For rocket launches assisted by non-rocket powered guideways, see rocket sled launch.
A rocket sled is a test platform that slides along a track (e.g. set of rails), propelled by rockets.
Sonic Wind No 1. This rocket sled was ridden by John Paul Stapp in the 1950s.
A rocket sled differs from a rocket car in not using wheels; at high speeds wheels would spin to pieces due to the extreme centrifugal forces. Apart from rare examples running on snow or ice (such as Max Valier's RAK BOBs of the late 1920s[1] and Harry Bull's BR-1 in 1931[2]), most rocket sleds run on a track. Although some rocket sleds ride on single beams or rails, most use a pair of rails. Standard gauge (1.435 m / 56.5 in) is common but sled tracks of narrower or wider gauge also exist. The rail cross-section profile is usually that of a Vignoles rail, commonly used for railroads. Sliding pads, called "slippers", are curved around the head of the rails to prevent the sled from flying off the track. Air cushions and magnetic levitation have also been used as alternatives, with potential benefits including reduced sled vibration.
A rocket sled holds the land-based speed record for a vehicle, at Mach 8.5.[3]
Usage
The vehicle that achieved Mach 8.5The Holloman Air Force Base track
Rocket sleds were used extensively early in the Cold War to accelerate equipment considered too experimental (hazardous) for testing directly in piloted aircraft. The equipment to be tested under high acceleration or high airspeed conditions was installed along with appropriate instrumentation, data recording and telemetry equipment on the sled. The sled was then accelerated according to the experiment's design requirements for data collection along a length of isolated, precisely level and straight test track.
Testing ejection seat systems and technology prior to their use in experimental or operational aircraft was a common application of the rocket sled at Holloman Air Force Base. Perhaps the most famous, the tracks at Edwards Air Force Base were used to test missiles, supersonic ejection seats, aircraft shapes and the effects of acceleration and deceleration on humans. The rocket sled track at Edwards Air Force Base was dismantled and used to extend the track at Holloman Air Force Base, taking it to almost 10 miles (16 km) in length.
Unmanned rocket sleds continue to be used to test missile components without requiring costly live missile launches. A world speed record of Mach 8.5 (6,416 mph / 10,325 km/h) was achieved by a four-stage rocket sled at Holloman Air Force Base on April 30, 2003, the highest speed ever attained by a land vehicle.[4]
Murphy's law first received public attention during a press conference about rocket sled testing.[5]
^Nakata, Daisuke; Yajima, Jun; Nishine, Kenji; Higashino, Kazuyuki; Tanatsugu, Nobuhiro; Kozu, Ami (2012). "Research and Development of High Speed Test Track Facility in Japan". 50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition. doi:10.2514/6.2012-928. ISBN978-1-60086-936-5.
^Sharpe, Mitchell R.; Lowther, John M. (1965). Progress in Rocket, Missile, and Space Carrier Vehicle Testing, Launching, and Tracking Technology. Advances in Space Science and Technology. Vol. 7. pp. 1–145. doi:10.1016/B978-1-4831-9965-8.50008-3. ISBN978-1-4831-9965-8.
