Hi Bruce,
I have not been able to get reasonable results
with a scale on the flaps. I have use two methods.
When I was learning what I needed to do I came up with
a cheap wing tunnel. I had my son drive the car and I
put the plane outside the passenger window. As you
speed up you can watch the flaps move and get a speed
at which they flex up. You can also go faster and
watch them fail. It is very interesting. You want
the flaps to start working around 30mph and at 60 or
70 failure usually occurs.
From doing a lot of testing and flying I just got
the feel for what it needed. Today, I typically build
the plane on the stiff/heavy side, then fly it and
sand/making the flaps more flexible. Typically you
just keep thining the wing down and the model keeps
doing better times until they fail, then you start
over and build another plane.
Kurt
--- Bruce McCrory <bruce_at_kbdmcc.net> wrote:
> Mrs. Scrouge stole my mouse Saturday, so now I'm
> posting results of
> my
> wavy wings experiment with the steam iron (oven). I
> posted 3 photos
> in
> the files under a new "Gliders" folder and "Misc.
> Stuff" a few
> minutes
> ago.
>
> This is the intended Cat. 2 design. Wood is about
> 4.5lb, (a/b)-grain
> with ray angle leaning aft at base. I hate first
> time "success"; but
> is probably not so. Read on. The steam bath
> exaggerated the waves.
> Very
> little was accomplished with the wing panels after I
> released them
> from
> the press. I rubbed, but they seem to like the shown
> shape. I was
> able
> to curl the root end to match the central dip. The
> two are a pretty
> close match.
>
> The bath plumped the TE about .004", and made the
> flap very stiff. 6g
> to 7 grams of loading will flex the curl slightly,
> before the whole
> panel twists. I'm reworking the sanding block. A
> better thickness may
> be about .012" through the last inch, or so.
>
> Kurt, and Bill, I do have your followups to my
> question, and am
> jumping
> ahead. Your tips and thoughts are encouraging. My
> assumption is:
> these
> flaps should be fairly flexible, flattening on
> launch, then tucking.
> Math beyond basic addition will return a glazed,
> dumb look, so I'll
> just use my standard empirical approach. The model
> will be
> approximately 2 grams; therefore, the flaps should
> flatten at
> slightly
> more load on a digital scale.
>
> Good building,
> Bruce in Seattle
>
>
>
>
Kurt Krempetz
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Received on Tue Dec 20 2005 - 08:51:46 CET