Blanik L-13 polar

We replaced our initial L-23 tail wheel suspension donuts at one year due to
failure. We've just encountered the second failure at the second year
point. We do not allow pushing backward of the glider. We do lift the tail
most times to rotate the glider when not on a paved surface. Most landings
are on the main, rather than two-point. As we are at 5500msl, our actual
touch down speeds are likely higher than most operations.

The rubber donuts are weak, likely by design, to prevent damage to the
frames. Since both sets failed about the same time of year, I suspect wear
plus heat may be the culprits. Air temps have been in the upper 90F to over
100F daily since 7/1. Surface heat is much higher and the support donuts
are both close to the surface and in an enclosed area that may act something
of a collector. I don't know what effect 120-140F temperatures may have on
the rubber and don't know if it's vulcanized or not. I doubt if they are
custom made, but probably from some other application and adapted to the
tail wheel design. As they are relatively cheap, it would appear a 6 month
replacement cycle would be appropriate for our operation.

YMMV

Frank Whiteley
Colorado


"BTIZ" wrote in message
news:ZPVZa.9576$2g.7946@fed1read05...
I'm wondering of your trouble with the L-23 tail wheel is ground
handling..

there is now a factory service bulletin to not push the aircraft backwards
across terrain, only paved surfaces.. the spring attach for the tail wheel
is not meant to flex when moved backwards.. only forwards..

BT

"nowhere" wrote in message
m...
I have not had a tail wheel problem with the L-23 and no flaps.

Conversely, my club has had quite a bit of trouble with our L-23's
tailwheel (and the bulkhead which it is attached to) but no trouble
with our much older L-13s. This is despite the fact that probably 75%
or more of the L-13's landings are done with flaps retracted. This
surprised me as the 23's tailwheel LOOKS much more sturdy!