Re: Aerodynamic obsessiveness

From: Nicholas <ndhuang83706_at_gmail.com>
Date: Sun, 28 Jan 2007 19:25:27 -0000

I've already streamlined the posts. They're about 1/8*3/32. One
thing that worries me is the junction between the film and the wing.
I don't have anything to attach the film to at the top. I think the
loose flim might flap around and make things even worse. I'm running
slightly low on time to do exhaustive testing, but we'll see what
comes out.
 Nicholas

--- In Indoor_Construction_at_yahoogroups.com, dgbj@... wrote:
>
> I wondered whether at this very low aerodynamic scale there are any
vortices
> behind the wing posts.
>
> According to Van Dyke, "An Album of Fluid Motion", Figure 46 on
page 30, the
> flow pattern transitions from steady to oscillating at around R =
41.0. A
> 1/16" wing post at 2 feet per second has a Reynolds number of about 65.
>
> Putting film between the wing posts might create more friction drag
than it
> eliminates. You would presumably still have a wake behind the rear
post.
> Might it be better to streamline the posts?
>
> The obvious way to get an answer is to try it. Replace the prop
with an
> equivalent weight of clay and glide test.
>
Received on Sun Jan 28 2007 - 11:25:44 CET