"Leaving room" doesn't leave much margin when operating in the mountains of Afghanistan. The question isn't can it yaw at all, but how fast can the helicopter yaw at its limits? Fast yaw has not been demonstrated to date.

I've got no Sikorsky bosses anymore. I moved to another UTC division when they closed Schweizer. I was the responsible engineer for the X2 flight controls though. And yes I've studied physics. Still use it at my space job. You?

You had mentioned the UH60 high tail rotor before. The torque would be the thrust from the tail rotor times the lever arm. Really no torque from the engines as you say. The torque from the X2 propeller would be the power it absorbs times 5252 divided by RPM. I'll leave it to the student to do the math.

The S300 - now spun off as a separate business?. I am retired from my day job, mechanical engineer, same industry as you, passing my time working on an invention.

Clearly the Raider rolled side to side pretty quickly when it crashed, with the rotors not parallel. You say the design is intended to keep the rotors parallel, I believe you.

I wasn't comparing a tail rotor torque to the pusher prop torque. Clearly most engine power goes through the prop at high speeds, unlike the tail rotor. I was just trying to point out, the tail rotor is a flight control device, but the pusher prop isn't. There is high speed flight, and there is low speed flight with the pusher disengaged. For high speed flight, what keeps the x2 type design going straight forward, if the main rotors are canted to offset prop reaction torque? Are the vertical stabilizers enough? Secondly at hover, is the only difference between a sideways movement and a roll, the degree of tilt of the rotors?

I never worked flight controls, so I may miss the obvious. I appreciate your input.

Think in terms of a fixed wing Cessna with two wing fuel tanks. One full, and one empty. You have to put in enough aileron to react the unbalanced fuel load, but the airplane still goes straight. Same as a helicopter using cyclic to balance other forces and moments. They can be prop torque, tail rotor twisting moment, unbalanced fuel/crew loading, or whatever.

Sikorsky pretty much destroyed Schweizer. Somebody bought the 269/300 type certificate and I think they are building them again. Probably with chinese parts but I don't know.

The cant itself will be largely irrelevant for straight flight because it is only relative to the fuselage. The only small effect would probably result from slightly increased drag of the rotors on the side where the rotors need to produce a bit more lift to counter the torque. On the other hand you will have a drag force on the opposite side resulting from the fuselage being displaced to the opposite side by the torque and the resulting cant.
But realistically this will be negligeable and be easily countered with a tiny bit of crab.

SB-1 FLRAA Proposal Submitted
 

It has been rather boring in the waning days of summer (coming not too soon) until this gem dropped on Verticalmag:

https://verticalmag.com/news/sikorsk...x-to-u-s-army/

This has a number of things to comment on:

Amazing that for the first time in the FLRAA program Sikorsky-Boeing actually met a schedule. Proves they are better at writing fiction than they are at program management and cutting metal (actually molding composites).

It has been EIGHT years since the FLRAA concept demonstrators were selected. Five years is a normal development cycle so where did the "very short time" come from?

This ignores the original goal of the FLRAA requirements to have a 250 kt minimum cruise speed. The final requirements were changed once the shortfalls of the SB concept were known. What does "speed where it matters" even mean? For a long range assault aircraft (the LRAA in FLRAA) where high speed matters is in the cruise segment of a mission getting to the objective. This shaves hours off a mission. Where does SB think speed matters more?

Was that a requirement in the final RFP? If it was? Why? Who cares?

What!!! The original concept made sense as it at least tried to keep the pusher prop out of the dirt. Going to a nose gear can only be a last resort to move the cg forward to reduce rotor loads at the sacrifice of operability. You strike the pusher on the ground flaring into a hot LZ, you are there for the duration.

Relative to the images released is it just me or does the gap between the rotors been significantly increase?

Amazing
 

“Amazing that for the first time in the FLRAA program Sikorsky-Boeing actually met a schedule.”

Sikorsky and Boeing saved a lot of RFP response time by not having to compile and analyze hundreds of hours of flight testing like Bell had to. Smart move by the Defiant program not to waste time and money in unnecessary flight testing to prove concept viability.

If there is any sanity in this world, this RFP submission is the beginning of the end of the ABC concept.

Didn't SB get millions $ more than Bell to fund this phase? Don't they have to account for this money? Time to check SB leaders 1offshore accounts.

SB Admits Technical Defeat
 

The latest Sikorsky-Boeing printed infomercial (attached) spends the whole "article" minimizing technical requirements/capabilities and initial cost by emphasizing the current boogieman of long term sustainment costs as a reason why the SB-1 should be selected for FLRAA. So basically ignore the tangibles of lower speed, shorter range, and higher acquisition costs of the SB-1 versus the Bell V-280 for an unknown promise of lower life cycle costs. This approach attempts to fearmonger using the F-35 unaffordability fiasco that has been in the headlines. What is so pathetic is the S-B team, along with Sikorsky parent LM, have failed repeatedly to control acquisition costs, meet schedules, and provide a sustainable spec compliant product. Additionally, this team are the poster childes for what they are warning about by supplying legendary acquisition failures including the Cyclone, Comanche, and CH-53K (Sikorsky); the KC-46, Starliner, and 737Max (Boeing); and of course the F-35 and F-22 (LM).

As a counterpoint the Bell V-280 has incorporated and demonstrated changes learned from earlier tiltrotors to simplify construction, reduce risk and cost, improve operability and (stunningly) met program requirements.

You almost have to feel sorry the S-B team as they grasp at this last straw to save themselves.

Sponsored Content: An acquisition strategy for the Future Long-Range Assault Aircraft: Focus on the mission - POLITICO

What about the CH-46, CH-47, SH-3, UH-60, and all their derivatives that have been operational for about six decades? Does The Sultan judge these to be legendary acquisition failures as well?

If it looks right, it'll fly right.
And that thing don't look right.

Heli

All the types mentioned are 50+ year old designs developed when Sikorsky and Boeing had competent engineering and management. The latest string of problematic designs from both companies shows they have lost the expertise needed to field a design worthy of being selected for FLRAA. The pathetic SB-1 testing program confirms this.

The choice of words by “the sultan” are interesting… it’s almost sounds as if he is afraid to loose his job because of the competition….

To me both programs are plain silly for a tactical vertical lift machine. They will never be able to replace a simple, cheap Blackhawk in terms of survivability/agility and especially costs. I don’t get why it is so important for the army to fly fast… is it plain envy to the airforce guys? It’s nice for semi-strategic movements to get the Christmas presents quickly from the main base to the various FOBs, but it will be interesting to see if a Valor OR defiant will still fly 200+ Kts, Limited to 20-30ft AGL due to a radar threat, or if they then slow down to half of that, like any other helicopter…. Then the government has payed an awful lot of money for the slightly quicker transport of MREs….

Choice of words are interesting indeed: “ when Sikorsky and Boeing had competent engineering and management.“.

But wait, what does the new Bell Invictus replicate?……..why, its the Boeing/Sikorsky Comanche! What is interesting is that the Bell Invictus design has dropped the copy of the canted, ducted fan tail of Comanche in favor of a conventional canted tail. Wondering why they did that as the Comanche ducted fan was quite powerful-good for 100 kias right sideward flight and capable of flying forward at 80 kias, swapping ends to fly backwards at 80 kias while staying in formation with the photo chase, then after the Ch Test Pilot from Euro-Copter was suitably impressed, Mr. Lappos returned it to a conventional, nose in front mode. Why would you drop such a capability? ( But then, truth be told, this was SA’s third ducted tail, with previous successful efforts on the S-67 and S-76 preceding, so for Bell it was going to be a first, and doubly so for the canted aspect, which had been flown on the S-61R and CH-53D before productionizing on the S-70 and CH-53E lines ).

John

Remind me how many $billion the development portion of the Comanche was projected to overrun the original budget when cancelled? Wasn't the projected recurring unit cost $70m in 2005 dollars? You do make a point how will SB produce a more complex design in 2025 for under $70m apiece? What about FARA? How is the Raider X going to be cheaper than the 2005 Comanche? I think the goal for FARA is under $30m apiece in 2025 dollars? Thats a long way from $70m.

I’m usually content to let people carry on in pissing contests, but thought I’d add for the record that Bell flew a ducted tail rotor on the Model 222 and the Model 407, so has that flight test data to use. The 525 also has a canted tail rotor, so they have some experience with that effect as well. As for the reasons why it was dropped, I assume it was power required in a hover, weight, and/or drag. There are some agility and acoustic advantages to a ducted tail rotor for sure, but when you are weight and or power limited (as even the Army seems to admit is a common concern for FARA competitors) it’s hard to beat lower disk loading for conversion of HP to thrust and less airframe structure in tail for weight and drag.

A few seconds of searching can dig up the 407 tail fan and there are images of the 222 one with a little more digging.

Sadly I think this take is very much on the money.
The Army does not have any coherent vision of what the next conflict may look like, so they chose to raise the bar on some well recognized aircraft performance metrics, even though these are militarily irrelevant.
Other less visible parameters, such as hours of maintenance per flight hour, even though more relevant, seem to have been ignored entirely.
I expect the entire effort to be cancelled, joining a long list of aborted Army development efforts.

Based on this logic, the US Army should have stayed with the Huey like the US Marines.

The Bell (independent of Boeing) V-280 Valor is not a V-22 when it comes to cost per flight hour. The V-280 is based on Bell developed commercial aircraft technology, not 40 year old V-22 military technology. Commercial customers care a lot more about cost per flight hour than the military.

No, you can have some speed increase with modern rotor systems, clearly range increase is interesting, but this can also be achieved with more modern engines/technologies. And clearly subjects like C4I, operation in DVE, etc are relevant… I just don’t see the “speed thing” and it’s crazy configurations to reach this goal, with all its drawbacks as really relevant.
Regarding “commercial technology” you mean that aircraft that is 20 years in development and still not certified and will be crazy expensive as well, only filling a niche market?

SD-Sorry. had not been aware of the testing you mentioned. I stand corrected.

The one thing mentioned by Sultan re the amount of money invested in Comanche etc, could use some clarification. The money and the problem wasn’t the aircraft: when the program was cnx’d, the ship was in great shape, but the mission systems were not, and that subject could have been the subject of a classic Harvard B-School Management Case example problem.

I was referring to the Bell 525 that first flew in 2016. Without Nick Lappos convincing Textron to fund a clean sheet FBW 525 development, Bell would have developed a warmed over 412.

The 525 program produced a strong engineering team and advanced technology just in time for the V-280 program. Additionally, the 525 forced Bell to completely revamp its manufacturing processes, which really hadn’t been updated for 50 years.

Sikorsky has not designed a new commercial Helicopter since the S 92, over 20 years ago. Boeing has not designed a new commercial rotorcraft in over 40 years.

When designing a commercial helicopter, operating cost is just as important as speed and payload. This is experience neither Boeing or Sikorsky have retained.

Understood! 👍

I appreciate that maintenance hours translate pretty directly into cost/flight hour.
That said, for military gear, serviceability is key. Hangar queens are rightly despised by all services, they are useless burdens impeding the ability to perform.
So imho the Army would be better served with stuff that works reliably, that has enough margin to continue even if something goes out. and that is easy to keep in shape, rather than with Avatar inspired contraptions that cost more but don't deliver proportionately.

Just like what I presume we will start hearing from the Sikorsky/Boeing camps in earnest - I think you are very much overselling the possible speed and range improvements from something like ITEP on the old platforms.

https://www.defensenews.com/digital-...n-the-pacific/

If you want to play with the professionals in the Pacific range and speed are all that count.

No, that is exactly what I meant before… ok, so the army does not envy the Air Force, but actually the marines….. yes they have speed: JSF, Osprey, but I bet they also still want Yankee hueys and Cobras at treetop level together with their troops on ground when hitting the coastline…. I simply cannot see how a defiant or valor could take that role with the same efficiency…. They could co-exist, like the osprey amd the Y-hueys… but completely replacing them???

That is exactly what the Marines are doing with their RFP for a new medium vertical lift. It is similar to the FLRAA except faster and longer range.

The range I understand. A bit faster as well say 160-170 KIAS at sea level. But without compromise to agility and surviveability of current platforms… and without crazy costs…simply cannot imagine that either defiant or valor is fulfilling those criteria. To my opinion only a “traditional” helicopter can fulfill that. But we will see in 20-30 years how it played out 👍

The Marines announced the program to replace UH-1Y/AH-1Z is called Aura. It will be more expensive and later than FLRAA. Among the requirements originally announced were a maximum continuous cruise speed of 295kt (546km/h) at 90% maximum continuous power and 330kt indicated airspeed at 100% of intermediate-rated power. It needs to be able to work with Osprey and in some missions be faster. Also,an un-refueled combat radius of 450nm (833km), with a 30min loiter. They want two plots and two door gunners in the -1Y replacement, plus eight riflemen. They also want an attack version with high commonality, like they did with the -1Y/Z

A modified V-280 might be able to meet those requirements, but it's more likely we'd see a separate aircraft, using some Valor-derived technology. No way a conventional helo could meet the need and personally I doubt if an X2 vehicle could either.

Indeed, this one has 'Tilt Rotor' written all over it. On the Downside, chances are there will be only one candidate for supplier. Might not help regarding pricing in the RfP.

What the Army wants, and what they can afford, are two different things. Buy some tilt-rotors for capability, and some upgraded Black Hawks for cost. Could also use modified Black Hawks to meet FARA, again based on cost.

The Huey H-1 was (and still is) far cheaper than the UH-60. Still due to realities in production cost and production rates, the only path was a clean break. The same was true when the USAF changed from the F-4 to the F-15. Which is why the USAF demanded MCAIR destroy the F-4 tooling.

Putting two new aircraft into production? Costs a lot of money. The Army will be lucky to get one. So what is plan B? The Black Hawk is very affordable. Combine some of Sea Hawk with Black Hawk would work, although not ideal, as you point out. I had read once the Army was so delusional they believed the new FLRAA would cost no more than existing aircraft. They felt new manufacturing technology would allow this. Yeah, what are they smoking?

The video is mildly interesting even though it is two years after the scheduled closure of the demo phase of FLRAA program.

On the claimed 236 knots level flight speed: Was it near max gross weight to simulate a real mission? Was power used at or less than max continuous? What was the aircraft’s range in tested configuration? How was the vibration? As stated previously Bell flew a modified short cabin Huey to a level flight speed of 274 knots (addition of two turbojets). In this configuration the aircraft had near zero range, no useful payload, and had brutal vibration levels.

As to the other achievements the maneuverability looked very sluggish and the ability to hover near trees is a feature of every vertical lift aircraft.

Interesting that Sikorsky decided to show a video ostensibly demonstrating "hover agility" while instead actually flying with not-insignificant flight speed. Rolling maneuvers coupled with forward speed are not the same as static hover having to overcome static inertia. Plus the real elephant in the room is yaw - a rigid coax is absolutely a dog in that category which is something historically ascribed to tiltrotors until V-280. This clip most certainly does not illustrate Level 1 HQ in pitch or roll, nor would I ever believe that claim in yaw.

If the SB-1 could match anything like its competition from a hover like below, I am sure they would have shown it by now. It's been 3 years since their (> year late) first flight for crying out loud.

The award for best film score goes to…..
 

It is very obvious that the Sikorsky video has better production values, attractive location, and a nice classical film score.

The Bell video appears to be filmed from a single camera, minimal editing, no attempt at a music score, and next to zero post production.

The award for best video goes to Sikorsky, the award for contract of a production aircraft goes to Bell.

I also note that it looks like they did not start or stop the pusher while airborne, a feature they've touted in the past, but kept it running the whole time, even on the ground.

PPRuNe needs a 'like' button!