We replace several tail wheel tires at Emergency Repair
every year during EAA AirVenture Oshkosh when the sidewalls are destroyed during the long taxis at the event. That
happens because the pressure in the tires is too low.
Also, make sure that the rudder and the tail wheel are lined
up. One can force any tail wheel to shimmy by touching
down with the tail wheel cocked to one side. So check the
springs so that the wheel and rudder are aligned.
Next, there should not be any side play of the wheel
on the axle. The axle nut tightness adjusts the wheel
bearings as well. If there is a lot of play, you might
have to put an additional washer on the axle. If there is
way too much play, check the wheel halves for damage or missing grease seals. Don't forget the cotter
key after adjusting.
One of my pet peeves is the grease zerk on the wheel axle.
I never ever used mine and you shouldn't, either. When you
use a grease gun to lubricate your wheel bearings you first
have to fill the big wheel cavity before any grease reaches
the bearings. This takes a lot of grease, adds weight, and
generally makes a big greasy dirty mess. How so? Between heat and centrifugal force, the grease has nowhere
to go but out of the hub to be slung all over the tail wheel
assembly, rudder, and tail of your clean airplane.
The amount of grease necessary to lubricate your bearings
is minimal. Pack your bearings by hand with a good-quality
automotive bearing grease designed for disk brakes. Just
fill the spaces between the balls or rollers. That is enough.
More will just get thrown out to ruin the friction of the
shimmy dampener. This is the last thing you want greased
on a tail wheel assembly.
Last, the friction of the pivot is the shimmy dampener.
On a Scott 3200 tail wheel, friction cannot be increased
by tightening the main pivot bolt. The assembly must be
disassembled and degreased carefully, and the condition
of the thrust plate checked. The thrust plate is held under
pressure (against Scott No. 3207, washer—No. 3) by three
small springs (Scott No. 3233, spring compression—No.
5). If there is not enough friction, either install a new thrust
plate or install stronger springs; or sometimes there are six
spaces for springs and you can add three more.
Remember, the newest and best tail wheel will shimmy if it
isn't positioned on the airplane correctly or if the tail wheel
isn't centered when it touches down.
Watch These Online Hints for Homebuilders Videos!
Here's four new videos that were released recently.
Servicing Your Brake Reservoir
Dick and Bob Koehler show how to add brake fluid to brake systems with remote- and
pedal-mounted reservoirs. Dick and Bob are both A&P; mechanics with IA authorization and
EAA SportAir workshop instructors.
Remove and Replace Landing Gear Wheel
A procedure for removing and replacing main landing gear wheels is demonstrated by Dick
and Bob.
Bleeding Hydraulic Brakes
Dick and Bob demonstrate the bleed up and bleed down methods to ensure all air is out of
the brake system.
Servicing a Gascolator
Bob Koehler demonstrates the sometimes difficult job of how to remove, service, and install
the gascolator.
EAA Experimenter
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