JMR (Joint Multi-Role) & FVL (Future Vertical Lift) Programs

[F-14D]

Beautiful drawing. Maybe Airbus (for FARA) thought an X3 wouldn't be cost competitive (or agile?) enough, or that they wouldn't get a fair shot, although European helos have been doing pretty well in US competitions lately...

 

[Grey Havoc]

The Lakota probably didn't do what is now Airbus Helicopters any favours either, though to be fair at least some of the UH-72's shortcomings were due to the U.S. Army being forced to try to shoe horn it in to front line theaters & roles it was never intended for.

 

[Moose]

Earlier in the Program, EADS cancelled their planned bid because it would require transferring too much proprietary technology to the US just to complete the bid. They feared taking that step and then losing the program, which would leave them having to develop X3 primarily through their US subsidiary (or dropping it). They also complained that the Pentagon wasn't putting up enough money to do development, and they were unwilling/unable to commit the same level of private resources as Sikorsy and Bell to be ready in the DoD's window. I'm sure they'd give it another look if they could hook up with an existing US prime, but Boeing, Lockheed/Sikorsky, Raytheon, Textron, and NG area all in teams already without needing to woo Airbus.

 

[yasotay]

Thank you Moose. That makes perfect sense.

 

[TomcatViP]

More probably that they were not really convincing. As stated earlier, the fact that Karem was selected but not Airbus that had received subsedies for their design from the EU (something that any cash strapped US services would have seen as a bonus) is a clear sign that not much of the offer raised their interest.

 

[MihoshiK]

More probably that they were not really convincing. As stated earlier, the fact that Karem was selected but not Airbus that had received subsedies for their design from the EU (something that any cash strapped US services would have seen as a bonus) is a clear sign that not much of the offer raised their interest.

I love how you entirely skip over the first part of Moose's post just to get in another dig at Airbus. Your obsession with that is getting rather tiresome.

 

[TomcatViP]

Say the man with a compulsive starring disorder toward my...
Get your fact in order, never has Airbus argued such when winning a market. Airbus prime customer... Is the US DoD.

 

[MihoshiK]

Not quoting someone when replying to them is a sign of dishonesty, because you're banking on them not noticing that you've replied to them.

Say the man with a compulsive starring disorder toward my...
Get your fact in order, never has Airbus argued such when winning a market. Airbus prime customer... Is the US DoD.

The only thing I star in is my own life.

And you are still making assumptions, with the only proof being... What, exactly? It would be nice for this board if you'd take your obvious animosity towards Airbus, and buried it somewhere in your backyard.

 

[TomcatViP]

And here we go again....

OK have fun.

 

[yasotay]

Boeing compound helicopter FARA design released today. Son of Cheyenne.

 

[AN/AWW-14(V)]

 

[VTOLicious]

Hmm, most probably it will not get extra points for visual appearance

 

[sferrin]

Yuck. That's as ugly as Karem's.

 

[fredymac]

It will have to be a really attractive price to have any chance.

https://twitter.com/x/status/1234863725389238274

 

[jsport]

Still not feelin that MH-6 replacement vibe. Maybe Airbus and Karem.

 

[AeroFranz]

Hmm, most probably it will not get extra points for visual appearance

Eh. I tend to agree with the visual part, but honestly from an aerodynamics point of view it is actually very streamlined.
The compound Apache CFD and wind tunnel campaign of the last couple of years must have taught Boeing were to put their efforts. I'm curious about the trend seen in both Bell and Boeing's offering of using an asymmetric inlet for the single engine. the Invictus looks good, but i would like to see a very good risk/benefit analysis of going with...what do they call it? APSU? the booster APU for high speed?

 

[F-14D]

Yuck. That's as ugly as Karem's.

Lest we forget Boeing's previous attempt at aerodynamic beauty:






I'm sensing a trend...

 

[Desertfox]

No wonder Boeing kept it under wraps so long...

 

[robunos]

It's to make the enemy drop their guard . . .

'Man, that thing is fugly . . .'
'HAHAHAHAHA, that's so stoopid lookin' . . .'
'How does that thing even fly ?'

And while they're wondering this, BAM ! death from above . . .

cheers,
Robin.

 

[F-14D]

Another consideration can be seen in this illustration. Given how low the vehicle sits on the ground and the mounting of the propulsor and tail rotor,, ground troops may give it the nickname of "Flying Cuisinart".

 

[Moose]

The tail seems even longer than Sikorsky's, which isn't going to help their argument if the Army's thinking urban battlefield

 

[TomcatViP]

@F-14D : In fact, they don't brake using the main rotor, so a flare close to the ground will be with the pusher prop providing the reverse thrust component while the fuselage seat in line with the trajectory.

Then the rotor is clutch mounted, meaning the vertical leg of the landing is done with that disengaged.

But I agree that the anti-torque for sure looks quite menacing.

 

[donnage99]

those sales guys at Boeing must be getting paid extra for bringing these on their powerpoints. Let's not forget their previous attempt at cutting edge rotorcraft :

 

[yasotay]

Hmm, most probably it will not get extra points for visual appearance

Eh. I tend to agree with the visual part, but honestly from an aerodynamics point of view it is actually very streamlined.
The compound Apache CFD and wind tunnel campaign of the last couple of years must have taught Boeing were to put their efforts. I'm curious about the trend seen in both Bell and Boeing's offering of using an asymmetric inlet for the single engine. the Invictus looks good, but i would like to see a very good risk/benefit analysis of going with...what do they call it? APSU? the booster APU for high speed?

Perhaps the one sided inlet is to reduce radar cross section? Or is there a drag component concern? Boeing, like Bell, is reading between the lines that while the Army wants super-duper cutting edge technology, they want to get it from the bargain basement. Boeing made a point of saying that there was no new technology in the design.

 

[F-14D]

@F-14D : In fact, they don't brake using the main rotor, so a flare close to the ground will be with the pusher prop providing the reverse thrust component while the fuselage seat in line with the trajectory.

Then the rotor is clutch mounted, meaning the vertical leg of the landing is done with that disengaged.

But I agree that the anti-torque for sure looks quite menacing.

My main concern is with any troops that get close to either of those props while they're turning, because they are really close to the ground. For the pusher, I wonder how long it takes to spin up/down, and whether there's some kind of brake along with a clutch ( a bit complicated, IMO).

 

[Sundog]

IIRC, the article on the Boeing concept states that the Pusher is clutched and can be disengaged. I don't see where it's that big of deal, as this obviously isn't a troop carrier. If they were flying troops, I would see it as problematic.

As for the single inlet and single exhaust these designs are using, that would be to minimize cost. It's less expensive to build one of each, rather than two. I also don't think the tail is any longer on this than any of the other vehicles. In fact, this appears to be the smallest vehicle, which makes it most likely the least expensive of the entrants. I think the tail just appears long due to the small/compact nose.

 

[Sundog]

Yuck. That's as ugly as Karem's.

Lest we forget Boeing's previous attempt at aerodynamic beauty:


View attachment 628340



I'm sensing a trend...

It was a brilliant design and was faster and more maneuverable than the competition. It was the way the STOVL propulsion was done that was the problem. Of course, the whole way the JSF program was handled was a giant cluster****, and antithetical to the way these, X-programs, were done in the past.

I should also note that I think the Boeing FARA submission is the best looking of the submissions. The AVX and Sikorsky designs are "fat" by comparison, they look like flying potato bugs. The Bell design isn't bad, if somewhat "bumpy". The Karem design is interesting, but the tail seems to be a bit complicated to me, in the tilt rotor sense. What's funny is the Karem design and the Boeing design appear to be the low drag "fighters" of the design group, but many appear to prefer the other "frumpy" designs.

 

[F-14D]

IIRC, the article on the Boeing concept states that the Pusher is clutched and can be disengaged. I don't see where it's that big of deal, as this obviously isn't a troop carrier. If they were flying troops, I would see it as problematic.

As for the single inlet and single exhaust these designs are using, that would be to minimize cost. It's less expensive to build one of each, rather than two. I also don't think the tail is any longer on this than any of the other vehicles. In fact, this appears to be the smallest vehicle, which makes it most likely the least expensive of the entrants. I think the tail just appears long due to the small/compact nose.

A scout will probably be living in and among the troops. Take a look again at Boeing's own illutration that I posted. Those are troops nearby. Your point on the intake/exhaust for this single engine craft is well taken, Bell adopted the same strategy on Invictus. Doesn't appear the tail is that long to me. More concerned with, given how small the craft is and how low it sits, is that in addition to the pusher, the canted tail rotor seems to come quite low as well, and you can't shut that off if you want to fly.

 

[F-14D]

It was a brilliant design and was faster and more maneuverable than the competition. It was the way the STOVL propulsion was done that was the problem. Of course, the whole way the JSF program was handled was a giant cluster****, and antithetical to the way these, X-programs, were done in the past.

I should also note that I think the Boeing FARA submission is the best looking of the submissions. The AVX and Sikorsky designs are "fat" by comparison, they look like flying potato bugs. The Bell design isn't bad, if somewhat "bumpy". The Karem design is interesting, but the tail seems to be a bit complicated to me, in the tilt rotor sense. What's funny is the Karem design and the Boeing design appear to be the low drag "fighters" of the design group, but many appear to prefer the other "frumpy" designs.

Although I like your post, wasn't the other problem with the Boeing X-32 that as flown it could not fly the required carrier approach operationally, so that was the reason for the proposed redesign?

As far as low drag fighters, remember the Army isn't asking for all that much speed. Nowhere near what is required for FLRAA, and both of those proposals have side-by-side seating. I think what AVX , Karem and Sikorsky are going for is offering the possibility of cabin space in the fuselage, maybe to carry a few troops/SOF personnel. Bell and Boeing, OTOH, think that since this is not an actual baseline requirement of FARA, they don't believe Army will pay enough extra to get it for them to be willing to increase the price of their bid sufficiently to include it.

 

[F-14D]

Have we reached the point where the FARA program itself (not the individual aircraft such as Invictus and whatever Boeing calls its Apache-Black Hawk love child) deserves its own topic and not just under JMR/FVL?

 

[Cordy]

 

[jsport]

View attachment 628381

Not being able to fly completely horizontally and suffering the drag of coaxial rotors both should be show stoppers in 21st century operational environment, where range is a paramount concern. Karem's obviating retreating blade stall phenomen is HUGE.
Dont see how hover performance is all that effected by wing swivel down on the Karem.
Hope this program doesn't become a S Show of politics over capability.

 

[yasotay]

A very good assessment by Cordy. Bell and Boeing are looking at the Army's traditional desire to go with the lowest bidding for the mission. Given the tempo of the program - risk - and the politics of the DoD are likely to be a factor in the selection process.

 

[fredymac]

The Boeing design doesn't offload the rotor blades at high speed to mitigate retreating stall. Is using 6 rotor blades really a solution for this?

 

[fredymac]

The rigid rotors on the Sikorsky design allow the rotor planes to be positioned closer together. The vertical skew in the lift force between the planes during retreating blade stall is reduced this way. This also reduces the dynamic shift in lift position as blades transition in and out of stall which would induce a vertical shaking force. Has anyone actually tried hinged coaxial rotors at high speed?

 

[yasotay]

The rigid rotors on the Sikorsky design allow the rotor planes to be positioned closer together. The vertical skew in the lift force between the planes during retreating blade stall is reduced this way. This also reduces the dynamic shift in lift position as blades transition in and out of stall which would induce a vertical shaking force. Has anyone actually tried hinged coaxial rotors at high speed?

Kamov?
Wonder if Boeing is going to slow the rotor at high speed? I have heard of this (Cheyenne?) but not sure how viable that would be.

 

[TomcatViP]

More blade, less pitch travel (up and down), less losses with the swachplate, GB, hence more power for greater speed and endurance... The problem is with inertia but Boeing seems to compensate the extra burden with a lighter weight design (that looks similar in part with the HAL from India).

Active vibration dampers are a must to have in tomorrow's battle space where direct energy weapons will target anything mechanical with a periodic cycle.

Karem: their swiveling wing set seems to me to be just an aerodynamic shell with no structural function (no underslung weapons). Hence their mass contribution (including the light weight swiveling mechanism that will act only under low aerodynamic loads) is IMOHO a minimal loss that allow them to have less (but seems to be) larger blade (hence less rotor radius and/or decreased rotational speed).

Rigid rotor: attenuate flapping motion and amplitude (the cone shape surface of the revolving blade around rotor shaft that naturally adapt to mechanical loads but increases rotational speed needs for lift). You can fly faster without having as much a power margin to fight air turbulence and attitude changes (just like driving full speed with a 2L or a 5L engine).

 

[sferrin]

It was a brilliant design and was faster and more maneuverable than the competition.

Are you talking about the X-32? You don't live in Colorado do you?

 

[F-14D]

The rigid rotors on the Sikorsky design allow the rotor planes to be positioned closer together. The vertical skew in the lift force between the planes during retreating blade stall is reduced this way. This also reduces the dynamic shift in lift position as blades transition in and out of stall which would induce a vertical shaking force. Has anyone actually tried hinged coaxial rotors at high speed?

Kamov?
Wonder if Boeing is going to slow the rotor at high speed? I have heard of this (Cheyenne?) but not sure how viable that would be.

Sikorsky repeatedly that their X2 technology is different from conventional coaxials which are basically two conventional rotors stacked vertically. Kamov's fastest helicopter, the KA-50/52 cruises @ 145- 167 knots and max speed in level flight is ~180, so it's below the threshold where these effects (including asymmetric lift and the advancing rotor tip going supersonic) become prominent.

In the case of Cheyenne, it was intended to slow its rotor, but it was also transferring some lift at high speeds to a real, no kidding, wing. Boeing doesn't have that luxury. Of course, Cheyenne was intended to go considerably faster than FARA., which I can't remember If X2s slow their rotors, but they might , even without a wing because at speed their rotor needs to provide only lift, not propulsion. the real one to check is Defiant, because the FARA requirement is still within conventional helicopter speeds, albeit at the high end.

 

[Sundog]

It was a brilliant design and was faster and more maneuverable than the competition. It was the way the STOVL propulsion was done that was the problem. Of course, the whole way the JSF program was handled was a giant cluster****, and antithetical to the way these, X-programs, were done in the past.

I should also note that I think the Boeing FARA submission is the best looking of the submissions. The AVX and Sikorsky designs are "fat" by comparison, they look like flying potato bugs. The Bell design isn't bad, if somewhat "bumpy". The Karem design is interesting, but the tail seems to be a bit complicated to me, in the tilt rotor sense. What's funny is the Karem design and the Boeing design appear to be the low drag "fighters" of the design group, but many appear to prefer the other "frumpy" designs.

Although I like your post, wasn't the other problem with the Boeing X-32 that as flown it could not fly the required carrier approach operationally, so that was the reason for the proposed redesign?

As far as low drag fighters, remember the Army isn't asking for all that much speed. Nowhere near what is required for FLRAA, and both of those proposals have side-by-side seating. I think what AVX , Karem and Sikorsky are going for is offering the possibility of cabin space in the fuselage, maybe to carry a few troops/SOF personnel. Bell and Boeing, OTOH, think that since this is not an actual baseline requirement of FARA, they don't believe Army will pay enough extra to get it for them to be willing to increase the price of their bid sufficiently to include it.

The reason for the design change was due to the Navy changing the bring back weight requirement for the CV variant.

Having said that, what are you doing posting here? Aren't you supposed to be working on a book about the YA-7F Strike Fighter program, for Steve Ginter? I mean, if not you, who? (Yes, I want a book on the aircraft and the program and you seem ideally suited for the task.)