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AVGAS weights and densities for weights and balance.


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GTSAS
GTSAS
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My weights and balances calculations are quite far out due to miscalculation on fuel.
My SD seems to be using 8.2 lbs/USG and 1.0 kg/l, are these set by SD or are they user definable?

Tim Dawson
Tim Dawson
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They are not user-definable, they are standards used throughout the industry. We use a specific gravity for avgas of around 0.72, for jet of around 0.8 and for mogas around 0.75 kg per litre.
MarkusM
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Apparent miscalculations often have their reason in not matching units for the entries done. With density fixed, you are not completely free in choosing which to use.
Monacos_Franz
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Tim Dawson - 3/4/2019 10:34:45 AM
They are not user-definable, they are standards used throughout the industry. We use a specific gravity for avgas of around 0.72, for jet of around 0.8 and for mogas around 0.75 kg per litre.

I have the same problem. I'm trying to use the weight and balance calculation but the program is calculating 87 US gallons into 330kg. When it really should be 237kg. Is there any way to fix this? This way the app is not really useable for weight and balance which I think is very bad.

Thanks

MarkusM
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Monacos_Franz - 4/19/2019 7:46:06 PM
Tim Dawson - 3/4/2019 10:34:45 AM
They are not user-definable, they are standards used throughout the industry. We use a specific gravity for avgas of around 0.72, for jet of around 0.8 and for mogas around 0.75 kg per litre.

I have the same problem. I'm trying to use the weight and balance calculation but the program is calculating 87 US gallons into 330kg. When it really should be 237kg. Is there any way to fix this? This way the app is not really useable for weight and balance which I think is very bad.

Thanks

You could attach your .aircraft file to the post and somebody have a look at what is wrong?

Tim Dawson
Tim Dawson
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Monacos_Franz, give SkyDemon support a call if you're having problems. I can assure you that after many years leading the European market in software of its kind, SkyDemon is not making basic weight and balance calculation errors.
GTSAS
GTSAS
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Tracked down the issue, it was as you can guess with SD's excellent piece of programming my fault.  SD not only calculates the take off, cruise and landing fuel but also includes a reserve and contingency.  Once these are taken into account the numbers produced by SD are correct.
Stefan Graf
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Tim Dawson - 3/4/2019 10:34:45 AM
They are not user-definable, they are standards used throughout the industry. We use a specific gravity for avgas of around 0.72, for jet of around 0.8 and for mogas around 0.75 kg per litre.

Hi Tim, I am a new SD user, and I have the same problem, plus another one, concerning weight and balance. My SD software equals 1 l of AVGAS to 1 kg (when it should be approx 0.72). Also, my program adds 134 kg to every weight and balance calculation, and I cannot find the reason why. I'm grateful for every hint how to solve these issues.
Tim Dawson
Tim Dawson
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It'll be a misconfiguration of the weight and balance, possibly a duplicate of a fuel tank or a miscategorisation of a fuel tank as a general loading point. Could you give us a quick call? We'll be able to help much easier on the phone.
Stefan Graf
S
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Tim Dawson - 1/27/2020 11:51:29 AM
It'll be a misconfiguration of the weight and balance, possibly a duplicate of a fuel tank or a miscategorisation of a fuel tank as a general loading point. Could you give us a quick call? We'll be able to help much easier on the phone.

I'll try to call tomorrow or Wednesday from work.
GO

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