Hot test of the scramjet engine was conducted successfully
- Category
Science & Technology
- Published
16th Dec, 2022
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Context
In a quest to launch satellites in predetermined orbits at a low cost, India has crossed a key milestone by successfully conducting a hot test for its scramjet’s engine.
Details:
- ISRO has conducted a hot test for its air-breathing scramjet engine.
- A hot test system is a 100% production test used to check all the engine operating parameters as they would function in real time.
- The test was conducted at its Propulsion Research Complexat Mahendragiri in the Tirunelveli district of Tamil Nadu.
- The test lasted for 11 seconds.

What is a scramjet engine?
- A scramjet engine is an improvement over the ramjet engine.
- India is the fourth country to demonstrate the flight testing of a Scramjet Engine.
- Thus, it is known as Supersonic Combustion Ramjet or Scramjet.
- In scramjet engines, the combustion takes place in supersonic airflow.
- Such engines use oxygen from the atmosphere in the combustion of fuel.
The scramjet advantages:
- Scramjet engine draws oxygen from the atmosphere:
- It results in significant savings in terms of the weight of the oxidizer that does not have to be carried onboard.
- These savings directly translate to higher payload capacity, and/or extended flight rangefor the vehicle.
- Vehicles can be cruised in a controlled manner:
- Scramjets allow for a certain level of on-demand accelerationand deceleration by regulating the fuel burn rate, enabling improved control.
- Difficult to intercept: Enhanced level of manoeuvrability of a scramjet-powered hypersonic vehicle adds to the degree of unpredictability of its flight path, making interception much harder than for a ballistic missile.
The main types of Jet engines based on how air is compressed in the engine are:
- Turbo Jet: Turbo jet engine is an air-breathing jet engine. This is one of the most common types of jet engines. It is still widely used in aeroplanes.
- Ramjet: High-speed forward motion is used to compress the air (no compressor). Fuel is injected into the combustion chamber where it mixes with the hot compressed air and ignites.
- The average speed of a Ramjet is 3-6 Mach.
- But the ramjet efficiency starts to drop when the vehicle reaches hypersonic speeds.
- Missiles and other flight systems designed for supersonic speeds (above Mach 1 and below Mach 5) commonly use a ramjet engine.
- Scramjet: Here also, the high-speed forward motion is used to compress the air (no compressor).
- It is an improvement over the ramjet engine as it efficiently operates at hypersonic speeds and allows supersonic combustion.
- Speed is greater than 6 Mach (Six times the speed of Sound).