The Real X-Men
Life came at you fast when you flew the X-15.
- By Peter Garrison
- Air & Space magazine, November 2007
(Page 2 of 6)
Armstrong was the most talented engineer in the group, and he occasionally let his intellectual curiosity get the better of his piloting instincts. “He would let things go a little bit farther than, say, Jack McKay might have,” says NASA flight planner and stability specialist Bob Hoey. Armstrong made a famous mistake in the program, accidentally bouncing back out of the atmosphere during reentry while focused on a technical question about the behavior of the flight control system. He later told James Hansen, author of the Armstrong biography First Man, that he “felt the obligation to demonstrate” every aspect of the control system; he had consulted on its design, and he flew the missions to test it.
He coasted all the way to the edge of the Los Angeles basin before managing to turn the airplane around and land it at Rosamond Dry Lake, miles short of the originally planned landing site. It was jokingly said that on his final approach he cleared the cactus at the edge of the lake bed by a good margin—but only horizontally. It was the longest-duration flight in the X-15 program: 12.4 minutes.
Armstrong had another role in the program: to assist in the development of the High Range, the flight route from Utah to Edwards along which all X-15 flights launched, at 45,000 feet and Mach .7, from a B-52 mothership. Radars and radio stations were placed on mountaintops, and miles-long runways were marked on a string of dry lakes so that an emergency landing site would always be available.
Bill Dana got to know the dry lakes well; the early part of his time in the program was spent setting out smoke flares at landing sites so that the X-15 pilot would know the wind direction. He didn’t become an X-15 pilot himself until 1965, but his first memory of the aircraft is much earlier: “I went to work October 1 of ’58, and they rolled the X-15 out at LAX [Los Angeles International Airport] on October 15. I got to see it the day after that, and I thought it was the ugliest airplane I’d ever seen. We’d spent our whole careers trying to reduce drag, and now they’d put a vertical tail that was square in the back. So I wasn’t too impressed with it until they put the big engine in it, and then it had to command your awe. It was a 33,000-pound airplane with 60,000 pounds of thrust, and it really left the scene immediately when you lit that engine.
“I got to see a lot of launches because I was launch chase, and it never failed to impress me. And I wanted in the worst way to fly the airplane, and eventually I got my chance. We went to ground school for six months. I knew the airplane pretty much backwards and forwards.”
Preparations for flying the X-15, once the pilots were out of ground school, consisted of long periods in the Iron Bird, a simulator in which pilots rehearsed flights over and over. Once every movement of the 10-minute adventure to come was second nature, the pilots ran through strings of unexpected emergencies, as space shuttle crews do today.
“The preparation was intense,” recalls Bob White. “We practiced the profile of the mission we were going to fly, and then we threw in failures of some of the rate dampers, the yaw, roll, or pitch damper, and the adaptive flight control system, and then when I was ready I would fly the profile again and they would throw things in unexpectedly I wasn’t prepared for.”
The part for which no amount of simulator time could prepare the pilots was the steep glide to a dead-stick, or engine-off, landing. The pilots accomplished it with a combination of guidance from NASA 1—a controller on the ground, usually another X-15 pilot—and every pilot’s ultimate tool, the eyeball. For every four and a half miles it covered over the ground, the X-15 lost a mile of altitude. Most airplanes were incapable of descending that steeply, but it was found that an F-104—whose general proportions were quite similar to those of the X-15—with its engine throttled back, flaps down, and landing gear and air brakes extended could match the X-15’s glide angle at 300 knots (345 mph). Actually, the F-104 could, in a pinch, descend even more steeply than the X-15. The late Joe Walker, asked whether it would be possible to land accurately out of such a steep approach, replied, “There’s no question of where you’re going to land, it’s how hard.” In fact, precise dead-stick landings in the X-15 were, in Bob White’s words, “a piece of cake.”