Danfearn77
Topic Author
Posts: 555
Joined: Thu Jul 10, 2008 11:52 pm

Military Aircraft And Turboprop

Sun Dec 28, 2008 12:16 am

Hi Guys

Now i know absolutely nothing about military aviation so be kind!

But something has been bugging me for ages. For 3 years since i finished a physics project on turbofans. Its simple really. Why do a large number of military aircraft use turboprops? Like the new A400m. So why do they use turboprop over jet engines like turbofans?

Thanks for your feedback.
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SkyyKat
Posts: 141
Joined: Wed Nov 05, 2008 6:58 pm

RE: Military Aircraft And Turboprop

Sun Dec 28, 2008 12:54 am

My personal hypothesis.

-Ability to operate from unprepared runways.
--(Turbofans are susceptible to FOD)

-Better short and high altitude field performance.

-STOL Performance

-Efficiency for certain roles they are used for Turbofans cant match.

-Ruggedness

I am sure there are many more reasons.
 
2H4
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Military Aircraft And Turboprop

Sun Dec 28, 2008 6:08 am



Quoting Danfearn77 (Thread starter):
So why do they use turboprop over jet engines like turbofans?

A perfectly fair question. But if you're intrigued by engine choices, and if you'd like to tackle a more challenging question, see if you can figure out why this aircraft used a jet engine instead of a turboprop:


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2H4
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ZBBYLW
Posts: 1612
Joined: Wed Nov 01, 2006 8:17 am

RE: Military Aircraft And Turboprop

Sun Dec 28, 2008 8:09 pm



Quoting 2H4 (Reply 2):
A perfectly fair question. But if you're intrigued by engine choices, and if you'd like to tackle a more challenging question, see if you can figure out why this aircraft used a jet engine instead of a turboprop:

Would it have anything to do with the soviets having an abundance of the A-25 (I think this is the engine) engines in such things as the L-39 so it would have been easier to find replacements etc?
Keep the shinny side up!
 
2H4
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Military Aircraft And Turboprop

Sun Dec 28, 2008 11:17 pm



Quoting ZBBYLW (Reply 3):

Would it have anything to do with the soviets having an abundance of the A-25 (I think this is the engine) engines in such things as the L-39 so it would have been easier to find replacements etc?

Perhaps, although I personally think the abundance of vodka had a bit more to do with the development of this particular aircraft.

2H4
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ebj1248650
Posts: 1517
Joined: Mon Jun 06, 2005 6:17 am

RE: Military Aircraft And Turboprop

Mon Dec 29, 2008 12:09 am



Quoting SkyyKat (Reply 1):
My personal hypothesis.

-Ability to operate from unprepared runways.
--(Turbofans are susceptible to FOD)

-Better short and high altitude field performance.

-STOL Performance

-Efficiency for certain roles they are used for Turbofans cant match.

-Ruggedness

I am sure there are many more reasons.

Where performance is concerned, don't turboprops accelerate the airplane a lot faster during takeoff? Makes for shorter takeoff runs, something perhaps even a high performance turbofan can't match.
Dare to dream; dream big!
 
Spacepope
Posts: 3151
Joined: Tue Dec 28, 1999 11:10 am

RE: Military Aircraft And Turboprop

Mon Dec 29, 2008 12:41 am

Turboprops also pu a lot of the wing in the propwash, generating some additional lift as well. Very few jets do this, save the AN 72/74 in servicem and the prototype YC-14.

Just look at the AN-32. The larger props and higher mounted engines throw a lot of wash over that wing compared to the AN-24/26.

Another fun one is the P-3, where there is barely any wing that is NOT behind props.
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