X-15 at Mach 6-8 (Model in Wind Tunnel) 1957 NACA Langley Research Center (Patreon)

more at http://quickfound.net/

Silent.

'This test was conducted in the NASA Langley Research Center's 11-Inch Hypersonic Tunnel in the 1950s.  The model of the X-15 is 1/50-scale and is coated with mineral oil and fluorescent dye.  The development and early testing of the X-15 was primarily at NACA, now NASA, Langley Research Center.

For more on the X-15, see http://crgis.ndc.nasa.gov/historic/X-15

 For more on the 11-Inch Hypersonic Tunnel and other tests conducted there, see http://crgis.ndc.nasa.gov/historic/1229

For more on the development of the X-15 at NASA Langley Research Center, see http://crgis.ndc.nasa.gov/historic/X-15 '

Originally a public domain film from NASA, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.

https://en.wikipedia.org/wiki/North_American_X-15

Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/

The North American X-15 was a hypersonic rocket-powered aircraft operated by the United States Air Force and the National Aeronautics and Space Administration as part of the X-plane series of experimental aircraft. The X-15 set speed and altitude records in the 1960s, reaching the edge of outer space and returning with valuable data used in aircraft and spacecraft design. As of September 2015, the X-15 holds the official world record for the highest speed ever recorded by a manned, powered aircraft. It could reach a top speed of 4,520 miles per hour (7,274 km/h), or Mach 6.72.

During the X-15 program, 13 flights by eight pilots met the Air Force spaceflight criterion by exceeding the altitude of 50 miles (80 km), thus qualifying these pilots as being astronauts...

Of the 199 X-15 missions, two flights (both by Joseph A. Walker) qualified as true space flights per the international (Fédération Aéronautique Internationale) definition of a spaceflight by exceeding 100 kilometers (62.1 mi) in altitude...

from "X-15: Extending the Frontiers of Flight" 2008

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20080008340_2008004059.pdf

FOREWORD: WILLIAM H. DANA

The X-15 was an airplane of accelerations. When an X-15 pilot looks back on his X-15 flights, it is the accelerations he remembers. The first of these sensations was the acceleration due to B-52 lift, which held the X-15 at launch altitude and prevented it from falling to Earth. When the X-15 pilot hit the launch switch, the B-52 lift was no longer accessible to the X-15. The X-15 fell at the acceleration due to Earth's gravity, which the pilot recognized as "free fall" or "zero g." Only when the pilot started the engine and put some "g" on the X-15 was this sensation of falling relieved.

The next impression encountered on the X-15 flight came as the engine lit, just a few seconds after launch. A 33,000-pound airplane was accelerated by a 57,000-lbf engine, resulting in a chest-to-back acceleration of almost 2 g. Then, as the propellant burned away and the atmosphere thinned with increasing altitude, the chest-to-back acceleration increased and the drag caused by the atmosphere lessened. For a standard altitude mission (250,000 feet), the weight and thrust were closer to 15,000 pounds and 60,000-lbf at shutdown, resulting in almost 4-g chest-to-back acceleration. The human body is not stressed for 4 g chest to back, and by shutdown the boost was starting to get a little painful. Milt Thompson once observed that the X-15 was the only aircraft he had ever flown where he was glad when the engine quit.

On a mission to high altitude (above 250,000 feet), the pilot did not regain any sensible air with which to execute a pullout until about 180,000 feet, and could not pull 1 g of lift until 130,000 feet. Flying a constant angle of attack on reentry, the pilot allowed g to build up to 5, and then maintained 5 g until the aircraft was level at about 80,000 feet. There was a deceleration from Mach 5 at 80,000 feet to about Mach 1 over the landing runway, and the pilot determined the magnitude of the deceleration by the use of speed brakes. This ended the high-g portion of the flight, except for one pilot who elected to start his traffic pattern at 50,000 feet and Mach 2, and flew a 360-degree overhead pattern from that starting point.

Flight to high altitude represented about two-thirds of the 199 X-15 flights. Flights to high speed or high dynamic pressure accounted for the other third...