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The Science behind air-breathing scramjet engine

14th September, 2020 Science and Technology

The Science behind air-breathing scramjet engine

  • Context: This indigenous engine is the centerpiece of the cruise vehicle flown by DRDO


  • The Defence Research and Development Organization (DRDO) performed a major technological, when it flew a cruise vehicle at a hypersonic speed of Mach six for 20 seconds.
  • The DRDO’s cruise vehicle Hypersonic Technology Demonstrator Vehicle (HSTDV) centerpiece was the indigenously developed air-breathing scramjet engine, which formed the HSTDV’s propulsion system.
  • Criticality of this test: The critical technologies developed for the HSTDV mission were the scramjet engine and its ignition, sustaining the ignition, ethylene fuel, generation of maximum energy from the engine, development of materials to take care of the high temperatures that occurred due to air friction on the leading edges of the cruiser’s wings, tail surface and nose tip, and controlling the HSTDV with minimum drag and maximum thrust.

How it function?

  • In an air-breathing scramjet engine, air from the atmosphere is rammed into the engine’s combustion chamber at a supersonic speed of more than Mach two.
  • In the chamber, the air mixes with the fuel to ignite a supersonic combustion but the cruiser’s flight will be at a hypersonic speed of Mach six to seven. So it is called supersonic combustion ramjet or Scramjet.

Launched from Odisha

  • The launch vehicle, which was derived from Agni 1 missile, rose from its launch pad in Odisha, carrying the HSTDV.
  • The Agni 1 booster climbed to a height of 30 km in 12 seconds at a speed of Mach 5.6.
  • All these events took place in micro seconds as planned.

Mode of operation

  • Air from the atmosphere was then rammed into the scramjet engine’s combustion chamber at a supersonic speed.
  • The air mixed with the atomized fuel, the fuel was ignited and the scramjet engine revved into action.
  • The HSTDV flew for the next 20 seconds at a hypersonic speed of Mach six and fell 40 km away in the Bay of Bengal. The mission was a success.
  • It will pave the way for developing many more critical technologies, materials and particularly hypersonic vehicles.

Indigenous technology

  • The DRDO’s missile complex in Hyderabad, comprising the Defence Research and Development Laboratory (DRDL), the Research Centre, Imarat (RCI), and the Advanced Systems' Laboratory (ASL) developed all the technologies needed for the mission.
  • Mastering the air-breathing scramjet technology will lead to the development of hypersonic missiles, faster civilian air transportation and facilities for putting satellites into orbit at a low cost.

Reference: https://www.thehindu.com/sci-tech/science/science-behind-air-breathing-scramjet-engine/article32588912.ece?homepage=true