Built but never flown aircraft?


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22 January 2006
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Here is a candidate

MosAeroShow (1995 or 1999?). It's the Bulgakov BULG-2 (sometimes the designer uses a French(?) transliteration for his family name => Boulgakov BOULG-2). I've never heard of a maiden flight, but I'm interested in information if I'm right. It seems to be one of the smallest jet aircraft ever built.


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In 1949 the Yakovlev OKB rolled out the Yak-1000 high-speed research aircraft which was the Russian answer to the Douglas Skystreak jet research aircraft. The smallest possible fuselage was built around a Lyulka AL-1 turbojet engine. The unusual bicycle landing gear arrangement made for horrendous ground handling characteristics and it was cancelled without ever having flown.

The Rockwell XFV-12 probably also falls into the buillt but never flown category as well.

The Fairchild/Dornier 728JET I don't believe ever took to the air either.

Don't forget also the Avro Arrow 2. When the Diefenbaker government cancelled the Avro CF-105 Arrow in 1959, only the J75-powered Arrow 1s had flown (there were 5). There was one completed Arrow 2 and four more Arrow 2s under construction at Avro Canada's plant at Malton (site of today's Pearson International Airport). The Arrow 2 was the definitive production version and much more capable than the Arrow 1.

The Arrow 2 had the definitive Orenda Iroquois engine which was far more powerful than the J75 and would have bestowed the Arrow Mk.2 with impressive performance specs.

Interestingly, a lot of the technology developed for the Iroquois engine would subsequently go to Rolls-Royce as a lot of Orenda's engineers went to work for RR. The engine that resulted was the Rolls-Royce Olympus.

And then there's the little-known Vought XF5U-1 "Flying Pancake" which had a revolutionary saucer layout to generate increased lift and thus shorten landing distances and lower landing speeds (making it ideal for carrier operations). The lack of wings meant it was compact and not needing any complex wingfold mechanisms. Two prototypes were completed in late 1945 and it wasn't until 1947 that flight testing was scheduled to begin at Edwards AFB. However, by this time the Navy lost interest in propeller-driven fighters and the prototypes never flew.

The Yak-44 was intended to provide AEW/AWACS cover for Russian carrier battlegroups centered around the new Admiral Kuznetzov-class carriers. I think a single prototype was built but never flown with the subsequent drawdown in Russian naval forces.
Sentinel Chicken said:
The Yak-44 was intended to provide AEW/AWACS cover for Russian carrier battlegroups centered around the new Admiral Kuznetzov-class carriers. I think a single prototype was built but never flown with the subsequent drawdown in Russian naval forces.

I had always assumed that the below picture was only a mockup?


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That's what I'm not sure about. I've seen that picture, but I'm trying to remember where I'd read that there was a single Yak-44 built. Perhaps our Russian colleagues may have better information?
This is full-scale mock-up, built in autumn of 1989. 1/5 scale model for radioelectronics compatibility tests in echoe camera was built as well.
Sentinal Chicken....Uh, No...The Olympus was NOT created from the Iroquois. Olympus engines first ran in 1950, whereas the PS.13 first lit up 4 years later. Remember, Canada didn't give away anything from those projects. Even if Rolls-Royce did manage to get some info for later version of the Olympus, the end result was nothing like the Iroquois. The PS.13 was known as powerful, but simple. The Olympus only had the powerful part.
The final developed version of the Olympus for the TSR.2, which formed the basis for the one in the Concorde, apparently did benefit from the Iroquois since the pieces of what was determined, by serial numbers, to be a flight-rated Iroquois were found in the UK a few years ago. The two engines were of similar basic configuration and performance, yet the Iroquois was 100 inches shorter, and thus likely lighter, than the Olympus 320R. IMHO, the Iroquois should've been an option for the TSR.2 since it apparently was not beset by the problems the Olympus had.
What's your source for your infomation about the pieces in the UK? ???
And I hate to point this out, but you said two opposite things. The Olympus benifitted from the Iroqious, but was beset by problems? So, what exactly did they did they improve on? :-\
As far as design, Olympus 22R was a progression of the Vulcans engines, which predate the PS.13 as I pointed out. Many engines of this class, be it British, Canadian, American or Russian floowed the same route and are bound to be similar in more ways than one. About the only thing the 22R may have benifitted from is the reheat section, since Vulcans didn't have it (by the way, I think that's the missing 100 inches). Other than that, if the British managed to swipe a PS.13, they really didn't learn much.
Help me out, 'cause what I'm being told isn't adding up... ??? ??? ???
There were items in the news a few years back about the discovery of those parts, I'd have to do some digging to find the references. The Olympus did benefit from some things on the Iroquois, but had some internal problems of it's own (the resonance effect on the engine shaft at certain rpm's is well known). Both Iroquois and Olympus 320R had reheat, and the Iroquois was still shorter by that much. Going from a subsonic engine, such as the Olympus 100 adn 200 series engines in the Vulcan to the supersonic engines like the Olympus 320R for the TSR-2 is a major design step and I believe it was in this that the Iroquois helped the Olympus.
Built but never flown Mirages ;)
Tons of prototypes scrapped in June 1940 (in order they would'nt fall in German hands). Most famous is the Bloch 140, a fabulous bomber (a Bloch 174 with four engines and better performances).

Mirage II (twin gabizo fighter, 1956).
Mirage G4

France considered the Iroquois for the Mirage IVB, but chose the J-75, then the Mirage IVA with Atar. ;D

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