Hi Ron,
I posted my solution to the forum a few years ago. Rather than have you sear
ch for it I resurrected it from archive. Typical of other Mono folks I too b
ent my tail wheel bolt which led me to creating the following mod I performe
d over 10 years ago. Never had a problem since. The original design relies o
n the AN5-21A bolt to counter the torsional load of the tail spring which is
n't ideal as you can attest too. I created a simple mod that takes the torsi
onal load from the tail spring and transfers it to the XTW15 steel support p
late rather than the AN5 bolt in bending. I installed an aluminum block with
a channel milled down the middle (the width and height of the mounting end o
f the tail spring) with a through hole in the center to pass the AN5 bolt. A
s shown in the attached drawing the block captivates the end of the tail spr
ing and transfers the load as described above. The AN5 bolt is now in double
shear instead of single shear and bending. A longer bolt is required to rep
lace the existing AN5-21A which is too short to pass through the block. That
's it. And it works a treat. You may not even require approval of the mod as
it could be considered a really thick washer of sorts. The mod also preven
ts the through hole in the bottom of the fuselage in which the AN5 bolt pass
es from wallowing out.
Also, regarding bonding of the tail spring to the rear stern post I deviated
slightly from the instructions. When I originally installed the tail spring
I was giving consideration to serviceability and realized if the spring wer
e bonded to the stern post I would need to deal with the Redux. Realizing th
e benefit of having the additional bearing surface of the Redux I installed t
he tail spring per the manual, however, I applied a release to the tail spri
ng such that the Redux wouldn't adhere. This allows the tail spring to be ea
sily removed without compromising the design.
Glad to answer any questions you may have.
Regards,
Erich
N28ET Classic Mono 914
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