Hi Andrew,
I had the same problem as you did. With the bushings dry-fit into the holes
into the cockpit module, it was a very tight fit for installing the wing
plus bolts into the module.
After scratching my head a little, I decided to split the difference, and
file the inboard part of both holes a little bit to prevent any offset
towards either side of the aircraft. Then if you set up your wings carefully
at the proper attitude at this stage, it should supply dividends throughout
the entire project. The front of the module was on the ground during this
procedure, and hence the leading and trailing edges of the wings were
pointed groundward and skyward, respectably. That way only two wing supports
were needed to be built up, and they doubled as wing holders for the rest of
the project. My wing pins still slide in easily, and the bushings never had
to be re-positioned later on. I Araldited (is that a verb? :) )and floxed
mine in at that early stage, but skipped putting in the 3mm plywood supports
over the bushings until the wing lift-drag pins were installed into the
fuselage...just in case the bushings didn't line up later, and needed to be
removed. All was good however, and I installed those plywood pieces about 6
months ago. I never had to support the bushings with anything but the
cockpit module.
If I remember correctly, my method of filing both holes in the cockpit
module was ok'd and verified by the company before I did it. It was only a
very small amount that needed to be filed.
To sum up, if the bushings are installed properly in the beginning (taking
lateral offsets and wing attitude into account) they should not ever have to
be removed or re-positioned later.
Regards,
Greg F
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Andrew Sarangan
Sent: Sunday, September 08, 2013 12:55 PM
Subject: Europa-List: Spar pin bushes
I am in the process of bonding the bushes into the CM and the guide sockets.
The pre-made spar bushes align perfectly with each other, and I can drop the
1/2" bolts in with no effort. However, the mating blank holes in the CM are
a tad too far apart, by about 1mm. The bush doesn't have much wiggle room in
the hole. Nevertheless, with a lot of force and torque I am able to drive
the bolt in. Removing the bolt is also a big struggle. This doesn't seem
right.
My thought was that the holes were either made with a small error, or,
possibly the cockpit module could have expanded or twisted with time.
I was going to lightly grind the inside of the hole to expand it and then
bond the bush with flox. My question is, which bush? We are only talking
about 1mm, so it may not matter but I didn't want to run in to problems
later due to this.
Another related concern is, given that the CM has some flexibility at this
stage, even if I make the bushes align perfectly now, I am concerned if they
may not align later. So one thought I had was to attach a long thick steel
plate to the bushes (like a dummy spar) and leave it in there until after
the cockpit module is bonded. Has anyone tried something like this, or is
this an overkill?
BTW, I am in awe of those who did this step by supporting the wings on
wooden blocks and beer crates. It took me a greater part of a week to tweak
the height and angles and lots of shimming to get the wings line up. This
was not trivial. I have some photos on my website.
_
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