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Guest metamarty

Variable irregularities

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Hello all,While accessing data from FSX with SimConnect I've come across these irregularities:- All Fuel tank capacity variables report irregular values when the unitsname is set to null. According to the docs, the default should be "gallons", but it's obviously something different (values are around 0.1). When setting the unit to "gallons", the data is correct.- Estimated fuel flow in gallons per hour seems to be multiplied by 1000. I'm not sure if the multiplier is exactly 1000, but the values seem reasonable after dividing by 1000.Does anybody with more information know the correct way to handle estimated fuel flow?Thanks,Marty

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>- All Fuel tank capacity variables report irregular values>when the unitsname is set to null. According to the docs, the>default should be "gallons", but it's obviously something>different (values are around 0.1). When setting the unit to>"gallons", the data is correct.I've always specified the units for every variable. I wouldn't trust leaving the value as 0 -- in fact that wouldn't have worked at all in the earlier Betas as far as I recollect.>- Estimated fuel flow in gallons per hour seems to be>multiplied by 1000. I'm not sure if the multiplier is exactly>1000, but the values seem reasonable after dividing by 1000.Which value are you reading? All the individual "RECIP ENG FUEL FLOW:index", "TURB ENG CORRECTED FF:index" and "TURB ENG FUEL FLOW PPH:index" values look sort of right (I think) when read with units explitly set to "pounds per hour". These are the only ones I read in FSUIPC4.RegardsPete

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>>I've always specified the units for every variable. I wouldn't>trust leaving the value as 0 -- in fact that wouldn't have>worked at all in the earlier Betas as far as I recollect.Ok thanks, that was not quite clear from the documentation. I'll specify the units when possible.>>>- Estimated fuel flow in gallons per hour seems to be>>multiplied by 1000. I'm not sure if the multiplier is>exactly>>1000, but the values seem reasonable after dividing by 1000.>>Which value are you reading? All the individual "RECIP ENG>FUEL FLOW:index", "TURB ENG CORRECTED FF:index" and "TURB ENG>FUEL FLOW PPH:index" values look sort of right (I think) when>read with units explitly set to "pounds per hour". These are>the only ones I read in FSUIPC4.I'm using the variable "Estimated Fuel Flow" and request it in "gallon per hour". I believe there's no dialog box inside FSX itself to read this value, but it seems that this variable returns reasonable values when you divide it by 1000, but it certainly can't be "gallons per hour". For example: it returns 7557.453 for the default cessna 172.>>Regards>>Pete>Thanks,Marty

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>I'm using the variable "Estimated Fuel Flow" and request it in>"gallon per hour". I believe there's no dialog box inside FSX>itself to read this value, but it seems that this variable>returns reasonable values when you divide it by 1000, but it>certainly can't be "gallons per hour". For example: it returns>7557.453 for the default cessna 172.Hmmm. Sorry, never noticed that one. Don't the actual fuel flow values work in the Cessna?Regards,Pete

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The actual values won't work. For our FS Economy project, we have a centralised database with aircraft information. This information is used by the central system to do calculations about jobs, payment and cost. Using the client program (which I'm updating for FSX now), people can submit their favourite aircraft so we can enter it into the database. This submit process grabs as much information from FS as possible, so we don't have to go hunting on the internet for it.I was actually delighted that these "estimate" variables were introduced, since we always had to enter them by hand. It's not a big deal if there are some problems, but it would be nice to have them. Do you happen to know if I can simply divide the estimateFuelFlow by 1000, or is there some deeper problem that causes unreliable data?Thanks,Marty

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>The actual values won't work. ...>I was actually delighted that these "estimate" variables were>introduced ...I see from the description that the value is supposed to be "estimated fuel flow at cruise", so presumably it is a *prediction* ? Is it therefore based on a plan? If not, wouldn't the estimate need to be based on the cruise altitude, amongst other things, or are cruise altitudes sort of taken for granted in such aircraft?It seems odd to see it bunched up with the aircraft data rather than the GPS/Planning information.>Do you happen to know if I can simply>divide the estimateFuelFlow by 1000, or is there some deeper>problem that causes unreliable data?Sorry, I really don't know this variable at all. I'm surprised that it exists and I don't know if it is calculated or fixed or what.Hmmm.RegardsPete

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This is a strange variable indeed. It appears to be fixed as I get the exact same values. The value if you don't specify a unit is returned in meter cubed per second. I wonder if this could be related to the BestPowerSpecificFuelConsumption entry in aircraft.cfg.As for the fuel tank capacity, the value you get if you don't specify a unit is cubic meters.

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That might explain why the value seems to be 1000x too high. Working with cubes, it's easy to mess up. If they were thinking in units of a decimeter^3, while they really had meter^3, it would result in a value 1000 times too high.

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