plmjohnson

Good question Larry.

I think a lot on unanswered questions exits on this one.

 

I would really would like to know why the pattern exists on the break at a 45 degree angle to the drilled hole.

The side brace is connected at 45 degrees (approx) so the load on the pin runs directly down the the line of the sidebrace. If you look at the pictures that Waiter presented the failed pin matches the line of force from the side brace. This suggests that the roll pin is no longer on the neutral axis and represents a significant part of the strength direction.

Regarding the timing of the events: It may be that the aluminium deformed elasticly alowing the steel to pass through the yield point and fail. As the failed pin started to move out of the press fit hole it further deformed the aluminium. If my hypothesis is correct then the pin failed on a landing and it took some taxi time before the remaining ping finally came out.

Regards

Phillip Johnson

Mine are the origional set and they do not have any offset either.

Phillip Johnson

HI Waiter,

I've just found this thread and am sorry to hear of your misfortune.

Regarding steel tubes I would be interested in a set for my Cozy.

Regarding how you secured the upper pin with the AN-3 I'm would be concerned that you will cause wear to the press fit end (on the backing plate) as the gear is operated. Since you have secured the outer point the pin will slide in and out of the backing plate as the L bracket flexes. When I did mine I drilled a coaxial hole through the centre of the pin and used a bolt through the length of the pin. I have a large washer on the outer end to secure the L bracket and have a nutplate inside the spar box to react against. In fact I have a large aluminium plate inside the spar box that covers the full area of the inboard four securing bolts and an additional three for the L bracket. Nut plates are used on all seven bolts.

I can provide photograph if any one needs it.

Regards,

Phillip Johnson

Building Cozy MK IV RG with Subaru I0-200

Installing Avionics at present and preparing for first flight late this spring (2009)