Take the 2-minute tour ×
Aviation Stack Exchange is a question and answer site for aircraft pilots, mechanics, and enthusiasts. It's 100% free, no registration required.

Airplanes with propellers were invented a long time ago. After that, jet engines came into existence. My question is: why do we still have propeller engines?

The reasons I can think of are:

  • They are cheaper;
  • They cannot achieve very high speed;
  • They are not very noisy (though not always).

Besides these, are there any other reasons general aviation airplanes built nowadays don't have jet engines?

share|improve this question
    
Ok, so in the non-confused sense: Would you like to know why we're still using propellers (rather than jet propulsion), or still using reciprocating engines (rather than turbine engines)? Or both? –  falstro Jan 28 at 18:16
    
Basically the former one. –  Farhan Jan 28 at 21:32
    
Somewhat related question: aviation.stackexchange.com/questions/1086/… –  Qantas 94 Heavy Jan 29 at 6:26
add comment

2 Answers

up vote 16 down vote accepted

Jet engines are only efficient at high altitudes and high speed (25,000+ feet or so and 300+ knots or so true airspeed). The cost of making and operating an airplane capable of flying there is very high, and most general aviation flights have no need of such performance (or expense) hence, propeller airplanes.

Reciprocating engine propeller airplanes are relatively efficient at low altitudes and airspeeds, they are more economical for the average types of general aviation flights. They are also much cheaper to build and operate than a turbine powered airplane.

Turboprops fill the efficiency gap between reciprocating and pure jet engines, being most efficient at mid altitudes and airspeeds. Still more expense and performance than most general aviation flights need though.

share|improve this answer
4  
I'll add that if you put a turbine on a C172 the 40 gallons of jet-A in the wings would probably not get you very far. –  casey Jan 28 at 16:28
    
Good answer! I'd say that the most important aspects though are that they are a) cheaper to build and b) cheaper to operate. –  Lnafziger Jan 28 at 17:05
1  
Don't forget the Turbo-fans which bridge the gap between turbo-props and pure jet by using a bit of both :) –  falstro Jan 28 at 18:17
    
Also, piston engines just make more sense until power demand reaches around 500hp –  ptgflyer Mar 29 at 12:55
add comment

It is all mission related.

Propeller engines - and I am including turboprops - are much more efficient at lower speeds and altitudes. Example: the C-130 Hercules cargo aircraft. It can get in and out of fields much shorter than a turbojet or turbofan can, while trucking a large load, because it has those huge propellers clawing at the air. Jets, as stated before, have the advantage high and fast. But that is not the mission of the Hercules.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.