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-   -   Sikorsky SB-1 flies for first time (https://www.pprune.org/rotorheads/619699-sikorsky-sb-1-flies-first-time.html)

SansAnhedral 20th Apr 2022 21:03


Originally Posted by JohnDixson (Post 11218458)
RePost 407:
I note the V-280 has already demonstrated that it at least meets the Army's FLRAA low speed agility requirements, which exceed that of Huey and Black Hawk while as yet Defiant has not.”
Can you be specific and pass along where the 280 is more maneuverable than the UH-60? Weight, speed pitch rate/roll rate/yaw rate etc.
Thanks.

https://cimg5.ibsrv.net/gimg/pprune....8b65cb57b3.png


Bell claimed that V-280 demonstrated Level 1 handling qualities in pitch, roll, and yaw. The compilation video below (among many others including public airshow performances) appears to confirm these statements. Actual rate values have not been made public.


Sikorsky claimed that SB1 demonstrated Level 1 handling qualities in slalom, with a video showing a slalom maneuver (note at 60-100 knots, not in a hover). To date they have showed zero footage of any actual hovering maneuvers, despite almost literally all of their marketing making heavy references to "agility at the X" and "low speed maneuverability".


Commando Cody 21st Apr 2022 05:16


Originally Posted by SplineDrive (Post 11218334)
https://www.army.mil/article/252221/...ly_sb1_defiant

Army XPs flew Defiant late last year, or is this the "non-company person" piloting an X2 you're referring to?


https://cimg2.ibsrv.net/gimg/pprune....85e8529913.jpg

Boy, am I embarrassed! Since Sikorsky usually puts out a triumphant press release if they successfully inflate a tire on the SB>1, I got lazy and didn't look hard enough. The 2020 situation I was referring to was in the S-97.

The referenced article refers to a September 2020 article about Army test pilots flying the V-280 that states, "Similar flights are scheduled later this year for the Sikorsky-Boeing SB>1 Defiant". Well, they missed that one by nearly a year. FWIW, the first time an Army guest pilot flew the V-280 was in February, 2018, less than two months after Valor's first flight.

Commando Cody 21st Apr 2022 05:24


Originally Posted by JohnDixson (Post 11218458)
RePost 407:
I note the V-280 has already demonstrated that it at least meets the Army's FLRAA low speed agility requirements, which exceed that of Huey and Black Hawk while as yet Defiant has not.”
Can you be specific and pass along where the 280 is more maneuverable than the UH-60? Weight, speed pitch rate/roll rate/yaw rate etc.
Thanks.

The reports are that V-280 has met of exceeded of the JMR KPPs, and Army has stated from the beginning that those agility requirements exceed those the UH-60 is required to meet. I don't know if actual hard numbers achieved will be available until after final selection since they are competition sensitive so I suspect everyone is going to talk in somewhat genreal terms until then.

Commando Cody 21st Apr 2022 05:39


Originally Posted by SASless (Post 11218355)
The Sikorsky view.....which towards the end of the article the question about if there is room for/need for the Tiltrotor and the new Sikorsky designs.....and the Sikorsky VP suggests that is the case....there is he says.

He qualifies his statement by offering a couple of criteria that should be used in making the distinction between the two concepts.

The question then becomes....how does the DOD make those decisions.....what factors should they use to score the Pro's and Con's of the two different aircraft designs?

https://www.thedrive.com/the-war-zon...gram-officials


An illustration of how things change as more is learned is in that article. In 2019 the Vice President, Sikorsky Innovations stated, "There is significant international and commercial interest in the technology. It will be interesting to see what fraction of traditional helicopter applications transition to this capability.". But in 2022 at the recent Heli-Expo Conference, Sikorsky's Vice President of Global Military and Commercial Systems stated, “We initially thought we would have to apply that to everything. But the benefit of what that brings in terms of agility is not so important in the commercial space. Speed is nice but from an overall efficiency perspective we don’t think it’s the right thing for commercial".

Commando Cody 21st Apr 2022 05:53


Originally Posted by SASless (Post 11218015)
What about CH-53's, CH-47's, UH-60's with AAR capability....they would have been able to make the same flight perhaps with more refuels along the way depending upon whether they had extra tankage installed.


One difference is that in the cases of CH-53s prior to the E, CH-47s and UH-60s, AAR is a modification applied in special models for special missions, whereas with the V-22 AAR capability/ operation was always intended as a normal capability/operation. it's the basis for its "self deployment" option. I also don't know if Chinook and Black Hawk can refuel from KC-135/10/46.


https://cimg0.ibsrv.net/gimg/pprune....15cec5c18c.jpg


JohnDixson 21st Apr 2022 12:51

Re CC Post 423. Comment: the low speed agility requirements in existence when the UTTAS requirements were published might have been met by the UH-1! But there were other maneuverability requirements that were more demanding, and of course meeting those led to a vastly more capable low speed aircraft. Let me be direct: there is no way that sideways tandem can outmaneuver the UH-60 at slow speed.
Just a follow-up: Sans posted the new ADS-33 handing requirements, and I wonder which category applied to the 280, if anyone knows.
I should add: every helo configuration brings with it some compromises. That is true for the single rotor as well as the tandem, be it fore/aft or lateral. My comment re the low speed maneuverability comparison is not a shot at the Bell designers-they are good troops-its simply noting the fallout of the relative compromises one inherits with the selected configuration.

SASless 21st Apr 2022 13:58

The Bell view of the situation.....I forgot to have some popcorn and soda pop ready for the video viewing as it were such a HOOAH moment!





https://www.thedrive.com/the-war-zon...trotor-systems

JohnDixson 21st Apr 2022 16:12

Re CC Post 425:

Just some additional information re the refueling/self-deployment ability question. The original Army plans for deployment to Europe involved a lot of UH-60’s and there was/is a limit to USAF transport space.
Therefore the Army requested a design for self deployment after the original production was started, and the result of that was the ESSS ( External Stores Support System ). ( Their thinking involved other possible uses of the ESSS “ wings ). The original configuration was two inboard 450 gallon tanks and two outboard 230 gallon tanks. Taking off at 24,500 lbs, they had enough fuel to fly from Newfoundland to the Azores.

SASless 21st Apr 2022 16:33

Osprey....2100 Nautical Mile. Range....with just one in-flight refuel?

"The US Marine Corps are preparing to complete the first transatlantic flight of a tilt-rotor aircraft in July 2006, after a successful practice flight of the MV-22 Osprey in June 2006. The Marine Tiltor Operational Test and Evaluation Squadron will fly two MV-22 Ospreys along with two KC-130J tanker aircraft for refueling from Goose Bay, Newfoundland to the UK in mid-July 2006. The aircraft will be turned over to manufacturer BellBoeing for participation in the Royal International Air Tattoo and Farnborough air shows to be held in July. One of the key performance parameters identified by the marine corps for the MV-22 is the ability for the aircraft to fly 2,100 n miles with only one refilling. The primary purpose of the transatlantic flight in July is to practice co-ordinating the MV-22 aircraft with the tankers and not to test an already proven ability of the aircraft to go the distance on one refueling.".

Does it have the ability to carry internal Aux Tanks now?

Certainly under wing tanks could pose an engineering design problem.

The Valor design cures that problem by its new design.

SplineDrive 21st Apr 2022 18:21


Originally Posted by JohnDixson (Post 11218850)
Re CC Post 423. Comment: the low speed agility requirements in existence when the UTTAS requirements were published might have been met by the UH-1! But there were other maneuverability requirements that were more demanding, and of course meeting those led to a vastly more capable low speed aircraft. Let me be direct: there is no way that sideways tandem can outmaneuver the UH-60 at slow speed.
Just a follow-up: Sans posted the new ADS-33 handing requirements, and I wonder which category applied to the 280, if anyone knows.
I should add: every helo configuration brings with it some compromises. That is true for the single rotor as well as the tandem, be it fore/aft or lateral. My comment re the low speed maneuverability comparison is not a shot at the Bell designers-they are good troops-its simply noting the fallout of the relative compromises one inherits with the selected configuration.

John, for what it’s worth, the V-280 video appears to show a 45 degree yaw maneuver in about 2 seconds, so ~22 deg/sec (I didn’t do a frame by frame level analysis). Based on the table Sans also posted, sounds like they’re shooting for Level 1 of the “Moderate Agility” classification. The “Aggressive Agility” class seems tailored for a scout aircraft. I don’t know what the UH-60 yaw rate in a hover is, but I recall a design requirement of 15 deg/s yaw in a 35 knot wind, so perhaps it’s 20-some odd deg/s in a no wind hover.

Yaw (and roll) inertia are certainly high on a tiltrotor, but Bell is clearly trying to address this by a large increase in flapping capability. Additionally, every pound removed from the nacelles is enhanced agility, so I’m sure the rotor, drive, and nacelle teams are feeling the steely-eyed gaze of the mass properties engineers.

Lonewolf_50 21st Apr 2022 21:15


Originally Posted by SplineDrive (Post 11218985)
I don’t know what the UH-60 yaw rate in a hover is, but I recall a design requirement of 15 deg/s yaw in a 35 knot wind, so perhaps it’s 20-some odd deg/s in a no wind hover.

It might be higher than that, or you might have nailed it.
For the CH-60S (which was based on the UH-60L) I find this limitation in an old NATOPS manual: Paragraph 4.5.6 (Prohibited Maneuvers) includes
Hovering turns at a rate in excess of 30° per second.
(TBH, that rings a bell in my memory from SH-60B days, less than 30° per sec for pedal turns, but that's been more than a couple of decades so I'm not gonna put any money on that).
Guessing the design spec was in that ball park, but they reduced the permitted envelope (as with ship landing envelopes) for normal operations.

JohnDixson 22nd Apr 2022 17:19

The USN qualification process* included a structural demonstration maneuver called “ Turn on a Spot “, the short description of which is: at a hover put in a pedal force of 180 lbs in each direction ( multiple maneuvers ) and after one complete turn put in an opposite pedal force of 180 lbs to stop the turn rate.
( One can suspect the lineage of this requirement by the 180 lb force requirement )
*Mil-D-23222
Anyhow, I can’t recall the max turn rate in either direction, but its higher than 30 deg/sec as the requirement actually results in a full pedal application and the control application time for all these maneuvers is written as 0.3 seconds. (Its better to be the pilot for all this stuff).

Structurally, the initial full right pedal turn produces the highest loads, concurrent with the application of full left pedal to stop the turn, and I think, but am not 100% certain that the limiting parameter for that full maneuver was the tail rotor torque “do not exceed” limit, which was not a static strength number but a fatigue strength number. The message then is, keeping the turn rates to 30 deg/sec and doing them at a frequency ( number of occurrences per so many flight hours ) will permit the tail rotor component lives to be within the stated number of hours.

I do not recall what the max turn rates for either direction were, but they were high. BTW,

There is another yaw maneuver required by both services ( with similar instructions from both ) and called a Dynamic Yaw Maneuver. Not related to this question, but send a PM and I will respond.

Commando Cody 22nd Apr 2022 18:15

SASless:

I believe that when necessary, the Osprey can carry up to three auxiliary tanks in the fuselage, each with an average of 428 gallons of usable fuel. Takes about 15 minutes to install/remove and they're crashworthy.

CTR 22nd Apr 2022 21:09


Originally Posted by Commando Cody (Post 11217064)
Now the way it was explained to me….

Here's a drawing of the Northrop-Grumman ATA proposal. Yes, it looks like a mini B-2, which shouldn't surprise anyone.


https://cimg7.ibsrv.net/gimg/pprune....fbd412cfd3.png

Now the way it happened, from the first hand account from a person who was there.

The Secretary of the Navy John Lehman, a former A-6 B/N, wanted to award the contract for the ATA replacement to the A-6 directly to his friends at Grumman. He ran into two problems however.

First problem, by 1985, Grumman had not won a clean sheet design contract since the F-14 in 1966. So Grumman had neither the technology or the engineering manpower for a conventional aircraft, let alone an stealth aircraft. The solution, team Grumman with Northrop who was building the B-2. Grumman took no convincing, since this was their last chance at remaining a prime contractor.

Second problem, a DOD contract this huge for an all new aircraft had to be a competitive bid. But what viable prime contractor would waste their engineering resources competing for a contract where the winner was already chosen? Both MCAIR and GD were viable prime contractors, and both had experience with stealth technology from IRAD and CRAD work (but not to the same level as Lockheed and Northrop). But both MCAIR and GD were in direct competition against each other for the ATF (to become YF-22 and YF-23). Not to mention decades of bad feelings from prior competitions. So MCAIR and GD had zero desire to compete on a ATA contract. Let alone team with each other.

Only under extreme pressure from the DOD and promises of future contracts did MCAIR and GD team for the ATA competition. From day one all the MCAIR and GD engineers knew they had no chance in hell of winning, unless the other team really screwed up. Which is what happened.

Arrogance by Grumman and Northrop management lead to them telling the Navy their specifications were wrong. To reduce development cost and risk, Grumman and Northrop proposed a scaled down B-2, like shown in your figure. However this results in a aircraft wing span with inadequate clearance to the carrier superstructure and other aircraft when using the aft deck for launch and recovery. Navy was not happy being told they could not use the aft deck on their carriers.

MCAIR and GD also had issues with the ATA specification, but they respected the Navy position and made recommendations of alternatives, crew seating is an example. The original ATA specification required side by side seating like the A-6. But this added width, drag, and created engine inlet distortion. A tandem seating configuration was best. But the old A-6 B/N Lehman wanted side by side. Once MCAIR and GD were awarded the contract, they were advised to change to tandem seating.

So the team that was never supposed to win, won. Not because of fixed price contract issues, but because they had the best technical solution to the specification. Grumman, failing to win the ATA contract, ceased to be a viable prime, and soon acquired by Northrop.

Why the A-12 contract was canceled, is a completely different and longer story.

Now bringing this back to the thread topic. What do we think is going to happen to Boeing Vertol if the Defiant is not chosen? It has been almost 40 years since they won the V-22 contract with Bell. Performing upgrades to the Chinook and Apache is not like doing a clean sheet design.



SplineDrive 22nd Apr 2022 23:47

What happens to Boeing Vertol is a good question, though I imagine they can make consistent money off supporting the AH-64 and CH-47 fleets for another generation and perhaps they have something cooking for whatever the heavy end of FVL becomes. I think your point is that not winning SB>1 hurts their ability to develop new products, but I’d argue that damage was done generations ago. The last clean sheet aircraft they developed all on their own was YUH-61 and even that had licensed MBB tech in the rotor system. BV is an agglomeration of other people’s old product support lines, not a full fat VTOL OEM.

CTR 23rd Apr 2022 00:41


Originally Posted by SplineDrive (Post 11219655)
I think your point is that not winning SB>1 hurts their ability to develop new products, but I’d argue that damage was done generations ago.

I agree fully.

Commando Cody 2nd May 2022 06:06


Originally Posted by SplineDrive (Post 11219655)
What happens to Boeing Vertol is a good question, though I imagine they can make consistent money off supporting the AH-64 and CH-47 fleets for another generation and perhaps they have something cooking for whatever the heavy end of FVL becomes. I think your point is that not winning SB>1 hurts their ability to develop new products, but I’d argue that damage was done generations ago. The last clean sheet aircraft they developed all on their own was YUH-61 and even that had licensed MBB tech in the rotor system. BV is an agglomeration of other people’s old product support lines, not a full fat VTOL OEM.

Picking a nit: What's in a name?

The name "Boeing Vertol" technically is no longer current. When Boeing bought the Vertol Company (which was formerly Piasecki) in 1960, they named the new Division "Boeing Vertol", or sometimes "Boeing Aircraft Company, Vertol Division" Then they changed it to "Boeing Helicopters" and then "Boeing Rotorcraft Systems". In 2002 it became the much more impressive sounding "Vertical Lift Division Boeing Defense, Space and Security". Of course, just to sow confusion, it still sometimes uses the older names. Image over substance?

Endorsing SplineDrive's note, Boeing-whatever has never put a helicopter of its own design into production. In fact, the four YUH-61/Model 179s it built were the only helos of its own design that ever even flew.

Been away for a bit. As might be inferred, I have a significantly different take on the A-12 than CTR (with whom I often agree). For example, the head of Lockheed's Skunk Works, said that the ATA specs and contract were so much trouble that Lockheed wanted no part of it and never attempted to get involved. When the much better A-X (renamed to) A/F-X program was launched, though, they were much more amenable and partnered on multiple teams. Since going on with that subject is s off topic, are people on this Forum interested?

CTR 2nd May 2022 14:23


Originally Posted by Commando Cody (Post 11223982)
Picking a nit: What's in a name?

The name "Boeing Vertol" technically is no longer current…..Endorsing SplineDrive's note, Boeing-whatever has never put a helicopter of its own……As might be inferred, I have a significantly different take on the A-12 than CTR (with whom I often agree). For example, the head of Lockheed's Skunk Works, said that the ATA specs and contract were so much trouble that Lockheed wanted no part of it and never attempted to get involved. When the much better A-X…..

Actually CC, I fully agree with all of your comments. As far as the Boeing Vertol name, I use that name out of homage more than anything else. I also continually call the Boeing St Louis facility, McBoeing for a similar reason.

Lockheed’s perspective of the ATA program is also spot on, from the Lockheed perspective. The Lockheed skunk works is used to writing their own contracts with the USAF. The NAVAIR ATA contract demanded an impossibility compressed development schedule, plus a max weight requirement based on customer furnished values for LO materials.

The ATA development schedule was impossibly compressed due to the need to race with existing USAF for rapidly shrinking DOD funds. The Soviet Union was rapidly falling apart, and many in the US government saw this as a opportunity for major reductions in DOD funding. Because of course, we would never need to worry about Russia as an adversary ever again.

To leverage existing LO material development funded by the DOD by Northrop and Lockheed, NAVAIR committed to providing this technology for ATA development to the winner. After The ATA contract was awarded, Both Lockheed and Northrop under a wink-wink from the USAF held up delivery of the technology to NAVAIR.

Bringing this back around to Helicopter’s. Why would a major prime enter into contract with impossible to meet requirements? Because that’s the way the game was played 40 years ago. Based on the US Army recently admitting that the FARA requirements are impossible to meet, nothing has changed.

Interestingly enough, I had the opportunity to briefly work on the AX program as a supplier to Grumman. A much smaller aircraft, with more reasonable specifications requirements, except for schedule. The AX program never went beyond the proposal stage, and the F-18 Super Hornet, now known as the E/F was developed as a low cost and risk alternative.

JohnDixson 2nd May 2022 16:11

CTR quote: “Bringing this back around to Helicopter’s. Why would a major prime enter into contract with impossible to meet requirements? Because that’s the way the game was played 40 years ago. Based on the US Army recently admitting that the FARA requirements are impossible to meet, nothing has changed.”
Great point. An observation from Army contract history: The UTTAS program RFP incorporated detailed requirements that essentially constituted a spec and throughout the competition changed nothing. The Comanche program was beset from early on with programmatic changes. In other words, the tech team and the leadership team that worked UTTAS wasn’t around for the Comanche. And why was there not a fly-off for Comanche?
I’m suggesting that the ills becoming evident in FARA are symptomatic of a larger, but resolvable problem, and the model is in their own files.

Commando Cody 3rd May 2022 08:02


Originally Posted by CTR (Post 11224143)
Actually CC, I fully agree with all of your comments. As far as the Boeing Vertol name, I use that name out of homage more than anything else. I also continually call the Boeing St Louis facility, McBoeing for a similar reason.

Lockheed’s perspective of the ATA program is also spot on, from the Lockheed perspective. The Lockheed skunk works is used to writing their own contracts with the USAF. The NAVAIR ATA contract demanded an impossibility compressed development schedule, plus a max weight requirement based on customer furnished values for LO materials.

The ATA development schedule was impossibly compressed due to the need to race with existing USAF for rapidly shrinking DOD funds. The Soviet Union was rapidly falling apart, and many in the US government saw this as a opportunity for major reductions in DOD funding. Because of course, we would never need to worry about Russia as an adversary ever again.

To leverage existing LO material development funded by the DOD by Northrop and Lockheed, NAVAIR committed to providing this technology for ATA development to the winner. After The ATA contract was awarded, Both Lockheed and Northrop under a wink-wink from the USAF held up delivery of the technology to NAVAIR.

Bringing this back around to Helicopter’s. Why would a major prime enter into contract with impossible to meet requirements? Because that’s the way the game was played 40 years ago. Based on the US Army recently admitting that the FARA requirements are impossible to meet, nothing has changed.

Interestingly enough, I had the opportunity to briefly work on the AX program as a supplier to Grumman. A much smaller aircraft, with more reasonable specifications requirements, except for schedule. The AX program never went beyond the proposal stage, and the F-18 Super Hornet, now known as the E/F was developed as a low cost and risk alternative.


If I may, a couple more notes confirming what you said. One of the things interesting about the ATA contract is that a lot of what went on wasn't known for years and only came out when all the lawsuits from both sides went to court. GD said the cancellation was a Termination for Convenience, which entitled them to recovery of some of the costs. Gov't said it was a Termination for Default, also known in some cases as a Termination for Cause, which meant the Contractor gets nothing and in some cases the Gov't gets some of its money back. During the discovery and testimony phases it came out that (I don't know what they were smoking) GD based their bid partly on the expectation that they would be provided data on Northrop's and Lockheed's test results and some of the particular techniques ways they used to achieve what they achieved. Both N and L responded at the time, "Uh, excuse me? Are you familiar with the meaning of the terms 'Proprietary Processes and Technology'"?. As far as the data on stealth in general that the Gov't itself owned, all of that was controlled by USAF. Now USAF wasn't too keen on potentially adopting another Navy aircraft but would rather develop their own aircraft and in any case, didn't want Navy to continue to be inveigled in long range attack, feeling that was one of their own missions and no one else should get to perform it. But they ah to appear to be playing the game. Sooo, they never actually refused to supply the data, but naturally they could only supply it to engineers and designers that could qualify for the stratospheric clearance level necessary to see and work with it. Now who do you think was the authority on who would qualify for such august access? What transpired is left as an exercise for the student.


With the end of the ATA and the upcoming retirement of the A-6, there was going to be too big a gap before the A-X could come on line. It was announced that the Super Hornet be procured as an "interim" aircraft to bridge that gap. Later A-X-A/F-X was canceled partly because USN was aware that the Bug/Super Bug and tremendous support in Congress and a bird in the hand...

"Why would a major prime enter into contract with impossible to meet requirements? Because that’s the way the game was played 40 years ago". Absolutely right. And then, as in now, when it's the only game in town you take the chance and hope that maybe the customer will come to its senses somewhere along the way. Don't you find it fascinating that the Program Management of the program has said it can't be built as specified and yet no one's head has exploded over this? I eagerly await further developments...


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