Scales.

Stewartb

Stewartb

Final Approach
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stewartb
Anyone have a brand or model of scales you like for $1k or less? I’m not concerned with the FAA stamp of approval, just that they’re good and accurate.
 
For light aircraft, I have occasionally wondered if one could use only one scale - weighing each wheel at a time...even raising the ones with no scale, by the thickness of the scale (would that even be necessary)
 
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Stewartb said:
Do you have user time with them?
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Yes. Very easy to use. Just need a ramp for each wheel to get each wheel up onto its respective scale. I used this type/model of scales doing the w/b on my RV-10.
 
Let'sgoflying! said:
For light aircraft, I have occasionally wondered if one could use only one scale - weighing each wheel at a time...even raising the ones with no scale, by the thickness of the scale (would that even be necessary)
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Yes. The airframe designer will usually provide guidance on how to level the airplane for W/B. If you can get the airplane to that attitude with one wheel on the scales, the scale will give you the weight for that wheel. Then repeat the process 2 more times and you have the data you need to perform the full w/b.

Getting the airplane to the right pitch attitude - or whatever the manufacturer calls level is a key. A friend didn't bother to read the "how to" notes when he weighed his RV-14 and got a very disappointing (aft) CG. Basically one that would have precluded carrying baggage. Since his airplane is configured identically to most of the other RV-14's, I smelled a rat and had him walk me through exactly how he'd weighted it. "I just rolled it up on the ramps and...". OK, go read the manual and do it the way they specify and voila - W/B as expected.
 
I have longacre scales from racing. No idea what they model they are.
 
Let'sgoflying! said:
For light aircraft, I have occasionally wondered if one could use only one scale - weighing each wheel at a time...even raising the ones with no scale, by the thickness of the scale (would that even be necessary)
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No problem at all. I bought a single 660# scale from Amazon, and milled two blocks of wood to the same thickness, along with a couple of ramps to easily roll the plane onto them without making things slide around. Haven't used it to weigh the plane yet, waiting until it gets warmer, but cross checking the scale against a couple of other electronic scales it seems accurate at least at my own weight.
 
Stewartb said:
Anyone have a brand or model of scales you like for $1k or less?
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As mentioned, racing scales are a good option within that price range and most hold calibration well. Another option is to rent a set scales when needed which I found to be the most cost effective over the long run.

Let'sgoflying! said:
For light aircraft, I have occasionally wondered if one could use only one scale - weighing each wheel at a time
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Yes. However as explained above you must repeat the aircraft leveling position exactly between scale moves to keep error to a minimum.
 
Dana said:
No problem at all. I bought a single 660# scale from Amazon, and milled two blocks of wood to the same thickness, along with a couple of ramps to easily roll the plane onto them without making things slide around. Haven't used it to weigh the plane yet, waiting until it gets warmer, but cross checking the scale against a couple of other electronic scales it seems accurate at least at my own weight.
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We've used two hardware store 350 pound scales supporting a wooden wheel fixture to get "close" (weighing one wheel at a time - with the aircraft blocked level in flight attitude) before getting an "official" weight on certified scales.
 
I’ve got a set of Longacre car scales that work well. The local FBO bought a set of inexpensive scales that were marketed as “aircraft scales” and were about the same price, had the same pads and control box as mine but they came with one less pad. In my opinion, all the inexpensive car scales are close enough to the same in function and quality to just shop by price.

Some EAA chapters have tools that they will loan out to members. The one local to me has a set of scales. You may look into that as an alternative, since weighing aircraft is not a frequent task.
 
Several years ago I bought two 12 ton hydraulic bottle jacks with 1/8 standard pipe plugs in the side. To that I connected a quick disconnect fitting and a pressure gauge and divided the pressure by the specified area of the lift cylinder bore. I have used them on trucks and trailers to get accurate weights, and I welded up a pair of side finger attachments for getting under frame rails when needed. It is pretty nifty and works well. I built all of it for less than $300, and had a good set of jacks with scales built in.
 
I have never weighed a aircraft. Know where to level the fuselage in my 172.
I did work for a scale company for 8 years years ago.
You must insure all 3 scale platforms are at the exact same height to get accurate numbers.
I held the stick while my boss shot the elevation heights of the scales we installed.
 
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Gary Ward said:
. . . . You must insure all 3 scale platforms are at the exact same height to get accurate numbers.
I held the stick while my boss shot the elevation heights of the scales we installed.
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IDK anything about the C-172.

But the aircraft has to be in flight attitude, level to the planet on both axis. I cannot recall offhand an aircraft that has it's nosewheel or tailwheel at the same height as the mains, and considering that the sea level on earth is roughly 502 million inches from the center of the planet, you'd need a mighty accurate scale to see any miniscule difference between having the blocking under or on top of the scale.
 
Gary Ward said:
I have never weighed a aircraft. Know where to level the fuselage in my 172.
I did work for a scale company for 8 years years ago.
You must insure all 3 scale platforms are at the exact same height to get accurate numbers.
I held the stick while my boss shot the elevation heights of the scales we installed.
Click to expand...
That's the procedure used in my sport. The setup pad and scales are assembled on the garage floor, then the four corners are shot and the pad screws adjusted as needed. It's critical to get it exact, because otherwise the cross weights won't be accurate.
 
Aircraft W&B is an interesting topic. Most are based on fictional weights and subsequent bad math. I’ve weighed my airplanes many times. My first, the certificated one, wasn’t even close to the very detailed calculated W&b, but the factory W&B began with a fairytale weight. Building Cubs has taught me a lot about weight and CG. Flying them, too. That education never ends.

My hangar serves more than just airplanes. I want a set of scales. I’m leaning toward Speedway’s house brand with wire connections and 15” square pads.
 
Let'sgoflying! said:
For light aircraft, I have occasionally wondered if one could use only one scale - weighing each wheel at a time...even raising the ones with no scale, by the thickness of the scale (would that even be necessary)
Click to expand...
It’s critical that the aircraft be at the manufacturers specified pitch attitude and wings level to get an accurate weight.
 
Jeff767 said:
It’s critical that the aircraft be at the manufacturers specified pitch attitude and wings level to get an accurate weight.
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And so long as the aircraft is correctly leveled on both axis while one wheel is resting on a scale it will be (accurate), macht nix what the other two are resting on. (Sure, it's more labor intensive, but less equipment is required.)
 
Gary Ward said:
I have never weighed a aircraft. Know where to level the fuselage in my 172.
I did work for a scale company for 8 years years ago.
You must insure all 3 scale platforms are at the exact same height to get accurate numbers.
I held the stick while my boss shot the elevation heights of the scales we installed.
Click to expand...
Your TCDS specifies how to level a plane for weighing. A Cessna usually uses the door header as a point to verify level flight attitude. That applies to nose draggers and tail draggers. The mains need to be elevated to achieve a level door header for a tricycle airplane. Maybe the nose strut can be collapsed. I’ve never weighed a nose dragger. The tailwheel is elevated for a conventional gear plane. My 180’s tailwheel is at about my eye level for weighing.
 
When leveled, most aircraft appear to be heading downhill.

Cessna also uses the top of the tail cone at times.

Note the the Weigh Points ( wheels) often move fore or aft as struts

compress during leveling. Dropping a plumb bob and measuring location

follows. Correct use of leveling materials ( tare) is important.

Roll-on - Roll-off will provide weights but not an accurate CG.


I wonder if anyone has weighed an aircraft only to later find

a tool box in the baggage compartment? Could this happen?
 
I got 3 of these off Amazon. Good for up to 600lbs. Worked great. I think they were $60 each.IMG_0608.jpegIMG_2069.png
 
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The 660 lb capacity may be marginal for some aircraft.

General “ rules”:

Tailwheel weight less than mains

Nosewheel:


Tripacers and Cherokees have small weight difference
Mains - Nose


Cessna have substantially less weight on nose vs mains
 
veterinarian scale x3. About $450 total. Used for dogs and small barn animals (goats, pigs…).

Work great.
 
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