SkyDemon Forums

Ease input of W&B values

http://forums.skydemon.aero/Topic25837.aspx

By camphorball - 4/25/2018 10:54:12 AM

In a similar vein, the Cessna 182R has a W&B profile that is different for takeoff and landing. The MTOW weight is 3100lbs which is frequently used (balancing 3 or 4 people and the fuel load) but the MLW is 2950lbs. It would be good to be able to present this on the W&B form which would eliminate the warning messages or provide both takeoff and landing warnings if fuel-burn would be insufficient for a safe landing.

It's a small point and may not apply to enough planes to warrant its inclusion.


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By maweb - 4/20/2018 4:17:02 PM

Hi
I fly a Cessna 172 with the following envelope:
* Moment = 52,5 and Weight = 1500 lbs
* Moment = 68,0 and Weight = 1950 lbs
* Moment = 88,5 and Weight = 2300 lbs
* Moment = 109,0 and Weight = 2300 lbs
* Moment = 70,5 and Weight = 1500‌‌ lbs

And when I manually do the W&B calculation, I use the Loading Graph with lines for each variant of moment factor.

From those lines I can plot the following values:
* Pilot and front passenger: Weight = 390 lbs and Moment = 14,5
* Fuel: Weight = 228 lbs and Moment = 11
* Rear passenger: Weight = 390 lbs and Moment = 28,5
* Baggage area 1: Weight = 120 lbs and Moment = 11,5
* Baggage area 2: Weight = 50 lbs and Moment = 6

And finally the manual says empty plane: Weight = 1366 lbs and Moment = 53,8‌‌.
(I know I need to read the correct values in the plane's weight and balance documentation)

SkyDemon can easily handle a W&B calculation of a plane with the above specifikation if I make the nessecary convertions from lbs to kg and from moment to length of arm.‌‌‌

My suggestion for SkyDemon is an option to enter the W&B envelope and loading points in weight‌‌ and moment as listed above. And if possible also an option for entering the W&B profile values with a different weight unit as used when entering the actual loading values.

The benefit of this suggestion is a much easier entering of W&B values with less risk of incorrect values.‌‌
I'm not sure how to implement this in SkyDemon, but the formulas to be used is simple and as far as I know also mentioned in the user manual to SkyDemon.

And finally, I miss a "Move up" and "Move down" in the list of loading points‌‌ if I missed entering a loading point. It's very easy to delete and create new loading points in the correct order, so this little extra suggestion has a low priority compared to the input of W&B values.
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