Question

Describe about any two
1) ram jet engine
2) pulse jet engine
3) Aerodynamic center

.......Solve it

Answer 1

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1) Ramjet Engine

RamJet Engine is one type of propulsion system used for Jet propulsion.

Propulsion is nothing but force to drive or to provide thrust in case of aeroplanes.

If we classify Aircraft and Jet propulsion systems, the list goes like this…

1. Ramjet engine.
2. Turbojet
3. Turbofans
4. Turboprop
5. Turboshaft
6. Scramjet ( an extension to Ramjet).

Ramjet engine is the most basic type of jet engine available yet capable of attaining speeds of 3Mach. Though this engine has no moving parts inside it, there are only three parts…

1. Converging Inlet
2. Combustion chamber
3. A nozzle

• At the converging inlet, the air is compressed to a very high ratio and is sent inside.
• In the combustion chamber, fuel is injected and flame holders burn the fuel-air mixture. Thus combusted mixture has high enthalpy, due to which they flow rapidly towards nozzle.
• After they enter the nozzle, with decrease in pressure the jet velocity will increase to a great extent, majority of thrust is obtained from here.
• These have increasing efficiency with increase in their speeds, because higher velocity means higher compression ratio at the inlet. So these are super efficient at supersonic speeds.

• BrahMos: World's only hypersonic cruise missile made by Indian DRDO & RUSSIA, which is capable of attaining speed of 3Mach.

See this, ain't it awesome..!!!! Enemy trembles in fear when they hear it's name, there is no missile currently which can match it's speed.

This missile uses Ramjet engine for it's propulsion.!!

Hunts like an eagle, attacks like a cheetah…!!!

And now DRDO is planning for the next version which can go upto 8 Mach, reports say it will take upto 5 years..!!!

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2) Aerodynamic Center

There is a point in the airfoil where moment is independent of angle of attack- that point is called as Aerodynamic center.

For every object flying through the air there is at least one point where it is a stable forward flight and all other points rotate around that point as the center of stability. Now this does not immediately have to be a single point. It may be many points, so that stability is not achieved right away, or even at all in the flight, or even before the object falls to the ground. It is like the center of mass, or of gravity, but the air pressures move it away from that point. That’s for any mass of any shape whatsoever. For an aircraft that point, in cross section, is usually somewhere in the front part of the wing, or wings, and the aircraft attains and maintains stability at that point, or line through the body and wings, so that it does not pitch forward, flip backward, or twist in flight.

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Hope it will help u.................... :- )