Kurt
The wood wing is pretty much like a giant Cat I glider wing. Of course it doesn't need the strength of a glider wing and it doesn't have to flex. I think the front part was made from .040 wood and the rear part from .030. I used a few ribs to shape the airfoil. The top surface is a very close approximation of an NACA 4702 - 4% camber, 70% high point and 2% thick. The built up wing has a 4% arc airfoil with 1/16 sq. spars.
I tested the model as a glider while ballasted up to 9 grams without a prop. The wood wing had a significantly better sink rate. I expected that it would fly on less torque than the built-up wing, but it didn't work out that way.
The wood wing has been lying around my shop for several months now and wasn't as straight as I would have liked. I still expected it to perform a lot better than it did.
----- Original Message -----
From: Kurt Krempetz
To: Indoor_Construction_at_yahoogroups.com
Sent: Saturday, December 02, 2006 9:48 PM
Subject: Re: [Indoor_Construction] LittleSquare finally earns its wings!
Hi Bill,
Thanks for reporting your testing of your
LittleSquare. Could you clairify what the difference
was between the built-up wing that turned 3:25 and the
wing that turned 3:04.
Thanks,
Kurt
--- Bill Gowen <b.gowen_at_earthlink.net> wrote:
> Yep - I finally got to actually fly LittleSquare
> today. The model was
> set up with the wood wing so I flew it that way
> first. After hitting
> everything possible on something like 6 or 8 flights
> I finally got
> one clean flight of 3:04. This was on 5/99 rubber
> about .092". All of
> the other flights were over 2 minutes.
>
> Then I switched to the built up wing, retrimmed the
> model and
> launched a full wind flight on the same motor and at
> the same torque.
> It climbed much faster and smacked the ceiling and
> hung. This was not
> really the expected result! On the next flight I
> dropped the launch
> torque considerably and got a clean flight of 3:25.
>
> The model is so ultra-stable that I think some CG
> adjusting might be
> in order to get the flight time a little higher. I
> wasn't able to do
> that today.
>
> The most important thing I learned about the design
> today is that it
> is absolutely and positively rock solid in the air.
> Every flight made
> was picture perfect until some obstruction got in
> the way. If you
> build one of these according to the plan it should
> do what it's
> supposed to do.
>
>
>
Kurt Krempetz
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Received on Sat Dec 02 2006 - 19:57:35 CET