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I have found this website that lists a lot of turboprop engines. I would like to compare them with as few values as possible. As an example, there are tons of different values that describe a jet engine, but the most important/significant values are thrust and bypass ratio. Out of the many different values for a turboprop engine, which would be the few most important/significant to include?
My goal with the data is to approximate (very roughly) comparative fuel usage.

EDIT: To clarify the question, what are the most important engine values/specifications that can be used to estimate the general fuel economy of the turboprop engine?

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  • $\begingroup$ The main problem I see in this list is that it does not differentiate between turboprops and turboshafts. $\endgroup$ – DeepSpace Oct 22 '18 at 11:20
  • $\begingroup$ That's good to know, thank you. Is there a big difference performance-wise? I might add that I'm not interested in helicopters and such $\endgroup$ – Matias Lq Oct 22 '18 at 11:21
  • $\begingroup$ Are you planning to design one into an airplane? $\endgroup$ – CrossRoads Oct 22 '18 at 11:34
  • $\begingroup$ The idea is to estimate fuel usage of one aircraft compared to another aircraft. It doesn't have to be actual litres/minute, but more along the lines of "aircraft A uses 1.5x more than aircraft B". The engine performance plays a big role in determining fuel usage, e.g. a turbojet uses more fuel per thrust than a turbofan regardless of aircraft it is mounted on. $\endgroup$ – Matias Lq Oct 22 '18 at 11:41
  • $\begingroup$ @DeepSpace. A turboshaft and a turboprop both provide shaft power. There is no difference. $\endgroup$ – Penguin Oct 23 '18 at 10:27
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This database covers turboshaft and turboprop engines. Typically, the key factors one would use to compare such engines are:

  • SFC: Specific fuel consumption. This is how many kg/s (or lb/s) of fuel the engine consumes to produce 1 kW (or 1 hp). To calculate the SFC, divide the fuel flow at a throttle position by the amount of shaft power produced at that throttle setting. SFC decreases as overall pressure ratio increases. A low SFC means a more fuel efficient engine.
  • Specific power. This is, how much shaft power (kW) is produced per kg of air ingested by the engine. To calculate this, divide the shaft power by the air mass flow. A high specific power means you can get the power you need from a smaller, and hence lighter engine. A higher figure occurs when the engine has a high turbine temperature, and aerodynamically efficient compressors and turbines.
  • Power to weight ratio. To calculate this, divide the shaft power produced by the engine weight. As above, a higher figure occurs when the engine has a high turbine temperature, and aerodynamically efficient compressors and turbines.
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  • $\begingroup$ Specific power is dependant on the properties of the propeller, yes? Since we are talking turboprops $\endgroup$ – Matias Lq Oct 23 '18 at 15:34
  • $\begingroup$ @MatiasLq. No, specific power is purely a performance metric about the engine. It’s the shaft power provided by the engine (to the prop), divided by the air ingested by the engine. The efficiency of the propeller is a completely separate metric, that describes how well the prop turns that shaft power into thrust. $\endgroup$ – Penguin Oct 24 '18 at 12:01

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