Paul
For those willing to build with epoxy, I think, the best would be to
purchase directly made sheets to be glued on rib
Not the cheapest way, but by far the quickest giving a superb
result.
https://www.rockwestcomposites.com/plates-panels-angles/carbon-fiber-plate/carbon-fiber-fabric-plate/plate-carbon-fiber-qiso-tri-axial-gloss-matte-48-x-120-x-0-050-inch-thick-options
pascal Virlouvet
Thanks Pascal
I have the wing rib problem decided. This is a Teflon mold .75 inches
thick. The procedure is wet out the fabric and place it over the
center piece hole. Press the rib form into the center mold. the
flanges will be automatically formed. Put it in an oven set to 200 F.
Let cure.
Teflon is good to 500 F.
Each rib will be precisely the right size. Cut a hole for the spar
and use sort pieces of carbon fiber angle to bond and pop rivet the
rib to the side of the spar.
This will be much faster then making each ribs out of foam and
covering it by hand with fabric glass or carbon.
Patent applied for :-)
Paul Lamar
Very nice. It seems feasible to do the spar locator hole the
same way at the same time. Cut an X in the hole and put plug in.
Michael Nash
A little problem with that. The dimensions of the spar will vary
due to load on it. Top and bottom will have varying layers of uni.
A list of spar hole dimensions should be made for all the rib locations.
Here is a stress diagram for a typical wing load more or less.
Paul Lamar
Paul the point of the built up spar is you can vary the ply schedule to
get the strength you want over the spar with the same outside diameter
or even easier with the box spar. Then all your rib holes can be the
same size for easy molding
Bill Jepson
Yes all the ribs are the same out side dimensions.
If made on a SIMPLE square tube male mold the thickness of the caps
would step down starting at the root rib. You can start with an off the
shelf cured square or rectangular carbon tube.
If all the holes in the ribs are the same size the spar then must be
made in a female box mold.
Lets call it a square tube female mold. How do I lay up inside a 20 foot
long square tube?
Not possible of course. Or at least extremely difficult.
OK say I made a rectangular male mold that was tapered in height.
The small vertical dimension was near the root rib where the caps are
thickest.
Could be carved out of 20 ft long blue foam I guess. Could also be made out
of four ten foot long steel or aluminum bent up tapered channels and
welded up.
Kind of tricky getting the right taper. Probably calculate at the
proper number
of ply schedules and then adjust according to needed height.
The next problem is cutting the square holes in the rib plies before
saturating and molding. That is not practical. Particularly in carbon.
Plan B. Makes two part ribs. One front one rear twice the rib lay up time.
That will also work.
Nay.
I would rather cut different size holes in the cured ribs :-)
Lots of options.
BTW the cost of solid Teflon is out of sight.
Garbage bag material can be used as a mold separator with a plywood mold.
The same stuff you use to saturate the fabric.
Add a couple more layers before you put in the plywood mold.
Room temperature or 150 F max in oven cure. Otherwise the
garbage bag might melt :-)
The actual plan form I intend to use is that of a C182. The 2/3 span
center section
is straight to accommodate the fowler flaps and the outer panels with
the ailerons
are tapered so those ribs are not all the same size. I am doing that for
the known excellent handing and stall characteristics of the C182.
No point in reinventing the wheel and do all that R&D on handling.
Paul Lamar
Paul, Just a thought, make the centerline a pusher / puller twin engine,
add two seats to the rear of each pod. Much like the Cessna 336
Skymaster / 337 Super Skymaster, but in a over the wing mount. Design in
some fuel pods, make one nice long legged seaplane with added comfort of
twin engines.
George F. Curtis Jr.
Since it is a kit everybody is free to do it any way they see fit.
My guess is the gross weight would go up to 4,000 or 4,500 pounds so you
better
beef up everything :-) I am not sure the Balloon tires would take it.
Paul Lamar
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