Forebody nozzle for aircraft directional control

DETAILED DESCRIPTION Theoretical considerations and an experimental study of the control of forebody vortex flow fields using forebody pneumatic jets are described in the article by Cornelius et al, entitled "An Experimental Study of Pneumatic Vortex Flow Control on High Angle of Attack Forebody Model", AIAA 92-0018 (January 1992), and background material and experimental test results on forebody vortex control provided by the invention are presented in the article by Guyton et al, entitled "X-29 Forebody Jet Blowing", AIAA 92-0017 (January 1992), the teachings of both articles being incorporated by reference herein.
Referring now to the drawings, FIG.
1 is a schematic side view of thrust nozzle 10 of the invention as mounted on surface 11 of the forebody of an aircraft.
FIG 1a is a view in axial section along A--A of FIG.
1, and FIG 1b is a view along line B--B of FIG.
1.
Nozzle 10 structure and sizing according to the invention may best be described in terms of the inner diameter d thereof.
Nozzle 10 may be fabricated from tube stock of internal diameter d selected from considerations of the mass flow requirements and pneumatic pressure supply of a particular system to which nozzle 10 is applied.
Accordingly, nozzle 10 may comprise short upright tubing section 13 to which is joined at preselected angle a short section 15 of tubing, or, alternatively, sections 13,15 may be configured as a single angled tubing segment.
Section 13 is chosen to have a centerline length l.
sub.
1 of about 1.
0 to 1.
3 times d and preferably 1.
1d, and section 15 is selected to have a centerline length l.
sub.
2 of about 1.
4 to 1.
7 times d and preferably 1.
5d.
The invention works best with diametric slot 19 cut in the end of section 15, shown in FIGS.
1a,1b,1c in a plane substantially coincident with l.
sub.
1 and l.
sub.
2.
Test data referenced herein shows that slot 19 effect is maximum when the width a is about 0.
5 to 0.
9 times d and preferably about 0.
75d, and slot 19 length b is about 0.
75 to 1.
25 times d and preferably about 1