Forty-seven years ago this month, the No. 1 USAF/North American XB-70A Valkyrie aircraft was officially unveiled to the aviation public in a rollout ceremony conducted at USAF Plant 42 in Palmdale, California.  The Great White Bird’s public debut occurred on Thursday, 11 May 1964.

The XB-70A Valkyrie was designed as an intercontinental bomber.  Its original mission was to penetrate Soviet airspace and drop nuclear ordinance at Mach 3 and 70,000 feet.  However, that mission was cancelled before the type ever flew.  It was ultimately relegated to the status of an experimental flight research vehicle.

The XB-70A graced the skies of America between September 1964 and February 1969.  It is to this day the largest triple-sonic aircraft ever flown.  The aircraft measured 189 feet in length and had wing span of 105 feet.  Gross weight topped out at around 540,000 lbs.  Over half of that weight (290,000 lbs) was JP-6 jet fuel.

The Valkyrie was powered by six (6) General Electric YJ93 all-afterburning turbojets.  These engines were designed to operate in continuous afterburner at Mach 3.2 and 95,000 feet.  Total sea level thrust of the “6-Pack” was in excess of 185,000 lbs.  The YJ93 was a contemporary of the Pratt and Whitney J58 turboramjet which powered the fabled USAF/Lockheed SR-71 Blackbird.

Only a pair of XB-70A airframes were built and flown; Air Vehicle No. 1 (S/N 62-0001) and Air Vehicle No. 2 (S/N 62-207).  Together, these aircraft flew 129 flight tests totaling 252.6 flight hours.  Ship No. 1 flew two-thirds of the XB-70A flight tests.  The highest Mach number achieved during the XB-70A flight test program was Mach 3.08.  This feat was accomplished by Ship No. 2 on Tuesday, 12 April 1966.

XB-70A Ship No. 2 also achieved the highest altitude of the XB-70A Program.  Specifically, this aircraft attained a cruise altitude of 74,000 feet on Saturday, 19 March 1966.  This mission included 32 minutes of continuous Mach 3 flight.

Eight (8) men flew the XB-70A.  This line-up included Alvin S. White and Van H. Shepard of North American, Col Joseph E. Cotton, Lt Col Fitzhugh L. Fulton, Lt Col Emil (Ted) Sturnthal and Maj Carl S. Cross of the United States Air Force, and Joseph A. Walker and Donald L. Mallick of NASA.

The Valkyrie pioneered the use of numerous technologies including exploitation of the NACA Compression Lift Principle, development  of honeycomb sandwich structural materials, and use of its fuel as a heat sink.  The XB-70A was also used as a testbed for sonic boom research and a myriad of other aerodynamic and aerothermodynamic experiments.  The Valkyrie also provided significant support to the ill-fated American Supersonic Transport (SST) effort.

XB-70A Ship No. 2 was lost in a collision with a NASA F-104N Starfighter near Edwards Air Force Base on Wedneday, 08 June 1966.  This mishap took the lives of Maj Carl S. Cross and Joseph A. Walker on what is still referred to as the “Blackest Day at Edwards”.  Ship No. 1 survived the XB-70 flight test program and is displayed today at the National Museum of the United States Air Force in Dayton, Ohio.