On Feb 4, 6:19*am, Herbert kilian wrote:
On Feb 4, 3:49*am, gemerson wrote:

It's fairly standard for tractors to have their tires filled with
water. *Curious if anyone has put water in their pneumatic tailwheel
to provide a little more aft CG. *Brass tailwheels exist, but they are
pricey.

Sounds like a really bad idea. *The volume is so small that even
filling the inner tube completely will likely only give a liter of
water or so (2.2 lbs). *If you do fill the inner tube to more than
50%, the damping qualities of the wheel will rapidly deteriotate since
water is incompressible (but then, so is brass).
Don't do it, look for a way to safely attach lead plates to the
bulkhead in front of the rudder or by other means.

2.2 lbs may not sound like much, but on my Ventus adding 2.2 lbs of
water to the tail tank will move the CG aft 9%! If that is enough,
why not try it? If the valve doesn't rust, and you have a way to
evacuate the tube (first of air, then later of water if you reverse
your decision), then it seems like a painless way to experiment with
trimming the CG.

BTW, I ran the numbers on this in about 20 seconds using "SeeG", a
weight and balance program I created (shameless plug) just for this
type of "what if" question. see http://www.glideplan.com

Matt