Graham,
Thanks for the warning to all of us. Haven't done much beyond the leading
edge setup but it is nice to know of an impending problem before it
eventuates and before I encapsulate the torque tube in the tail. I imagine
the size of the holes for the pins that locate the TP 12's was determined
recognising the forces coming into play, so therefore if the hole is
enlargening it must be unknown to Europa? The demonstrators would
definitely display these symptoms, and I suppose it begs the question as to
why the TP 12's aren't welded directly onto the torque tube? There must be
something later in the build that justifies this method of attachment that
I am not yet aware of . Do you know why these aren't welded?
Reg
Tony Renshaw
>Re. the recent traffic on strengthening the TP6 bond, it seems possible that
>we may have been trying to cure the result and not the cause. I have now had
>to do them twice in spite of considerable roughening, inserted screws and
>dimpling. More than one of us has now found this to be associated with
>slightly slack drive plates (TP12). These are held to the tailplane tube by
>pins. If there is any slackness at all here, then the load is immediately
>taken by the pip-pins and through the TP6's into the bond which is not
>designed for such loads.
>
>I find that the rear of one tailplane can be lifted relative to the other by
>4mm and another builder is finding 10 mm ! Neither of us believe this to
have
>been present at build time. This points to development of a significant
>enlargement of the hole(s) carrying the pins which secure the TP12's.
>Effecting a cure here inside the fuselage is difficult. Either the existing
>holes need re-boring and larger pins fitted, or extra pins/rivets are needed
>to attach the TP12's.
>This is significantly major for us to await a factory response. In the
>meantime I would suggest everyone check for relative movement of the two
>TP12's on the tailplane tube. Both of these aircraft have done under 100
hrs.
>
>Graham C. G-EMIN
>
>
Reg
Tony Renshaw
Builder No.236
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