I would suggest that any engineering evaluation use the correct
approach in evaluating "stronger".
Adding thin sheets to a wing structure already designed and capable of
coping with the normal stresses of flight (plus a considerable safety
factor)would add little, if any, to the overall load carrying capacity
of an Ercoupe wing in terms of the additional stress said could carry
before it failed under load. The materials and procedures utilized by
the various STCs presently installed or available does not transform
the Ercoupe wing designed for grade A cotton covering into a monocoque
structure as would seem to have been inferred.
"Monocoque" construction is defined as "an aircraft structure in which
the outer covering skin carries all or a major portion of the
stresses".
The internal structural components, metal skin thickness, rivet type,
size, and spacing of a stressed skin wing design would be quite
different, and likely lighter.
Consider also these questions:
1. What practical purpose is served by increasing wing strength beyond
regulatory design requirements?
2. How much has the load capability of Ercoupe wing design increased
when covered with modern synthetic fabrics of higher tensional strength
abd durability than the original grade A cotton?
Regards,
WRB
--
On Sep 10, 2009, at 13:05, Art Langston wrote:
Chris, could you please share the engineering data with us and cite
the documentation where we can read it?
When finished, I believe the Polyfiber may actually be stronger than
the aluminum. I've de-skinned Ercoupe wings, and the metal is very
thin. Polyfiber is tough.
Thanks
Art N2666H
Chris wrote:A metal wing is stronger than a fabric one. The metal
distributes the loads over the surface. Would anyone want to consider
a fabric covered fuselage?
Chris
Santa Cruz
99674
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