How many engines was the AWACS aircraft planned with in…

How many engines was the AWACS aircraft planned with in 1970?

Short answer

Eight: Boeing dropped a clean-sheet aircraft because tests indicated it would not outperform the already operational 707, and the 707-based design was to carry eight General Electric TF34 engines to boost endurance. In July 1970 Boeing was chosen over McDonnell Douglas's DC-8-based proposal.

Published: November 4, 2026 · Updated: November 4, 2026 · Edited by Above Ten Thousand · Editorial policy

How many engines was the AWACS aircraft planned with in 1970?

Boeing 707 Air India Basle - 1976Eduard Marmet (CC BY SA), vía commons

From an own design to a 707 with eight turbofans

Boeing initially proposed an aircraft designed specifically for the mission, but tests indicated it would not perform better than the already operational 707, so the latter was chosen instead. To increase endurance, the 707-based design was to be powered by eight General Electric TF34 engines.

The AWACS competition

In 1963 the USAF requested proposals for an airborne warning and control system (AWACS) to replace its EC-121 Warning Star aircraft, which had spent more than a decade in the airborne early warning role. Contracts were awarded to Boeing, Douglas and Lockheed, and the latter was eliminated in July 1966; in 1967 a parallel program was opened to develop the radar, in which Westinghouse Electric and Hughes Aircraft competed for the system. In July 1970 Boeing was selected over McDonnell Douglas's DC-8-based proposal.

What came out of it

The E-3 Sentry's airframe is a modified Boeing 707-320B Advanced. E-3s are commonly known as AWACS. The E-3's unpressurized rotodome measures 9.1 m (30 ft) in diameter and 1.8 m (6 ft) thick at the center, and is held 3.4 m (11 ft) above the fuselage by two struts. Production ended in 1992, after 68 aircraft were built.