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W&B Spreadsheet

Downloadable Spreadsheet

W&B Download here :

Bearhawk W&B.
Download XLSX • 14KB

This spreadsheet uses Numbers or Excel, and operates on an ipad or iphone. It contains a list of equipment and arms from my aircraft so that builders can compare their own measurements for a gross error comparison, and explore the effect of placing different weights at various locations. The accuracy of the arms and formulas should be verified before use.

It can also be used to estimate the Weight and CG before each flight.

To begin, overwrite your wheel weights in the magenta boxes. Alternatively you can use the existing wheel weights which are for an IO540 powered Bearhawk, with a 3 bladed composite prop. You could for example use a friends wheel weights, and then start modifying the arm weights.

Yellow boxes = arms in inches (or mm)

Top grey boxes = total weight and CG

Green boxes = click and use slider to add people, cargo, fuel.

Blue boxes = click and use slider to add or subtract weight from that arm location.

Example 1. If you want to add heavier tires, click the blue box for tires and increase the slider the amount you wish to add. Then look at the top grey boxes to see the resulting total weight and CG.

Example 2. You want to see the effect of changing from your current 2 bladed prop to a 3 blade prop. Click the blue propeller box and increase by 20lbs. View the resulting weight and CG in the top grey boxes.

Example 3. You decide to take out next years STOL comp and add 30 lbs ballast to the aft fuselage grab handles. Click the blue box for ballast at grab handles and enter 30 lbs. enter your own weight in the green front seat row, and the liters (or gallons) of fuel you plan to carry in the green fuel box. View the resulting weight and CG in the top grey boxes.

Example 4. Aunt Sally weighs 300lbs. You figure she can fit in the back seat. Click the green rear seat box and move the slider to 300 lbs. Enter the two front seat weights, and some fuel. Then play around with the cargo weight to see if you're still within CG limits and below MTOW. View the resulting weight and CG in the top grey boxes.

If you plan to use it for another aircraft type and have measured the arms for that aircraft, you can "un-hide" all columns and overwrite your measured arm measurements. Then "hide those columns again. If you only plan to use it for a completed aircraft to calculate weight and CG prior to each flight, you can also "hide" the rows below the Cargo input to leave a very tidy small sheet that fits an iphone screen well.


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