

The goal is to reduce noise and fuel consumption








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RE: Numbers?
By Ringold on 6/24/2011 4:49:12 PM , Rating: 2
Would you be able to point out the key difference between a turboprop and propfan? A propfan looks like a slightly rearranged turboprop to my lay eyes, but it is very interesting.

RE: Numbers?
By Amiga500 on 6/25/2011 6:50:28 AM , Rating: 3
Broadly speaking, it sort of is.

However, a propfan can also form part of the inner engine core's compressive stages (for a tractor unit), or be directly linked to the turbine stages (for a pusher unit). A turboprop will tend not to do this - it'll use a gearbox to adjust rotation speeds.

A propfan with thus spin at much higher speeds, but due to the swept tips, still operates effectively. Here is graph of propulsive efficiency of the different types of engines.

I see some internet sites claiming that the distinction is that the exhaust of a turboprop is not used for additional propulsion - that is completely untrue.

