Ernie P.

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That would be it, rcguy59. Congratulations and you are now up to ask the next question. Thanks; Ernie P.


What warbird do I describe?
Clues:

1. This aircraft suffered from being “not available for production within the required time”. IOW; it couldn’t be brought into large scale production before the need had passed.
2. In addition, it was argued that the new aircraft could not do anything that couldn’t be done almost as well by existing aircraft already in production.
3. Part of the problem was that it was designed to fill one set of requirements; and then the requirements were changed completely.
4. Essentially, it was originally to have fulfilled one role; and then another role was substituted.
5. It was essentially a Frankenstein aircraft; a part of this one, a piece of that one; some of this and some of that; and a bit of the other.
6. Despite which it was actually a very capable aircraft.
7. The prototype aircraft were delivered, designed to meet the original requirements.
8. But the needs of the service had changed, and now they urgently needed a different type of aircraft.
9. So, a small handful of aircraft were ordered, modified to meet the new requirements.
10. A pretty sizeable order for the modified aircraft was also made; but with the stipulation that the entire order could be cancelled if the modified aircraft weren’t satisfactory for their new role.
11. And, guess what? By the time the modified aircraft was ready for production, the “urgent need” had passed and the powers that be decided it wasn’t satisfactory. So the order was cancelled.
12. In all, less than 20 (combined) of both variants were produced.
13. It had a great name.
14. It also had some initial development problems, as most new aircraft do.
15. The designers had missed the center of gravity a little bit.
16. The new engine wasn’t delivering the expected power, and it tended to overheat.
17. Worse, one of the control surfaces took a lot of effort to move in flight.
18. And even worse than that was the poor spin characteristics.
19. Corrections were made; a new canopy design, some engine improvements and a modified tail assembly.
20. From first flight of the modified aircraft to the date everything had been corrected was around nine months.
21. But nine months after the order had been placed, the world looked a lot different.
22. By then, the need for a new aircraft had passed. Existing aircraft were getting the job done, and the end was in sight.

Answer: The General Motors/Fischer P-75 Eagle

The General Motors/Fisher P-75 Eagle was a fighter aircraft designed by the Fisher Body Division of General Motors. Development started in September 1942 in response to United States Army Air Forces requirement for a fighter possessing an extremely high rate of climb, using the most powerful liquid-cooled engine then available, the Allison V-3420. 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.

[h=2]Design and development[/h]
The first XP-75 in flight
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 panels from the North American P-51 Mustang, the tail assembly from the Douglas A-24 (SBD), and the undercarriage from the Vought F4U Corsair in a general layout much as in the Bell P-39 Airacobra with the engine located amidships with the propeller driven through an extension shaft. At an early design stage, however, Curtiss P-40 Warhawk 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. 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. Bearing the name, "P-75 Eagle" was significant as the designation harkened back to the French 75 gun in World War I, considered a symbol of defeating the Germans. The "Eagle" was given extensive media coverage prior to its first flight, being trumpeted as a "wonder plane". The designations XP-73 and XP-74 were never issued.

[h=2]Operational history[/h]
Fisher P-75 Eagle on display at the National Museum of the USAF in the Research & Development Gallery
Powered by a V-3420-19 24-cylinder engine rated at 2,600 hp driving co-axial contra-rotating propellers, 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 test in September 1944.
By this time, the Army Air Force 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, along with the single-engine Republic P-47 Thunderbolt and North American P-51 Mustang, demonstrated excellent long-range capabilities, the production run of the P-75A Eagle was substantially 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.

[h=2]Specifications (XP-75)[/h]
Fisher XP-75 3/4 front view (S/N 43-46950)
General characteristics

• Crew: One
• Length: 40 ft 5 in (12.32 m)
• Wingspan: 49 ft 4 in (15.04 m)
• Height: 15 ft 6 in (4.72 m)
• Wing area: 347 ft² (32.24 m²)
• Empty weight: 11,495 lb (5,214 kg)
• Loaded weight: 19,420 lb[SUP][7][/SUP] (8808 kg)
• Max. takeoff weight: 18,210 lb (8,260 kg)
• Powerplant: 1 × Allison V-3420-23 liquid-cooled 24-cylinder double-Vee, 2,885 hp (2,150 kW)

Performance

• Maximum speed: 433 mph (697 km/h) at 20,000 (6,100 m)
• Range: 2,050 mi (3,300 km)
• Service ceiling: 36,400 ft (11,100 m)
• Rate of climb: 4,200 ft/min (21.3 m/s)
• Wing loading: 39.8 lb/ft² (194.3 kg/m²)
• Power/mass: 0.21 hp/lb (0.34 kW/kg)

Armament

• 6x .50 caliber (12.7 mm) wing mounted machine guns
• 4x .50 caliber (12.7 mm) fuselage mounted machine guns
• 2x 500 lb (227 kg) bombs