Of all the aircraft ever flown by test pilot Joseph A. “Joe” Walker – P-38 Lightnings in World War II, “X” planes throughout the 1950s, as well as early versions of the Century Series fighters and the B-47 Stratojet – he never soared any higher than on August 22, 1963, when he piloted a North American Aviation X-15 to an altitude of 354,200 feet (67 miles, or 107.8 kilometers), well past the 50-mile/100-kilometer-high edge of outer space (as defined by the U.S. Air Force and the Fédération Aéronautique Internationale, respectively).
Walker and others would take the X-15 to the edge of space several times, but his altitude record for manned winged aircraft would stand for more than 40 years until Scaled Composites’ SpaceShipOne
took the Ansari X Prize in 2004.
North American’s rocket-powered research airplane, designed to explore extremes of altitude and speed, made its first flight in 1959. With its stubby wings, limited fuel capacity, and the high rate of fuel consumption necessary to reach hypersonic speeds, the X-15 had to be carried aloft by a mother ship to launch. Originally, program managers envisioned dropping the rocket plane from the gigantic B-36 Peacemaker’s cavernous bomb bay. But when the more altitude-capable B-52 came along, two of them were chosen as X-15 mother ships.
The first X-15 mother ship was a B-52A (tail No. 20003, also known as “Balls Three,” the third Stratofortress ever built); the second was a B model (No. 20008, or “Balls Eight”). The chief external difference between the two mother ships was at the aft end; 20003 was stripped of its gun turret and the opening faired over, while a larger section of 20008’s tail was cut off immediately behind the gunner’s canopy.
The X-15 wouldn’t fit in a B-52 bomb bay, so it was mounted on the starboard wing between the fuselage and right inboard engine pod. A wedge of inboard flap was removed to make way for the X-15’s vertical tail fin, and the inboard flaps were bolted in the up position. Thus, all flights were accomplished without the benefit of flaps – making takeoffs and landings especially interesting for the pilots!
Large tanks for the X-15 fuel system were installed in the bomb bay of the NB-52s for topping off the rocket plane during flight. A launch operator’s station was installed on the flight deck behind the pilots with an observation dome that allowed him to view the X-15 on its pylon, and several camera housings were mounted on the right fuselage to film the launches. Several of these are available for viewing on the Dryden Flight Research Center’s Web site
After launch, the X-15 blasted skyward as it accelerated to speeds between Mach 4 and Mach 7. At the apex of its flight – the edge of space, where flaps were ineffective in the thin atmosphere – the plane’s attitude was maintained by “reaction control” rocket thrusters. The X-15’s powered flight lasted two minutes at most, after which it made a powerless descent (like the present-day space shuttle), landing on its rear skids and nose-gear wheels at 200 mph just 30-40 minutes after its departure aboard the mother ship.
With 93 of the X-15’s 199 flights to its credit, The High and Mighty One
was retired in 1969 and is on display at the Pima Air & Space Museum in Tucson, Ariz. The other X-15 mother ship, “Balls Eight,” soldiered on after the X-15 program, serving in numerous other experimental programs, including the Northrop and Martin lifting bodies. Having made its first flight in 1955, it was finally retired in December 2004. At that time, it was the oldest flying B-52 – yet, due to its specialized role, it had the fewest flight hours of any operational B-52 (2,443.8).
To learn how Jeff converted Monogram’s classic 1/72 scale B-52 and an MPM X-15A-2 to model the record-setting flight of Joseph A. Walker, pick up the March 2010 issue of FSM
. View the March issue's complete table of contents
and watch Editor Matthew Usher's video preview
of the issue.
Want more online extras? Download desktop wallpaper of Erin Lantz's F-16
in digital camouflage.