Fuel Consumption and Afterburner

[pstrany]

Hi;

is there a way to increase fuel consumption when the afterburner is turned on? Again, I am doing a mixed powerplant aircraft (Me 262C) with jet and rocket engines, and using the afterburner to simulate the rocket thrust. The Me 262C carried 303 gallons of diesel fuel for the jets, and 402 gallons of rocket fuel. I have to find a way of burning off 402 gallons of fuel in 3.5 minutes of afterburner operation (plus whatever a pair of Jumo 004 engines burn in 3.5 minutes - oh oh, another question I have to answer!)

I'm of course operating under the assumption that fuel weight affects the flight model (if it doesn't, then this is a non-issue.) This is for both CFS2 and FS2004, so I need to know if there is a difference between the two.

Bear (hey, I like bears!) with my questions, I've built a few aircraft, but never done a flight model before, so I'm kind of new to the "dark arts"......

Thanks!


Paul

[errmail]

Hi;

is there a way to increase fuel consumption when the afterburner is turned on? Again, I am doing a mixed powerplant aircraft (Me 262C) with jet and rocket engines, and using the afterburner to simulate the rocket thrust. The Me 262C carried 303 gallons of diesel fuel for the jets, and 402 gallons of rocket fuel. I have to find a way of burning off 402 gallons of fuel in 3.5 minutes of afterburner operation (plus whatever a pair of Jumo 004 engines burn in 3.5 minutes - oh oh, another question I have to answer!)

I'm of course operating under the assumption that fuel weight affects the flight model (if it doesn't, then this is a non-issue.) This is for both CFS2 and FS2004, so I need to know if there is a difference between the two.

Bear (hey, I like bears!) with my questions, I've built a few aircraft, but never done a flight model before, so I'm kind of new to the "dark arts"......

Thanks!


Paul

Fuel weight affects the flight model but in the two sims you're working, there is no way to increase thrust-specific fuel consumption (TSFC) with the reheat on. Fuel consumption is in direct relation to pounds of thrust, so of course it will increase when the burner is on, but only to the degree that thrust is increased.

Now, in FSX, you can do this because you can specify the thrust-specific fuel consumption rate for both dry and wet operation.

[pstrany]

That's kind of what I thought. Thanks for the info, I guess I'll just have to recaculate the load, so that at the end of 3.5 minutes there is enough fuel left to power the two jets so that they would last for a fixed period of time.

Too bad, this bird was on overload to get off the ground, then lost 2500lbs in a hurry (or thereabouts.) Would be nice to simulate that, but I guess that isn't going to happen.

Time to go flying with the old stop-watch.........

Paul

[fliger747]

Paul:

One of the gauge guru's could probably make a 'fuel dump' setup for such a situation.

[sparks]

There is a way to increase SFC for afterburners in FS2000, FS2002, and FS2004. I don't know if it works in CFS2, but CFS2 followed FS2000, so it might.

Change Airframe Type in section 1101 to 5943, which is what MS used for the old FS2000 Concorde. This is the only 'airframe type' I know of that has any effect on the flight model.

Changing nothing else, fuel consumption rate (gph/lb) without afterburners will increase by about 40%. With afterburners engaged, the fuel consumption rate will be double the rate measured without afterburners.

Basically all this does is double the fuel burn rate with afterburners versus no afterburners. If that helps, great, but it's still not very flexible as you don't get to choose your own ratio.

[pstrany]

Thanks! I'll have to try that out Sparks, and see if it'll do the trick. I'll also look into a gauge, though the "greens" may frown on dumping all that fuel like that...... :d

Paul

[errmail]

Thanks! I'll have to try that out Sparks, and see if it'll do the trick. I'll also look into a gauge, though the "greens" may frown on dumping all that fuel like that...... :d

Paul

If what you are concerned about is weight loss, why not just have a couple of drop tanks and drop them after you cut the afterburners? That'll give you your weight loss and work in both sims.

[pstrany]

Yeah, that might work, though it would be better if they could drop at intervals. I did a cluster bomb like that for CFS2, using a visible bomb, and then a bunch of invisible bomblets that actually exploded, in this case I would make the drop tanks invisible (or I may have to make them bombs - does the flight model add weight for drop tanks?) and just drop them periodically, lightening the aircraft as the aircraft ascends (the ME 163 was the same way, a pig on the ground, lost like half its weight in the climb, by the time she burned all her fuel, she was a very light and manouverable glider. Weird to look at a climb curve for it, got faster in the climb as she lost weight.....)

Paul