Scott
& Aaron,
You
guys got me thinking around this problem a lot more. So I took some more
measurements, and now think I have worked out what is wrong. It appears the
original builder placed the rear face of the GM 13 about ¼” further back
than the rear face of GM 12. (This is a very early kit. I think later kits
came with the GM 13 already installed, if I understand correctly). This has
resulted in the gear leg and the GM 4 not being parallel when the gear leg is
in the wheel well.
The
solution is not going to be easy however. Firstly because I have already
incorporated the support brace for the GM 13 between it and the upper spar
cap, and secondly because even if I fix that problem, the rear face of the GM
12 would need to be set at a slightly different angle (in relation to the
lateral axis of the aircraft) to take up the new alignment of the GM 4. As it
is , the AN4-13A bolts which bolt the GM 12 to the GM 4 are only just long
enough, and the top ones which have to be placed with the heads to the front
only just fit into the space between the spar web and the front face of
the GM 12 when installing them. So installing longer bolts appears
impossible. Thus I can’t simply build up the rear face of GM 12 with a couple
more BID to correct the misalignment. The only other option I can see would be
to grind away the 2 bid and ½” phenolic which make up the GM 12, to the
correct angle, and then re-apply 2 bid over that. Given the significance of
this structure to the integrity of the whole undercarriage, I am not sure this
is an acceptable solution.
As
I said earlier, I don’t have any engineering qualifications, so I am only
guessing at the structural issues all of this raises. I know that the simplest
solution is to grind the bolt heads down, but I am again only guessing whether
this would compromise anything that really matters.
Ah,
the joys of home building!
Thanks
guys for your support.
Rob
From:
Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of
marv@lancair.net
Sent: Tuesday, 3 June 2014 2:14
AM
To: Lancair Mailing List
Subject: [LML] Re:
Undercarriage bolt clearance
Posted
for Aaron Collins <nwacollins@centurytel.net>:
>
Rob, Scott,
>
> Could this be a possible solution and/or
addition? . . .
>
> If the original builder had to add any BID
between the aft GM5 plate and
>the forward face of the rear center spar
to take up any fore to aft slack of
>the GM1 weldment, could that BID
be removed to gain some clearance room? Of
>course, you would probably
have to add back the same bid to the aft face of
>the GM12 and GM13
phenolic mounting points so as to take up that same fore to
>aft slack
that existed originally.
>
> If there is BID behind the GM5 and
you remove it for clearance, the
>original bolts mounting the GM5
through the aft spar may now be a bit too
>long. Scott is always good
to remind us about proper bolt length so check
>that thread
count.
>
> Regards,
>
>
Aaron
--
For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html