Difference Between Subsonic and Supersonic

Seeking thrill is one of the basic human needs. One tries to do things that are difficult and daring just to feel better. Seeking greater speed in the means of transportation is a practical matter but here too the element of thrill-seeking jumps in.

Man has now achieved speed greater than the speed of sound and the next frontier is the speed of light. This will play a pivotal role in making space travel easier and pave way for better understanding of the universe.

When discussing the speeds of aircrafts, one often hears the terms subsonic and supersonic. There are some basic differences between the two.

Subsonic is speed that is below the speed of sound. On the other hand, supersonic is the speed that is greater than the speed of sound.

The commercial planes are subsonic as the speed level is reasonable for normal travel. The supersonic technology is used mainly by the militaries all over the world who need high speed aircrafts for various reasons.

The materials used in subsonic jets are generally aluminium, titanium and various composite materials including carbon fibre polymers. The supersonic jets are made from titanium primarily.

The wing structure in the subsonic aircrafts is straight and has a slight angle. Supersonic aircrafts have special wings known as the delta wings or swept wings.

The propulsion of subsonic aircrafts can be done by turboprop engines, propeller driven piston engines or high bypass turbofan driven engines. Supersonic aircrafts on the other hand, are propelled by low bypass turbofan engines.


  • 1

    Subsonic Aircraft

    These aircrafts are the most common type, seen almost everywhere. These are mainly used at the commercial level to transport travellers. There are many subtypes within the main type and performance and speed varies in all these.
    The maximum speed achieved by a commercial jet is 0.85 mach. Most aircrafts however operate below this speed.

    Image Courtesy: corrosionda.com

  • 2

    Supersonic Aircraft

    These aircrafts have the ability to fly at speeds greater than mach 1. These aircrafts are extremely aerodynamic and move with maximum efficiency.
    These are mostly used by air forces all over the world. Such high speed is generally available for fighter and experimental aircrafts. Concord and Tu-144 were the only commercial passenger jets which could operate at supersonic speeds but they were shelved due to high costs.

    Image Courtesy: businessinsider.com

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