Neil Armstrong is the keynote speaker at the suborbital conference, which has just started in Palo Alto. I’ll be live blogging his speech. Alan Stern is introing him, describing him as a pioneer in suborbital spaceflight with the X-15.
[Standing ovation]
Thanks for the warm welcome, and appreciate the opportunity to describe suborbital flight generations back. As a boy was an admirer of great aircraft designers, and in recent decades, Burt Rutan has earned a place on that list. Burt occasionally ribs the government for spending hundred of millions to attain same altitude as he did with SS1. Back in his day the hot aerodynamics field was transonic flight. Transonic wind tunnels were unreliable with shock waves bouncing off the walls giving poor results. Interest grew in a special aircraft for investigating transonics, a purely research airplane. Research aircraft weren’t new — the Wrights’ first plane was one, but the government did do it until the forties, when they started the X series with the X-1 (first to break the sound barrier in level flight) in 1947. Other aircraft were tailless, swept-wing, delta wing, etc. These led to the Century-series fighters.
(Navy) Skyrocket in particular taught us a lot in the early fifties, setting altitude records and first aircraft to reach Mach 2. Air Force decided to recapture record, and achieved it with Mach 2.44, but lost the aircraft with pilot recovery. X-2 was made of stainless steel, first flight in 1955, new speed record of almost Mach 3, and new altitude record of over 130,000 feet. Final flight hit exceeded Mach 3, losing both aircraft and pilot, due to flying into region of steadily decreasing stability, due to high altitudes where conventional aircraft controls were ineffective. Hydrogen peroxide thrusters were added to the X-1B, which Armstrong flew, but it was retired due to fatigue cracks with limited RCS control results.
Then came Sputnik, and the NACA became NASA. NACA, Navy and Air Force had decided earlier in the decade that they needed a faster airplane capable of higher altitude. Heat could be handled by hot, insulated, or cooled or ablatively cooled structure. Highest temperatures could be handled by nickel alloys. New research aircraft would be hot structure and fly to highest operating temperature of those metals, which was about Mach 7, which was audacious, because no aircraft had flown past Mach 2 without going unstable. So that was the X-15, whose purpose was to fly fast and hot, not to fly high. But an aircraft that could reach those kind of speeds would have enough energy to achieve a hundred miles altitude, though that wasn’t the goal. But since it could do it, the NACA decided to utilize a peroxide RCS system, testing it first in the NF-104, which Armstrong flew to 90,000 feet, where the aerosurfaces were completely ineffective. Used yaw motion induced by spinning turbines to do control tests.
X-15 designed to hold one human and enough propellant to get to Mach 7. X-15 had 22-foot wing with low aspect ratio and no ailerons. Roll control by differential elevators. High-Mach directional stability provided by upper and lower fins which were both flying rudders. Lower tail was jettisoned for landing, and if it didn’t jettison, Joe Walker said it would be the “fastest plow in the world.”
Rocket engine was 57,000 lbf thrust, with anhydrous ammonia and LOX. In first flight some parts got to 1500 deg F, cherry red. Velocities and altitudes above the atmosphere used an inertial measurement unit, doing analog single integrations (digital far too slow then to do real-time position and velocity). Did a lot of research, including flow studies, astronomy, heat transfer, etc. Had a remarkable record. Three aircraft, many tens of flights over a period of years. Showing a short film of a mission profile while taking questions.
Q: What does he think about commercial/government collaboration?
A: NACA’s job was to “investigate problems of flight and potential solutions,” which they did, making results available to industry in general, and was very successful for aviation. We’re in a new environment now with different objectives, participants and goals. Certainly in the suborbital area a lot of things to be done. Has been absent for four decades since the end of the X-15 program, a lot of work to be done and a lot of opportunity. Hope that some of the approaches now being provide will be profitable and useful.
Q (Alan Stern): Did you foresee the kind of commercialism and tourism applications fifty years ago that we’re starting to see today?
A: We had a lot of vision, and thought we were making a roadmap for people to follow, and whether they did or not was up to them. We weren’t any better at looking ahead than anyone else.