Fisher XP-75 / P-75 Eagle (2024)

History of Fisher XP-75 / P-75 Eagle

When World War II hit the United States, General Motors became a major player in American manufacturing. With its auto factories adept at mass production, it's fitting that the U.S. military turns to such facilities to produce war gear such as bullets, guns, tanks, and of course, aircraft.

GM has a smooth transition to production on new orders (domestic and foreign) and already has a presence in the aircraft industry with Allison Engines.

Allison is a major supplier of aircraft engines to the U.S. Army and begins development of a new series called the V-3420, which is a combination of two V-1710 series engines. In theory it was a very powerful engine, but it was completely untested in the real world wartime market.

Still, a new product guaranteed new sales for the division, and GM didn't want to abandon the development of its new engine -- not during a world war.

By 1942, the war unfolded with increasing pain for the U.S. military. While the North American P-51 Mustang, Republic P-47 Thunderbolt, and Lockheed P-38 Lightning have successfully assembled a line of legendary "stalking fighters", these planes typically don't reach their true pinnacle for years to come. Therefore, the need for More powerful, high-flying and deadly interceptors to help repel any air superiority the Luftwaffe had before that.

Therefore, it was necessary to develop a fighter jet capable of dealing lethal blows to fighters and bombers and dealing with incoming threats with excellent climb capability and top speed.

General Motors saw this as a great opportunity to introduce a new Allison engine and rebuilt its Fisher Body Plant in Cleveland, Ohio to produce not only the Allison engine but a new Interceptor to To meet the needs of the U.S. Army. So they awarded a design that specifically matched their engine and submitted it for review. It's surprising that the U.S.

Army took notice and embraced GM's idea -- especially given that this new fighter could be produced quickly while still meeting the Army's required performance requirements. The contract called for two complete prototypes and specified the XP-75 designation.

In order to keep the design and development of the new system simple, the idea proposed was to build the aircraft from proven components of the existing airframe, with the entire mixture built around the Allison V-3420. The outer wing surfaces were towed from the P-51 Mustang, while the wings themselves were originally planned to resemble the inverted "gull-wing" setup on the Vought F4U Corsair fighter.

Inverted gull wings were removed from the design and replaced with wings from the Curtiss P-40 Warhawk, although the F4U's landing gear was still chosen. The tail was supposed to consist of the systems of the Douglas Dreadnought dive bomber.

The end result became one of the most unique - if not dysfunctional - aircraft designs to emerge in WWII. The fuselage became slender, and the co*ckpit was located quite far in front of the low-lying monoplane. The nose protrudes slightly and is covered with a set of counter-rotating three-bladed propellers (six blades on the nose).

The design called for the Allison engine to be mounted mid-fuselage, with driveshafts running below the co*ckpit floor and connected to each propeller system. As a liquid-cooled engine, the V-3420 does not require an air cooler and can be installed as such.

The radiator is powered by two blades mounted under the rear of the fuselage. The rear wing retains its curved character, with a smaller vertical rear wing and accompanying horizontal plane on top.

The landing gear consists of two main landing gear (one mounted under each wing) and a small tail wheel. The canopy initially featured a heavy-duty frame that provided adequate visibility around the fuselage. Overall, the XP-75 is built with an all-metal stress skin.

As with most other WWII "X" aircraft design attempts, weapons played an increasingly important role in lethality. American fighter jets tend to prefer the proven high rate of fire of the air-cooled Browning. 50 caliber machine guns, almost always mounted in pairs on the wings or upper forward fuselage. Other world powers at the time preferred the more powerful 20mm, 30mm and 37mm cannons, albeit at slower rates of fire and supplemented by machine guns. So Fisher XP-76 will have 6 x . 50 caliber machine guns on their wings (of the P-40 Warhawk) and an additional 4 x .50 caliber machine guns on her upper forward fuselage.

This 10-machine gun would have made the XP-75 impressive with a single shot, but fate was that none of the advancing XP-75s (or production P-75s) had the armament installed.

As it prepares the plane for production, GM sinks into the patriotic fervor that hangs over corporate America. In response, the XP-75 is now named "Eagle". The XP-75 was completed and flew for the first time on November 17, 1943.

The initial results of the XP-75 in the air were far from what the U.S. Army or General Motorsor Allisonhad envisioned. The system proved to be severely challenged and sluggish in control. The overall performance was far from what was advertised, and everyone blamed the Allison engine as the culprit.

The second completed prototype soon joined the first in the air, and their Allison engine produced similar results.

As the war unfolded, the U.S. Army changed its stance on the current product. While the original 1942 request identified the need for a new pursuit fighter to fit the interceptor mold, advances in air and ground warfare in 1943 instead led to a new need for long-range "penetrating" fighters. Aircraft now require long-range capabilities to escort bombers deep into enemy territory for defense, leaving formations tangled with equally skilled enemy fighters.

Still, the Army saw some promise for the XP-75 and ordered 2,500 production P-75 Eagles.

Knowing that the specification completely changed their plans, Fisher submitted a new contract to purchase six additional prototypes to meet the Army's changing requirements. Work on the further development of the basic design of the XP-75 began immediately after the order was placed.

The improved Allison powerplant came under the name V-3420-23 and promised improved performance and performance. The old frame canopy has also been redesigned into a more modern "bubble" assembly, providing a greatly increased viewing angle from the pilot's seat. To meet the long-range mass of the penetration fighter, additional fuel tanks were added.

A new tail unit with a larger vertical tail and associated vertical tail unit was installed.

Six long-range XP-75 Eagles are ready for further testing and validation. These systems perform as well as their predecessors, but fall well short of expectations. As a fighter jet, the XP-75 is simply too big, an underpowered aircraft, and not much use.

Since the XP-75 is practically useless in any combat environment, its maneuverability and handling suffer as well.

By 1944, production of other tried and tested systems was well underway, and the war had begun to turn in many ways in the Allies' favor. Thus, the XP-75 program was completely phased out by the U.S. Army on October 6, 1944, putting an end to the failed Eagle program.

Despite the cancellation, the Army allowed the construction of six P-75s (P-75A-1-GC) to test the Allison engine for future use.

Testing of the engine proved to be a limited effort, resulting in the loss of the first prototype in an accident. The rest were left to their own equipment, with only one example surviving in the scrap yard as a (fully restored) museum exhibit at the U.S. Air Force Museum in Dayton, Ohio.

Fisher assigns the following performance specifications to its aircraft. Many of those numbers are estimates, but the pesky Allison V-3420-23 (rated at 2,600 hp) never hit it: a top speed of 404 mph and a cruising speed of 250 mph. 40,000 feet of service cap with a climb rate of 4,200 feet per minute.

Range is estimated at 1,150 miles. The reported weight is 11,255 pounds empty and 19,420 pounds fully loaded.

The first two prototypes have serial numbers 43-46950 and 43-46951. The serial numbers received by the remote XP-75 are 44-32161, 44-32162, 44-32163, 44-32164, 44-32165, and 44-32166. The six production Adlers received serial numbers 44-44549, 44-44550, 44-44551, 44-44552, 44-44553 and 44-44554.

Fisher XP-75 / P-75 Eagle Specification

Basic

Year:

1943

Status:

Cancel

Staff:

1

Production

[14 units]:

Fisher Plant (General Motors) - USA

Roles

Dimensions

Length:

12.59m

Width:

49.31 ft (15.03 m)

Height:

15.49 ft (4.72 m)

Weight

Curb Weight:

5,105 kg

MTOW:

8,808 kg

(difference: +8.164lb)

Performance

1 x Allison V-3420-23 inline piston engine (rear mounted) producing 2,600 hp and driving 2 x three-bladed nose mounted propeller units.

Performance

Maximum Speed:

404 mph (650 km/h; 351 knots)

Service Limit:

40,000 ft (12,192 m; 7.58 mi)

Maximum range:

1,150 miles (1,850 km; 999 nautical miles)

Rate of climb:

1,280 m/min (4,200 ft/min)

Armor

Changes

XP-75 "Eagle" - basic series name