A word to the wise on the type of scales mentioned above. They don't stay turned on long enough to allow a person to practically weigh an airplane. I have similar scales and found them to be useful, but only marginally so.
The process for weighing is...
- jack airplane above scale
- press on scale to turn it on
- lower airplane wheel onto scale
- wait for reading to stabilize
- write down the reading before the scale automatically shuts off. If you missed it, you have to start over again.
There's no way I've found to be able to weigh all 3 wheels at once, short of using 4 people, one at each wheel and one to operate the overhead crane or underbody jacking system necessary to raise and lower the entire aircraft.
BTW, with respect to accuracy and repeatability, I can't vouch for the exact scale mentioned here, but the ones I have, rated at 300lbs, are very accurate and very repeatable at normal room temperature. They are NOT repeatable at anything other than room temperature as it appears their strain gauges are not well temperature compensated.