14.99 Weight and Balance

This entry is part 34 of 38 in the series 14 - Final Assembly / FInishing

One of the final tasks before having the airplane inspected is to perform the weight and balance.

Before the airplane can be weighed there are a couple tasks that need to be performed.

First, anything that will be in the plane for flight has to be installed. No problem there. About the only thing that hasn’t been installed is the interior trim and that’s not “required for flight” and it’s not going in until after I flown off the required test flight hours anyway. But the spinner has never been installed so that has to be done.

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Second, all usable fuel has to be removed. Arrgh!  Back over to the factory building to borrow a bunch of 5 gallon fuel cans and then siphon out the fuel.

Finally, rather precise measurements need to taken. On the Velocity, the datum point is the nose. This is a reference point that is used to identify where the weight is located. (on many single engine production aircraft, the datum point is the firewall). So I used a plumb-bob to mark the floor where the nose is. Then the distance to the center of the nose wheel axle and main gear axles is located. This is used to determine the balance part of the weight & balance which is then used to determine the CG (Center of Gravity).

Now it’s weighing time. The factory has digital scales so I borrowed them (being in Sebastian has it’s advantages).

To get the plane on the scales, I had to jack up the plane. But my (homemade) jacks didn’t have enough travel to clear the jacks so I had to raise the plane. put some wood under the wheel, lower the plane, adjust the jack and repeat (fortunately, only once). The nose was easy since all I had to do was lift it up by hand.

Checking the weight

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And the verdict is:

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1,919 pounds.

Now there’s still fuel left in the strake tanks and sump. But that can be subtracted to give the true empty weight.

I was surprised at the weight on the nose. I was given to understand that around 80-90 pounds was typical and I’m at 102 pounds. If I had to guess, I would say the 24v battery and ground power receptacle are adding at least 6 pounds to the nose weight. And at least I’m not going to have to worry about hauling around bags of shot to keep the nose down when I’m not in it.

I took the weight and wheel dimensions over to the builder’s center where Rick used a spreadsheet to back out the usable fuel and calculate the CG (Center of Gravity).

N621CM W&B

Series Navigation<< 14.1.7 – Vortilon Installation14.99 Airworthiness Inspection >>