Hi! Andrew,
I don't profess to be an authorised person to pass a professional comment
but since often I do ......!
It is an established fact that the wings fail forward which means that the
starboard spa tip will tend to want to be loaded towards leaving the port
pin AFT taking the metal socket with it off the port spa. Without the pip
pin the only restraint will be the CUFF which is wrapped round both spa's in
their centre portion and the socket bonded to the aft of the Port spa . So
an additional restraint on the starboard spa tip to keep it clamped to the
aft side of the Port spa when rigged is an obvious bonus.
( Just in passing it would be of prime interest as to the state of all these
items on the William Mills catastrophe aircraft? And surely the
investigators would do us all a big favour to circulate such fine detail for
our consumption?)
However to improve on the pip pin being used for this purpose I think would
need a pin threaded for a nut to be tightened and if you can develop a way
of access to a fully assembled aircraft for applying a bolt and nut I would
be pleased to hear of it ! In the meantime the pip ball rules!
Best regards
Bob Harrison G-PTAG
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Andrew Sarangan
Sent: 27 October 2013 03:57
Subject: Europa-List: Pip pin logic
I am hoping someone can help me understand the logic behind the spar pip
pin. According to a posting by Neville Eyre some time back, the pin is
important for preventing the spar tang from migrating aft and jamming the
aileron crank. This makes sense, especially given how close the spar is to
the cranks. However, in my limited experience, I have only seen pins used
for shear stresses, not longitudinal stress.
The latter would mean the ball at the end the pin has to be load bearing.
This seems a bit odd to me, but I am sure there must be a logic behind this
setup. I am hoping someone can shed some light on this for me.
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