mike h wrote:

Speaking of moldless construction, are there any decent websites for
researching this process? I've done the usual google/1blink search and

come

up with some good general 'glass stuff, but most folks want to sell me a
$100 tape for building an airplane (which isn't *quite* what I had in

mind).

Thanks!

Mike Harrington

Bill did a tape. Looks like there is money in it Bill :-)>

Paul Lamar

Mike,
A mouldless construction is a term for using a Jig to hold the foam in place
while you place your glass and post-cure. It doesn't matter what it is as
long as it holds the foam to shape during the process. Cheap timber is the
most common material for such a Jig. All the Jigs are similar in
design -some are exterior Jigs , some are interior Jigs. An interior Jig is
one on which you drape your foam and fibreglass, an exterior Jig is one in
which the foam is placed inside, them fibreglassed. Once one side is
completed it is removed from the Jig and the other side of the foam is
glassed. Very simple process, however care must be made that the shape is
not lost in the process of removing the Jig and doing the other side. So
perhaps the exterior Jig is the best in this case as it allows for the
placement of bulkheads  which help maintain rigidity.

OTOH if you wish to make more than one (go into production) them a mould is
suggested.

To make a mould a similar proces is used, set your Jig up on a rigid centre
piece with stands on each end that allows the Jig to rotate on a centre
axle.
The set-up of the jig is similar to the mouldless design however the foam
and fibreglass are a permanent part of the core - off which you make your
mould.
Simple who needs a video tape !

All the design parameters would be similar to the aluminium ie. bulkheads,
wing ribs, spars etc.

The real problem is the lay-up of the fibreglass for that particular design
to give the best strength and lowest weight.
This is a very general description OK!
George (down under)

Not all mold-less construction requires a jig. The wing airfoil shape is hot
wired out of blue foam and then the fiber is laid up on top.
The devil however is in the details. I would go for the tape.

Paul Lamar
 
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