Hi Jim,
You're absolutely correct in that the donuts absorb bumps from taxiing
on irregular surfaces since the weight of the airplane will fully
deplete all possible oleo travel/action after the oleos absorb any
"shock" incurred in the actual process of landing and the movement of
the fully extended trailing arm-oleo combination up into the normal
taxi configuration.
Obviously there is SOME give in rubber donuts that aren't ten years old
and hard. If one's oleos don't extend upon takeoff, the majority of
crosswind landings by a proficient pilot (or one that does not fly in
crosswinds exceeding 20 mph or so) might well seem "normal" at the
moment of touchdown. More damage is likely from the movement of free
but dry oleos slamming to a stop at the end of undampened travel than
touching down with frozen oleos.
No one would go out and practice crosswind landings in a brisk, gusty
breeze if reasonable proficiency and decent landings under such
conditions were not possible for most. If there is the slightest doubt
as to being in full control at the time of touchdown, DO NOT LAND but
go around until an opportunity for a "good" touchhdown is perceived and
timely accepted. The process should not be one of "shut your eyes and
pray".
More than a few Ercoupes have changed hands with marginally functional
oleos and been flown without apparent damage until the next annual by a
competent mechanic. A new owner with no Ercoupe experience may have no
"frame of reference" to call attention to the problem until their first
poor landing ;<)
The trailing arm gear works fine without oleo action. Excess stress to
the spar and landing gear imparted by a poorly controlled "arrival" is
less likely to result in permanent damage when the generous amount of
shock absorption provided in the design is maintained and available.
Regards,
WRB
--
On May 24, 2010, at 16:20, Jim Gall wrote:
I may mistaken, but I though the donuts were for taxiing, and the
hydraulic piston with the small hole in the button that was forcing
the hydraulic fluid up into the piston was for landing.. I can’t see
how anyone could land in a crosswind with the piston stuck in the
cylinder?
JIM GALL 94020
