--- On Mon, 10/27/08, GARY ROBISON <djgaryl...@verizon.net> wrote:
From: GARY ROBISON <djgaryl...@verizon.net>
Subject: KR> Your Thoughts on my Thoughts
To: "KR_NET" <kr...@mylist.net>
List-Post: krnet@list.krnet.org
Date: Monday, October 27, 2008, 6:49 PM
Hello all,
I have had my plans for a few weeks now and I am chewing on some ideas
that need to be addressed before I get started with the 88.
I really like the idea Mike suggested on his comment page.
Mikes thought was to incorporate the dihedral bend for the spars
"inside"
the fuselage.
Find it here: http://home.hiwaay.net/~langford/kopinion.html#bent
My thoughts are to do exactly that only not cut the caps into quarter inch
strips, but to steam
and bend them with a jig holding the proper angle until set. Do them both at
the same time,
sitting on top of each other, they would be exact complements. Once the
vertical spreaders
and shear ply was glued on it should be as strong as the strait spar ever
was.
That covers the front spar, the rear one is going to be a little more work.
I will require a dihedral
bend and one that sweeps it forward. My thought is to put the dihedral bend
inside and make the
bend forward just as it leaves the fuselage. Again top and bottom at the
same time in the same jig
one on top of the other.
Talking to a few wood workers they seem to think the small angles would be a
easy to do.
They suggested I practice on some clear tighter grain pine to get a feel for
the small spring back that will occur.
Why?
For very little extra work I will be able to extend the flap area / sand and
cover
the wing as one unit / it will look super!!!
Ron Smith wrote:
There is no reason to make the bend "inside" the fuse. If you do that, you will
have a difficult task of aligning the front and rear spar.
Also they will not be resting on the longerons, and that would be not as
structurally sound, at least in my mind (I'm not a structural engineer).
Think about what you are doing before you do it. The front, and the rear spars
MUST have the same bends.
I think that Mark (and I agree he is a smart guy) agreed with me, that the bend
should be on the outside of the fuse.
That way the straight section of the bottom of the spars rest on the longerons,
and they will then be naturally aligned. Putting the bend on the inside makes
for some weird calculations as to where,
and how much to bend to get the 5 inch dihedral. Remember the plans call for 5
inches of dihedral at the end of the outboard spar. How are you going to get
that right with the bend on the inside?
I guess you could figure that out, but that task would make my brain hurt for
sure. (not a difficult thing to do)
The bend section at the top of the spar also presents itself for a beautiful,
and necessary fillet.
I also made the fuse bend up to meet the rear spar which makes the shape perty
darn cool.
That is the way I did mine.
BTW there is no need to "steam" the spar cap material. 1/4 inch bends real easy.
See my spars on the list.
Good luck,
Smitty
