Improper pilot technique can cause damage
to your tail boom as well as other components on your helicopter.
I have seen several Rotorway helicopters with
crinkled tail boom skins between bulkheads one and two.This can
occur during solo practice when the new student is setting the helicopter
down with a lot of power applied, a lot of right anti-torque pedal
applied pushing the tail boom to the left, and usually some rotation
of the helicopter to the right. When the skids contact the surface
and grab they stop but the anti-torque force is still being applied
by the tail rotor with right pedal, the weakest point seems to be
between bulkhead one and two. This is where the lateral force applied
by the tail rotor at its far end is concentrated by the helicopters
rigid frame, something may give and sometimes it is the skin on
the left side that is being compressed that gives. Below are a couple
of photo of what I occasionally have seen..
In the photo below the builder
attached an extra piece of skin to the area that he hade damaged
prior behind the first bulkhead but it does not extend back to the
second bulkhead. He thought that just adding more support where
the buckles occurred would prevent them from occurring again. You
can see that the boom simply buckled just aft of the additional
skin reinforcement when he again applied to much stress to his helicopters
tail boom.
This pilot not only needs
a new tail boom but some additional training in proper set down
technique.
Here is a photo of a support brace
installed between the bulkheads one and two by the builder in the
hope to keep the tail boom from rippling in that area. This photo
is of Andrew Burr’s Rotorway . He installed threaded end plugs into
the ends of a piece of aluminum tubing and then drilled a hole in
bulkheads one and two on the lower and upper left sides of the tail
boom. He then made sure that the reinforcement rod was a tight fit
and had to be forced into place and bolted into position. These
two rods now carry the compression loads of the tail boom to the
frame and help prevent the skin from buckling.
Shawn Mack's tail boom strengthened
with three pieces of angle aluminum on the pilot side.
After the boom is supported
between bulkhead one and two, I have never seen the skin buckle
further back on the tail boom. The tail rotor force does not seem
have enough arm to apply sufficient force closer to the rear of
the boom.
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