In article ,
"Peter Dohm" wrote:

"Bart" wrote in message
ups.com...
I hope I'm not intruding here, but I'm building a car with a plywood
monocoque chassis bonded to fiberglass body panels. It's not as
bizarre as it may sound: the chassis design is based partly on that of
the Marcos GT, which used exactly that model of construction. The
chassis designer was Frank Costin (the "cos" of Marcos), who had done
a great deal of the design work on the deHavilland Mosquito, the
British plywood monocoque WWII fighter-bomber. As I'm sure you
aircraft folk know, a plywood monocoque has exceptional torsional
rigidity for its weight.

The car I'm building is open, so the rigidity loss inevitable with an
open cockpit will be largely restored by the use of deep, boxed side-
sills, fore- and aft-bulkheads, and a deep, chassis-long central boxed
spine, much like the Lotus Élan.

I'm looking for advice on bonding and bond-strengthening plywood box
structures (Marcos, for example, used spruce reinforcements at all
joints), and what thickness and kind of ply (Marcos used marine).

Any suggestions (besides the obvious!) greatly appreciated...

Bart Brown

Actually, a number of aircraft have been designed with boxed spars, but I
don't know of any that might help with the tie-in between the boxed side
sills, or the central box structure, and the fore and aft bulkheads.

Regrettably, my woodworking knowledge is in the home-handyman range, so I
can only suggest looking for a treatise on the construction of the original
Marcos cars. Your side and center sections will be no more than 25% of the
height of the original car, so the tie-ins will probably need to be at least
4 times as strong. If that won't work, you may need to consider a different
material, such as fiberglass or riveted aluminum.

BTW, was Frank Costin the same person who was part of Cosworth?

Peter

He was the brother of Cosworth co-founder *Mike* Costin. Cosworth was
founded by Mike Costin and Keith Duckworth.

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling four feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect if you
sit in the bottom of that cupboard."