Scramjet programs refers to research and testing programs for the development of supersonic combustion

ramjet A ramjet is a form of airbreathing jet engine that requires forward motion of the engine to provide air for combustion. Ramjets work most efficiently at supersonic speeds around and can operate up to . Ramjets can be particularly appropriat ...

s, known as

scramjet A scramjet (supersonic combustion ramjet) is a variant of a ramjet airbreathing jet engine in which combustion takes place in supersonic airflow. As in ramjets, a scramjet relies on high vehicle speed to compress the incoming air forcefully b ...

s. This list provides a short overview of national and international collaborations, and civilian and military programs. The USA, Russia, India, and China (2014), have succeeded at developing scramjet technologies.

USA

X-15

When the second

X-15 The North American X-15 is a Hypersonic speed, hypersonic rocket-powered aircraft which was operated by the United States Air Force and the National Aeronautics and Space Administration (NASA) as part of the List of X-planes, X-plane series of ...

aircraft (piloted by John B. McKay) crashed on flight 74, it was damaged but survived well enough to be rebuilt.

North American Aviation North American Aviation (NAA) was a major American aerospace manufacturer that designed and built several notable aircraft and spacecraft. Its products included the T-6 Texan trainer, the P-51 Mustang fighter, the B-25 Mitchell bomber, the F- ...

rebuilt it as the X-15-A2. Among other things, one of the changes was provisions for a dummy scramjet to test if wind tunnel testing was correct. Unfortunately, on the final flight of the X-15-A2 ( flight 188), the shock waves sent out by the scramjet at Mach 6.7 caused extremely intense heating of over . This then drilled into the ventral fin and melted large holes. The plane survived but never flew again. Test data were limited due to the limited flights of the scramjet before the X-15-A2 and the X-15 project on the whole were cancelled.

SCRAM

From 1962–1978, the Johns Hopkins Applied Physics Laboratory (APL) undertook a classified program (declassified in 1993) to develop a family of missiles called SCRAM (Supersonic Combustion RAmjet Missile). They were intended to fit on to the Talos MK12 launcher system or the Terrier MK10 launcher. Testing of engine modules in a direct-connect, and a free-jet, facility took place at a variety of

Mach The Mach number (M or Ma), often only Mach, (; ) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a Boundary (thermodynamic), boundary to the local speed of sound. It is named after the Austrian physi ...

numbers and pressures (altitudes). These included Mach 4 (24,000 ft), Mach 5.3 (46,000 ft), Mach 7.8 (67,000 ft) and Mach 10 (88,000 ft). Tests showed that acceptable

combustion efficiency Combustion efficiency refers to the effectiveness of the burning process in converting fuel into heat energy. It is measured by the proportion of fuel that is efficiently burned and converted into useful heat, while minimizing the emissions of po ...

was only achieved with over 20%

pentaborane Pentaborane may refer to: * Pentaborane(9) (B5H9) * Pentaborane(11) (B5H11) {{Short pages monitor