Space Cover #499: Mother Planes - Unsung and Seldom EasyAbove is a rather plain looking cover, postmarked almost 60 years ago on February 13, 1959, at Edwards, CA, and autographed by Captain Charles C. Bock, the chief test pilot for the NB-52A "mother plane" that would eventually launch the X-15 rocket plane and many more. This was the third B-52A bomber that was produced and was heavily modified by North American Aviation in 1958 to become the first X-15 mother plane. The aircraft was delivered to Edwards on November 14, 1958 and underwent a number of flight tests prior to the first X-15 captive flight on March 10, 1959. The cover above was postmarked during the time of those flight tests and autographed by the chief test pilot. Was it postmarked on a test flight date? I have never seen a log of the NB-52A test flights prior to the first captive flight, so I don't know. Has anyone else seen such a log?
And if you think the test flights of the NB-52A might have been a piece of cake, think again. Modifications to the airplane included adding the pylon that would carry the heavy X-15 under the right side wing, cutting a notch out of the right side wing (to clear the X-15's vertical stabilizer), disabling the inboard wing flaps (so they couldn't be lowered into the X-15 on its pylon), and adding the myriad systems needed to support and check out the X-15 prior to launch. The heavy weight of the NB-52A along with no inboard flaps made it land and take off about 30 knots faster than a normal B-52. And it had to land in a way totally different from production B-52's. And not to mention testing a liquid oxygen tank and plumbing that had to work just right to top off the X-15's oxidizer tanks inflight without going "boom".
But work it did, culminating in a successful captive flight of the X-15 on March 10, 1959 (photo above). And, along with a second NB-52, they performed 199 drops of the X-15 through 1968. This mother plane went on to carry a variety of other payloads on its wing pylon long for after the X-15 program was over.
The history of US rocket planes being launched by a mother plane spans back to the X-1, carried aloft suspended under the bomb bay of a WW-II era B-29 bomber plane in the late 1940's (photo above). A similar B-29 bomber, called a P2B-1S by the Navy, carried the D-558-II Skyrockets aloft in the 1950's. And a souped-up B-29, called a B-50 did the same for the X-2's in the 1950's. And it wasn't easy…
On May 12, 1953, X-2 no. 2 exploded onboard its B-50 mother plane resulting in the deaths of X-2 pilot Jean "Skip" Ziegler, and B-50 observer Frank Wolko. And on August 8, 1955 the X-1A exploded onboard its B-29 mother plane, luckily with no fatalities.
Above is the Smithsonian Milestones of Flight Cover no. 68, commemorating the first ever Mach 2 flight, achieved in the D-558-II Skyrocket rocket plane in 1953, and autographed by a number of Skyrocket pilots. The cachet artwork shows the Skyrocket being dropped from its P2B-1S mother plane, and in the middle of the artwork is the autograph of Stan Butchart who had made flights in both the Skyrocket and its' mother plane.
On March 22, 1956, Butchart and Neil Armstrong (yup, THAT Neil Armstrong) were flying the Skyrocket's mother plane. Suddenly an engine on the mother plane went into an overspeed condition that the pilots could not stop. They prudently jettisoned the Skyrocket (with pilot John McKay inside). Within seconds after the drop, the propeller on the overspeeding engine began shedding its blades, one of which sliced through the bomb bay of the mother plane, right where the Skyrocket (full of rocket fuel and McKay) had just been! Fortunately, Butchart and Armstrong were able to nurse the mother plane back to the ground, and McKay landed the Skyrocket successfully. Not what you'd call easy duty!
Today there is a whole new generation of mother planes: a Lockheed L1011 that launches the Pegasus launch vehicle, White Knight that launched SpaceShipOne, White Knight Two that launches SpaceShipTwo, and Stratolaunch to launch many different payloads into space. May their jobs be easier...
posted 01-20-2019 06:23 AM
advertisement