Thanks folks!
Alex: Well spotted! The de Schelde S.21 was exactly what I was going for ... with all due apologies to Theo Slot
Evan: Yep, Bell offered its prototype Model 18 fighter ... and any similarity to the Me 309 is purely coincidental
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http://beyondthesprues.com/Forum/index.php?topic=351.msg126122#msg126122Agreed on the Vought-Sikorsky concept. Overall, the airframe would've just been too big for the engine. US DB 603, perhaps?
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And now, the final installment on US Hudson V-2070-powered fighters ...
Lockheed had made several attempts to develop a twin-engined fighter under various Model 22 concepts. It was the radial-engined, twin-boomed Model 24 which finally received a contract -- but in the photo-reconnaissance role as the F-4A Lightning. One F-4A airframe was held back for conversion from bulky radials to more streamlined Hudson V-2070 V-12s. Fitted with nose-mounted machine guns, this aircraft was redesignated XP-38
Lightning. [1]
(Top) Lockheed XP-38
Lightning prototype conversion. Note boom-mounted radiators for V-2070 engines.
The production P-38A fighter achieved some success operating from bases in Iceland as a long-range interceptor against German Fw 200 raiders. But, the P-38A was a low-rate production aircraft -- being neither fast enough nor manoeuvrable enough to operate against the best enemy fighters.
Lockheed, together with NACA, had studied methods for improving the Model 24's aerodynamics. The most promising was a new, underslung central fuselage pod. (Centre) Other, non-aerodynamic benefits of this revised fuselage arrangement was greater internal fuel tankage (all close to the aircraft's c/g) and a shorter (and therefore lighter) nose gear. The prototype XP-38 was fitted with such a nacelle as the XP-38C. [2]
(Bottom) Sole prototype Lockheed XP-38C conversion. Note nose-mounted machine guns.
As a fighter, the XP-38C Lightning left much to be desired. It was faster and longer-ranged than the P-38A but visibility from the cockpit was poor in all directions other than directly in front. However, this lack of all-around visibility was not a major disadvantage for the photo-recon role. Accordingly, the XP-38C was disarmed and fitted with camera equipment as the prototype XF-5A
Lightning -- the first of many high-speed photo-reconnaissance F-5As.
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[1] For the production P-38, each V-2070 engine was also to be fitted with a 20 mm motor-cannon.
[2] The XP-38B had been a production P-38A employed as an armaments trials airframe.
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