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Gladio
Apr-22-2014, 13:49
Based on the graphs below it seems the higher you fly, the more fuel you burn. I must admit I'm lost.

http://www.pumaszallas.hu/Private/VO101_Tom/Tests/E4fuel3.jpg

http://i1020.photobucket.com/albums/af321/farber82/datasheets/bf109E1datasheet_zps441c0638.png

Kling
Apr-22-2014, 13:58
hmm will have a look at it

Gladio
Apr-22-2014, 14:00
Actually the altitude is clearly reported

Kling
Apr-22-2014, 14:03
Actually the altitude is clearly reported

Yes... I edited my post... weak moment from my side...

Gladio
Apr-22-2014, 14:03
Sorry bud, wasn't aware.

Kling
Apr-22-2014, 14:24
I havent flown piston engines for a while but to my memory fuel consumtion should be more or less constant for the same power setting and rpm no matter what altitude ure at.

The only thing changins is your TAS but that doesnt change your fuel consumption.

Had the graph been with constant IAS instead of constanr ATA it would make more sense as to maintain the same IAS the higher you go the more ATA you will need and as as a concequence a higher fuel consumption.
Can it be a mistake in the graph and it should actually be constant IAS from sealevel to 7k?

Canister
Apr-22-2014, 15:35
I havent flown piston engines for a while but to my memory fuel consumtion should be more or less constant for the same power setting and rpm no matter what altitude ure at.

The only thing changins is your TAS but that doesnt change your fuel consumption.

Had the graph been with constant IAS instead of constanr ATA it would make more sense as to maintain the same IAS the higher you go the more ATA you will need and as as a concequence a higher fuel consumption.
Can it be a mistake in the graph and it should actually be constant IAS from sealevel to 7k?

The fuel consumption should decrease with altitude as you can (not in this case) lower the mixture, but in the same way also performance decrease with altitude due to turbocharger limits, thin air...

As you said the problem (imho) in the chart is that it consider costant ATA and therefore it displays higher consumption for higher altitude.

Would be interesting btw to have a graph that display the fuel consumption @cruise and @ max for various altitudes, I searched the web but I got different datas and I don't know which the sim uses..

JV44Rall
Apr-22-2014, 15:38
I havent flown piston engines for a while but to my memory fuel consumtion should be more or less constant for the same power setting and rpm no matter what altitude ure at.

The only thing changins is your TAS but that doesnt change your fuel consumption.

Had the graph been with constant IAS instead of constanr ATA it would make more sense as to maintain the same IAS the higher you go the more ATA you will need and as as a concequence a higher fuel consumption.
Can it be a mistake in the graph and it should actually be constant IAS from sealevel to 7k?

I'm not sure what VO101_Tom is representing here - is it the amount of fuel burned in one hour at the indicated power setting and altitude? So one hour at 1.3 ATA at 3K burns 280 liters, while 1.3 ATA at 5K burns 360 liters? Maybe Tom can clarify.

In any event, I don't find it particularly surprising. It takes extra fuel to climb higher and the turbocharger craps out above 4K. So as you climb to 5K, you need to push more fuel into the engine to generate the same ATA.

But I could be wrong - the older I get, the more I'm sure I don't know anything. :salute:

RAF74_Buzzsaw
Apr-22-2014, 16:22
The excessive fuel consumption is a function of the physics errors which are in the vanilla game and which affect performance at high altitudes.

TF has created temporary mods to correct the errors and to allow performance at higher altitudes, but in doing so, this has increased fuel consumption at higher altitudes where the mod has the most effect.

A permanent fix for the core physics errors is on the way for TF 5.0.

This should eliminate the anomalies in fuel consumption.

In addition, we will be looking at overall fuel consumption in more detail for TF 5.0 to align the rate of consumption with known engine data.

Thanks for your patience. :salute:

Kling
Apr-22-2014, 16:48
aaaah is the graph showing the fuel consumtion from the 109 in game?!?!?

I thought this was real life figures which is why i got so confused!

Dutch
Apr-22-2014, 20:32
A permanent fix for the core physics errors is on the way for TF 5.0.

Can this post be framed, preserved in formaldehyde and buried in a virtual pyramid, so that BBC 4 can make a really interesting documentary about it in a few year's time?

VO101_Tom
Apr-22-2014, 21:34
I'm not sure what VO101_Tom is representing here - is it the amount of fuel burned in one hour at the indicated power setting and altitude? So one hour at 1.3 ATA at 3K burns 280 liters, while 1.3 ATA at 5K burns 360 liters? Maybe Tom can clarify.

In any event, I don't find it particularly surprising. It takes extra fuel to climb higher and the turbocharger craps out above 4K. So as you climb to 5K, you need to push more fuel into the engine to generate the same ATA.

But I could be wrong - the older I get, the more I'm sure I don't know anything. :salute:

Sorry if it was not clear that graph was made after testing TF 4.0 ingame values.
Fuel consumption of one hour flying time on various altitudes, various power settings.

These values may changed couple of percentage in 4.312 but basically still stands (I don't repeated this test with 4.312 yet).

As Buzz mentioned this is the fault of the basic phisics engine. This test is not intended to make debate about the consumption, it was made help calculating onlie war missions, patrol areas and available flying times with various power settings (patrol or dogfight).

Canister
Apr-23-2014, 03:40
Sorry if it was not clear that graph was made after testing TF 4.0 ingame values.
Fuel consumption of one hour flying time on various altitudes, various power settings.

These values may changed couple of percentage in 4.312 but basically still stands (I don't repeated this test with 4.312 yet).

As Buzz mentioned this is the fault of the basic phisics engine. This test is not intended to make debate about the consumption, it was made help calculating onlie war missions, patrol areas and available flying times with various power settings (patrol or dogfight).

Thank you for the clarification!
Knowing the consumption in game in different situation was also our goal to determinate how much time and fuel we can use or spare for the flight back..