badass plane…

• Lockheed SR-71A Blackbird (thingiverse)
  • I Modeled the SR-71 blackbird in blender and 3D printed it.

see also

• The SR-71 Blackbird Story
• The World’s Fastest Bomber: The XB-70 Valkyrie
  • Why the XB-70 Program Crashed Before Take-Off
• How Was The Blackbirds Program Kept Secret?

BILL WEAVER SR-71 Breakup

Among professional aviators, there’s a well-worn saying: Flying is simply hours of boredom punctuated by moments of stark terror. And yet, I don’t recall too many periods of boredom during my 30-year career with Lockheed, most of which was spent as a test pilot.

By far, the most memorable flight occurred on Jan. 25, 1966. Jim Zwayer, a Lockheed flight test reconnaissance and navigation systems specialist, and I were evaluating those systems on an SR-71 Blackbird test from Edwards AFB, Calif. We also were investigating procedures designed to reduce trim drag and improve high-Mach cruise performance. The latter involved flying with the center-of-gravity (CG) located further aft than normal, which reduced the Blackbird’s longitudinal stability.

We took off from Edwards at 11:20 a.m. and completed the mission’s first leg without incident. After refueling from a KC-135 tanker, we turned eastbound, accelerated to a Mach 3.2-cruise speed and climbed to 78,000 ft., our initial cruise-climb altitude.

Several minutes into cruise, the right engine inlet’s automatic control system malfunctioned, requiring a switch to manual control. The SR-71’s inlet configuration was automatically adjusted during supersonic flight to decelerate air flow in the duct, slowing it to subsonic speed before reaching the engine’s face. This was accomplished by the inlet’s center-body spike translating aft, and by modulating the inlet’s forward bypass doors. Normally, these actions were scheduled automatically as a function of Mach number, positioning the normal shock wave (where air flow becomes subsonic) inside the inlet to ensure optimum engine performance.

Without proper scheduling, disturbances inside the inlet could result in the shock wave being expelled forward–a phenomenon known as an “inlet unstart.” That causes an instantaneous loss of engine thrust, explosive banging noises and violent yawing of the aircraft–like being in a train wreck. Unstarts were not uncommon at that time in the SR-71’s development, but a properly functioning system would recapture the shock wave and restore normal operation.

On the planned test profile, we entered a programmed 35-deg. bank turn to the right. An immediate unstart occurred on the right engine, forcing the aircraft to roll further right and start to pitch up. I jammed the control stick as far left and forward as it would go. No response. I instantly knew we were in for a wild ride…