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  #1  
Old 09-21-2018, 01:51 PM
Bavafa Bavafa is offline
 
Join Date: Oct 2007
Location: Sacramento, CA
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Default Bathroom scale for aircraft

Just wondering what are the general consensus for using bathroom scales for the W&B of the aircraft? There are some models that goes to 550-600 LB which should be sufficient in weighting most RVs. Some are advertised in .2lb accuracy, thought that remains to be verified.

I am still searching in my area and within the EAA chapters to see if there is an aircraft scale available for use/rent.
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  #2  
Old 09-21-2018, 02:43 PM
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Mel Mel is online now
 
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Quote:
Originally Posted by Bavafa View Post
Just wondering what are the general consensus for using bathroom scales for the W&B of the aircraft? There are some models that goes to 550-600 LB which should be sufficient in weighting most RVs. Some are advertised in .2lb accuracy, thought that remains to be verified.
I am still searching in my area and within the EAA chapters to see if there is an aircraft scale available for use/rent.
Older "spring-type" scales were not known to be accurate. However most bathroom scales are now based on load cells and they can be quite accurate. There is no regulation that says the scales have to be "certified", but certified scales are pretty common now and most people use them.
Many EAA Chapters will have scales to rent or loan.
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  #3  
Old 09-21-2018, 02:56 PM
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Race car scales work great. Most bathroom scales Iíve used make you stand on them for 2-3 seconds to give a reading, then the reading goes away. You also usually have to tap on them to turn them on, then have a couple of seconds to step on them or they give an error. If you find one that works, make sure you have platforms under the other tires to keep things level or the weights will not be accurate.
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  #4  
Old 09-21-2018, 03:12 PM
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Mark Dickens Mark Dickens is offline
 
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I bought one of them a couple of years ago rated for up to 550lb. The challenge with them is that they don't stay on long. Not long ago, though, I weighed my plane with one of them. I used two thicknesses of 3/4" plywood (very close to the height of the scale) under one main tire, the tail leveled on a stand, and lowered the other main wheel onto the scale after it was on and zeroed out. I did this for each wheel. Tedious, but it worked. About a day later, the plane was re-weighed using three actual aircraft digital scales. The difference between the two weighings was less than a pound and 0.16" CG. Pretty darn close for a bathroom scale. Just make sure you spread the load across the surface of the scale with a piece of plywood or something similar, and include it when the scale is initializing.
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  #5  
Old 09-21-2018, 03:36 PM
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Mark Albery Mark Albery is offline
 
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I bought a set of these

They've proven to be pretty accurate and consistent when I've loaded them up with known weights.

You're welcome to borrow then if you're ever in the Bay area.
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  #6  
Old 09-21-2018, 03:54 PM
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az_gila az_gila is online now
 
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Quote:
Originally Posted by Jesse View Post
Race car scales work great. Most bathroom scales Iíve used make you stand on them for 2-3 seconds to give a reading, then the reading goes away. You also usually have to tap on them to turn them on, then have a couple of seconds to step on them or they give an error. If you find one that works, make sure you have platforms under the other tires to keep things level or the weights will not be accurate.
Another problem with bathroom scales it that some (most?) tend to lock in a number for a while.

Try taken your weight, step off and get back on with a 1lb book or something in you hand. It will probably show the earlier weight.
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  #7  
Old 09-21-2018, 08:15 PM
Robert Anglin Robert Anglin is offline
 
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Location: houston, texas
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Default Sure.

We found that a set of doctors scale that go up to 400 Lbs. work very well.
You set the aircraft up on blocks the same height as the scale then weight each station one at a time. The doctors scale are not that costly and are very accurate. If you use two at a time it even works better, because the weight will be split between the two at the med range of the scale on the unit. Just calibrate each of the two before you use them. I like to step on a digital scale, weigh myself then step on the two scales and check them or set them to the same weight. Then you just put a plate across the two and set the station "wheel" in the middle of the two and weigh that station. You total the weight of the two and subtract the weight of the plate. This give you a very good reading of what that sight weighs. I have checked this against other high dollar scales and found the readings to be with-in a pound or two of each other.
Just a thought for this use. I like it because we can weight the aircraft any time we work on anything that may add or take away weight with a couple of scales that set on the shelf with little cost. Yours, R.E.A. III # 80888

Last edited by Robert Anglin : 09-22-2018 at 08:09 AM.
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  #8  
Old 09-21-2018, 08:26 PM
arffguy arffguy is offline
 
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Mehrdad,

The Sacramento RVators has had a set of scales for years. They are in a hangar at Executive Airport. I thought you used to be a member of the group?
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  #9  
Old 09-21-2018, 09:05 PM
BobTurner BobTurner is offline
 
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EAA at LVK has a set of race car scales. I don't have their current contact number, but you can probably get it from EAA HQ.
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  #10  
Old 09-21-2018, 09:27 PM
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RV8Squaz RV8Squaz is offline
 
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When I first weighed my airplane 11 years ago, someone had loaned me a set of four (I only needed three) dirty, old, rusty, full of cobwebs, agricultural scales. I didnít trust them so I checked them against some known weights (my own weight and some barbells). I was shocked to find out they were accurate to within half a pound!
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