Was that due to the newer PCB 'swirl' burners in place of the colanders? Ian Clapham and others did a lot to make the colanders work on the PCB Harrier rig and NGTE seemed happy in the end.
All the Tandem fan work we did was cold front nozzle aimed at pre JAST studies. I briefly saw several aircraft concept architecture but can’t recall the designation… details of these were shared sparingly with the engine team especially the more junior members.
A GR.1 demonstrator was actually built and flown, nothing on the US side though, beyond the artwork and model.
I was being a pest in the Advanced AV-8 and V/STOL Group at the time, pushing for supersonic performance while literally everyone else was "proving" to me that a fighter could and should be subsonic, which just shows how deeply ingrained the Harrier's limitations had become in people's minds. In the end, to shut me up, the head of our Aero group did a whole series of performance calculations based on the AV-8B's geometry, ignoring the extra mess that PCB nozzles would create with cross-sectional area at the mid-fuselage, and arbitrarily adding more and more thrust. In other words, all the benefits of PCB without any of the liabilities. He proved that you could double and even triple the thrust but the basic airframe was so pudgy that you just couldn't break through the transonic drag rise. You'd need a much thinner wing and narrower fuselage to have any chance at all. The AV-8B's supercritical wing had become its major advantage (it's hard to remember those days) because it was all-composite, rare back then. Thinning it down would take away volume from its integral fuel tank, while adding PCB or any other form of afterburning would suggest that you needed more fuel, not less. The so-called "Big Wing" variant had been looked at in the UK as well as in St Louis and while it might have gained back the tank volume, it was too wide to be compatible with LPH/LHA/LHD elevators and hangar deck spaces, without adding the weight and complexity (and potential loss of fuel volume again) of a wingfold system. So there wasn't going to be any PCB-equipped Harrier variant, but then Rolls Royce came up with a repackaged Pegasus engine core that changed everything about the mid-fuselage geometry, and we were off on what became the Harrier 21.
At the time when 279-3 was about to be junked and replaced with 4629, I was still on the Advanced AV-8 and V/STOL team, working with Harrier 21, so I don't know all the issues involved with early incarnations of ASTOVL. Once MDC's corporate geniuses decided to halt H21 in favor of ASTOVL, not knowing that the latter was nothing more than a cover program for behind-the-scenes work between DARPA and Lockheed on the shaft-driven lift fan technologies, I migrated over to ASTOVL myself and worked in their Systems Engineering section on Risk Management. By then the configuration had definitely changed.
Hi Steve
Popular myth has it that the shaft-driven lift fan...well, I'm not going to reopen that old argument. Within the JSF/JAST/ASTOVL context, it has a rather convoluted history. As soon as the AV-8B started going into service, the Services started thinking about what might follow it in the next generation of STOVL. Putting "Advanced" up front yielded the generic acronym "ASTOVL" around 1983, but after a few years of looking at stretching existing technologies, it was apparent that there was only so much growth left in them, not nearly enough to achieve desirable goals for mission capabilities. So by 1987 the desired path forward didn't seem to have any obvious answers. At that point DARPA did a dirty thing. They approached Lockheed, and only Lockheed, in secret to see whether they might have ideas on where to go next. Lockheed said (naturally) yes, they had ideas, and so DARPA started funneling money to them to develop those technologies, chief among which was the shaft-driven lift fan. Meanwhile, to cover their tracks, DARPA pretended that it was still a wide-open game with ASTOVL, and funded a cover program as ASTOVL Phase II to preserve the false belief that there was an open competition. Lockheed took their share of that money as well, leaving everyone else drastically underfunded without realizing it. At the same time, Lockheed was also engaged in an unacknowledged technology development effort with NASA aimed at a supersonic stealth STOVL fighter, so that was another big pile of money that they had been given in secret to develop shaft-driven lift fans, while the rest of the "competitors" in ASTOVL Phase II worked away on radically less money without realizing it. This NASA-initiated program eventually became the multi-Service STOVL Strike Fighter (SSF). As the years went by, ASTOVL and SSF went through several identity iterations before eventually becoming JAST and then JSF. By then, of course, the millions of secret dollars and many years of time had given Lockheed such a lead on STOVL technologies that there was no way for anyone else to catch up. And the center core of those technologies was the shaft-driven lift fan.
Yes. Although some would say it was enough for the USMC before max stealth was added.
It's quite the saga, I wonder what in the first place drove DARPA to go to Lockheed and nobody else. Lockheed's work on fixed-wing VTOL at that time doesn't seem to have been anything remarkable. The "go-to" guys at the time definitely would have been McDonnell Douglas who had all of that Harrier experience.
Lockheed had a way of hiring retiring Service and Government people from "relevant" places, who naturally thought of their trusted former coworkers when new business opportunities arose. They weren't shy about how they went after new business either, their strategic business strategy briefing charts were shown at conferences and were readily available online. But how and why those initial feelers were put out for VTOL technologies, I've never heard.
It's interesting that you mention industrial base support, because at that time MDC looked unstoppable. I can remember walking through Building 1 and seeing 4 different tactical aircraft in production for USAF, USN, USMC, and a bunch of foreign countries. When I first came to St Louis in 1979 there was so much going on that the MDC buildings couldn't hold all the designers and engineers. You could walk through one of the local malls and look into the glass front windows of the stores at shoes here, clothing there, and guys working over drafting boards too, designing bits and pieces for aircraft or missiles or who knew what. I wish I'd thought to take a photo. But with so much going on at MDC, while Lockheed was seemingly confined to one major tactical program, industrial base support may well have come into play. If so, it was ill advised, and late to the party after a lot of consolidation had already happened in the industry through normal business processes.
FWIW, wiki here says Lockheed got a working prototype of Yak-141 in 1993, apparently with documentation and all.
Russian wiki brings this link:
Taking a quick peek around this forum would help resolve some of your questions.
Bolded by me.
DARPA ASTOVL SDLF award to LM far precedes the shenanigans with Yak. 3BSD was not a Yak invention. Most likely, what Yak was involved with is the optimization of LM's VSTOL design, as they had practical experience and could contribute their own know-hows on some of the issues LM could encounter.
That's the realistic figure, yes. Several transactions post-1991, documentation, etc. Likely exactly what happened.
Titanium....
I'd honestly expect that an engine with 3 vectoring nozzles would happen.
I meant more like the P.1214/P.1216, honestly. 2x Cold Nozzles up front and a single hot nozzle.
In something with the P.1216 shape? One weapons bay in each boom, kinda like the Boeing EWP proposed for the Super Hornet.
In 1988, we at RR Patchway had a very nicely built, working scale model of a 3 bearing nozzle which was kept in a locked wooden box;- only shown to authorised employees. It wasn’t new either but I didn’t ask where it came from, just assumed it was associated with the P1214 (ie it central nozzle) a dayglo orange scale model of which was still installed in one of the gas flow recirculation rigs. I didn’t know it was the P1214 at the time, discovered that later.. if you have a three post thrust vectored architecture you really need some kinda solution for making that central stream do what you want.
Probably not. The forward nozzles would be in the way of significant blending there. At best, it'd probably be as blended as the XP-67 Moonbat.
LOL. Sure does!
It's the split tail that worries me and the effect of the whole shape on radar signature.
Boeing JSF style?
