Re: Questions on weighing the airplane
My EAA Chapter bought a set of auto scales, 4 load cells, we use 3, it gives the weight at each station and you can tare it if you need to put any blocks on the scale.
You might check your EAA Chapter or any local auto clubs to see if they have scales you can borrow.
Ralph
Re: Questions on weighing the airplane
Used a platform grain scale ( certified ) and a bathroom scale. Jack the plane up and put the mains on small platforms that are the EXACT night as the platform scale. Now raise the tail to level the plane with the tailwheel resting on the bathroom scale. Now the weighing begins. Jack up one main one inch and slide out the platform under that main then roll the platform scale under that wheel and weigh it. Do the same for the other main. Read the bathroom scale for tail weight.
For my S7. Left main 366#. Right main 367#. Tail 61.75#
Total 794.75#
Be sure to measure the moment arms while the plane is leveled.
Re: Questions on weighing the airplane
Quote:
Originally Posted by
PaulSS
very good article. thanks!
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Re: Questions on weighing the airplane
The pictured item was once available at Aircraft Spruce. It essentially multiplies the capacity of a typical bathroom scale by two or three. One for each of the main gear wheels and the scale only on the tailwheel. I have a small work bench that I positioned under the tailwheel and several pieces of wood for shims helped level for weighing.
Re: Questions on weighing the airplane
Quote:
Originally Posted by
HighWing
The pictured item was once available at Aircraft Spruce. It essentially multiplies the capacity of a typical bathroom scale by two or three. One for each of the main gear wheels and the scale only on the tailwheel. I have a small work bench that I positioned under the tailwheel and several pieces of wood for shims helped level for weighing.
I have a set of those Ruggles scales also, Lowell (purchased from Aircraft Spruce). I've weighed a lot of airplanes and loaned them to many fellow builders also over the years. Correct me if I'm wrong, but I believe that the 2 positions for the wheel platforms give 2 to 1 or 4 to 1 ratios, not 3 to 1. In other words, a 300 pound "bathroom" scale can weigh up to 600 lbs. or 1200 lbs., but I've never had to use the 4 to 1. Any errors are twice as great in that position of course.
A few years ago I saw a great deal on some low profile digital scales on eBay (I think they might have been found by someone on this forum). I believe that they cost me less than the three bathroom ones. They work beautifully, and are extremely accurate. They can be powered by batteries or a plug-in power supply. I built a couple of simple wooden ramps out of 3/4" boards. They work great too... there's no tapering, you just roll the mains up over a 3/4" high lip 3 times to reach the level of the scales. There's no tendency to roll backwards as you get to each level, like there would be with tapered ramps. Works great.
Re: Questions on weighing the airplane
John you are right about the ratios. Placing the platform on the center mount - multiply the reading by 2. On The outboard, multiply BY 4.