Scale for initial weight and balance

[Bryan Cotton]

Thanks Ryan! I'm considering buying one for general hangar use. One of my neighbors bought a set of real scales. He gets them calibrated annually, and funds that with a $50 donation for using the scales.

[Kai]

Use three identical scales.

Be aware of a potential issue when specifically lowering a Sonex with the rod main gear legs upon them. The gear legs flex- unloaded wheels on the scales will impose side loads on the scales when the rods take up the weight of the aircraft. Some scales do not like this side load at all and will show faulty readings.

Better to roll the Sonex on the scales- that way the issue is eliminated.

Thanks
Kai

[builderflyer]

Also, since its generally easier to weigh the airplane in a 3-point attitude, first weigh the airplane with the tail down to obtain the "empty weight". Then, when you raise the tail to level the airplane for weight and balance purposes, you'll have a second "empty weight" to compare against the first. If the two empty weights agree with each other as they should (and they may not), you'll have more confidence in the numbers you're going to use for your weight and balance calculations.

And, definitely use three scales. When moving a single scale around, It's way too easy to not have the airplane in exactly the same position laterally, and longitudinally for that matter, to obtain reliable results.

Art,,,,,,,,,,,,,,,,,Sonex taildragger #95,,,,,,,,,,,,,,,,,,,Jabiru 3300 #261

[9GT]

This exact scale is now only $35. I'm tempted to buy 3. Reviews are mixed. Lots of negative reviews for people trying to weigh 6 oz on a 440# scale. Some negative reviews for the scale dying. Any further group perception on this option?

Thanks for that update. I have been on the fence buying these for some time and the price drop was enough for me to try them out. I ordered a set of three.

[CoClimber]

I have that exact Amazon scale. Normally keep it in the bathroom but just took it out to weigh my almost complete Kitfox (Sonex is next!). I have no way of knowing if it is accurate but I would expect any error to be in gain and not non-linearity so for my tri-gear Kitfox, the CG should be pretty accurate. It also reads quite consistently in the bathroom.

[9GT]

Amazon Scale Update. Well,, they arrived in one day. I opened one box up to have a look and the first thing I see is a warning label "Do Not Stand On Scale!" They are pretty light and flimsy. The weight probably needs to spread evenly across the whole platform. I decided to put a piece of plywood on the scale, then a couple 2 x 4's to spread the load. That might work for distributing the load and I could envision putting a main gear leg wheel on there without anything and watching the center of the scale bend down! I stood on the scale and thought i got an accurate weight, then kind of shifted my weight up and down to see how sensitive it was, and the reading did not change. I am sending them back. I just don't trust them for something as important in establishing an accurate W&B.