In the early days of PBS member station WGBH-Boston, they in conjunction with MIT produced a program called Science Reporter. The program’s aim was explaining modern technological advances to a wide audience through the use of interviews and demonstrations. This week, we have a 1966 episode called “Ticket Through the Sound Barrier”, which outlines the then-current state of supersonic transport (SST) initiatives being undertaken by NASA.
MIT reporter and basso profondo [John Fitch] opens the program at NASA’s Ames research center. Here, he outlines the three major considerations of the SST initiative. First, the aluminium typically used in subsonic aircraft fuselage cannot withstand the extreme temperatures caused by air friction at supersonic speeds. Although the Aérospatiale-BAC Concorde was skinned in aluminium, it was limited to Mach 2.02 because of heating issues. In place of aluminium, a titanium alloy with a melting point of 3,000°F is being developed and tested.
A second important consideration was one of aerodynamics. The normal drag and subsequent shock waves produced by subsonic crafts may be marginalized through the use of piercing nose designs and sleeker wing profiles and configurations. Lastly, the engines must push out very little air at high velocities. [Mr. Fitch]’s first interview is with [Mark Kelly], Ames’ Chief of Large-Scale Aerodynamics. [Mr. Kelly] describes the SST initiative’s goals in everyday terms—the cruising speed, the size of the crafts, the passenger capacity, and the estimated flight time between New York and Los Angeles (about two hours).
[Mr. Kelly] introduces the idea of supersonic testing in subsonic wind tunnels using models. First, we tour a 1/5-scale Boeing SST with adjustable-sweep wings. The wings are set to 70° sweep for supersonic cruising and 20° sweep for takeoff and landing, an important transformation designed to meet the stringent speed and noise requirements for takeoff and landing. We also see a 1/4-scale Lockheed double delta featuring fixed wings with two triangular sections. The front portion generates a high-energy vortex that produces a low-pressure field over the aft wing. This design, in combination with the sheer size of the aft delta and its control flaps creates lift very quickly.
[John Fitch]’s next interview is with [Robert Shade], a project engineer at Langley. We learn that NASA performed SST flight testing using existing subsonic planes like the F5D and the XB-70. More interestingly, they hacked a Boeing 707 into all kinds of test configurations with a special computer. The pilot operates the 707 as intended, and this computer intervenes, translating his inputs into SST-caliber operations. Finally, [Mr. Fitch] is treated to the co-pilot seat of a landing simulator that be changed to simulate the parameters of any SST and simulates approach from 1,000 feet over a realistic landscape.
[Thank you to Dave for sending this in]
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