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Weighing an airplane

Posted By:
Leon Adelstone
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#1 Posted: 12/12/2010 12:20:23

Allrighty, then....  Let's weigh an airplane to determine it's empty weight..  First, we need to "Level" the airplane.  Which brings us to the question:  Where do we place a level???  is it in the floor of the cabin?  If not, where ?



Frank Giger
Homebuilder or Craftsman
117
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#2 Posted: 12/13/2010 01:17:46 Modified: 12/13/2010 01:20:04

Assuming the plane doesn't have a gear on one side shorter than the other and the tires are inflated properly, I believe checking to see if the surface the plane is standing on is level is probably the way to go.

I'd put the level on the hangar or garage floor....because they can have a slope.  My garage, for example, started out as a carport and the concrete has a slope going away from the house as they originally designed it to have water drain to the outside edge.

 



Rod Witham
Homebuilder or Craftsman
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#3 Posted: 12/13/2010 03:32:35 Modified: 12/13/2010 03:46:35

Hi Leon,

As you likely know, the weighing procedure will determine not only the empty weight of the aircraft, but the measured weight (on each wheel) will also help you determine the center of gravity (CG). This becomes very important in the nose to tail (longitudinal) axis, as you can use the information to determine not only 'how much' the aircraft can haul (useful load), but also where you should load it to attain proper CG.

How the aircraft is leveled (especially in the nose to tail axis) is critical in accurately weighing and finding the starting point for the CG of the aircraft. Most plans will show exactly how to level it prior to weighing, and it depends on the specific plane. Some may require leveling at a 'root tube' at the cabin top, some may require leveling the wing spar bottoms near the strut attach points, some may use other references. Tailwheel aircraft will typically require the tail be raised to near the flying position, and it will make a difference. Check the plans for the proper leveling method.

Here's some good reference material for weight & balance, once you get your plane properly weighed.

http://www.faa.gov/library/manuals/aircraft/media/FAA-H-8083-1A.pdf

http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/PHAK%20-%20Chapter%2009.pdf

http://avstop.com/AC/apgeneral/AIRCRAFTWEIGHINGPROCEDURE.html

http://www.eaavideo.org/video.aspx?v=666144934001

 

 

 

 

 

 



Leon Adelstone
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#4 Posted: 12/13/2010 09:24:19

Thanks for your input, Frank.

 

I think Rod's post is more directly pointed toward my question.



Leon Adelstone
16
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#5 Posted: 12/13/2010 09:26:28

Thanks, Rod, for the comprehensive reply.   - Exactly what I was looking for.   I've saved the information for future reference