As I understand the conversion, Ercoupe wings that are metalized are
actually converted to a "semi-monocoque" structure, same as the old T-28.
Ribs are actually removed in favor of the structural strength contributed by
the aluminum skin.
Anybody out there to confirm this?
Dave W
=========]-(§)-[==========
// \\
From: [email protected] [mailto:[email protected]] On
Behalf Of William R. Bayne
Sent: Thursday, 10 September, 2009 13:54 PM
To: Ercoupe Tech List
Subject: Re: {Disarmed} [ercoupe-tech] Metal Wings are stronger.....
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
--o-O-o--
