Northrop F-89 Scorpion - Design and Development

Design and Development

The Scorpion stemmed from a 1945 United States Army Air Forces Army Air Technical Service Command specification ("Military Characteristics for All-Weather Fighting Aircraft") for a jet-powered night fighter to replace the P-61 Black Widow. Bell Aircraft, Consolidated-Vultee, Douglas Aircraft, Goodyear, Northrop and Curtiss-Wright all submitted proposals.

Northrop submitted four different designs, prepared by Jack Northrop's team, including a radical flying wing but settled on the N-24, a slim-bodied aircraft with a cantilevered mid-mounted wing and two Allison J35 turbojet engines with afterburners. It was to have radar and a crew of two, with an armament of four 20 mm (.79 in) cannon in a unique trainable nose turret. One of the unusual aspects of the design was the use of Northrop's "Deceleron", a clamshell-style split aileron which could function as a dive brake (like the SBD Dauntless dive bomber's perforated-panel flaps did) or flap as needed on landing approach, that could be accommodated in the slim wing design. The unique feature added to the prototype during development was to become a Northrop trademark, still used today on the B-2 Spirit. Contracts for two prototypes were issued in December 1946, while Douglas with their XF3D-1 Skyknight and Curtiss for their XF-87 Blackhawk prototypes also were awarded development contracts.

The initial XP-89 prototype made its first flight on 16 August 1948, with test pilot Fred C. Bretcher at the controls. For much of the testing period, Curtiss's entry had been the front-runner for the contract, but in a competition fly-off with its main competitors, the Northrop design proved superior. Other USAF interceptors such as the F-94 Starfire and F-86 Sabre had been adapted from day fighter designs.