Analysis of an Inclined Thrust Axis as Applied to a Ramjet Propelled Aircraft

Author: Welch, Frank

Year: 1950

Degree: Engineer's thesis

Advisors: Tsien, Hsue Shen; Marble, Frank E.

Committee Member: Unknown, Unknown

Option: Aeronautics

DOI: 10.7907/T1QH-QJ51

Abstract

The low values of lift-drag ratio attained by supersonic wing configurations provide the opportunity for the utilization of an inclined thrust axis. The exhaust jet of a ramjet propelled aircraft is inclined in order to use some of the jet force to supply additional lift. This has the effect of augmenting the lift by the relatively large sine component of the jet force whereas the thrust in the flight direction is reduced only by the smaller change in the cosine component.

It was found that this principle offers a substantial decrease in fuel consumption over that of a normal ramjet for probable values of lift-drag ratios above Mach number 1.5. Almost all of the possible decrease can be obtained with jet inclination angles of 15° or less.

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