The Murphy Builders Site

Just when you think things are going well you have a oh #%!@ moment. Wayne,
you told me there would be days like this. Fortunately most have been with
small parts I could manufacture. This time it's a big one and I'm sure the
neighbors heard me.

I mounted the wings to drill the struts and mounting blocks. After what I
thought was careful alignment with two digital levels (taking level off the
box) I ended up with 1.7 degrees on one side and 3 degrees on the other. The
box was within .1 degree off of true level anyway. Yes, all the holes were
drilled as the level read between .8 and 1.1 degrees, but alas, something
must have been out of whack. Did anyone else experience this, and if so, is
there a fix aside from ordering new parts. Perhaps I am not measuring the
angles correctly.

Roland
R56







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In short form here is what I did...from what I can remember. It was as per
the instructions.

1. wings on, supported at each end.
2. used digital level on the cage and came within .1 of true level without
adjusting the fuselage on the gear. As the 36" level has an error range of
+/- .1 degree I took this as my level point. Checked this a few times with
two different levels. So I set the level on the forward cage and re-set it
to 0. Now I was starting with the cage as my level point.
3. transferred the level to the top of the wing about five feet from the
root and on the main spar.
4. adjusted the end of the wing to achieve as close to 1 degree as I could
get.
5. measured hole distance as per plans and cut strut as per plans
6. installed the struts and blocks and marked as per the plans

I think I may have been OK up to this point, now is where the mistakes
probably happened.

7. removed struts and marked as per the plans, lined up block on outside of
strut and drilled single hole through end
8. marked and drilled remaining holes in block
9. lined up block on outside of strut again, pinned drilled hole and drilled
out new holes
10. inserted block into strut and drilled holes all the way through
11. installed bolts and checked level still on top of the wing - still at .9
12. removed support at end of wing and thought I had done well.

Went on to do the other side the same way. Once all bolts were in and
supports were removed I was surprised to see the first wing I did at 1.7
degrees and the second at 2.7 degrees. Double checked by taking my level off
the forward cage (which was extremely close to true level anyway) and
setting the level in the exact spot I had it. I am most likely missing
something that should be very obvious, but my frustration level keeps me
from seeing it.

Ron's point about ensuring you have the correct angle on the blocks is so
very true. One of mine was off by a hair and translated into a 1/4 inch
variation at the other end.

Darryl will be sending me new parts $116 for the struts, and $85 for each
block. Expensive lesson, but critical parts.

Roland
R56



-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Bruce
Rose
Sent: Wednesday, August 24, 2011 6:59 AM
To: rebel-builders@dcsol.com
Subject: Re: [Bulk] Re: [rebel-builders] And the saga continues...Rebel #56
Build

Roland: You have to find out where you made the mistake before you try to
fix the problem or it may happen again. Can you write the exact procedure
that you used to line up the wings to the fuselage.
Bruce
----- Original Message -----
From: "Roland Kriening" <kriening@rogers.com>
To: <rebel-builders@dcsol.com>
Sent: Tuesday, August 23, 2011 2:22 PM
Subject: RE: [Bulk] Re: [rebel-builders] And the saga continues...Rebel #56
Build

Thanks Ron,

Haven't messed up too many parts during my build... thus this came as a
shock. By the "box" I meant the forward frame or cage. Obviously something
happened between the measurement and the drilling. Even though I was
extremely careful, used two digital levels, etc. I must have checked them
5-6 times before drilling.

Already have a request into MAM for new parts. I know they won't be cheap,
but then again what is these days.

Roland
R56





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It is great to get everyone's input on this. What a great group we have.

I believe Cessna 150s have 1 degree dihedral. I would not be that upset if mine came out to 1.5 (but no more) on both sides, as I agree that a bit extra dihedral should make it a bit more stable. But then again with flaperons and VGs how much more stable can one get.

Roland
R56





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