The four engine fighter – part two

As World War II ended, the new jet technology made the U.S. Army Air Forces Air Technical Service Command issue a specification (military characteristics for all-weather fighting aircraft) for a jet-powered night fighter to replace the P-61 Black Widow.

Several companies entered the competition, but the sentimental favorite was the Curtiss-Wright company – one of the oldest military aircraft producers in the United States and one that had produced memorable aircraft like the Curtiss “Jenny” and the “Hawk” fighter.

However, the company had languished since the mid-1930s. During World War II, Curtiss had shown a singular lack of innovation. It’s P-40 “Warhawk,” while famous from its work with the Flying Tigers, was a decidedly second rate fighter.

While the company had produced many prototypes, only its C-46 Commando had become a successful production aircraft, and that was considered a poor second to the Douglas C-47. The bottom line was if Curtiss Wright lost the night fighter contract, it would mean the company would go out of business.

The Curtiss design was the XP-87 – a large, conventional looking aircraft with straight flying surfaces, a high mounted tail and tricycle landing gear. A large radar was carried in the nose and the engines were carried in nacelles on each wing at mid-span.

What was mounted in the nacelles, however, was not usual. Instead of two engines, as might be expected, the low thrust of the jet engines at the time meant that each nacelle had to carry two Westinghouse XJ-34 engines with 3,000 pounds of thrust for a total of four, making it a four engine fighter.

There were other unusual features. The pilot and radar operator sat side-by-side, rather than in the normal tandem two-man cockpit, but the ergonomics of the side-by-side seating were excellent, having been designed and tested before the prototype aircraft was finished.

Another unusual feature of the XF-87 was its armament. In the large nose, under the radar, the XF-87 was to carry the Martin XMX-769 remote-controlled, moveable turret with a wide angle of fire. The turret was to carry four 20 millimeter cannons.
The XP-87 prototype was built in Columbus, Ohio, and then shipped to Muroc Air Force Base in California for tests in early November 1947. An accident on the way (the tall tail hit a bridge span) delayed the first flight until March 1, 1948.

The Curtiss test pilots found some problems. The four J-34s were unreliable, there was significant buffeting in the tail that kept the aircraft from reaching its maximum speed and altitude and it was 12 percent slower than predicted.
Air Force test pilots found that the stall speed was exceptionally high and its high altitude maneuverability needed improvement.

To fix these problems, Curtiss proposed sweeping back the tail surfaces to fix the buffeting and adding a larger wing and more powerful engines – only two, but with afterburners.

The Air Force agreed, and on June 10, 1948, they ordered 57 F-87A night fighters and 30 RF-87 reconnaissance versions. The next day on June 11, 1948, the Air Force changed all its “P” (Pursuit) designated aircraft to “F” (Fighter) and it became the XF-87, informally named the “Blackhawk” for its glossy, all-black color scheme.
Unfortunately for Curtiss-Wright, the XF-87 had to take part in a fly off with competitors – the twin engine Northrop XF-89 Scorpion and the Douglas X-F3D Skyknight from the Navy.

Though the XF-87 was the initial favorite, the XF-89 proved to be a superior, if not spectacular, performer and won the contract.

The F3D, though superior to both, was apparently never considered because it was a Navy aircraft.

On Oct. 10, 1948, the U.S. Air Force cancelled the F-87 program including the orders for the F-87As and RF-87s. This ended Curtiss-Wright as a player in the military aircraft market. It was sold to North American Aviation and its Columbus plant used it to produce F-86 Sabres.

Interestingly, when the Korean War began in 1950, the F-89 was in the throes of huge developmental problems and was not sent into combat.

The Air Force had to make do with a night fighter version of the Air Force’s T-33 jet trainer – the F-94, which was only marginally successful compared to the rejected Navy’s F3D. And probably all of these were inferior to a German jet night fighter in production in 1945 – the Messerschmitt Me 262B-1a/U1, which was equipped with FuG218 radar.

For questions or comments, contact Dr. Michel at marshall.michel@ramstein.af.mil.