Gary
If you join the flaps at the center - assuming a wing with center dihedral - you will probably be locking the wing in the cambered configuration. I think it would be hard to generate enough bending force on the wing to make the flaps function. But I could for sure be wrong. As for thin wings I'm pushing that idea as hard as I can. One of my fairly large unlimiteds that I flew at Kent last year had a wing made from 1/16 sheet plus a lot of carbon. It flew pretty well but not long enough, which seems to be a common problem. I feel like getting a very light glider to high Cat 2 altitudes requires a thin wing to cut drag.
Don
My usual airfoil for low ceiling consists of a forward part of the wing as thin as I dare make it. The LE is shaped from both sides. I normally use a carbon rod either whole or split in half for the LE reinforcement. At the rear of the front part I sand only on the bottom and try to make an edge thickness that matches whatever I'm using for flaps. I join the front part to the flaps with the wing upside down to get a nice flush joint on the top of the wing. When the wing is close to being finished I bend the front part to give whatever camber I'm looking for and massage the flaps to form the rear of the airfoil. The finished airfoil looks somewhat similar to Kurt's Time Machine airfoil except that the step is smaller and farther back.
I don't have any hard numbers for camber. I usually keep adding camber when I'm testing until I feel like the sink rate is the best I can get.
----- Original Message -----
From: dgbj_at_aol.com
To: Indoor_Construction_at_yahoogroups.com
Sent: Sunday, February 11, 2007 9:03 PM
Subject: Re: [Indoor_Construction] IHLG Flappers
Bill,
"Regardless of how hard the flap function is to analyze, they definitely do
work."
Yes, and Aki brings up an interesting point. Maybe the flattening of the
whole wing is what does it, not just the flap. Maybe making the whole wing
thinner and softer will work better. I have been wondering what would happen if
there was no slot at the flap root.
Gary
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Received on Sun Feb 11 2007 - 18:42:26 CET
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