SonexBuilders.net

HI All,

I'm Tom and I am a new member on the forum.

I am going to check out an A model Sonex taildragger with Aerovee 2180 this weekend.
I want to check and verify weight and balance data for the plane as part of the "prebuy" inspection. I have scales that should be adequate for the task.

I don't have the plans or builders manual. I'm guessing the weight and balance instructions are in there.

On most of my previous planes - Kolb, Challenger, Volksplane and Cherokee 140 I have made an Excel spreadsheet where I just enter the stuff that changes, passengers/weights, baggage, fuel and have built the calcs into the sheet to show total weight and CG. I do a calc based on estimated fuel at end of flight to verify CG at landing.

I will do this for the Sonex also. However, I don't know the details of the weighing procedure. I did search and find the page 20 info to check and record the distances from the spinner tip to everything.

How do I correctly position the plane while weighing? What is my horizontal level plane? Does the process start with no oil, fuel, etc?

This plane will have oil and probably some fuel. What is the distance from the datum to use for those? When adding my bulk to the mix, what is the distance from datum for me and/or passenger?

If anyone has already done a spreadsheet, are you able/willing to share it? I know I will have to check that the distances match.

Thanks,

Tom

Tom,

Message me your email and I'll send you a spreadsheet and the datum and arms.

Of course the plane SHOULD have a W&B if its flying.

One thing to watch - don't try weighing it outside. Or if you have no choice - you need still air. Even a slight breeze across the wings generates some lift and reduces the weight on the scales.

there is a series of videos on weight and balance on hints for home builders.Joe Norris shoes how to do a weight and balance on a Sonex.You have to be an EAA member to watch the videos.

AC 43.13 Chapter 10 covers Weight and Balance pretty good.

I did some documentation here, near the end of the page.
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