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Turbine Jet engine...? Answered

If the intake turbines' speed is regulated by the compressed exhaust over the rear turbines, would it be more effecent to have 2 props in a row, or a single large one at the rear of the engine to control the rotation speed?



Best Answer 8 years ago

Turbine engines are different than jets; jet is using the pressure differential of intake and exaust to push an aircraft, turbine is using the hot exaust to turn a shaft at high speed to power another apparatus such as a propeller or transmission. Various types of turbine engines are designed for different applications.

The type that I see on a daily basis are dual-stage power turbine and single stage power turbine. each has advantages and each have disadvantages. In other words, it depends. Size, weight of turbine, fuel requirements, power requirements, etc., play a big part in the design of an engine. Helicopters usually have only two speed settings, with a variable power output dependant upon requirements at the time (change in pitch of the blades, head position, flight parameters, etc.) Fixed-wing have similar outputs. For power units (generators and such) only one speed is necessary. The fuel control is set to maintain RPM and torque (power output)  within set limits. 

In orher words, it depends.

I was studying a diagram from a commercial jet engine, and there are front props and rear props. I understand that the rear props regulate the speed of the front based on the fuel pressure output, but i was trying to see if there was a way to simplify the rear prop effeceintly.  In the diagram I was looking at there was 2 props at the rear and I was wondering if 2 was more effeceint than one larger one... I would like to build one thats more compact.  Thank you for your help.

If you put 2 props at the back it wouldn't be very efficient nor a large one the best way to make it efficient is to make the exhaust prop thin an aerodynamic.

turbine engine.jpg

i am very sorry for any grammer or spelling mistakes english is my forth language. 
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