IndianGuy
Posts: 3126
Joined: Fri Jul 07, 2000 3:14 pm

Pistons Vs Turboprops

Tue Jan 22, 2002 12:43 pm

What r the relative advantages/disadv of a single/twin turboprop vs comparable pistons for
Corporate/Private users? ANd Economics?

For eg Turbo Porter/King Air vs Cessna Singles/Beech Twins.
 
TWAMD-80
Posts: 962
Joined: Tue Oct 16, 2001 8:25 am

RE: Pistons Vs Turboprops

Tue Jan 22, 2002 2:40 pm

An advantage of a turboprop over a piston is that it can cruise at a faster speed. A disadvantage of turboprops is that the operating cost is higher than a piston's operating cost. However, I'm not exactly sure about the economics.

TWAMD-80
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Goldenshield
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Joined: Sun Jan 14, 2001 3:45 pm

RE: Pistons Vs Turboprops

Tue Jan 22, 2002 2:52 pm

The turboprop is the least expensive turbine to operate, due to the fact that there is a prop, pushing lots of air, at a relatively slow speed. It is usually most efficient in the .3-.5 mach range.

The piston often cant go as high as a turboprop, since it relies on normal aspiration to feed the engine. A turboprop uses a turbine, which is relatively the same pressure in the air, as on the ground.
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Jeff G
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Joined: Fri Jan 18, 2002 9:56 am

RE: Pistons Vs Turboprops

Tue Jan 22, 2002 3:34 pm

Pistons in general are much cheaper to operate than similar size turboprops. Turboprop engines are far more expensive than their piston counterparts to purchase and maintain, and burn more fuel. But turboprops are more reliable and easier to use. It's relatively easy to wreck a high-end, especially turbocharged, piston engine with sloppy handling. Turboprops are almost bulletproof. Just keep temperatures out of the red, and you're good to go.

BTW, Goldenshield, you have it exactly backward: turbocharged piston engines are the engines that see higher pressures to the engine than at sea level. All turboprops are normally aspirated and lose power as they climb. You can get around that limitation by flat-rating the engine, in essence behaving like a turbocharged engine, but they are still normally aspirated.
 
IndianGuy
Posts: 3126
Joined: Fri Jul 07, 2000 3:14 pm

RE: Pistons Vs Turboprops

Tue Jan 22, 2002 5:47 pm

Arent there piston aircraft that cruise around 240 knots? That should be just a little slower than Turboprops cruising @270, and with much lower complexity,.

Also cant pistons be presurrised so they fly higher?
 
Goldenshield
Posts: 5005
Joined: Sun Jan 14, 2001 3:45 pm

RE: Pistons Vs Turboprops

Wed Jan 23, 2002 4:42 pm

Sorry about that, thats what happens when you post post your bedtime  Smile
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XFSUgimpLB41X
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Joined: Fri Aug 25, 2000 1:18 am

RE: Pistons Vs Turboprops

Wed Jan 23, 2002 8:27 pm

Some pistons like the Cessna 421 are pressurized...it's pressurization comes off of the turbocharger.

I've never heard of a piston that is as fast as its turbine counterpart....and Jeff G is right.. you lose power as you gain altitude. You can see the torque fall off as you climb up and have to up the power levers just like you do in a piston...just the fact that you are putting out an unholy amount of torque at any altitude though makes up for that fact.  Smile

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