Velocity XL RG Owner's Manual - page 17
33
O
WNER
’
S
F
LIGHT
M
ANUAL
32
XL
Step 8 - Calculating the various ARMs
It will be necessary for you to calculate the ARM for each of
the following:
• “Pilot/co-pilot” ARM
• “Rear passenger” ARM
• “Header sump tank fuel” ARM
• “Fuel” ARM
• “Baggage” ARM
Here is an example using the factory Velocity N81VA to calcu-
late the “Pilot/co-pilot” ARM:
Nosewheel Axle ARM = 31”
Nosewheel weight = 146 lbs
Main gear axle ARM = 144.6
Main wheels (L+R) combined weight = 1600 lbs
Pilot Weight = 185 lbs
• First, find the CG of the aircraft with pilot:
(146 x 31) + (1678 x 144.6) 24716664.8 Inch lbs
_______________________ = ________________
= 135.5”
1640 + 1825 1825 lbs
• Second, subtract the moment of the empty aircraft (247164.8
inch lbs) from the moment of the aircraft when loaded with the
pilot (232280 inch lbs)
247164.8 - 232280 = 14884.8 inch lbs
• Third, verify that the weight difference between the aircraft
with pilot (1825 lbs) and the weight of the empty aircraft (1640
lbs) equals the pilots weight (185 lbs).
• Fourth, divide the difference of the moments by the difference
of the weights (the pilot weight), and the result will be the
“Pilot/co-pilot” ARM:
14884.8 inch lbs
_______________ = 80.45” aft of datum
185 lbs
Repeat this procedure for all the various ARMs and
record the results below:
• “Pilot/co-pilot” ARM =
• “Rear passenger” ARM =
• “Header sump tank fuel” ARM =
• “Fuel” ARM =
• “Baggage” ARM =
• “Ballast/Nose” ARM =
Note: For the fuel ARM, add the two Fuel ARMs (15 gal + Full),
divide by 2 to get an average Fuel ARM
Here are some sample ARMs for N97XL:
• “Pilot/co-pilot” ARM =80.0
• “Rear passenger” ARM =124
• “Header sump tank fuel” ARM =145
• “Average Fuel” ARM = 132
• “Wing Strake Storage” ARM = 115
• “Ballast in nose” ARM = 24”
Step 9 - Calculating the CG now that you known the
ARMs for your aircraft:
Ok, now we have all the data we need to set up a weight &
balance worksheet. You can set up a worksheet using a computer
with spreadsheet software (eg. Excel, Lotus, etc.) or simply make
photocopies of the worksheet (OM-WB) and do it longhand.
Refer to the “sample only” weight & balance spreadsheet for a
“standard” Velocity.
It is pretty much self explanatory after all that you have been
through to get this far, but to be safe, let’s run through it. First, if