raider flight (specifically the vibration). The fact it was explicitly mentioned that he was muzzled about the experience is telling.

When I first saw the article, I was expecting that a customer pilot was finally flying the SB>1 Defiant. I can’t quite understand all the hype for an Army customer Pilot flying the S 97. I would’ve expected this to have already occurred years ago.

The article did note that an Army customer Pilot flew the V-280 back in February 2018. Would have enjoyed reading an article comparing the handling qualities of the two aircraft by the same pilot.

It's definitely eyebrow raising that it took over 5 years for a pilot to set foot into the S-97. The V-280 had the Army XP flight 2 months after first flight!

Commando Cody

9th Sep 2020, 21:22

Firstly, that was not a flight of (an actual FVL aircraft) Defiant. Secondly, I must have missed the part in there where Charlie was permitted to make a single comment about the Raider flight (specifically the vibration). The fact it was explicitly mentioned that he was muzzled about the experience is telling.

It's definitely eyebrow raising that it took over 5 years for a pilot to set foot into the S-97. The V-280 had the Army XP flight 2 months after first flight!

The V-280 has had multiple guest pilots including, I believe, four Army. It's like they did decades ago with the XV-15, including at least one Senator.

CTR

10th Sep 2020, 01:04

Before it was sent to the Smithsonian Air and Space Museum, the actor Harrison Ford flew the XV-15. Maybe he will be the next V-280 guest pilot ;-)

CTR

29th Sep 2020, 02:02

SplineDrive

30th Sep 2020, 16:55

I thought the Army wanted the FLRAA to have a top speed of 250 knots, and potentially up to 280 knots. However I was advised today that the Army was dropping the requirement down to 230 knots. Can any one confirm?

Honestly, other than that Sikorsky press/media day, I can’t find an official looking requirement for 230 knots. Everything I can find says 250 knots as a threshold speed and 280 knots as objective. Has the Army given them a lower bar to clear?

IFMU

15th Oct 2020, 01:46

Defiant at 211 kts s&l, 232 in a descent, 2/3 prop torque.
https://news.yahoo.com/amphtml/sb-1-defiant-coaxial-demonstrator-131114297.html

https://youtu.be/cNszG1Sefss

CTR

15th Oct 2020, 14:43

Thanks IFMU,

In the article text was my earlier question answer:

”WASHINGTON — The Sikorsky-Boeing developed SB-1 Defiant coaxial demonstrator (https://www.defensenews.com/land/2020/02/20/defiant-raider-and-sara-fly-together-in-first-public-demo/)aircraft hit 232 knots in a descent, and 211 knots in straight and level flight, meeting the U.S. Army’s speed requirements for its future long-range assault aircraft it plans to field by 2030.”

However I believe any new lower speed requirement of 230 Kts would be in level flight, not in descent.

IFMU

15th Oct 2020, 14:51

At 2/3 power and 211 kts S&l, I'd project 258 kts max s&l.

SansAnhedral

15th Oct 2020, 15:15

At 2/3 power and 211 kts S&l, I'd project 258 kts max s&l.

Interesting extrapolation using only one data point.

Lets establish a curve based upon Sikorsky's own statements:

https://www.janes.com/defence-news/news-detail/sb1-defiant-reaches-new-top-speed-of-205-kt-in-flight

The Sikorsky-Boeing SB>1 Defiant coaxial helicopter on 9 June reached a new top speed of 205 kt in flight while using less than 50% of the installed propeller power.

https://www.defensenews.com/digital-show-dailies/ausa/2020/10/14/sb-1-defiant-coaxial-demonstrator-aircraft-hits-230-knots

211 knots in straight and level flight...the aircraft was using about two-thirds prop torque and engine power to achieve the speeds.

So that's 205 kt @ "less than" 50% power, followed by 211 kt @ 66% power, which would yield a best case blistering 224 kt at MCP (empty)

The Sultan

15th Oct 2020, 15:42

So that's 205 kt @ "less than" 50% power, followed by 211 kt @ 66% power, which would yield a best case blistering 224 kt at MCP (empty)

And 4 months to go 6 knots faster. So basically at this blistering pace of development we can expect MCP in 8 months.

IFMU

15th Oct 2020, 16:47

So that's 205 kt @ "less than" 50% power, followed by 211 kt @ 66% power, which would yield a best case blistering 224 kt at MCP (empty)
So - you are using a linear relationship between power and speed? Care to explain?

My quick estimate was by the square root of the increase of power. Also how do you know the weight? Any flight test program I've been involved with at Sikorsky has never been anywhere near empty weight.

IIRC you said you were a key player on the X2, which means you know the effect weight has on speed for an X2 rotor.

Edit: my bad, you said you did a bit on X2. So maybe you don't know.

SplineDrive

15th Oct 2020, 17:32

I don’t really think the data from press releases is sufficient to build any sort of credible speed-power polar, even for trash-talking purposes. The time required to advance another 6 knots is a legitimate issue, though. Makes me wonder if the 205 knot speed claim earlier was actually in a descent as well.

IFMU

15th Oct 2020, 18:03

SansAnhedral

15th Oct 2020, 18:21

So - you are using a linear relationship between power and speed? Care to explain?

You're right. Assuming linear was probably being generous on a fuselage+rotor like SB1.

https://iili.io/3HsAZJ.png

Even the hotrod low drag/FE X2TD fuselage power required slopes up with airspeed on the upper end of the envelope

IIRC you said you were a key player on the X2, which means you know the effect weight has on speed for an X2 rotor.

Edit: my bad, you said you did a bit on X2. So maybe you don't know.

Most definitely not a key player on X2. However I do have a copy of AGARDograph 197 on my desk at the moment.

Commando Cody

17th Oct 2020, 01:06

Interesting extrapolation using only one data point.

Lets establish a curve based upon Sikorsky's own statements:

https://www.defensenews.com/digital-show-dailies/ausa/2020/10/14/sb-1-defiant-coaxial-demonstrator-aircraft-hits-230-knots

So that's 205 kt @ "less than" 50% power, followed by 211 kt @ 66% power, which would yield a best case blistering 224 kt at MCP (empty)

Fascinating discussion so far; there's something in the Defense News article that puzzles me: "...232 knots in a descent, and 211 knots in straight and level flight, meeting the U.S. Army’s speed requirements for its future long-range assault aircraft..."

How does "...232 knots in a descent and 211 knots in straight and level flight..." meet FLRAA requirements? Am I missing something"?

SplineDrive

17th Oct 2020, 16:33

How does "...232 knots in a descent and 211 knots in straight and level flight..." meet FLRAA requirements? Am I missing something"?

It doesn't and to Lockheed's credit, I don't think they have officially claimed it does, but some journalists have gotten "excited" about the 232 knot value.

CTR

17th Oct 2020, 19:24

Has Lockheed or Boeing recently advertised how many total flight hours the Defiant has accumulated to date?

SplineDrive

18th Oct 2020, 04:14

Has Lockheed or Boeing recently advertised how many total flight hours the Defiant has accumulated to date?

i read 23 hours in one of this week’s articles.

CTR

18th Oct 2020, 17:52

i read 23 hours in one of this week’s articles.

Thank you SplineDrive for the information. But is that information from a recent press release? It’s been 17 months since first flight.

Commando Cody

18th Oct 2020, 19:50

Thank you SplineDrive for the information. But is that information from a recent press release? It’s been 17 months since first flight.

Actually, in three days it'll have been 19 months. On August 28 SansAnhedral posted a quote from Graham Warwick (a reliable source) indicating that SB>1 had flown 20 hours. So given the nearly two months that have elapsed since then, three more hours would be in line with its average flight rate (actually it's somewhat better than their average rate) since first flight.

The Sultan

18th Oct 2020, 19:53

From above article:

Defiant was close to hitting the 230-knot goal in June when it reached a speed of 205 knots (https://www.defensenews.com/land/2020/06/16/the-experimental-sikorsky-boeing-defiant-helicopter-hit-a-new-speed-milestone/). The demonstrator hit 100 knots in January (https://www.defensenews.com/land/2020/01/17/defiant-exceeds-100-knots/).

Again the PR department falls down, in what world is 205 kts close to 230? Time to rename the Defiant BS-1. Also, in one of the articles it’s claimed they fly on average once a week, so 16 flights since the June 205 knot flight if they are to be believed.

With the four months between press releases I have pondered what serious problems are crippling the program. When one of the pilots commented that the June-ish test card called for a 30 degree bank, but they did 45 degrees instead I suspected flight control issues (no competent flight test pilot would intentionally miss the targeted bank angle that much). Four months is about right for a flight control software mod so that accounts for one of the claimed sixteen flights. We know the S-97 top speed has been reduced to the 180 to 200 kt range by excessive drag and brutal vibration. It is a safe bet one or both of these are issues they are having to address as they are minimizing the FLRAA requirements to avoid outright cancellation.

Any one want to give odds on another press release this year?

Commando Cody

18th Oct 2020, 20:52

Actually Sultan, maybe we should be giving props to the PR department rather than denigrating them. Their job is to promote the company's interests and put the best spin on what's going on. Their job is to keep accomplishments in front of the audiences' and customers' eyes. They really haven't been given a lot to work with here and so they're doing the best they can with what they have.

SplineDrive

18th Oct 2020, 23:13

Any one want to give odds on another press release this year?

Put me down for another press release in mid-December highlighting the hundreds of ground turn hours accumulated on the test beds and "thousands" of hours of simulations in various integration labs as totally validating the design. Probably a mention of a 220 knot level flight achievement, too. Unless of course, the Army lowers the FLRAA requirements further, in which case we'll hear breathless claims of meeting all requirements and being the next step in Army aviation.

The Sultan

19th Oct 2020, 19:47

Commando Cody

21st Oct 2020, 04:37

Spline,

Current progress would indicate 214 knots by end of the year. As you are aware they have gotten all of the easy knots. Bell is probably in a similar position on the V-280 except their baseline is starting at 300 Kts+.which they reached a long time ago.

One minor note, unless I'm misunderstanding your context: Bell's promise was 280 knots (hence the name of the craft). They made that some time ago, and have since gone well beyond to over 300 knots.

SplineDrive

27th Nov 2020, 14:48

The Sultan

31st Dec 2020, 19:33

https://verticalmag.com/news/defiant-roars-through-flight-test-milestones-2020/

More gaslighting from the Sikorsky-Boeing PR team. Apparently their definition of roaring through milestones are:

1. Flying only 26 hours in 20 months at the most benign gross weight/cg.
2. Achieving a pathetic top speed in level flight of 211 knots against an original target of near 250 knots (later reduced to 230 knots which they still could not achieve).
3. Not flying any gross weight/altitude/range expansion flights.

They also state the team is putting "the final touches on an official pitch to replace the U.S. Army’s long-serving UH-60 Black Hawks." So they admit they have completed all they can do with the SB-1, even though they were given a govt funded one year extension to the FLRAA demo program deadline to try to make it appear they were a viable alternative to the 300Kt++ Bell V-280, It appears their plan is to lobby the Army to water down the FLRAA speed/range requirements so much that even the SB-1 could meet them. If that fails I expect them to no bid the program and try to get FLRAA cancelled because there are not two competing for the development contract.

SplineDrive

1st Jan 2021, 13:48

CTR

1st Jan 2021, 14:24

Robbo Jock

1st Jan 2021, 15:23

Rather worryingly it appears that sensibility and trust in science took a precipitous nosedive in 2020. I'm certainly with you in your hope but extremely worried about what will actually happen.

etudiant

1st Jan 2021, 17:34

Interesting that despite the S-97 being promoted as a test bed for it’s bigger brother the SB>1, it has only accumulated 93 flight hours. So the two X2 technology aircraft combined have only 119 flight hours, compared to over 200 hours on the Bell V-280.

I fear that politics and the changing world post COVID may make a bigger difference in the future of FVL than the obvious technical maturity benefits of the V-280.

Let us all hope that sensibility and trust in science prevails in 2021.

Fact is that reality is what Washington decides it is.
I just see two very expensive, very large bits of complex gear, neither of which appears fit for the purpose. They are too big to do recon and too fragile to do combat.
The idea of helicopters massed to defeat tank armies is dead as a dodo, as was demonstrated in the recent Armenia/Azerbaijan war.
Aging a dumb idea does not make it smarter.

CTR

1st Jan 2021, 19:12

Fact is that reality is what Washington decides it is.
I just see two very expensive, very large bits of complex gear, neither of which appears fit for the purpose. They are too big to do recon and too fragile to do combat.
The idea of helicopters massed to defeat tank armies is dead as a dodo, as was demonstrated in the recent Armenia/Azerbaijan war.
Aging a dumb idea does not make it smarter.

Both the SB>1 and the V-280 primary mission is troop transport. As long as soldiers need to get in and out of battle, this mission is not going away.

The Raider and Valor (correction Raider-X and Invictus) are being designed for recon and attack. I concur, that mission may soon be made obsolete by unmanned technology.

Copter Appreciator00

2nd Jan 2021, 02:12

[QUOTE=CTR;10958698]Both the SB>1 and the V-280 primary mission is troop transport. As long as soldiers need to get in and out of battle, this mission is not going away.

The Raider and Valor are being designed for recon and attack. I concur, that mission may soon be made obsolete by unmanned technology.

No biggy, but you mean the Raider-X and the Bell 360 Invictus (hardly an easy-to-remember name)
I can't post URLs but like how the V-280 Valor transport flew autonomously in December 2019, the B360 will be built to accommodate pilot-less flight.

CTR

2nd Jan 2021, 13:27

No biggy, but you mean the Raider-X and the Bell 360 Invictus (hardly an easy-to-remember name).

Thanks for the correction. Should not reply to post after a long New Year’s eve. :-)

henra

6th Jan 2021, 08:08

Both the SB>1 and the V-280 primary mission is troop transport. As long as soldiers need to get in and out of battle, this mission is not going away.

The mission isn't going away but the question remains if they are not too expensive/complex, too big and too fragile for the mission.
The big plus of the Blackhawk for this mission is that it is extremely rugged, rather nimble and small and not excessively complex and expensive. Almost the opposite of the new vertical lift high speed platforms. The most dangerous phase for the helicopter in combat has historically been the landing/de- boarding phase. And that is the phase where especially the valor is a huuuuge and beautiful target with lots of critical parts widely spread and is also rather limited in its agility and descent rate compared to the nimble Blackhawk. I'm not really convinced that they are not going to cancel the current bid. For certain special missions the new platforms surely offer very interesting possibilities but I have a hard time to figure them as real replacement for the rugged 'bread and butter' combat mule that is the Blackhwak.

SplineDrive

6th Jan 2021, 12:01

The mission isn't going away but the question remains if they are not too expensive/complex, too big and too fragile for the mission.
The big plus of the Blackhawk for this mission is that it is extremely rugged, rather nimble and small and not excessively complex and expensive. Almost the opposite of the new vertical lift high speed platforms. The most dangerous phase for the helicopter in combat has historically been the landing/de- boarding phase. And that is the phase where especially the valor is a huuuuge and beautiful target with lots of critical parts widely spread and is also rather limited in its agility and descent rate compared to the nimble Blackhawk. I'm not really convinced that they are not going to cancel the current bid. For certain special missions the new platforms surely offer very interesting possibilities but I have a hard time to figure them as real replacement for the rugged 'bread and butter' combat mule that is the Blackhwak.

Both FLRAA competitors have agility requirements at the LZ similar to the UH-60 platform and the V-280 has demonstrated that capability. It also has the ability to rapidly drop from cruise to LZ and back to cruise again. Conversion isn’t a long, involved process and can be done in as little as 12 seconds on other tilt rotor platforms. The V-280 is a larger target than a H-60, but it’s exposure time near the LZ is less than an H-60 and widely separating critical components is an important aspect of system design.

Fact is, the H-60 cannot do the missions the Army has envisioned for FLRAA and a tilt rotor can. Of course, this is the SB>1 thread, so we should mention that vehicle, which in nearly two years of flying hasn’t reached Vh, so perhaps it’s not well suited to the missions, either.

SansAnhedral

6th Jan 2021, 14:57

is also rather limited in its agility and descent rate compared to the nimble Blackhawk.

Sorry, but this has been shown in flight testing to be demonstrably false.

Of course, Sikorsky also claims the same thing with Defiant, but over 5+ years of trickled flight testing neither it nor S-97 have demonstrated anything approaching even what the V-280 has done in YouTube videos or in front of public audiences.

chopper2004

25th Jan 2021, 13:11

Welcome to the Defiant X

https://www.youtube.com/watch?v=tVOzZnjVBww

cheers

The Sultan

25th Jan 2021, 16:33

Defiant X article.

https://verticalmag.com/news/defiant-x-is-the-meaner-pointier-sikorsky-boeing-pitch-to-replace-black-hawk/

From the article:

Defiant has logged 1,500 hours in Sikorsky’s systems integration laboratory (SIL), and 135 hours on the ground-based propulsion systems test bed (PSTB). After a rocky start, Defiant roared through a series of test milestones in 2020 (https://verticalmag.com/news/defiant-roars-through-flight-test-milestones-2020/).

In the two years since its first flight, the demonstration aircraft has performed 31 test flights, accumulating 26 total flight hours, according to the Defiant team.With two-thirds prop torque and engine power, Defiant has achieved 211 knots in straight-and-level flight and 232 knots during a descent (https://verticalmag.com/news/sb1-defiant-tops-230-knots-in-descent/).

While this may just be the article's author cherry picking past articles it confirms that SB has not released any updated information since June 2020. This seems to confirm no progress or flights (?) in six months. So what is wrong. If it was just drag keeping the top speed low they could have flown it to expand the GW/CG and ALT/TEMP envelopes which would gather meaningful data for any proposal and padded the flight hours to look less than the pathetically low 26 hours. I believe the demo was suppose to be at least 100 flight hours with the 280 demo ship good for at least a 200 flight hour campaign.. Giving up in doing anything since June when they needed to make substantial progress to even be a dark horse alternative to the 280 if Bell stumbled (which the Bell team didn't) points to a flight safety issue (or issues) that could not be overcome. Many have speculated high vibration, but in my experience pilot bonus money overcomes that issue. So we are looking at loads so high that catastrophic failure within a limited number of flights could occur or a danger the rotors could collide like what was already demonstrated on the S-97. It will be interesting to find out what metaphorically killed the SB-1 prototype.

SplineDrive

25th Jan 2021, 17:11

Defiant X article.

https://verticalmag.com/news/defiant-x-is-the-meaner-pointier-sikorsky-boeing-pitch-to-replace-black-hawk/

From the article:

While this may just be the article's author cherry picking past articles it confirms that SB has not released any updated information since June 2020. This seems to confirm no progress or flights (?) in six months. So what is wrong. If it was just drag keeping the top speed low they could have flown it to expand the GW/CG and ALT/TEMP envelopes which would gather meaningful data for any proposal and padded the flight hours to look less than the pathetically low 26 hours. I believe the demo was suppose to be at least 100 flight hours with the 280 demo ship good for at least a 200 flight hour campaign.. Giving up in doing anything since June when they needed to make substantial progress to even be a dark horse alternative to the 280 if Bell stumbled (which the Bell team didn't) points to a flight safety issue (or issues) that could not be overcome. Many have speculated high vibration, but in my experience pilot bonus money overcomes that issue. So we are looking at loads so high that catastrophic failure within a limited number of flights could occur or a danger the rotors could collide like what was already demonstrated on the S-97. It will be interesting to find out what metaphorically killed the SB-1 prototype.

Looking back at this thread, there were some flights between summer (20 hrs) and October (23 hrs), and a few more at the December (26 hrs) articles. None in Jan so far. So it’s not quite as bad as “Giving up in doing anything since June” but definitely as sign that something isn’t well. We can all speculate, but there are several likely issues, some of which you’ve identified. In any case, it’s ballsy to ask the USG for billions to develop a production aircraft based on two demonstrators that, if we’re being honest, haven’t met their design goals. There is something wrong with the aircraft concept, the design execution, or both.

As for Defiant-X, the RAH-66 exhaust is interesting... that’s a lot of mass flow in some long ducts. The hubs looks radically smaller than on SB>1, though their success in sweet talking the Army down on speed would allow for lower hub loads and smaller structure. Or it’s just fanciful artwork.

etudiant

25th Jan 2021, 17:28

Both FLRAA competitors have agility requirements at the LZ similar to the UH-60 platform and the V-280 has demonstrated that capability. It also has the ability to rapidly drop from cruise to LZ and back to cruise again. Conversion isn’t a long, involved process and can be done in as little as 12 seconds on other tilt rotor platforms. The V-280 is a larger target than a H-60, but it’s exposure time near the LZ is less than an H-60 and widely separating critical components is an important aspect of system design.

Fact is, the H-60 cannot do the missions the Army has envisioned for FLRAA and a tilt rotor can. Of course, this is the SB>1 thread, so we should mention that vehicle, which in nearly two years of flying hasn’t reached Vh, so perhaps it’s not well suited to the missions, either.

Whatever the SB-1 situation, the mission the Army envisions may also be less than realistic. The US Army has a history of poorly conceived requirements, which have resulted in very expensive but only marginally useful hardware.

The Sultan

25th Jan 2021, 18:21

Spline noted:

Looking back at this thread, there were some flights between summer (20 hrs) and October (23 hrs), and a few more at the December (26 hrs)

You are correct I falsely attributed the 211 knots speed to the 205 kt June press release. I am sure the customers have taken note of the great advancements made from June to October. Now the question is what did they do from October to December. In one article they stress how great the Defiant is at sling loading and that tilt rotors have minimal sling loading capability. Have I missed a video of Defiant with a sling load? I saw the 280 sling load demo and know the V-22 has a very significant high speed sling capability. In fact the V-22 sling speed capability exceeded a Humvee’s ability to withstand it. If SB is betting on slinging as a winning differentiation between Defiant and the 280 they are definitely on losing path.

SplineDrive

9th Mar 2021, 20:50

So, according to FlightRadar24, V-280 (N280BH) is back in flight status having gone out for flights a couple of times this month. Still nothing on SB>1 (N100FV). Are there even any rumors that Defiant is still flying? Or is she grounded and done, never having reached Vh? If so, that’s a worse miss on cruise speed than Raider. Wonder what they’re doing different for Raider-X?

Commando Cody

11th Mar 2021, 06:24

Any day now, I expect the SB>1 team to excitedly put out a press release that proudly proclaims as one of their accomplishments in the two years since their first flight that their vehicle has required far less fuel than the V-280.

Commando Cody

11th Mar 2021, 06:33

The mission isn't going away but the question remains if they are not too expensive/complex, too big and too fragile for the mission.
The big plus of the Blackhawk for this mission is that it is extremely rugged, rather nimble and small and not excessively complex and expensive. Almost the opposite of the new vertical lift high speed platforms. The most dangerous phase for the helicopter in combat has historically been the landing/de- boarding phase. And that is the phase where especially the valor is a huuuuge and beautiful target with lots of critical parts widely spread and is also rather limited in its agility and descent rate compared to the nimble Blackhawk. I'm not really convinced that they are not going to cancel the current bid. For certain special missions the new platforms surely offer very interesting possibilities but I have a hard time to figure them as real replacement for the rugged 'bread and butter' combat mule that is the Blackhwak.

One of the requirements for FLRAA is that the aircraft has to to be able to fit the same number of their craft into a given space as the UH-60.. Both competitors meet this requirement. Another is that they have to meet the agility requirement. In some areas V-280 has already demonstrated that it exceeds thisrequirement. I don't know about SB>1 yet.

Commando Cody

13th Mar 2021, 05:11

FWIW, here's a comparison of the footprint of the V-280 vs. UH-60

https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/917x778/v280uh60_53b3118c3e55462f3a44f9780a6c9d095f2b39fe.jpg

CTR

17th Mar 2021, 02:22

The FLRAA RFP responses are due in less than three months. Isn’t time running out for the SB>1 to prove it can meet the US Army threshold requirements?

Commando Cody

19th Mar 2021, 05:00

The FLRAA RFP responses are due in less than three months. Isn’t time running out for the SB>1 to prove it can meet the US Army threshold requirements?

For some reason, Army has been going through all kinds of gyrations to keep Lockheed & Boeing in the competition despite its consistently disappointing performance (although they do get points for creative press releases). SB>1 was built for the "technology demonstration" phase. One wonders, in the two years since its [delayed] first flight and having only flown ~26 hours how much technology has actually been demonstrated The next phase is "risk reduction". This is what Defiant-X is being touted for, After that comes the competition to actually go to production.

I guess they're not going to do that much more with the SB>1 airframe. The consensus here seems to be that it'll never reach its promised speeds. I don't know, but then again S-97 Raider (to be replaced by "Raider-X") never reached its promised speed, either. I wonder if Army is thinking that if they don't have two "competitors" regardless of how they're doing, Congress, not paying attention as usual, will complain about the lack of competition and that could hurt funding.

CTR

19th Mar 2021, 14:14

....The next phase is "risk reduction". This is what Defiant-X is being touted for, After that comes the competition to actually go to production....

I didn’t think it was going to be another competition of flight demonstrators. Isn’t the next competition phase just a proposal?

etudiant

19th Mar 2021, 17:06

The FLRAA RFP responses are due in less than three months. Isn’t time running out for the SB>1 to prove it can meet the US Army threshold requirements?

Apart from some US Army bureaucrats, I don't think anyone cares.
The Biden administration is trying to come up with a coherent approach to China without breaking too many eggs. It is obvious the Afghanistan withdrawal will be prelude to a mess at best.
After the very public failure in this small arena, no one can trust the Pentagon claims about their strategy for deterring China.
The US needs a 'come to Jesus' moment, to admit they have not won a war in 75 years and that more of the same will only stretch that string to a century or more.
Hopefully the Biden team will catch on before the NATO allies do.

Commando Cody

19th Mar 2021, 19:12

I didn’t think it was going to be another competition of flight demonstrators. Isn’t the next competition phase just a proposal?

The phase they''ve been in for the past year is the Competitive Demonstration and Risk Reduction, for which Bell got $84 million and Sikorsky got $97 million, which will “include initial conceptual designs, requirements feasibility and trade studies using model based systems engineering", In other words, they are spending almost as much time analyzing the data they got from the JMR-TD phase (in which SB>! barely flew) as the entire length of that first phase! "Ultimately, this information and industry feedback are vital to understanding the performance, cost, affordability, schedule risks and trades needed to successfully execute the FLRAA program". This will, “will inform the refinement of the capability requirements, system performance specification and identify risk areas.” Translation: "We're going to push lots of paper so we don't get protested too much". Not sure if there will be any required flying during this phase. Frankly, though, unless they can get some serious flying in, even at their own expense, I don't see how the selection could go to Sikorsky-Boeing

After this phase comes the actual request for Best and Final Offers and selection scheduled (for now) in 2022. Then there will be more design reviews, and reviews, until delivery of the prototype of the winning design in 2025, and delivery to the first Army unit in 2030. No I don't know why the Army wants it to take so long.

SplineDrive

22nd Mar 2021, 12:12

After this phase comes the actual request for Best and Final Offers and selection scheduled (for now) in 2022. Then there will be more design reviews, and reviews, until delivery of the prototype of the winning design in 2025, and delivery to the first Army unit in 2030. No I don't know why the Army wants it to take so long.

I think the Army sees keeping both V-280 and SB>1 funded during the current concept development and risk reduction phases as political cover and investment to make sure no one can protest that it wasn't a good competition when V-280 is chosen next year, despite Bell not being the incumbent VTOL supplier for the Army. Next year will be crucial for the X-2 concept... I'm assuming SB>1/Defiant-X will stop work and all X-2 hopes and dreams get pinned to Raider-X. If that thing can't have first flight on schedule and make Vh in a reasonable amount of time (less than two years, lol) then it's toast and so is the X-2 platform. A decades' worth of engineering effort and a ton of money for zero return.

Commando Cody

25th Mar 2021, 05:27

Interesting tidbit I missed before... when Sikorsky Boeing unveiled Defiant-X in January, they said it was optimized for, "...speed where it matters". To me that seems to say, "No, we won't be as fast as we said we would be, but it's not important anyway. Pay no attention to that man behind the curtain". What they seem to be trying to push everyone to focus on is how fast they promise they will be able to decelerate from whatever speed they do achieve while staying in a level attitude (have they actually demonstrated that in the nearly six years since S-97 first flight?) by putting the pusher in Beta.

Or am I reading too much in?