Where was the engine located in the Bell P-39 Airacobra?

Short answer

In the center of the fuselage, behind the pilot: the P-39 drove a propeller in the nose through a long shaft. That shaft, 10 feet (3 m) long and built in two sections, ran through a tunnel in the cockpit floor to a gearbox housed in the nose.

Published: November 5, 2026 · Updated: November 5, 2026 · Edited by Above Ten Thousand · Editorial policy

Where was the engine located in the Bell P-39 Airacobra?

Bell P-39 Airacobra 061019 F-1234P 020

Engine behind the pilot

The P-39 had an unusual layout, with the engine mounted in the center of the fuselage, behind the pilot, driving a propeller in the nose through a long shaft. The aircraft, originally known as the Bell Model 4, was designed to serve as a platform for the 37 mm T9 cannon. It was also the first fighter fitted with tricycle landing gear. Bell's limited prior work in fighter design had earlier produced the unusual Bell YFM-1 Airacuda.

The drive shaft

The tractor propeller was driven by a 10-foot (3 m) shaft built in two sections, which incorporated a self-aligning bearing to absorb fuselage flexing during violent maneuvers. That shaft ran through a tunnel in the cockpit floor and connected to a gearbox in the nose of the fuselage, which in turn drove the three-blade propeller — or four-blade on later examples — through a short central shaft.

Production and shipments to the USSR

P-39 production ended in August 1944, after Bell built 9,558 Airacobras. Nearly half of all P-39s were sent to the Soviet Union, where they accounted for more than a third of all fighters supplied by the United States and the United Kingdom to the VVS. Those shipped to the USSR under the Lend-Lease program were mostly -39N and -39Q models.