Gee Bee question

On Mon, 12 Jan 2009 03:57:11 -0800 (PST), wrote:

On Jan 12, 1:15*am, Ron Wanttaja wrote:
wrote:
I'm studying the Gee Bee series of planes and I have a question that
may be obvious to you, but not me. *I know that flying wires are
supposed to be dual for safety purposes. *The flying wires on the
outboard part of the wing ( Gee Bee R2 and Z models ) are dual, OK. *I
am assuming that the load of these wires goes through the landing gear
strut and back up to the fuselage where it is anchored and therefore
is where the actual load is transferred from. *But the wire from the
inboard part of the landing gear strut to the fuselage is only a
single wire. *Am I missing something?

Gee Bee wing bracing is very similar to that of Fly Babies.

First, the wires themselves attach to the wing spars. *If the wing spar
isn't co-incident with the normal center of pressure, putting ONE set of
wires on either spar will cause the wing panel to twist under load. *A
bracing wire on the aft spar is lighter than building the wing so stiff
it doesn't twist.

The center-section bracing wires attach to the opposite side of the
flying wire attachment point on the gear structure. *There's no need for
a pair of wires, since there's no torque imparted. *If the cross-braces
couldn't attach to the gear structure there, they WOULD need two sets.

Having two separate flying wires also allows them to adjust each wing's
angle of incidence individually. *If the plane flies right-wing heavy,
they can tighten the rear flying wire and add a bit of twist to the wing
to make it produce a tad more lift.

Ron Wanttaja

Thanks for the info. I incorrectly assumed the dual wires was for
safety. I know the Pitts S-1 and Christen Eagles have dual wires, but
only at the main spar and I though I read somewhere that they had to
be dual for safety. Obviously these planes can alter their incidence
by adjustments at the outboard wing struts. They must have a
different pressure distribution to keep them from twisting? And
thanks Ron, I saw your explanation of the Fly Baby wire structure on
your web site. Learned quite a bit from that illustration.

Neal

dual wires will *never* be for funk safety.
if one of the wires were to break the transference of load to the
other wire (immediately doubling its stress) would likely cause a
catastrophic failure. far better to have one adequately sized wire.

Stealth Pilot