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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)
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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.
One idea… The SUNTAN Project [Jenkins], p. 6
Another idea...Project Oxcart - Archangel II [Jenkins], p. 7
A12 - the definitive idea [Whitford], p. 188
The U2 and the SR-71 Drendel p 36
The several versions Drendel 8
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-25engines 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
More on T/W x W/S Comparison MIG-25 SR-71 Concorde XB-70 [Whitford], p. 39
Wing Geometry ComparisonSpeed increase demands thinner wings. [Whitford], p. 30
Speed increase also demands larger turn radii. [Jenkins], p. 93
Aerodynamic ConsiderationsAnother 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 [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 dr ≠ 0 • stay on the correct side of the vortices shed by the nacelles - reduced VT deflection at low speed with ≠ 0 Whitford, p. 195
Vortices - I Crickmore p 66
Vortices - II Crickmore p 181
The all-moving VTs. Crickmore p 44 Drendel p 20
Stable or unstable? Drendel p 45
YF-12 needed improved directional stability Drendel p 17 Drendel p 12
Fins must fold for landing. Drendel p 15
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 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
Typical Reconnaissance Mission Crickmore p 69
A modern ship, but alsoa mother-ship. Jenkins p 50
The mother-ship delivery. Jenkins p 44
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
Bye-bye, Blackbird. [Jenkins], p. 85
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”.