At 14:57 28 June 2016, WB wrote:
On Monday, June 27, 2016 at 8:30:22 PM UTC-5, Duster wrote:
Our club needs to do a weight and balance on our Grob 103 after
refinishi=
ng and some other mods. We are wanting to use calibrated/certified
scales,
=
but the cost of having it weighed or purchasing a set of scales is quite
hi=
gh. What have others done to get their W&B completed yet not break the
bank=
? We are in the San Antonio area.
=20
From reading FAA circular 8083-1a and Part 91, it isn't even clear that
w=
e are required to use certified scales (not that we wouldn't want to).
W&B
=
apparently can even be calculated mathematically w/o weighing the
aircraft
=
and not every production e.g., Cessna 172s, need be weighed at all (they
ca=
n weigh 10-20% of the run).

I bought a 660 lb floor scale off Ebay for $50 plus shipping to W&B on my
o=
wn glider. That's too small for your Grob, but there are higher capacity
sc=
ales on Ebay or you can double up with two of the 660 lbs scales. Just a
qu=
ick look on Ebay yielded a 5000lb digital floor scale for $499.

A cheaper solution would be to find your nearest public weighbridge (not
sure
if they are called something else in the US) and get the trailer weighed
empty
and again with the glider in it, simply subtracting the trailer weight
would
give you the glider weight, as these weighbridges are for commercial use
they should be calibrated and would give you an accurate figure.