Wednesday, April 18, 2012

Calculating Center of Gravity in a Tricycle Gear Ultralight Aircraft

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A few days ago, I posted information on how to calculate the Center of Gravity in a Belite taildragger ultralight airplane.  Today, I provide an update for tricycle gear aircraft.

You should review my original post, here.  After you review it, consider the following example for a tricycle gear plane.

Note that the nose wheel has a NEGATIVE arm, as it's distance is negative from the firewall.  All other arms are positive.  Remember to weigh the aircraft with an empty fuel tank; add the fuel and the pilot weight as shown in the equations as below.

Center of Gravity, Tricycle gear ultralight aircraft calculations:

DESCRIPTION, WEIGHT (in lbs.), ARM (in inches), MOMENT (lbs x inches)
Front nose wheel, 70, -5, -350.
Main wheels, 180, 49, 8820.
Pilot, 200, 39, 7800.
Fuel, 30, 56.6, 1695.

Total weight is 480.
Total moment is 17965 (-350+8820+7800+1695)

ARM of the aircraft is 17965 / 480 = 37.42"

This aircraft is in the CG range. 

REMEMBER, you must measure the actual ARMs of your ultralight airplane using a plumb bob from the firewall, and the aircraft must be level.  (This may be a little easier to do in a tricycle gear plane, as the plane is mostly level to begin with.)

I hope you find this useful, no matter what kind of aircraft you fly.

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