History presents not just a record of the past, but a wealth of
stories to interpret and learn from. In November I indulged my own
focus in aviation and space history with a field trip to
the eastern states. Highlights were long talks with Bob White and Neil
Armstrong, each a
research pilot who flew the rocket-powered X-15. Filling out the trip
were archive searches at the National Air and
Museum, NASA headquarters, and the Air Force Museum.
The X-15 research program was one of the "giant leaps" of the twentieth century, acknowledged by the first X-15's residence in NASM's Milestones of Flight Gallery. North American Aviation's three X-15s made 199 research flights from 1959 through 1968, advancing both aviation and space technology. They pushed the world speed record up from Mach 3.2 to Mach 6.7 -- 6.7 times the speed of sound -- and raised the altitude record from 126,200 to 354,200 feet, about 67 miles. They were the first to test aerodynamic heating in winged reentry from space, with parts of the X-15's skin glowing red hot at 1,200 degrees F. Beneficiaries of their research included Apollo moon flights and the Space Shuttle.
Heavily instrumented X-15s collected masses
of flight test
data at hypersonic speeds, logging more time over Mach 4 than any
winged vehicle until the Space Shuttle. They pioneered hypersonic
stability and control, human
factors, and flight in the vacuum of space. They tested the first
inertial guidance in a manned craft. X-15s carried experiments to the
edge of space; one
an early star tracker, developing technology for celestial navigation
Bob White is Air Force Major General Robert M. White, Retired. During X-15 flight envelope expansion he became the first pilot to fly faster than Mach 4, then Mach 5, then Mach 6. He was the first of eight X-15 pilots to qualify for astronaut wings, setting a record of 314,750 feet in 1962. Four decades later that official world record as a winged aircraft still stands.
In General White's own words, "My flights to 217,000 feet and 314,750 feet were very dramatic in revealing the earth's curvature ... at my highest altitude I could turn my head through a 180º arc and wow! - the earth is really round. At my peak altitude I was roughly over the Arizona/California border in the area of Las Vegas ... Looking to my left I felt I could spit into the Gulf of California. Looking to my right I felt I could toss a dime into San Francisco Bay."
General White had a long and distinguished career in Air Force
aviation. His later career included command of the Air Force Flight
Test Center at Edwards Air Force
and heading program management to develop the F-15 fighter. Most
summaries say he was shot down over southern Germany in
1945, but that's only a shadow of the story.
In truth he was finishing low altitude pursuit of a Messerschmitt 109, close on its tail while gunning it down. Debris from the Me-109 flew back and hit his his P-51 Mustang, yielding a flood of oil from his engine that instantly covered the canopy. He quickly jettisoned the canopy and tried to climb, realizing that the engine would soon seize. He exited with a standard Mustang bailout, diving over the right wing and hurtling just under the horizontal stabilizer. Pulling the rip cord as soon as he was clear, his feet hit tree tops just as the parachute popped open.
Neil Armstrong had a classic adventure in an X-15 flight, producing a research result that changed reentry planning for both the X-15 and the Space Shuttle. In performing a planned pullup maneuver on reentry he skipped off the atmosphere, zooming back into air so thin that it's effectively space. He shot past Edwards AFB at just over 100,000 feet and Mach 3, unable turn back for lack of air to generate aerodynamic force. As the X-15 finally dropped into denser air Armstrong established a 3 G turn but still overshot by 45 miles, overflying Pasadena before heading back toward Rogers Dry Lake. He stretched his glide to the max, dropping no less than 9,000 feet per minute, and barely made it. A chase pilot reported his clearance from the joshua trees at the edge of the lakebed as "about 100 feet -- on either side".
All twelve X-15 pilots were engineers, and Neil Armstrong is one of those who was an engineer first, a research pilot second. He constantly contributed to ground-bound engineering as well as to flight test, starting with the X-1B rocket plane in the early 1950s. A later example was preflight analysis of Apollo's drogue parachute, which would open at supersonic speed after reentry. An engineer's first thoughts are "Won't that produce a chaotic pattern of shock waves impinging on the flexible airfoil? Will it work???" Armstrong's analysis showed it was safe, helping to clear Apollo for flight.
Robert White and Neil Armstrong are among those who made the fifties
and sixties a time in air and space history that carried us across new
It was a time when we rapidly expanded our scientific knowledge of
is" and resoundingly pushed our horizons to engineer "what can
be". This forward-looking spirit can serve us well in reaching
"giant leaps for mankind".