Why no plywood monocoque homebuilts?

"Morgans" wrote in message
...

"Capt. Geoffrey Thorpe" The Sea Hawk at wow way d0t com wrote

The hard part would be to come up with a reasonable replacement for the
spars in the wings. To avoid the big expensive spruce planks, one might
have to consider an engineered product like Laminated Veneer Lumber
(LVL)...

Have you ever used those? They are HEAVY, with a capital "H".

More fitting would be something like an engineered product such as "silent
floor" joists, which is best described as a wood "I" beam. A cheaper
wood, like fur could be used, because the wider flange top and bottom of
the "I" is the only part that is real wood, and there is not that much
volume of wood to incur very much weight penalty.

Holes can be put in the plywood web to help lighten it, with very minimal
strength loss.

Of course, this is a practice very similar to what is currently being used
in some homebuilt designs, today. g

A box spar is one of the best uses of strength to weight for spars, not
using a solid plank. The amount of real wood, top to bottom and spanwise
varies, so there is no extra wood where it is not needed, thus giving
maximum strength to weight. Also, you do not have to use expensive Sitka
Spruce, and if you do, you can cut up smaller (cheaper-no waste) pieces,
and splice them, and laminate them, to get all of the grain going in the
right direction.


I was thinking of a routed spar to save some of the weight, but you are
absolutely correct - a box spar would be the way to go in order to avoid the
big expensive spruce plank.


--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.