The Fisher P-75 Eagle was an American fighter aircraft designed by the Fisher Body Division of General Motors. Development started in September 1942 in response to

United States Army Air Forces The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...

requirement for a fighter possessing an extremely high rate of climb, using the most powerful liquid-cooled

engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ...

then available, the

Allison V-3420 The Allison V-3420 was a large experimental piston aircraft engine, designed in 1937 by the American Allison Engine Company. Design and development In 1937, at the behest of the United States Army Air Corps, the Allison Engine Company agreed t ...

. The program was cancelled after only a small number of prototypes and production aircraft had been completed, as it was no longer required in its original role, could not be quickly deployed, and possessed no significant advantages over aircraft already in production.Norton 2008, p. 131.

Design and development

Fisher XP-75-GM In flight (SN 43-46950, 1st aircraft built) 061024-F-1234P-043

In October 1942, the contract for two prototypes, designated "XP-75", was signed with the Fisher Body Division of GM. The design concept was to use the outer

wing A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is e ...

panels from the

North American P-51 Mustang The North American Aviation P-51 Mustang is an American long-range, single-seat fighter and fighter-bomber used during World War II and the Korean War, among other conflicts. The Mustang was designed in April 1940 by a team headed by James ...

, the tail assembly from the Douglas A-24 (SBD), and the undercarriage from the

Vought F4U Corsair The Vought F4U Corsair is an American fighter aircraft which saw service primarily in World War II and the Korean War. Designed and initially manufactured by Chance Vought, the Corsair was soon in great demand; additional production contract ...

in a general layout much as in the

Bell P-39 Airacobra The Bell P-39 Airacobra is a fighter produced by Bell Aircraft for the United States Army Air Forces during World War II. It was one of the principal American fighters in service when the United States entered combat. The P-39 was used by t ...

with the engine located

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with the

contra-rotating propellers Aircraft equipped with contra-rotating propellers, also referred to as CRP, coaxial contra-rotating propellers, or high-speed propellers, apply the maximum power of usually a single piston or turboprop engine to drive a pair of coaxial propell ...

driven through extension shafts. At an early design stage, however,

Curtiss P-40 Warhawk The Curtiss P-40 Warhawk is an American single-engined, single-seat, all-metal fighter and ground-attack aircraft that first flew in 1938. The P-40 design was a modification of the previous Curtiss P-36 Hawk which reduced development time an ...

outer wing panels were substituted for the P-51 panels. In mid-1943, the need for long-range escort fighters became more urgent than fast climbing interceptors so a decision was made to order six more XP-75 airplanes modified for the long-range role. At this time, an order for 2,500 production aircraft was also let, but with the stipulation that if the first P-75A was not satisfactory the complete order might be canceled. At the time, General Motors was busy in several projects towards the war effort, including the mass production of several different aircraft types, among them the

Grumman TBF Avenger The Grumman TBF Avenger (designated TBM for aircraft manufactured by General Motors) is an American World War II-era torpedo bomber developed initially for the United States Navy and Marine Corps, and eventually used by several air and naval a ...

. Some sources claim that the P-75 was the result of a scheme to get General Motors out of being forced to build Boeing B-29 Superfortresses; the P-75 project being a "high-priority" project to help GM avoid the added strain of Superfortress production. The "Eagle" was given extensive media coverage prior to its first flight, being trumpeted as a "wonder plane".O'Leary 1994, p. 81.

Operational history

Fisher P-75A in flight 061024-F-1234P-045

, the XP-75 flew for the first time on 17 November 1943. The second XP-75 flew shortly thereafter, with all six long-range XP-75s entering the test program by the spring 1944. The test program brought up numerous teething problems, including miscalculation of the fighter's center of mass, failure of the engine to produce its expected power, inadequate engine cooling, high aileron forces at high speed, and poor spin characteristics. Redesigns were introduced into the long-range XP-75s including a modified tail assembly, new "bubble" canopy, and a V-3420-23 engine that corrected most of the deficiencies by the time the first P-75A Eagles entered flight testing in September 1944. By this time, the Army Air Forces had decided to limit the number of combat aircraft types in production and not enter into large-scale production of new types that might not be available before the war ended. As the twin-engine Lockheed P-38 Lightning and

demonstrated excellent long-range capabilities, the production run of the P-75A Eagle was subsequently terminated on 6 October 1944. It was decided to use the six completed production aircraft for experimental work and development of the V-3420 engine. As a result of those events, the P-75A did not complete formal performance trials due to termination of the production contract. Ultimately, only eight XP-75s and six P-75As were built.

Aircraft on display

* AAF Ser. No. 44-44553:

National Museum of the United States Air Force The National Museum of the United States Air Force (formerly the United States Air Force Museum) is the official museum of the United States Air Force located at Wright-Patterson Air Force Base, northeast of Dayton, Ohio. The NMUSAF is the ...

at Wright-Patterson AFB in

Dayton, Ohio Dayton () is the sixth-largest city in the U.S. state of Ohio and the county seat of Montgomery County. A small part of the city extends into Greene County. The 2020 U.S. census estimate put the city population at 137,644, while Greater D ...

. For many years this aircraft was on display in the museum's Experimental Aircraft Gallery. Extensive deterioration of the airframe was discovered by the staff in 1999, which forced the Museum to undertake a full restoration of the aircraft. The work has been completed and the aircraft returned to display in the museum's Experimental Aircraft Gallery.

Specifications (XP-75)

References

Notes

External links

Fisher P-75A Eagle Fact Sheet

P-75 in National Museum of the Air Force

A Detroit Dream of Mass-produced Fighter Aircraft: The XP-75 Fiasco

Fisher Body Division Operating Report
– Includes detailed information about the XP-75's production {{Authority control Aircraft with contra-rotating propellers P-075 Eagle Mid-engined aircraft Fisher P-75 Aircraft first flown in 1943