I hate to but in, but weight and balance is not a sorta, kinda, maybe
about this many pounds measurement. We all spend hours making sure our
aircraft is within .1 degree and exact sweep and incidence and then
weigh the aircraft and measure the balance points with a grease pencil
and a bath scale certified by our last physical weigh in.
I know calibrated scales are expensive, but go to your airports
certified weight and balance professional or if you insist on doing it
yourself, go to the racing community and find a set of certified scales
of the proper size and range and rent them or borrow them for a day..
Load cells are best, but I must admit some spring types are quite
accurate. It amazes me that the car guys and go cart enthusiasts have
superb scales. I have seen them for as low as $500 new. I know this as
I lived next door to a sprint car builder and he had the neatest stuff.
Use a good level, plumb bobs, and tape measures and be accurate. Follow
the operators handbook instructions. I recently had a plane in the shop
that was touted as only 875 lbs, using bath scales. The actual weight
was 904 and his CG was off by a half and inch because he used the
dimensions in the book instead of measuring his own plane. Luckily our
little bird is tolerable of many things, including loading and weight
and balance errors. Putting a 2 X 6 between two scales can work, but
verify with accurate weights and get a good tare of the scales. Make
sure the weigh ins are repeatable and use a known set of weights to
verify the scales range and accuracy. If using two scales with a beam
between, verify the positon of the beam and where the tire center will
sit.
It costs me a couple of hours and a couple hundred bucks for Walter
Hudson (FAA Certified weight and balance tech, A&P and homebuilder) to
come by and weigh the planes in my shop. Dead on, certified, and
repeatable results.
Kevin, I do the same thing. I built ramps and blocks the exact height
of the scales and of course from plumb bobs down the cowl line, the
axles and then careful measurements to get my distances for the moments.
Jigs like this make things simple. For the mono I must admit, to being
extremely lazy and use a finger to balance the wing by pushing up on the
heavy wing and down on the light wing and average the difference. I
have not found a mono more than a couple of pounds out of perfect
balance.
Bud Yerly
----- Original Message -----
From: K BURNS<mailto:kjburns@btinternet.com>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Sunday, March 20, 2011 2:20 PM
Subject: Re: Europa-List: Weight and Balance Scales
Hi,
One set of scales would do with two spacer blocks under the wheels
same height as scale, weigh at one wheel then either with jacks or 3
ramps move the scale from wheel to wheel , replacing with a block to
keep the a/c level , recording your figures as you go on your balance
sheet.
(easier to use 3 blocks if only using one jack so you can lift remove
scale lower on spare block then move jack to next wheel)
Kevin
-------------------------------------------------------------------------
-----
From: Robert Borger <rlborger@mac.com>
To: europa-list@matronics.com
Sent: Sunday, 20 March, 2011 14:44:45
Subject: Re: Europa-List: Weight and Balance Scales
Mike,
I played on balances.com<http://balances.com/> for a bit and on a 400
lb search I found a Siltec 440LB GS1 digital scale for $78.95. It's a
bathroom scale but three of them ($236.85) would probably do the job as
long as your aircraft is under 900 lbs and you are careful getting the
mains onto the scale.
Bob Borger
On Mar 20, 2011, at 1:36,
DuaneFamly@aol.com<mailto:DuaneFamly@aol.com> wrote:
In the USA, what are people using with regard to scales when they do
their weight and balance calculations? What capacity is needed?
Mike Duane
Redding, California
Europa XS Conventional Gear
http://www.matronics.com/Navigator?Europa-List<http://www.matronics.com/N
avigator?Europa-List>
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