Prop Engines

[Rambler 1-1 9]

Hey all,

 

I'm working on a plane with a P&W R-2800-8W engine, and one of the things I want to do is give it reasonable range and fuel load. Unfortunately, there seem to me no entries for fuel consumption in the .ini, just an entry for the idle consumption. I was wondering what entries are supposed to be there (if any), and especially what measurement they are supposed to be in (lbs/hr? Kg/min? M/Ns?). I know that for jets, the entries are TFSC0 and TFSC1 and you enter a value, but what that value is and what it represents, i don't know, just that a lower number is more efficient. Maybe that's efficiency ratio of fuel burned to thrust produced. I DONNO!

 

I DLed the Corsair and the Hellcat, which both use the R-2800 as well, to see if the entries were there, but no banana. Any help?

[Wrench 9,846]

Since I think I know of which aircraft you speak (which, btw, is a bit over modeled in the FM department), methinks THIS below is the section you be looking fer...

 

[Engine]

SystemType=PROP_ENGINE

InputName=THROTTLE_CONTROL

EngineID=1

SLPowerDry=775840.0

ThrustAngles=0.0,0.0,0.0

ThrustPosition=0.0,4.186,-0.08

ThrottleRate=0.5

AltitudeTableNumData=10

AltitudeTableDeltaX=1524

AltitudeTableStartX=0.0

AltitudeTableData=0.99,0.99,0.993,0.996,1.00,0.70,0.60,0.50,0.25,0.000

PropRotationDirection=LEFT

ReversePropOrientation=TRUE

SpinnerNodeName=Spinner

RotationAxis=Z-Axis

StaticPropNodeName=Prop_Blade

SlowPropNodeName=

FastPropNodeName=Slow_Prop

SlowPropRPM=90

FastPropRPM=600

MaxPropRPM=650

IdlePropRPM=95

BSFC=0.01 <---I belive THIS is it

ExhaustEmitterName=CleanExhaustEmitter

ExhaustPosition=0.0,1.10,0.0

FireSuppression=TRUE

MinExtentPosition=-0.447,3.733,-0.462

MaxExtentPosition=0.49,2.3,0.32

MaxPowerAnimationTime=0.1

MinPowerAnimationTime=0.3

ConstantSpeed=TRUE

NumBlades=3

PropDiameter=3.352

PropEfficiencyAdvanceRatioTableNumData=11

PropEfficiencyAdvanceRatioTableDeltaX=0.2

PropEfficiencyAdvanceRatioTableStartX=0.0

PropEfficiencyAdvanceRatioTableData=0.023,0.40,0.70,0.80,0.86,0.87,0.87,0.87,0.87,0.86,0.85

MomentOfInertia=0.05

 

IIRC, it's Brake Specific Fuel Consumption. What I don't know is, is it liters/hour, gallons/hour, beer/minute????

Right now, I"d say that's pretty damn low, even for the R-1820 (or whateve the original single-row was)

 

Wrench

kevin stein

 

 

EDIT:

 

found this, it may help. math is over my pointy little head...

 

http://en.wikipedia.org/wiki/Brake_specific_fuel_consumption

[+p10ppy 2]

Brake Specific Fuel Consumption in FE works out empiracly to

KG of fuel per KW Minute or

G of fuel per W Minute (same number)

not the same as wiki but any other formula seems to give silly results (in FE)

 

so the engine Wrench posted uses 775840*0.01 grams of fuel a minute = 7.76 kg fuel/minute = 465.5 Kg/hour

at full power

 

i think

Edited March 16, 2009 by p10ppy

[Rambler 1-1 9]

well, actually, this is the engine from the plane in question. Assuming that the dry power there is in W, it was actually running a slightly less powerful R-2800-8 (without the water injection).

 

//P&W R-2800-8W

[Engine]

SystemType=PROP_ENGINE

InputName=THROTTLE_CONTROL

EngineID=1

SLPowerDry=1677000.0 <--- was 1502000.0

ThrustAngles=0.0,0.0,0.0

ThrustPosition=0.0,2.0,-0.0

ThrottleRate=0.5

AltitudeTableNumData=8

AltitudeTableDeltaX=1524

AltitudeTableStartX=0.0

AltitudeTableData=1.000,0.995,0.99,0.985,0.98,0.358,0.277,0.000

SpinnerNodeName=Spinner

StaticPropNodeName=Prop_Blade

SlowPropNodeName=Slow_Prop

FastPropNodeName=Fast_Prop

SlowPropRPM=200

FastPropRPM=2000

MaxPropRPM=2750

IdlePropRPM=900

BSFC=0.01 <--- ?

ExhaustEmitterName=CleanExhaustEmitter

ExhaustPosition=0.0,1.10,0.0

FireSuppression=TRUE

MinExtentPosition=-0.447,3.733,-0.462

MaxExtentPosition=0.49,2.3,0.32

MaxPowerAnimationTime=0.1

MinPowerAnimationTime=0.3

ConstantSpeed=TRUE

NumBlades=3

PropDiameter=4.00

PropEfficiencyAdvanceRatioTableNumData=11

PropEfficiencyAdvanceRatioTableDeltaX=0.1

PropEfficiencyAdvanceRatioTableStartX=0.0

PropEfficiencyAdvanceRatioTableData=0.023,0.40,0.70,0.80,0.86,0.9,1.0,0.87,0.87,0.86,0.85

MomentOfInertia=0.2

 

so, using my reliable internet sourse (wikipedia!), I found out that fuel consumption is 540g/KWh, = 0.009g/Wm. That means that at full throttle, I'll be burning 15.1 kg of fuel per minute. That sounds about right. Now I'll just enter 0.009 into the "?" space and be done with it. Thanks, guys!