To measure the thrust, I actually use a force gauge we have here at work. They're like $500, but can measure them to the .01lb. But I hear you can get mechanical force gauges (which is nothing more than a spring and a face plate with the tick marks to show you how much you're pulling). I think people have called them fish scales. They're similar to the scales in super markets. You might be able to find some at www.mcmaster.com. Do a search for force gauge.

Although, you could make one of your own. Using a spring with a known spring rate (which is usually given when you buy them-units are force/distance), you could calculate how far it needs to be stretched for a given load. Calculate this out for a handful of different loads and distances, and you can make up your own gage. It's really not as hard as it seems. You'll know the rate, and know the force you want: then figure the distance it needs to be pulled.

I set the plane on the ground, attach the back of it to the gage, and fire it up and give it full throttle. I know the wheels and ground add some friction, but that's negligible.

So there you have it. That's how I do it.

Hope this helps.

Russ