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Aircraft of the Month for March 2000

Fisher P-75 Eagle

XP-75
XP-75

XP-75
The USAAF issued a RFP for a fighter/interceptor with a 28.5m/s (5600ft/min) climb rate, maximum speed of 708km/h (380kt) at 610m (2000ft), an operational ceiling of 11,582m (38,000ft), and a range of over 4023km (2170nm) in February 1942, at a time when they desperately needed a fighter with a high rate of climb. Donovan Reese Berlin, deigner of the Curtiss Model 75 and P-40, submitted his design in 1942. The design used the wings of the P-51, the tail of the A-24, and the landing gear of the F4U, to save cost and time. On 10 October the USAAF ordered two XP-75 prototypes and the name Eagle was assigned. They were built at the Cleveland, OH factory which was been built to build the engine nacelles for the B-29. The XP-75 had the wings of the P-40 instead of the P-51. The most powerful engine available, the 2600hp Allison V-3420-19 24-cylinder model, was mounted mid-fuselage like the P-39 and cooled by a large duct in the ventral fuselage. A long shaft, linked to a reduction gearbox in the nose, drove two three-bladed coaxial conter-rotating propellers. Four .50in (12.7mm) machine guns were located in the nose and the other six were in the outer wing. The first XP-75 (43-46950) first flew on 17 November 1943. The other XP-75s made their first flights in 1944. However, the engine's performance was disappointing and it had a tendancy to overheat. The aircraft also exhibited alarming instability due to its center of gravity being calculated incorrectly.

XP-75 #1
XP-75 #1

(X)P-75A
Before the XP-75 had flown the USAAF realized it needed a long range escort fighter and ordered six considerably changed XP-75A prototype long-range fighters on 6 July 1944. Numerous modifications were made into the XP-75A to correct the faults of the XP-75, including a new cockpit canopy, a residigned tail, and a different engine. By this time the idea of using shared airframe components had to be abandoned. On 7 June 1944 the USAAF ordered 2500 P-75A escort fighters requiring them to meet the specified performance. The XP-75A first flew on 15 September 1944. By the time the first XP-75A had commenced test flights, the P-47 and P-51 had developed enough range to be used as escort fighters for bombing missions over Germany (in the P-47D and P-51D versions), and the USAAF did not neet a new escort fighter. As a result it canceled its order of P-75s on 27 October 1944. Only five were completed and they were used for tests.

P-75A

P-75A
P-75A

Fisher P-75 Eagle Specifications
XP-75XP-75AP-75A
TypeInterceptor/FighterLong-range fighter
PowerplantTwo Allison V-3420-19 24-cylinder double-banked Vee pison engines, 1939kW (2600hp) eachTwo Allison V-3420-23s, 2151kW (2885hp) eachTwo Allison V-3420-23s, 2151kW (2885hp) each
AccommodationPilot only
Armament10 .50in (12.7mm) forward-firing Browning machine guns + 907kg (2000lb) of bombs
10 .50in (12.7mm) forward-firing Browning machine guns + two 227kg (500lb) bombs on racks under the wing center section
Fuel Capacity2021L (534 US gal)/2850L (753 US gal)2415L (638 US gal)/3248L (858 US gal)
Performance
Max speed673km/h (363kt) at 21,600ft650km/h (351kt) at 20,000ft644km/h (348kt) at 20,000ft
Cruising speed505km/h (273kt)
402km/h (217kt)
Landing speed142km/h (76kt)
140km/h (76kt)
Range3299km (1780nm)1851km (1000nm)3460km (1870nm)
Max Range5633km (3040nm)6196km (3350nm)
Service Ceiling1109m (3640ft)11,095m (36,400ft)11,582m (38,000ft)
Absolute Ceiling12,040m (39,500ft)11,582m (38,000ft)No data
Climb Rate21m/s (4200ft/min)18m/s (3448 ft/min)
Weights
Empty5214kg (11,495lb)5105kg (11,255lb)
Gross6263kg (13,807lb)8081kg (17,815lb)8108kg (17,875lb)
MTOW8260kg (18,210lb)8809kg (19,420lb)
Dimensions
Wingspan14.96m (49ft 1in)15.03m (49ft 4in)
Length12.64m (41ft 6in)12.59m (41ft 4in)
Height4.72m (15ft 6in)5.02m (16ft 6in)
Wing Area31.77m² (342sq ft)32.23m² (347sq ft)

Photos courtesy of the US Air Force Museum