Pilots calculate aircraft weight and balance and their method is a good way
to check axle weights as you make modifications or load your motor home for
trips.
I use this method to run the numbers in advance to see how modifications
influence weight distribution since one of my goals is good handling.
For you pilots, I use the front wheel center as datum point zero and the
center of the bogies as datum point +160 inches on my 26 footer. A 23
footer bogie is at +140 inches.
The factory used these points for their wheel base and they assume weight is
evenly divided between the rear axles. I do likewise.
I weigh the items I remove or install and measure the distance from datum
zero.
Until I have my coach weighed I am using the published curb weights of 3680
front and 5820 rear as my starting point. This may be close but it
certainly is not accurate since those same numbers were published for all
units.
For those who never calculated weight and balance the math is simple.
1. For each item removed or added multiply the weight by distance in
inches to determine the moment.
2. Add all the weights then add all the moments.
3. Divide the total moments by the total weights to determine the datum
point of the combined changes.
4. The answer is a point in inches from the front wheels.
5. You then proportion the total weight at this point between the front
and rear axles (bogies).
If you have never done this it would be easier to have a pilot show you how.
A spreadsheet simplifies the process.
Don
75 Glennbrook
Shenandoah Valley of Virginia
to check axle weights as you make modifications or load your motor home for
trips.
I use this method to run the numbers in advance to see how modifications
influence weight distribution since one of my goals is good handling.
For you pilots, I use the front wheel center as datum point zero and the
center of the bogies as datum point +160 inches on my 26 footer. A 23
footer bogie is at +140 inches.
The factory used these points for their wheel base and they assume weight is
evenly divided between the rear axles. I do likewise.
I weigh the items I remove or install and measure the distance from datum
zero.
Until I have my coach weighed I am using the published curb weights of 3680
front and 5820 rear as my starting point. This may be close but it
certainly is not accurate since those same numbers were published for all
units.
For those who never calculated weight and balance the math is simple.
1. For each item removed or added multiply the weight by distance in
inches to determine the moment.
2. Add all the weights then add all the moments.
3. Divide the total moments by the total weights to determine the datum
point of the combined changes.
4. The answer is a point in inches from the front wheels.
5. You then proportion the total weight at this point between the front
and rear axles (bogies).
If you have never done this it would be easier to have a pilot show you how.
A spreadsheet simplifies the process.
Don
75 Glennbrook
Shenandoah Valley of Virginia
