Presentation on theme: "The BLACKBIRD, revisited in BLACKSBURG. Presented by: Pedro De Oliveira Michael Libeau on April 21, 2000."— Presentation transcript:
The BLACKBIRD, revisited in BLACKSBURG. Presented by: Pedro De Oliveira Michael Libeau on April 21, 2000.
Motivation for the project American intelligence forecasted U-2 vulnerability –Subsonic cruise speed –70 kft ceiling –1750 nm range Improved Russian missile technology plotted (SAM’s) U-2 being shot down on May 1, 1960 over U.R.S.S. reinforced the idea Government asked for a new aircraft –low radar cross-section aircraft –Mach 3+ cruising speed (continuous!) –altitudes in excess of 80 kft.
SR-71A General Data Primary function: Strategic Reconnaissance Wing span = 55 ft 7in (16.942 m) Length = 107 ft, 5 in (32.741 m) GTOW = 140,000 lbf (63,500 kgf) Engine@Thrust = 2 J58@32,500 lbf (65,000 lbf SLST) Max speed = Mach 3.31 (World record speed) Rate of Climb = 10,000+ fpm Ceiling = 85,069 ft (also a World record) Range = 2,982 nm at Mach 3, 74,740 ft, on internal fuel Endurance on internal fuel, at loiter speed= 7h, At above range 1h20min over target area Manufacturer: Lockheed (McNamara ordered tooling destroyed)
Speed Comparison (“faster than a rifle bullet”) Mig-25 engines reported being destroyed after flying at 3.2M. Unofficial maximum speed was 2.8M XB-70 only dashed at 3.2M - most of the flight was subsonic. The SR-71 used to fly at 3.0M+ for hours.
Thrust-to-Weight Ratio Comparison The Mig-25 fuselage has a much smaller fineness ratio. Jane’s, 74/75
Speed increase also demands larger turn radii. [Jenkins], p. 93
Aerodynamic Considerations Another application of the KISS methodology High fineness ratio bodies Highly swept double-delta wing. [Whitford], p. 188
Aerodynamic Considerations - FUSELAGE High fineness ratio for minimum wave drag Use of chines: –better directional stability: reduction of the side-force –offset the backward movement of the A.C. with Mach number [Whitford], p. 150
Aerodynamic Considerations - WING Double-delta plan form allows high (t/c) ratio to minimize wave drag Swept keeps most of the wing in Mach cone : –For Mach 3.0 flight –SR-71 wing sweep angle: Conical camber –moves the center of lift inboard –relieves loading on engine nacelle structure due to outboard wing –reduction in high rolling moment due to sideslip inherent to highly swept wings [Whitford], p. 188
Aero Considerations - VERTICAL TAILS All moving tails (+20/-20 deg) Cant angle to –reduce induced rolling moment when r ≠ 0 –stay on the correct side of the vortices shed by the nacelles - reduced VT deflection at low speed with ≠ 0 Whitford, p. 195
Aero Considerations - Aerodynamic Heating The SR-71, a hot airplane: –600 F at nose (aerodynamic heating at Mach 3+) –520 F at the windshield glass –1200 F at the exhaust nozzle (fuel burned) 93% of the structural weight built of Titanium alloys Cord-wise corrugations on wing skin The utility of the black paint (lower temps., lower RCS) Nitrogen both in tires and in fuel tank
Aero Considerations - Aerodynamic Heating Fuel used also as coolant JP-7, a high-flashing point fuel Fuel leakage always a problem Special hydraulic fluids (powders?) to operate at 600 F Special tires, retracted into the fuselage fuel tank area
Fuel leakage always a problem Air&Space Magazine, Feb/Mar 99, vol. 13 (6)
Propulsion: Turbojet or Ramjet? At Mach 3 cruise, turbojet engine makes only 17% of total thrust AIAA-69-757, p. 7
Turbo-ramjet: a hybrid propulsion system AIAA-69-757, p. 7
Flow must decelerate from supersonic to subsonic before the compressor first stage http://www.airspacemag.com/asm/mag/supp/fm99/oxcart.html
Missions Reconnaissance (it should be RS, Pres. Johnson turned it SR) Interceptor (YF-12) Mother-ship Research Vehicle
SR-71 in High Speed Research NASA Dryden currently is conducting high speed flight research using two SR-71 aircraft. Excellent platforms to carry out research and experiments in a variety of areas (aerodynamics, propulsion,structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies and sonic boom characterization) Data from the SR-71 high-speed research program will be used to aid designers of future supersonic/hypersonic aircraft and propulsion systems, including a high-speed civil transport.
NASA’s SR-71 and A-12 http://www.dfrc.nasa.gov/Projects/SR71/home.html
One airplane, several names A(rchangel)-12 Blackbird Cygnus Habu Senior Crown SR-71 as Strategic Reconnaissance, but also... YF-12
Reference List Burrows, William E., “The Oxcart Cometh,” Air&Space Magazine, Vol. 13 (6), Smithsonian Institution, Washington, D. C., Feb./Mar. 1999. Crickmore, Paul F., “LOCKHEED SR-71 – The Secret Missions Exposed,” BAS Printers Limited, Great Britain, 1993. Drendel, Lou, “SR-71 Blackbird in action,” Squadron/Signal Publications, Inc., Carrolton, TX, 1982. “Jane’s All the World Aircraft” from years 68/69, 69/70, 74/75. Jenkins, Dennis R., “SR-71/YF-12 BLACKBIRDS”, WARBIRDTECH series, vol. 10, Specialty Press Publishers and Wholesalers, 1997. Johnson, Clarence L., “Some Development Aspects of the YF-12A Interceptor Aircraft,” AIAA Paper No. 69-757, 1969. Whitford, Ray, “Design for Air Combat”.