Tests on an engine installation for a slender gothic wing at M=1.82

Tests on an engine installation for a slender gothic wing at M=1.82

Griffiths, R.T.

Royal Aircraft Establishment RAE

1964-08-31

Tests were made at M = 1·82 over an incidence range of ±10º on an engine installation mounted at the rear of an uncambered slender gothic wing with different values of the boundary layer bleed height and at various mass flow ratios. In addition an investigation was made of the flow conditions at the inboard and outboard edges of the inlet and of the effects of the nacelles on the longitudinal characteristics of the wing. The installation represented a design in which four engines were mounted side by side in each of two nacelles, one on each half of the wing with the engines partially buried in the wing. It was found aerodynamically preferable to mount the engines on the lower rather than the upper surface of the wing in order to avoid the possibility of the leading edge vortices entering the intake and to take advantage of the reduced local Mach number present under lifting conditions. With a reasonable boundary layer bleed height, addition of the nacelles to the wing caused a 15% increase in drag, almost independent of incidence. About 30% of this increase was the drag of the boundary layer bleed duet; the remainder could be calculated closely from a knowledge of the nacelle geometry. The nacelles caused small displacements of the lift and pitching moment curves.

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Ministry of Aviation, Royal Aircraft Establishment

Campus only

RAE Technical Note No. Aero 2982

Aerospace Engineering Reports

report

© 1964 Ministry of Aviation, Royal Aircraft Establishment