Jetrader - November/December 2009 - 19

aviation history Disintegrates Around Pilot During SR-71 Flight Test 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 by Bill Weaver, Chief Test Pilot, Lockheed Weav mong professional aviators, there’s a well-worn sayprof ing: 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 pe with Lockheed, most of which was spent as a test Lo pilot. pilot. pilot. By far, the most memorable ﬂight occurred B on Jan. 25, 1966. Jim Zwayer, a Lockheed ﬂight test reconnaissance and navigation sysig tems specialist, and I were evaluating those te systems on an SR-71 Blackbird test from s 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. ©2005, Aviation Week, a division of The McGraw-Hill Companies. All rights reserved. Reprinted with permission. Jetrader 19

Jetrader - November/December 2009

Table of Contents for the Digital Edition of Jetrader - November/December 2009

Jetrader - November/December 2009
A Message from the President
Contents
Calendar/News
Q&A: John Vitale
Aircraft Financing in 2009: A Retrospective
Details from Dubrovnik
By the Numbers
Racing in Reno
Aircraft Appraisals
From the ISTAT Foundation
Aviation History
Advertising Index
Jetrader - November/December 2009 - Jetrader - November/December 2009
Jetrader - November/December 2009 - Cover2
Jetrader - November/December 2009 - A Message from the President
Jetrader - November/December 2009 - 4
Jetrader - November/December 2009 - Contents
Jetrader - November/December 2009 - 6
Jetrader - November/December 2009 - Calendar/News
Jetrader - November/December 2009 - 8
Jetrader - November/December 2009 - Q&A: John Vitale
Jetrader - November/December 2009 - Aircraft Financing in 2009: A Retrospective
Jetrader - November/December 2009 - 11
Jetrader - November/December 2009 - Details from Dubrovnik
Jetrader - November/December 2009 - Racing in Reno
Jetrader - November/December 2009 - 14
Jetrader - November/December 2009 - Aircraft Appraisals
Jetrader - November/December 2009 - 16
Jetrader - November/December 2009 - From the ISTAT Foundation
Jetrader - November/December 2009 - 18
Jetrader - November/December 2009 - Aviation History
Jetrader - November/December 2009 - 20
Jetrader - November/December 2009 - 21
Jetrader - November/December 2009 - Advertising Index
Jetrader - November/December 2009 - Cover3
Jetrader - November/December 2009 - Cover4
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