Humoring Indoor Ribs/was, No-Non Cents NPP

From: Mark <f1diddler_at_yahoo.com>
Date: Mon, 17 Mar 2008 15:56:13 -0000

--- In Indoor_Construction_at_yahoogroups.com, "Erich Reinbolz"
<erich44_at_...> wrote:
>
> Regarding the plans in Ron Williams book (page 90), the rib airfoil
> used is described as: 6% "simplex". This airfoil doesn't look
> simetrical. The high point seems to be near the front. The planform
> for this plane is somewhat eliptical. So some ribs will be much
> shorter then others. My question is; does one cut the rib on TE or LE,
> or both evenly?
>
> erich


This is not to refute any of the fine answers you are receiving. But
with slow motion indoor, there's a relatively wide envelope of what
works concerning wing shape, camber and % of camber.

Often it comes down to aesthetics. It just feels good to know you
trimmed the simplex ribs from behind, preserving the "correct" percent
camber. But if you trimmed from the front, your times would not suffer-
-it would only look funny, up close. No doubt, more than one building
error have become enshrined as something worth copying thanks to an
impromptu aerodynamic explanation devised to spare embarrassment.
Example, one of my F1d wings somehow acquired two dihedral break
(outer) ribs that are noticeably higher camber (at least 2% more) than
the 2 center ribs. OF course, the span of film in the middle area of
wing billows out the most in flight, so the inner ribs bend up a bit
more, thus more closely equaling the camber of the outer ribs in
flight, where it counts. Ha, ha. Works for me, and I don't hesitate
to use this wing when it really counts.
Mark F1diddler
(In spring break mode. Where's a contest when ya really need one?)
Received on Mon Mar 17 2008 - 08:56:29 CET