Re: Humoring Indoor Ribs/was, No-Non Cents NPP

From: Bill Gowen <b.gowen_at_comcast.net>
Date: Mon, 17 Mar 2008 12:01:41 -0400

On the other hand a lot of really slick sounding aerodynamic
"improvements" result in models that don't fly as well as before you
"improved" them.

On Mon, 2008-03-17 at 15:56 +0000, Mark wrote:
> --- 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?)
>
>
>
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>


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Received on Mon Mar 17 2008 - 09:01:23 CET