SCRAMJET ENGINE (CONTENT BEYOND SYLLABUS)

Consider the following statements with respect to Scramjet engine:
1. ISRO successfully test fired scramjet engine and realized the critical technology of Air Breathing Propulsion System in 2016.
2. The Scramjet engine designed by ISRO uses Oxygen as fuel and the Hydrogen from the atmospheric air as the oxidizer.
Which of the following codes below given is/are NOT correct?

• 1 Only

• 2 Only

• Both 1 & 2

• Neither 1 nor 2

Recently ISRO carried out successful testing of scramjet engine. Which of the following statements is/are true with respect to it?

1. It uses atmospheric oxygen to burn the fuel

2.It is more efficient than conventional rocket engines at low speeds.

3.A rocket using scramjet engine would be significantly lighter,smaller and therefore cheaper

• Only 1

• Only 1 & 3

• Only 1 & 2

• All of the above

rocket and a jet engine differ because
A.their working principles are entirely different.
B.a rocket uses only liquid fuels whereas a jet can use solid fuels as well.
C.while a rocket carries its own oxygen supply a jet draws its air out of the atmosphere.
D.a rocket can propel vehicles into outer space whereas a jet cannot.

• B, C and D are correct

• C and D are correct

• A and B are correct

• A, C and D are correct

1)   Which of the following is/are true?

1) Ramjet accelerates the air to supersonic velocities before combustion.
2) Scramjet engines are faster and efficient than ramjets.

• a. Only 1
  

• 
  b. Only 2
  

• 
  c. Both 1 and 2
  

• 
  d. Neither 1 nor 2

Scramjet is

• a. Supra-sonic combustion ramjets
  

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  b. Subsonic combustible ramjets
  

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  c. Supersonic combustion ramjets
  

• 
  d. Supra-sonic combustible ramjets

Gas turbines are suitable for aircraft propulsion because

• a. gas turbines are light weight
  

• 
  b. gas turbines are compact in size
  

• 
  
  c. gas turbines have a high power-to-weight ratio
  
  

• 
  
  d. all of the above

The propulsive efficiency is the ratio of

• a. the propulsive power to the energy input rate
  

• 
  b. the exit velocity rate of exhaust gases to the energy input rate
  

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  c. the work done by the turbine to the energy input rate
  

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  d. velocity of aircraft to the energy input rate

Why do the airplanes fly at higher altitude during the long flights?

• a. to avoid collisions as they are at very high speed and controlling will be difficult if something (like towers, hills) comes in the way
  

• 
  b. it is easy to communicate with satellites at high altitudes
  

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  c. to save the fuel as air at higher altitude exerts smaller drag force on aircraft
  

• 
  d. none of the above

What is the effect of increasing bypass ratio of a turbofan engine on its trust?

• a. trust increases with increase in bypass ratio of turbofan engine
  

• 
  b. trust decreases with increase in bypass ratio of turbofan engine
  

• 
  c. trust of the turbofan engine only depends upon the fuel rate, so no change of thrust with increase in bypass ratio
  

• d. cannot say

How is the shock layer in case of hypersonic flow?

• a) Thin

• b) Thick

• 
  c) Non existent
  

• d) Increases with increasing Mach number