McDonnell XP-67
XP-67 "Bat" / "Moonbat" | |
---|---|
Role | Interceptor |
Manufacturer | McDonnell Aircraft
|
First flight | 6 January 1944 |
Status | Cancelled on 13 September 1944 |
Primary user | United States Army Air Forces |
Number built | 1 |
The McDonnell XP-67 "Bat" or "Moonbat"
Design and development
This section includes a list of general references, but it lacks sufficient corresponding inline citations. (February 2017) |
Origins
In 1940, the U.S. Army Air Corps issued Request for Proposal R-40C, requesting designs for a high-speed, long-range, high-altitude interceptor intended to destroy enemy
Final design
McDonnell engineers returned on 30 June 1940 with the Model II, which was also rejected, so it was reworked into the Model IIa, which emerged on 24 April 1941. The new design was powered by a more traditional layout, a pair of engines in wing-mounted nacelles with four-bladed propellers in a tractor configuration. However, the design was still quite ambitious; the design team tried to maintain a true airfoil section through the center fuselage, merge the rear portions of the engine nacelles with the wing, and radically fillet all edges of the fuselage and nacelles into the wings in an effort to reduce drag. The design used laminar airfoil sections throughout. McDonnell designers promised that the design would deliver a top speed of 472 mph (760 km/h) with a gross weight of 18,600 lb (8,440 kg), although the anticipated gross weight was soon increased to a somewhat more realistic 20,000 lb (9,070 kg).
On 30 September 1941, the
Testing
An extensive aerodynamic test program of the numerous advanced aspects of the design was begun by McDonnell,
The first XP-67, 42-11677, was ready for ground trials on 1 December 1943. The aircraft was fitted with XIV-1430-17/19 engines and General Electric D-23 turbo-superchargers but no pressurization equipment or armament was installed. On 8 December, the aircraft was damaged by fires in both engine nacelles, caused by a malfunction of the exhaust manifold slip rings. By 6 January 1944, the damage was repaired and the XP-67 made its first flight, which ended after six minutes due to engine trouble. After modifications were made to the engine installations, two test flights were carried out. On the fourth flight, the engine bearings burned out when the engines were accidentally overspeeded.
By this time, it was becoming obvious that the XP-67 was hampered by a serious lack of power. The engines were only delivering 1,060 hp (790 kW), well short of their promised 1,350 hp (1,007 kW) rating.
Trials
On 23 March 1944, flight trials restarted. U.S. Army Air Forces pilots finally got to fly the aircraft on 11 May 1944, and judged the cockpit layout fair and ground handling satisfactory, but deemed the aircraft underpowered due to its poor initial rate of climb, slow acceleration, and long takeoff roll, particularly when operating with only one engine.
Upon return to the factory, the cooling ducts were reworked. Several problems were cured during the ensuing test flights, but the engines continued to be plagued by chronic overheating and deficient power output. The XP-67 only reached a confirmed top speed of 405 mph (652 km/h), which was far short of its promised top speed of 472 mph (760 km/h), and was unremarkable compared to other fighters in service at the time.
Cancellation
On 6 September 1944, the
The destruction of the lone flying prototype dealt a serious blow to the entire program because the second prototype was only 15% complete at the time. Army leaders decided to reevaluate the XP-67, ultimately deciding on 13 September that it offered no significant advantages over existing fighters already in service.[6] The project was canceled, the remains of the first prototype scrapped, and work halted on the second prototype.[N 3]
Specifications (XP-67)
Data from McDonnell Douglas Aircraft since 1920[7]
General characteristics
- Crew: one, pilot
- Length: 44 ft 9.25 in (13.65 m)
- Wingspan: 55 ft 0 in (16.76 m)
- Height: 15 ft 9 in (4.80 m)
- Wing area: 414 sq ft (38.50 m2)
- Empty weight: 17,745 lb (8,049 kg)
- Gross weight: 22,114 lb (10,031 kg)
- Max takeoff weight: 25,400 lb (11,521 kg)
- Powerplant: 2 × Continental XIV-1430-17/19 twelve cylinder inverted vee liquid-cooled engine, 1,350 hp (1,007 kW) each
Performance
- Maximum speed: 405 mph (650 km/h, 352 kn) at 25,000 ft (7,600 m)
- Cruise speed: 270 mph (435 km/h, 235 kn)
- Range: 2,385 mi (3,837 km, 2,074 nmi)
- Service ceiling: 37,400 ft (11,400 m)
- Rate of climb: 2,600 ft/min (12.7 m/s)
- Wing loading: 53.4 lb/sq ft (260 kg/m2)
- Power/mass: 0.12 hp/lb (0.2 kW/kg)
Armament
- Guns: 6 × 37 mm (1.46 in) M4 cannons(never installed in prototype)
See also
Aircraft of comparable role, configuration, and era
- Westland Dreadnought - an earlier type having all-aerofoil aerodynamic profiles
- Curtiss XP-71
Related lists
- List of aircraft of World War II
- List of military aircraft of the United States
References
Notes
- ^ It is unclear if either name was an official USAAF designation; both are used in various sources. It is possible that both are informal nicknames that refer to the aircraft's unique appearance.
- ^ The USAAC became the USAAF on 20 June 1941.
- ^ The ultimate fate of the incomplete second prototype is not revealed in the consulted reference sources.
Citations
- ^ Boyne 2001, p. 146.
- ^ Boyne 2001, p. 148.
- ^ a b Boyne 2001, p. 149.
- ^ a b Baugher, Joe. "McDonnell XP-67." Joe Baugher's Encyclopedia of American Military Aircraft: USAAC/USAAF/USAF Fighter and Pursuit Aircraft, Original Fighter Series-1922 to 1962, 18 September 1999. Retrieved: 27 January 2009.
- ^ a b c Boyne 2001, p. 150.
- ^ a b Mesko 2002, p. 5.
- ^ Francillon 1979, p. 372.
Bibliography
- ISBN 1-57488-368-2.
- Francillon, René J. McDonnell Douglas Aircraft since 1920. London: Putnam & Company Ltd., 1979. ISBN 0-370-00050-1.
- Mesko, Jim. FH Phantom/F2H Banshee in action. Carrollton, Texas, USA: Squadron/Signal Publications, Inc, 2002. ISBN 0-89747-444-9.
- Richardson, Steve & Mason, Peggy. McDonnell XP-67 "Moonbat". (X-Planes, Vol. 17.) Oxford: Osprey Publishing, 2022. ISBN 978-1-4728-5303-5