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View Full Version : Turbine Time


CAPTAINxJSB
09-28-2006, 02:47 PM
Is turboprop time considered turbine?


rickair7777
09-28-2006, 02:57 PM
Is turboprop time considered turbine?

Always. If somebody is looking for turbojet time, they will specify "turbojet". Otherwise turbine means turbo-prop or turbojet.

Major airlines routinely hire folks with only turbo-prop regional PIC time, although jet time does make you more competetive in most circumstances.

Laxrox43
09-28-2006, 03:28 PM
Rickair is dead on...

Just don't confused Turbo-props with a Turbo-Charged Reciprocating (Piston) engine...Whole different ball game...

Lax


LAfrequentflyer
09-28-2006, 03:55 PM
Turbo-prop is a turbine jet engine with the blades on the outside (propellers) - right?

WhiteH2O
09-28-2006, 05:17 PM
Turbo-prop is a turbine jet engine with the blades on the outside (propellers) - right?

Well, they still have the same blades on the inside, but they also have propeller blades on the outside. The propeller blades on the outside are usually driven by the air being moved by the jet engine. Sort of like an automatic transmision without fluid. Others are driven off of the shaft of the turbine through a gear reduction gear box.

ctd57
09-29-2006, 07:24 AM
Well, they still have the same blades on the inside, but they also have propeller blades on the outside. The propeller blades on the outside are usually driven by the air being moved by the jet engine. Sort of like an automatic transmision without fluid. Others are driven off of the shaft of the turbine through a gear reduction gear box.

That is kind of right but doesn't really explain it clearly. There are 2 types of turbo props, direct drive and free-spinning. A direct drive propellor is driven directly from the compressor shaft through a reduction gear assembly. A free-spinning is not directly connected to the engine. A free turbine power section is added to the engine after the turbine section. The exhaust gases from the engine drive the free power turbine . The power turbine is connected to the propellor gearbox by a shaft. A PT-6 is a free spinning turbine, you can spin the prop without spinning the engine, with a direct drive, when you spin the prop, you are actually spinning the engine itself. You can tell which type of engine is the aircraft just by looking at it. A free-spinning prop, when shut down, is in the feathered position, a direct drive engine it is the low pitch high rpm position, or flat looking if you stand infront of the aircraft and notice alot of blade is exposed when shut down. But as said before, they are all turbines, they just function slightly differently.

rickair7777
09-29-2006, 08:36 AM
The term turbojet is often used to mean turbofan...most modern jet engines are turbo fans. A true turbojet takes 100% of the air through the engine and burns it with the fuel in the core...all of the thrust is from hot core air. Real turbojet are rarely used because they are very fuel ineffecient.

Modern jets of all sorts (military, airline, corporate) use turbofans...the guts of these engines are very similar to the free-spinning turboprop, it produces hot gas that is then used to drive a seperate turbine that drives a large fan on the front of the engine. Modern high-bypass turbofans take 100% of the air through the fan, but only 15% of that air then goes through the core section to get burned and produce thrust, the other 85% passes through the fan and then goes around the outside case of the core. This fan bypass air provides about 80-85% of the thrust, with the rest provided by leftover core air. Sounds complicated but it is more effecient than a real turbojet (but less effecient that a turboprop).

Basically we are flying turboprops...just with different propellors.