Consolidated Vultee XP-81

XP-81
Role	Escort fighter
Manufacturer	Consolidated Vultee Aircraft Corporation
First flight	11 February 1945
Status	Cancelled
Primary user	United States Army Air Forces
Number built	2
Unit cost	US$4.6 million for the program[1]

The Consolidated Vultee XP-81 was a development of the Consolidated Vultee Aircraft Corporation to build a single seat, long range escort fighter that combined use of both a turbojet and a turboprop engines. Although promising, the lack of a suitable engine combined with the end of World War II doomed the project.

Design and development

Two prototype aircraft were ordered on 11 February 1944 that were designated XP-81. The engine selection was an attempt to couple the high-speed capability of the jet engine with the endurance offered by the propeller engine. The XP-81 was designed to use the General Electric TG-100 turboprop engine (later designated XT31 by the US military) in the nose driving a four-bladed propeller and an GE J33 turbojet in the rear fuselage. The turboprop would be used for normal flight and cruising and the turbojet added for high-speed flight.

Operational history

The first XP-81 (serial 44-91000) was completed in January 1945 but because of developmental problems the turboprop engine was not ready for installation. A decision was then made to mount a complete V-1650-7 Merlin engine package from a P-51D aircraft in place of the turboprop for initial flight tests. This was done in a week and the Merlin-powered XP-81 was sent to the Muroc airbase where it flew for the first time on 11 February 1945. During 10 flight test hours, the XP-81 displayed good handling characteristics except for inadequate directional stability due to the longer forward portion of the fuselage (this was rectified by enlarging the vertical tail).^[2]

While 13 YP-81 pre-production aircraft had been ordered, the capture of Guam and Saipan removed the need for long-range, high-speed escort fighters and, then, just before VJ Day the contract was cancelled, after 85% of the engineering was completed. The YP-81 was to be essentially the same as the prototype but with a lighter, more powerful GE TG-110 (XT41) turboprop engine, the wing moved aft 10 inches (0.25 m), and armament of either six .50 cal (12.7 mm) machine guns or six 20 mm cannon.

After the XP-81 was returned to Vultee Field, the TG-100 turboprop was installed and flight testing resumed. However, the turboprop engine was not able to produce its designed power; producing only the same output as the Merlin (1,490 hp or 1112 kW) with the resultant performance limited to that of the Merlin-powered configuration.

With the termination of hostilities, the two prototypes continued to be tested until 1947 when they were both consigned to a bombing range as photography targets.^[3][4]

Survivors

• XP-81, s/n 44-91000, is in storage at the National Museum of the United States Air Force near Dayton, Ohio.^[5]

• XP-81, s/n 44-91001, is also in storage at the National Museum of the United States Air Force near Dayton, Ohio.^[6]

Operators

 United States

• United States Army Air Forces (testing only)

Specifications (XP-81)

Note: Performance is estimated with "full powered" TG-100. Armament is projected only.

XP-81 side view.

General characteristics

• Crew: 1
• Length: 44 ft 10 in (13.67 m)
• Wingspan: 50 ft 6 in (15.39 m)
• Height: 14 ft 0 in (4.27 m)
• Wing area: 425 ft² (39.5 m²)
• Empty weight: 12,755 lb (5,786 kg)
• Loaded weight: 19,500 lb (8,850 kg)
• Max takeoff weight: 24,650 lb (11,180 kg)
• Powerplant:
  • 1 × General Electric J33-GE-5 turbojet, 3,750 lbf (16.7 kN)
  • 1 × General Electric XT31-GE-1 (TG-100) turboprop, 2,300 hp (1,700 kW)

Performance

• Maximum speed: 507 mph (440 knots, 811 km/h)
• Range: 2,500 mi (2,200 nm, 4,000 km)
• Service ceiling: 35,500 ft (10,800 m)
• Rate of climb: 5,300 ft/min (26 m/s)
• Wing loading: 106 lb/ft² (518 kg/m²)

Armament

• Guns: 6 × 20 mm (0.787 in) cannon
• Bombs: 2,000 lb (900 kg)

See also

Related development

• Vultee XA-41
  

Aircraft of comparable role, configuration and era

• Fisher P-75 Eagle
• North American F-82 Twin Mustang
• Ryan XF2R Dark Shark
  

Related lists

• List of fighter aircraft
• List of military aircraft of the United States
  

References

Notes

1. ^ Knaack 1978
2. ^ Green 1961, p. 34.
3. ^ Winchester 2005, p. 74.
4. ^ Ginter 2006, pp. 22–23.
5. ^ "AFD-061222-016: Disposition of USAF assets, p. 4." National Museum of the United States Air Force. Retrieved: 18 July 2010.
6. ^ "AFD-061222-016: Disposition of USAF assets, p. 4." National Museum of the United States Air Force. Retrieved: 18 July 2010.

Bibliography

• Ginter, Steve. Consolidated Vultee XP-81 (Air Force Legends Number 214). Simi Valley, California: Ginter Books, 2007. ISBN 0-942612-87-6.
• Green, William. War Planes of the Second World War, Volume Four: Fighters. London: Macdonald & Co. (Publishers) Ltd.,1961. ISBN 0-356-01448-7.
• Green, William and Gordon Swanborough. WW2 Aircraft Fact Files: US Army Air Force Fighters, Part 2. London: Macdonald and Jane's Publishers Ltd., 1978. ISBN 0-354-01072-7.
• Jenkins, Dennis R. and Tony R. Landis. Experimental & Prototype U.S. Air Force Jet Fighters. North Branch, Minnesota, USA: Specialty Press, 2008. ISBN 978-1-58007-111-6.
• Knaack, Marcelle Size. Encyclopedia of US Air Force Aircraft and Missile Systems: Volume 1 Post-World War II Fighters 1945-1973. Washington, DC: Office of Air Force History, 1978. ISBN 0-912799-59-5.
• Winchester, Jim. The World's Worst Aircraft: From Pioneering Failures to Multimillion Dollar Disasters. London: Amber Books Ltd., 2005. ISBN 1-904687-34-2.

External links

• Convair XF-81 on National Museum of the U.S. Air Force