Scales for Weighing Plane Components

I'm thinking that it will probably be a good idea to start weighing things before the gluing starts. Balsa weights vary somewhat and proper placement of building material weight can be critical on a plane to minimize additional weight/adjustments for flight trimming. I am looking at digital scales... one has accuracy to .1 gram, another to .01 gram, ...or should I be satisifed with 1.0 gram accuracy? The smallest plane I will be building will be .15 sized.

Your comments are appreciated!

Eugene S. Chernosky
AMA 639635

1 gram is too coarse, a sheet of 1/16 X 3 X 36 4lb balsa only weighs about 7 grams. You should get 10+ wing ribs for a .15 size plane from a sheet like this so each would weigh @.5gram or less.

Go with the finest readings you can find that is within your budget.

I use a digital scale and measure w/ an accuracy of 0.1 oz. (2.8 grams). This is plenty accurate for me. I have been sucessful in building some reasonably light stuff.

I keep very accurate weight records of everything that goes into the airplane.

Before construction begins, I create a complete weight forecast. I use actual weights of piece parts I have on hand (mostly hardware). I use past history (or calculations) to forecast everything else, mostly strutural and finishing weights. As construction proceeds, I capture the actuals of each little bit. I can always compare any piece parts actual vs. forecast weight. I also have an accurate forecast of the finished weight at all times.

The benefits for me are:

1) Rational decsion making on hardware choices
2) Rational decision making on how much filler, paint, and clear coats. My scale tells me when I'm done filling or putting on pigment.
3) Accept/reject criteria on sub components like stab, wings, ect.
4) No surprises at the end w/ an overweight ship.

This technique has shown me where the REAL weight comes from. Surprisingly, (to some) hardware choices and finish weight will make or break the bank. The total amount of balsa wood in a stunter is not as big a driver as is sometimes believed.

A truly light airplane is the result of getting 0.1 oz out of 80 different places.

Jim Hoffman

Check the scales available from www.myweigh.com

I got the i2600 which is .1 gram up to 2600 g (about 5.7 lbs.), and operates on A/C or batteries. It's a true "strain guage" (no springs) unit which has "tare" function (put a container on the platform and re-zero) , and displays grams, ounces, pounds, etc.

About $120 from:

http://balance.balances.com/scales/844