Re: ARC radius airfoils question....long

From: <mkirda_at_sbcglobal.net>
Date: Wed, 30 Oct 2013 15:35:22 -0000

Hi Ren.

Looking at both 3 and 6% arcs in xflr5, they both seem to have a best point at Cl=0.8 with a Cd 0f 0.05 at Re10000. Beyond that on the 3%, drag goes up quickly. On the 6% you can get much higher Cl levels (Cl=1.2) with Cd of only 0.065.

A slightly educated guess: higher ceilings = less chance for upset. Lower drag overall pays off = Lower camber.
Lower ceilings = Lots of ceiling scrubbing. Higher camber will likely pay off due to quicker recovery.

Regards.
Mike Kirda

--- In Indoor_Construction_at_yahoogroups.com, <nmonllor@...> wrote:
>
> AArrg!
>
> 3 replies and still no answer to the question, dang it!
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> Yes Gary, I should have said camber and not hump. I must have camels on the brain today or I'm just getting old, sorry.
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> It's nice to know that I'm not the only one who finds this worthy of question.
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> If anybody can come up with the answer, I'd really appreciate it.
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> Thanks,
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> Ren
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>
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> ---- Warthodson_at_... wrote:
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> > Ren,
> > That is an interesting question. Sorry I do not have the answer, but I will add this to your question: Assuming one of the two airfoils will have a better L/D ratio, I would think the better L/D ratio would be the best choice for both a low & a high ceiling.
> >
> > Also, I do not understand your statement below. A 6% arch has a higher camber than a 4% arch. Is that what you are refering to? If not, what did you mean?
> >
> > Gary H
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> > A smaller percentage would create a higher hump in the air foil increasing lift according to Bernulli, but yet it is suggested for a lower cieling. Whyis this?
> > What am I not seeing?
> >
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> >
> >
> >
> >
> >
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Received on Wed Oct 30 2013 - 08:35:24 CET