Fuel flow variation with change in ambient air temp
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Fuel flow variation with change in ambient air temp
Situation: You have air at +20 degrees C entering your turboprop engine and with the current settings you are producing 75% torque - fuel flow is 500 lb/hr.
If you change the ambient air temp to -30 degrees C and adjust the power lever to maintain 75% torque, will the fuel flow be 500 lb/hr?
The engine is direct-drive and the RPM is at 100% and does not get adjusted.
I'd also be interested in what happens in a free-turbine or turbojet/fan where the spool speed is allowed to change.
Cheers!
If you change the ambient air temp to -30 degrees C and adjust the power lever to maintain 75% torque, will the fuel flow be 500 lb/hr?
The engine is direct-drive and the RPM is at 100% and does not get adjusted.
I'd also be interested in what happens in a free-turbine or turbojet/fan where the spool speed is allowed to change.
Cheers!
Join Date: Aug 2003
Location: Sale, Australia
Age: 80
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Some figures taken from a PT-6 powered airframe
ISA-30 384pph
ISA-20 399
ISA-10 404
ISA 409
ISA+10 413
ISA+20 418
ISA+30 423
ISA+37 439
With increasing temp the N1 spool will need to increase RPM
ISA-30 384pph
ISA-20 399
ISA-10 404
ISA 409
ISA+10 413
ISA+20 418
ISA+30 423
ISA+37 439
With increasing temp the N1 spool will need to increase RPM
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With increasing temp the N1 spool will need to increase RPM
I'm assuming that's for the same torque setting?
Do you know what happens for a direct-drive engine like a TPE331 where the N1 speed doesn't change?
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I'm assuming that's for the same torque setting?
-15 376
-5 377
5 380
15 384
25 389
35 395
45 402
