Bob, The AAIB report on William's plane made it clear that
the starboard wing broke away from its spar. Although not
specifically mentioning the pins or the strap system, that
implies that thy hadnot failed before the forces became
big enough to break the spar. Regards, David
"Bob Harrison" <ptag.dev@tiscali.co.uk> wrote:
><ptag.dev@tiscali.co.uk>
>
> 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
> To: Europa List
> Subject: Europa-List: Pip pin logic
>
><asarangan@gmail.com>
>
> 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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