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The Boeing XP-4 was a prototype United States biplane fighter of the 1920s that was grounded permanently after just 4.5 hours of flight testing.
Development and design
In 1926, the United States Army was very interested in the turbo-supercharger as a way of improving engine performance, and requested that one be added to the last of the PW-9s, and the engine upgraded to a 510 hp Packard 1A-1500. This machine was designated XP-4.
In addition, the basic PW-9 armament of one .50 and one .30 cal. machine guns in the nose was supplemented by two added .30 cal. guns mounted under the lower wing, far enough out to be outside the propeller arc (thus not needing synchronization).
All these modifications added weight, so the lower wing span was extended by 9.5 feet.
The airplane was delivered to Wright Field for testing on July 27, 1927, but it quickly became apparent that the Packard engine did not have sufficient power to compensate for the 800 lbs of extra weight, the craft performing more poorly than its predecessor, and the project was quickly abandoned.
pecifications (XP-4)
aircraft specifications
plane or copter?=plane
jet or prop?=prop
ref= Fighters of the United States Air Force [ Dorr and Bishop 1990, p.33-34.] ]crew=One
capacity=
length main= 23 ft 11 in
length alt= 7.29 m
span main= 32 ft 1 in
span alt= 9.78 m
height main= 8 ft 10 in
height alt= 2.69 m
area main= 245 ft²
area alt= 22.8 m²
airfoil=
empty weight main= 2,783 lb
empty weight alt= 1,264 kg
loaded weight main=
loaded weight alt=
useful load main=
useful load alt=
max takeoff weight main= 3,650 lb
max takeoff weight alt= 1,655 kg
more general=
engine (prop)=Packard 1A-1500
type of prop=supercharged liquid cooled piston engine
number of props=1
power main= 510 hp
power alt= 380 kW
power original=
propeller or rotor?=
propellers=
number of propellers per engine=
propeller diameter main=
propeller diameter alt=
max speed main=146 knots
max speed alt= 168 mph, 270 km/h
cruise speed main= 104 knots
cruise speed alt= 120 mph, 193 km/h
never exceed speed main=
never exceed speed alt=
stall speed main=
stall speed alt=
range main= 326 NM
range alt= 375 mi, 604 km
ferry range main=
ferry range alt=
ferry range more=
ceiling main= 22,850 ft
ceiling alt= 6,965 m
climb rate main= 1,400 ft/min
climb rate alt= 7.1 m/s
loading main=
loading alt=
thrust/weight=
power/mass main=
power/mass alt=
more performance=
guns= one 0.3 in and one 0.5 in machine guns firing through propellor disc "plus" two wing mounted 0.3 in machine guns
bombs=
rockets=
missiles=
hardpoints=
hardpoint capacity=
avionics=
ee also
aircontent
related=
similar aircraft=
lists=
* List of military aircraft of the United States
* List of fighter aircraft
References
Bibliography
*
* Dorr, Robert F. and Donald, David. "Fighters of the United States Air Force". London: Temple, 1990. ISBN 0-600-55094-X.
* Lloyd S. Jones, "U.S. Fighters" (Aero Publishers, Inc., 1975) pp. 20-22 ISBN 0-8168-9200-8
External links
* [http://home.att.net/~jbaugher1/p4.html Joe Baugher page on the XP-4]
* [http://www.wpafb.af.mil/museum/research/p4.htm USAF Museum page, with pictures]
