Consolidated Vultee XF-81
     The XF-81 was designed to solve the very limited range problem
 of early jet fighters. The aircraft had two engines: a General
 Electric XT-31 gas turbine turboprop of 1,650 hp. and an Allison
 J-33 turbojet of 3,750 lbs. thrust. The concept was to use use the
 turbojet only during combat and takeoff and the turboprop for
 cruise.
     Two XF-81's were ordered (S/N 44-91000, 44-91001) on 11 Feb 44.
 The first flight was 11 Feb 45; however, because of delays with the
 turboprop engine, a Packard V-1650 "Merlin" engine was fitted to the
 aircraft instead. Convair retrofitted the first aircraft for the
 XT-31 which flew for the first time with the design configuration
 on 21 Dec 45.
     Performance with the turboprop was barely better than with the
 Merlin and disappointing overall. An order for 13 YF-81's was
 canceled, but the XF-81's continued as test aircraft until
 29 Sep 47 when they were declared obsolete.
 TYPE      Number built/Converted
 XF-81             2
 YF-81             0
 Remarks
 1st AF turboprop fighter  13 canceled
 SPECIFICATIONS
 Span: 50 ft. 6 in.
 Length: 44 ft. 10 in.
 Height: 14 ft. 0 in.
 Weight: 24,650 lbs. max.
 Armament: Designed for six .50-cal. machine guns or six 20mm cannon
 and two 1,000 lb. bombs
 Engines: One Allison J-33 and one General Electric T-31 gas turbine
 Crew: One
 PERFORMANCE
 Maximum speed: 507 mph
 Cruising speed: 275 mph (turboprop only)
 Range: 2,500 miles
 Service Ceiling: 35,500 ft
 ===
--- DB 1.39/004487
---------------