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North American Aviation's XB-70A Valkyrie, also known as Weapons System (WS) 110A, was conceived to meet a 1955 Strategic
Air Command requirement for a supersonic bomber with intercontinental range. By the time the first prototype was completed,
however, in August 1964, the bomber version of the Valkyrie was dead, and the two aircraft were used solely for supersonic
research, mostly in support of the stillborn US Supersonic Transport (SST) programme. The second, more advanced, prototype,
the XB-70A-2, was lost in a spectacular collision with an F-104 piloted by veteran test pilot Joe Walker on July 8, 1966;
XB-70 copilot Major Carl Cross was also killed. The number 1 aircraft continued in flight test at Edwards Air Force
Base until February 4, 1969, when it was ferried to the US Air Force Museum at Wright-Patterson Air Force Base. It remains
there to this day as one of the largest and most expensive exhibits in the museum.
Love it or hate it (and there are plenty of people in both camps), nobody can deny that the XB-70 was a spectacular airplane,
and one of a very select group to fly (and cruise) at Mach 3. It is also, with a gross weight of almost 550,000 pounds, by
far the largest airplane to ever fly supersonically. It is unlikely we will ever see anything remotely like the XB-70A
ever grace the skies again. These photos were taken on a variety of occasions at the USAF Museum; the photo above was
taken in 1988, when the XB-70A-1 was essentially a gate guard at the museum entrance. Since then, the aircraft has spent
most of its time in the Modern Flight Gallery.
It is difficult to appreciate the size and lines of the XB-70A inside the Modern Flight Gallery, due to the number of aircraft
parked around and under it. This photo, taken when the XB-70A was moved outside to allow rearrangement of exhibits in
the Modern Flight Gallery, gives an excellent impression of the size of this plane - an overall length of 194 feet, and a
height of 30 feet. Barely visible directly under the nose is a person for scale.
The nose gear sat almost 90 feet behind the nose of the aircraft, and taxying must have been a challenge.
The wheels were coated with silver paint to help them cope with the high temperatures in the wheel bays generated from the
friction of flying at Mach 3. Note also the black line painted on the fuselage side and the aft nose gear strut; this
was a guide to help chase pilots comfirm that the nose gear was down and locked.
A similar photo of the starboard main landing gear bogie shows the four wheels, plus the smaller sensing wheel, that make
up the main gear. The sensing wheel was added after the first flight to reduce the chance of skidding and blown tires.
Again, notice the line on the gear strut and fuselage side to help determine the correct orientation of the landing gear.
The XB-70A-1 was propelled by no less than six General Electric YJ-93 engines, each producing an unprecedented 30,000 pounds
of thrust using JP-6 fuel. Some of the compelxities of the engine exhuasts, as well as the exposed structure of
hte engine bay, are visible in this view. Two of the dozen elevons, which provide control for the aircraft,
can be seen just outboard of the engine, while one of the struts used to secure the rudders can be seen at the top of the
photograph. The gray area at the lower left of the photo is the wingtip of Northop's Tacit Blue stealth reconnaissance
aircraft.
This unusual view is down the belly of the beast, so to speak. Looking forward from the rear of the aircraft, one
can appreciate the very flat profile of the lower aft fuselage of the XB-70. At the top can be seen some details of
the engine bays, while in the centre is the aft-sliding weapons bay door and its tracks. The door was over 30 feet long,
and was optimized for high supersonic weapons release; the system was never tested, however, and an XB-70A never opened this
door in flight, nor did it ever carry even inert weapons. Instead, the bay was filled with flight test equipment.
I hope these photos are of use to anybody brave enough to attempt the AMT/Ertl 1/72 scale kit of the XB-70A-1 (the XB-70A-2
had a wing with 5 degrees dihedral, and would be a major conversion from the the XB-70A-1).
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