Hi Ren,
If you use the link Jeffrey provided, you can fill in the chord of the rib
aswell as the percentage of the arc. It will calculate the needed circle
radius. So if your model has a chord of 4 inch and you want a rib of 5%, the
calculator will give you a radius of 10.1 inch. If you now just make a
circle this size out of cardboard, you can use it as template.
Generaly, more camber (so 6% instead of 5%) will produce more lift, aswell
as more drag. The optimum is found by a lot of test flying :), to start
with, just use the number on your plans.
Kind regards,
Kevin
2010/1/14 Ren <nmonllor_at_tampabay.rr.com>
>
>
> Thank you Fred,
>
> I'm building the IMS Penny Plane and in as much as the rib outline is there
> and I've already made my template from brass sheet, I was wondering... on
> plans that I have that don't show the outline for the template, but only
> give the percentage of arc, how do I determine the curve (circumference of a
> circle). Is there a table I can obtain which will tell me what size circle
> to draw to get the arc from? Or do I just draw a bunch of circles in
> different sizes and start measuring arcs from those circumferences?
> Is a 6% arc going to facilitate more lift than a 5% arc?
>
> I hope I'm not being to much of a pain in the butt, it's just that this is
> all truly new and facinating to me.
>
> I've been sending video links of Indoor Duration Flight to most of my
> friends (old farts like myself)and they too are just facinated by what
> they're seeing.
>
> Thank you all for your patience!!!!!
>
> Ren
>
>
> --- In Indoor_Construction_at_yahoogroups.com<Indoor_Construction%40yahoogroups.com>,
> "Fred or Judy Rash" <frash_at_...> wrote:
> >
> > Ren,
> >
> > I don't remember what you are building, and this will be only a partial
> answer. Sometimes a partial answer will smoke out a good answer from someone
> who really knows.
> >
> > For an indoor duration model, use a rib curvature that gives a thickness
> that is 4 to 6 percent of the wing chord. Stabs are usually about 2% thinner
> than the wing - maybe 2 to 4 percent of the stab chord.
> >
> > Fred Rash
> >
> >
> >
> >
> > From: Ren
> > Sent: Thursday, January 14, 2010 8:29 AM
> > To: Indoor_Construction_at_yahoogroups.com<Indoor_Construction%40yahoogroups.com>
> > Subject: [Indoor_Construction] Re: Dang it....
> >
> >
> >
> > Thank you guys,
> > How do you figure out what percent of the cord is required?
> >
> > Ren
> >
> > --- In Indoor_Construction_at_yahoogroups.com<Indoor_Construction%40yahoogroups.com>,
> "jeffrey.hood" <jhood_at_> wrote:
> > >
> > >
> > > Here is a link to a page with both the formula, and a calculator to
> make it easy...
> > >
> > > http://www.indoornews.com/custom/utilities/arc_calc.php
> > >
> > > JH
> > >
> > >
> > > --- In Indoor_Construction_at_yahoogroups.com<Indoor_Construction%40yahoogroups.com>,
> "Ren" <nmonllor_at_> wrote:
> > > >
> > > > I for got to post my second question...
> > > > when an airfoil is stated as a 3 or 4 dgree arc. How do I figure out
> what to draw on a plan.
> > > > I've seen that they are some how related the section of a
> circumference, but I don't know how to figure out what the curve would be
> when it is stated in degrees.
> > > > Could some one explain to me what the formula is???
> > > > Thank you,
> > > > Ren
> > > >
> > >
> >
> >
> >
> >
> >
> >
> > ----------------------------------------------------------
> >
> >
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>
>
>
Received on Thu Jan 14 2010 - 09:43:42 CET