Design and Development of the Blackbird: Challenges and Lessons Learned

Abstract

The Lockheed Blackbirds hold a unique place in the development of aeronautics. In their day, the A-12, YF-12, M-21, D-21, and SR-71 variants outperformed all other jet airplanes in terms of altitude and speed. Now retired, they remain the only production aircraft capable of sustained Mach 3 cruise and operational altitudes above 80,000 feet. In this paper the author describes the design evolution of the Blackbird from Lockheed's early Archangel studies for the Central Intelligence Agency through Senior Crown, production of theAir Force's SR-71. He describes the construction and materials challenges faced by Lockheed, the Blackbird's performance characteristics and capabilities, and the National Aeronautics and Space Administration's role in using the aircraft as a flying laboratory to collect data on materials, structures, loads, heating, aerodynamics, and performance for high-speed aircraft.

Conceptual study of supersonic transports employing airframe-integrated advanced nozzle configuration

“…This is because the existing turbofan engines (Merlin, 2009) may have an overall pressure ratio of approximately 40, thus making the total pressure of the combustor approximately 4.0 MPa. The on-design conditions are summarized in Table 1 along with other parameters for the engine exhaust flow.…”

“…The viscosities µa and µw for the freestream and at the wall, respectively, were calculated by the Sutherland viscosity law. The wall temperature Tw was assumed to be 1000 K because the temperature is expected to be close to that of the turbine disk (Merlin, 2009). Because the effect of shock wave impingement on the wall was not considered in this study, the skin friction was estimated by taking the mean value over the entire spike surface.…”

Performance Evaluation of Airframe-Integrated Aerospike Propulsion Systems in Off-Design Flight Conditions

“…The viscosities e and w for the free stream and at the wall, respectively, were calculated by the Sutherland viscosity law. The wall temperature (Tw) was assumed to be 1000 K because the temperature is expected to be close to that of the turbine disk [24]. As mentioned above, since the effect of shock wave impingement was not considered in this calculation, the skin friction was estimated by taking the mean value over the entire spike surface.…”

“…The combustion chamber pressure, which corresponds to the total pressure of the cell nozzle, was fixed at 4.0 MPa [24].…”

“…The temperature at the combustor exit was assumed to be 1500 K [24], and that at the cell nozzle exit was calculated by assuming isentropic flow process. The gas constant of the cell nozzle flow was assumed to be 400 J/(kgK), which is similar to the value for hydrogen combustion with air at 4.0 MPa.…”