Hi all,
The half inch play tolerance as specified by the factory means that, in a m
ore than one degree range, the tailplanes are not balanced at all. This is
a possible cause for flutter. I consider that any play in the chain between
the mass balance arm and the tailplanes is unacceptable: that means zero p
lay between TP4 and TP9 and zero play between TP 4 and TP12. The factory so
lution is Mod 62: replacement of the =C2=BC=9D pins by 3/8=9D p
ins. This mod is known to only delay, not eliminate, the problem. As far as
I know, there are 3 solutions which have been implemented successfully by
builders:
- gluing TP9 and TP12 to TP4
- replace the straight pins TP14C and TP14D by AN486 taper pins
- replace the straight pins TP14C and TP14D by AN bolts
As some builders have mentioned in this forum in the past, all these soluti
ons have their own inconveniences and must be implemented carefully, but I
believe these inconveniences are far outweighed by the safety of a fully ba
lanced tailplane in all conditions.
Regards
Remi Guerner
F-PGKL, XS S/N395 monowheel, 912S, Airmaster, 482 hours
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