Supersonic aircraft jet engine installation
Jet engine inlet structure of a supersonic aircraft comprising the structure having an inlet ramp and an cowl lip spaced outwardly of the ramp so that entering air flows between the ramp and lip, the lip and ramp configured to produce a first oblique shock that extends outwardly from a forward portion of the ramp to pass ahead of the lip, and a terminal shock that extends outwardly from a rearward portion of the ramp to one of the following x o ) a region just ahead of the lip x 1 ) substantially to said lip. A non-uniform shock system is created that generates a central region of nearly isentropic compression and relatively ram recovery and an outer region of reduced ram recovery but entailing reduced cowl angle and drag. Translating cowl structure and also nozzle integration with the fuselage contour to reduce boat tail drag are also provided.
1 . A supersonic aircraft jet engine installation having at least one of the following, A, B and C:
A. an inlet cowl assembly comprising
a) said cowl assembly having three separate generally tubular sections,
b) said sections including a forwardly movable forward inlet section, a second movable bypass section, and a third section fixed to the engine structure,
B. a nacelle in proximity to the aircraft fuselage, and a nozzle comprising
a′) the nozzle having a boat tail portion and an exhaust expansion ramp,
b′) said boat tail portion located laterally closer to the fuselage than the expansion ramp, and
C. engine inlet structure, comprising
a″) an inlet ramp and an cowl lip spaced outwardly of the ramp so that entering air flows between the ramp and lip,
b″) the lip and ramp configured to produce a first obligue shock that extends outwardly from a forward portion of the ramp to pass ahead of the lip, and a terminal shock that extends outwardly from a rearward portion of the ramp to one of the following
x 0 ) a region just ahead of the lip
x 1 ) substantially to said lip.
2 . The combination of claim 1 wherein the engine has at least two of sub-paragraphs A, B and C.
3 . The combination of claim 1 wherein the engine has all of sub-paragraphs A, B and C.
4 . The cowl assembly of claim 1 , sub-paragraph A, wherein the second section has a forwardly translated position relative to the third section wherein a side air intake is opened for bypassing of air into the engine.
5 . The cowl assembly of claim 4 wherein the first section has a forwardly translated position relative to the second section, wherein a circumferential air intake is opened for bypassing of air into the engine.
6 . The cowl assembly of claim 5 wherein the second section has an arcuately blunted leading edge exposed for efficient entrainment of additional intake air at low aircraft speeds, in response to first section translation forwardly relative to the second section.
7 . The cowl assembly of claim 5 wherein the first and second sections have simultaneously forwardly translated positions, relative to the third section, whereby an opening between the second and third sections is increased to allow excess inlet air to bypass to the exterior.
8 . The cowl assembly of claim 6 wherein the first and second sections have simultaneously forwardly translated positions, relative to the third section, whereby a circumferential opening between the second and third sections is increased to allow excess inlet air to bypass to the exterior.
9 . The cowl assembly of claim 7 wherein the first section has a tilt position relative to the second section as the first and second sections are translated forwardly.
10 . The cowl assembly of claim 8 wherein the first section has a tilt position relative to the second section as the first and second sections are translated forwardly.
11 . The combination of claim 7 wherein circumferential openings are opened with co-existence when the first section is translated forwardly relative to the second section, and the second section is translated forwardly relative to the third section.
12 . The combination of claim 7 including actuator means holding the first and second sections in relatively fixed closed positions when the second section is translated forwardly relative and the third section.
13 . The combination of claim 1 , sub-paragraph A, wherein
c) said cowl assembly has forward and rearward separable in line air intake sections,
d) said sections have primary relatively closed positions,
e) said sections have secondary relatively separated positions to provide an air passing gap therebetween,
f) and means for controlling relative tilt of the sections to controllably vary the geometry of said air passing gap.
14 . The combination of claim 13 wherein said f) means includes an actuator operatively connected to the forward section to vary tilt thereof relative to the rearward section.
15 . The combination of claim 1 sub-paragraph B wherein the nacelle has a rearwardmost looping edge defining a nozzle outlet, said edge angled forwardly and toward the fuselage.
16 . The combination of claim 1 sub-paragraph B including a second jet engine that also includes a nacelle in proximity to the fuselage, the second jet engine also extending in a longitudinally forwardly direction and having a nozzle, said engines being at generally opposite sides of the fuselage, the second jet engine also having a boat tail portion and an exhaust expansion ramp wherein the boat tail portion is located closer to the fuselage than the expansion ramp.
17 . The combination of claim 1 , sub-paragraph B, including the fuselage which has reduced lateral cross sections along fuselage length at zones closest to the first jet engine nacelle.
18 . The combination of claim 16 including the fuselage which has reduced lateral cross sections along fuselage length at zones closest to the first and second jet engine nacelles.
19 . The combination of claim 17 wherein the reduced cross sections of the fuselage relative to the first jet engine nacelle define an area ruled configuration or configurations.
20 . The combination of claim 18 wherein the reduced cross sections of the fuselage relative to the first and second jet engine nacelles define an area ruled configuration or configurations.
21 . The combination of claim 17 wherein said boat tail portion and exhaust expansion ramp are located laterally of sections of the fuselage that are increasing in lateral cross section, lengthwise of the fuselage.
22 . The combination of claim 1 sib-paragraph B wherein the aircraft has a wing, the first jet engine nacelle having a forward portion lapping the wing.
23 . The combination of claim 4 wherein the aircraft has a wing, the first jet engine nacelle having a forward portion lapping the wing, and wherein the fuselage has reduced cross sections along fuselage length at zones closest to the first jet engine nacelle forwardmost portion.
24 . The combination of claim 23 wherein the reduced cross sections of the fuselage relative to both the first jet engine nacelle and the wing section closest to the fuselage define an area ruled configuration or configurations.
25 . The combination of claim 16 wherein the aircraft has a wing, both jet engine nacelles lapping the wing.
26 . The combination of claim 15 wherein the first jet engine nacelle has a forward portion lapping the wing, and wherein the reduced cross sections of the fuselage relative to both jet engine nacelles and to wing section or sections closest to the fuselage define an area ruled configuration or configurations.
27 . The structure of claim 1 sub-paragraph C, wherein the ramp in axial radial planes has a first intermediate portion that has outwardly shallow concavity, configured to produce an additional oblique shock or shocks that extend from said first intermediate portion generally forward of said lip and within the flowpath of air through the inlet structure.
28 . The structure of claim 27 wherein said ramp has a relatively intermediate extent that is outwardly relatively straight, and located rearwardly of said first intermediate portion, and followed by a second ramp section that is shallowly concave and configured to produce an oblique shock or shocks that extend from said second intermediate section toward a part of said terminal shock that is spaced from the lip.
29 . The structure of claim 28 wherein the ramp has an additional intermediate extent that is relatively straight and follows said second ramp section, close to the terminal shock.
30 . The structure of claim 1 , sub-paragraph C, on an aircraft engine having a nacelle, and including the aircraft fuselage and wing, the nacelle and cowl lapping the wing and located proximate the side of the fuselage.
31 . The structure of claim 30 wherein the side of the fuselage facing the nacelle is indented.
32 . The structure of claim 30 wherein the cowl lip is angled outwardly and rearwardly from a lateral plane normal to the longitudinal axis of the fuselage.
33 . The structure of claim 30 wherein there are two of said aircraft engines, respectively at opposite sides of the fuselage, the wing located aft of the mid point of the fuselage length.