Boeing JAST / JSF / X-32 /PWSC F-32 projects

[Hydroman]

What's interesting, both X/F-32 and X/F-35 carried the same basic payload internally, one bomb, one missile. X/F-32 on the sides and F-35 underneath. I think the X-32 could have evolved into a pseudo A-4/A-7 type attack jet (the redesigned shaping, inlet and the H-tails), god knows we need a good mix of aircraft mission types on our flattops now, not just F-18's and F-35's.

 

[SteveO]

If I remember correctly the X-32 met all the JSF program targets as did the X-35. The main difference between them was the complexity of the V/STOL method. The X-32 team chose a relatively simple low weight solution while the X-35 went with a more complex higher performance solution. The X planes produced didn’t fully represent an operational fighter due to budget constraints.

Remember that the Joint Strike Fighter program was basically going to provide F-117 stealth capabilities plus air to air (2x 2000lb bombs and 2x AMRAAM) to replace all the Harrier, F-16 and FA-18 fleets. Pretty impressive really!

Using JSF airframes to replace the F-14, F-15 and A-6 and F-111 roles doesn’t seem as good though does it! Shame the JSF program didn’t cover two airframes really. Single engine lightweight to replace Harrier and F-16, then twin engine heavy to replace F-14, F-15 and FA-18. Same gear, but heavy has twice the weapons etc.

I always thought that the simpler X-32B/F-32B was the way to go for the UK Harrier replacement. The RAF could have operated them in STOL mode most of the time if bring back weight was the issue on land operations. Even if the internal payload was reduced to 2x 1000lb bombs and 2x AMRAAM as in the F-35B it would have beat the Fleet Air Arm Sea Harrier FA2’s 4x AMRAAM maximum load (6x AMRAAM or 4 plus 2x ASRAAM maybe?).

Anyway, I’m a Boeing X-32/F-32 fan!

 

[Colonial-Marine]

The redesign of the X-32 didn't have anything to do with problems with stability. It had to do with meeting the Cl required for the carrier approach once their, the Navies, requirements changed. Otherwise, he X-32 was faster and more maneuverable than the X-35. STOVL has always been hard especially for the mission being pushed for JSF. However, Boeing always knew that if LM got the lift fan to work they couldn't compete in the STOVL realm. LM got the lift fan to work and that was that.

I would assume the X-32 was more maneuverable than the X-35, at least at some speeds, due to the 2D thrust-vectoring nozzle. But was it really faster? I had thought both were designed for a max speed of about Mach 1.8, although I don't think either did flight testing at such speeds since it was beyond the scope of what the demonstrators were supposed to prove. Most of the later sources on the subject only mention speeds as being Mach 1.6+ or so.

I do wonder how much the redesigned wing and tail intended for the production "F-32" would have changed flight characteristics.

 

[Purpletrouble]

If I remember correctly the X-32 met all the JSF program targets as did the X-35.

You aren’t remembering correctly I’m afraid.

The main difference between them was the complexity of the V/STOL method. The X-32 team chose a relatively simple low weight solution

Low weight, low capability. It could barely hover. The weight difference was <2000lb btw, 10%. X-32 appears to have had a more powerful engine btw.

And that’s just wrong, it wasnt stovl “complexity” the main difference - it was the entire conceptual design of the aircraft. Look at the planform, crucially where the engine is, where and how the wing joins the fuselage, the cockpit, what control surfaces you do/dont have. What that means for stability and control and how this thing flies and is manoeuvred.

Everything on X-32 was subordinated to a layout barely moved on from Harrier and hopelessly compromised by the stovl “solution”. Everything on X-35 is a layout that decades of operational aircraft had always shown was the layout for a combat aircraft and a decade plus of R&D looking at options to design a stovl system that worked with the layout, not vica versa.

while the X-35 went with a more complex higher performance solution. The X planes produced didn’t fully represent an operational fighter due to budget constraints.

Nothing to do with budget constraints, they were concept demonstrators to enable a downselect. A level of maturity commensurate with the timeline and desire to then initiate the main program. The planform, STOVL, cv-ctol-stovl commonality (incl conversion), LO and FCS working were what they wanted to see in the flesh before going further. As we saw the X-35 with all its potential took many billions to mature to an operational platform.

Remember that the Joint Strike Fighter program was basically going to provide F-117 stealth capabilities plus air to air (2x 2000lb bombs and 2x AMRAAM) to replace all the Harrier, F-16 and FA-18 fleets. Pretty impressive really!

Using JSF airframes to replace the F-14, F-15 and A-6 and F-111 roles doesn’t seem as good though does it! Shame the JSF program didn’t cover two airframes really. Single engine lightweight to replace Harrier and F-16, then twin engine heavy to replace F-14, F-15 and FA-18. Same gear, but heavy has twice the weapons etc.

That’s two completely different aircraft. The entire point was a single program. Can you point to any such twin program ever?

I always thought that the simpler X-32B/F-32B was the way to go for the UK Harrier replacement.

It was absolute rubbish. Really, this thing had no potential and could hardly carry itself. It’d have been a step back from Harrier.

It quite literally could never have entered service, it would never have met the full (ie not experimental) set of flight requirements (handling etc) and had zero (if not negative) margin to cope with adding systems and development growth etc.

The RAF could have operated them in STOL mode most of the time if bring back weight was the issue on land operations. Even if the internal payload was reduced to 2x 1000lb bombs and 2x AMRAAM as in the F-35B it would have beat the Fleet Air Arm Sea Harrier FA2’s 4x AMRAAM maximum load (6x AMRAAM or 4 plus 2x ASRAAM maybe?).

You are making a huge leap of utterly unsubstantiated faith that it could do that. It couldn’t.

Anyway, I’m a Boeing X-32/F-32 fan!

Enthusaism is one thing, dismissing reality is another. X-32 got absolutely owned by X-35’s demonstrated and potential capability. So much so that X-35 was able to take a decade and a half development program with all the compromises and back steps that imposes and still come out with a credible platform. X-32 never started even close to that place and no amount of fanboism changes that.

Had X-35 failed, the program would almost certainly have been cancelled soon after with STOVL stripped out and a new one started for the USAF/USN. Possibly the latter would have gone sole SH (although this was in serious trouble at the time ?perhaps a little earlier? with flight safety handling/control issues) and so we’d have got a USAF single engine FAsomething. Probably very similar to F-35A in layout as funny old thing, that’s what combat aircraft should look like. Take a punt on LM or Boeing doing/winning that, perhaps the latter would listen to Macair folk this time and design something decent. I guess F-22 would have seen more attention also and not the later cessation of its build.

 

[Purpletrouble]

Funny, the X32 had a weapons bay while the X35 didn't.

And were the doors (and actuators) of those bays fitted for the STOVL flights (not the PR ones, key test points), or any internal gubbins of any sort…

 

[Scott Kenny]

And were the doors (and actuators) of those bays fitted for the STOVL flights (not the PR ones, key test points), or any internal gubbins of any sort…

I don't know.

But that means that there was still all the structure inside the airframe even if you rip out the actuators etc.

 

[BLACK_MAMBA]

And were the doors (and actuators) of those bays fitted for the STOVL flights (not the PR ones, key test points), or any internal gubbins of any sort…

Only the X-32A (CTOL) had a bay. The X-32B did not.

Perhaps I'm influenced by the Nova documentary, but I always understood that Boeing's failure to get their advanced and giant composite wing skin right was a primary killer as suddenly their demonstrators gained a huge amount of mass late in the construction thanks to a change in material. Not to mention that their early design freeze limited them in what they could demonstrate. I won't go so far to say it could not be made to work, but there was significantly more risk in the X-32. The X-35 had riak, but the rewards were more visible and tangible.

 

[Purpletrouble]

Only the X-32A (CTOL) had a bay. The X-32B did not.

Wasnt that the one converted? I forget now.

Perhaps I'm influenced by the Nova documentary, but I always understood that Boeing's failure to get their advanced and giant composite wing skin right was a primary killer as suddenly their demonstrators gained a huge amount of mass late in the construction thanks to a change in material. Not to mention that their early design freeze limited them in what they could demonstrate. I won't go so far to say it could not be made to work, but there was significantly more risk in the X-32. The X-35 had riak, but the rewards were more visible and tangible.

It’s the conceptual layout of the entire aircraft and system that is fundamentally flawed. All 3 variants completely dominated by the need to have thrust post and thus engine near CG.

Getting the wing that wrong is a terrible mistake and points to the the real lack of expertise they had.

I also don’t think it hides their STOVL numbers just didn’t add up - “voodoo engineering” to qoute an ex macair chief who was also incredulous how little they knew about stovl aerodynamics - and frustrated as hell they were too arrogant to listen.

 

[Scott Kenny]

Wasnt that the one converted? I forget now.

It’s the conceptual layout of the entire aircraft and system that is fundamentally flawed. All 3 variants completely dominated by the need to have thrust post and thus engine near CG.

And Weapons Bays! You end up with a very chunky shape when you need engine and weapons bays in the same place.

F-35 is a lot better in that sense, though the LiftFan still eats a lot of space where you would prefer to put weapons bays (or a fuel tank).

Getting the wing that wrong is a terrible mistake and points to the the real lack of expertise they had.

Wasn't that the same technology that Mitsubishi used for the F-2?

 

[Purpletrouble]

And Weapons Bays! You end up with a very chunky shape when you need engine and weapons bays in the same place.

F-35 is a lot better in that sense, though the LiftFan still eats a lot of space where you would prefer to put weapons bays (or a fuel tank).

Its a fat thing to be sure, but if you want STOVL something has to give

Wasn't that the same technology that Mitsubishi used for the F-2?

And the AV8B iirc. The fact they even went down that route tells you they knew their numbers were marginal to begin with.

 

[stever_sl]

All speculations and opinions aside, the simple fact is that X-32 lost for two basic reasons. (My credentials: I worked on AV-8B, advanced Harrier variants, McDonnell Douglas's ASTOVL and JAST, then Boeing's JSF after the merger.) First, the years-long secret relationship between Lockheed and DARPA to develop and mature the shaft-driven lift fan gave Boeing no choice but to go with what they knew worked. Second, the design effort was going on from Day One of the merger between Boeing and MDC, so all sorts of organizational incompatibilities were having to be fixed, reaching from program control all the way down to the fact that MDC used Unigraphics to design parts while heritage Boeing used CATIA. There was an entire unit in each location whose only task was to take drawings from the other site and convert them from CATIA to UG or UG to CATIA, whichever was needed by that site. This introduced delays and was a significant drain on resources, but not nearly as much as the squabbling over who was in charge of what. The original ugly X-32 tailless delta was purely a Seattle idea, and I believe they had patented it. It wasn't capable of meeting the requirements, as I recall particularly for the USN variant, and it was only after a great deal of time-wasting struggle that a tail section was finally put on the basic design, which, along with the change away from the backward-facing inlet, (in my opinion) made it look 100% better. But it was always overweight, and the basic engine core had been stretched as far as it could be without spending billions to develop a whole new engine. In a very strange move, the St Louis site leadership brought back a senior exec from retirement to secretely form a small team whose charter was to find a way to get rid of the excess weight. I was on that team. It was found that replacing the 2D rear nozzle with an axisymmetric one would buy back the weight we needed. When the axi nozzle was sprung on Seattle, they reacted with vehement negativity to this unexpected and unasked-for St Louis idea. Instead, they revealed in one of our periodic coordination meetings that they were going to fix the weight problem by adding "lift thrust augmentors" (small jet engines) for vertical operations. I was on the conference call where that was announced, and there was consternation not only in St Louis (because we knew the Marines would never accept a multiengine VTOL solution) but also among the Seattle crowd, whose subsystem people objected that they hadn't been consulted about things like what would have to be relocated to make room for these LTAs and how the things were to be provided with fuel and air and electrical power. Whoever was in charge of that meeting told them that the decision had been made, and LTAs were going into the aircraft. I recall that we St Louis people knew the jig was up, and we muted our end of the call and filed back to our desks. We were right. None of this would have happened if the Harrier 21 had been allowed to go forward years earlier instead of being quashed by MDC's ASTOVL group, but that's a whole other story.

 

[SteveO]

Thanks stever_sl!

Fascinating post. As usual facts beat wishful thinking, what iffery?

Are you allowed to tell us more about the Harrier 21?

Sorry, you already had in the advanced Harrier projects thread

 

[Sundog]

All speculations and opinions aside, the simple fact is that X-32 lost for two basic reasons. (My credentials: I worked on AV-8B, advanced Harrier variants, McDonnell Douglas's ASTOVL and JAST, then Boeing's JSF after the merger.) First, the years-long secret relationship between Lockheed and DARPA to develop and mature the shaft-driven lift fan gave Boeing no choice but to go with what they knew worked. Second, the design effort was going on from Day One of the merger between Boeing and MDC, so all sorts of organizational incompatibilities were having to be fixed, reaching from program control all the way down to the fact that MDC used Unigraphics to design parts while heritage Boeing used CATIA. There was an entire unit in each location whose only task was to take drawings from the other site and convert them from CATIA to UG or UG to CATIA, whichever was needed by that site. This introduced delays and was a significant drain on resources, but not nearly as much as the squabbling over who was in charge of what. The original ugly X-32 tailless delta was purely a Seattle idea, and I believe they had patented it. It wasn't capable of meeting the requirements, as I recall particularly for the USN variant, and it was only after a great deal of time-wasting struggle that a tail section was finally put on the basic design, which, along with the change away from the backward-facing inlet, (in my opinion) made it look 100% better. But it was always overweight, and the basic engine core had been stretched as far as it could be without spending billions to develop a whole new engine. In a very strange move, the St Louis site leadership brought back a senior exec from retirement to secretely form a small team whose charter was to find a way to get rid of the excess weight. I was on that team. It was found that replacing the 2D rear nozzle with an axisymmetric one would buy back the weight we needed. When the axi nozzle was sprung on Seattle, they reacted with vehement negativity to this unexpected and unasked-for St Louis idea. Instead, they revealed in one of our periodic coordination meetings that they were going to fix the weight problem by adding "lift thrust augmentors" (small jet engines) for vertical operations. I was on the conference call where that was announced, and there was consternation not only in St Louis (because we knew the Marines would never accept a multiengine VTOL solution) but also among the Seattle crowd, whose subsystem people objected that they hadn't been consulted about things like what would have to be relocated to make room for these LTAs and how the things were to be provided with fuel and air and electrical power. Whoever was in charge of that meeting told them that the decision had been made, and LTAs were going into the aircraft. I recall that we St Louis people knew the jig was up, and we muted our end of the call and filed back to our desks. We were right. None of this would have happened if the Harrier 21 had been allowed to go forward years earlier instead of being quashed by MDC's ASTOVL group, but that's a whole other story.

Yeah, there was no way the LTA version was going to fly, metaphorically speaking. That's precisely why the Northrop/BAe design didn't make the cut. I'll have to check out the Harrier 21. I was always partial to the model 279, myself. Also, I know what you mean about the lift fan B.S. There were all of the NASA contracts to develop better means of STOVL and the development of the lift fan should have been independent of a contractor, then used as part of the requirements.

 

[Scott Kenny]

There was an entire unit in each location whose only task was to take drawings from the other site and convert them from CATIA to UG or UG to CATIA, whichever was needed by that site.

*facepalm*!!!!!!

 

[Dew]

8x6ft wind tunnel pics via NARA:

 

[aim9xray]

8x6ft wind tunnel pics via NARA:

Now how the hell can NARA get around 'proprietary" markings when AFHRA is wrapped around the axle handling such marked (PROPIN) material from 70 years ago? (Not that I'm complaining.)

 

[VTOLicious]

The only aircraft that looks better upside-down