Wing Airfoil
12-06-2004 | 11:23 PM
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From: Regina, SK, CANADA
Wing Airfoil
I am familiar with symmetrical, semi symmetrical and flat bottom wing airfoils. Has anyone tried a wing with the top and bottom of the wing parallel (like a plank), possibly about one inch thick.
I am thinking of a wing about 48" long and maybe a 9" chord. If anyone has tried this type of wing, I would be pleased to know how well it works. I know that some flying wings have an airfoil of this type and they seem to work well. Any responses would be much appreciated.
I am thinking of a wing about 48" long and maybe a 9" chord. If anyone has tried this type of wing, I would be pleased to know how well it works. I know that some flying wings have an airfoil of this type and they seem to work well. Any responses would be much appreciated.
12-07-2004 | 12:53 AM
#2
RE: Wing Airfoil
The old vintage style combat models used a wing not far from what you're considering. I also used it on a sportflying model that closely copied the wing shape. I think this must be the type of flying wings you are reffering to as no self respecting designer that is looking for efficiency would give this a second glance.
It was basically a 1x1 inch preformed symettrical SIG leading edge with 1 inch x 1/8 ribs cut off to length. A 1 1/4 by 1/4 trailing edge is nothed into the rear of the ribs flat on the center line. A clever little jig template is then used to form the rear of the ribs after the model came off the board. The ribs being about 4 or 5 inches apart and a strong covering being used. WIth the sag the shape away from the ribs is actually quite airfoil like with noticable ridges at the rear of the ribs. The trailing edge curve being a simple down curve of about 2 inches in length.
As you can imagine this is a very fast wing to build this way. It's all flat, tapers are super easy and the ribs are simple to cut off long strips of wood. I tend to cut them to length as needed and then stack them all together with the trailing edges flush, notch for the trailing edge stock leaving about 1/2 inch of trailing edge protruding and then build the wing and slide in the trailing edge stock. Lift the wing, use the handy template to adze the curve at the rear of the ribs and yer done.
The RC sport model I built this way flew well but that was because of low weight and lots of power. The glide is also decent but certainly not up to soaring level. About as good as any other sport model. Really tight loops tended to result in a high G stall and the model sort of stalls, turns, stalls, turns, etc around the loop in little bobbles when pushed really hard. Make it big and light for the power and your's will fly well enough to please you as well.
It was basically a 1x1 inch preformed symettrical SIG leading edge with 1 inch x 1/8 ribs cut off to length. A 1 1/4 by 1/4 trailing edge is nothed into the rear of the ribs flat on the center line. A clever little jig template is then used to form the rear of the ribs after the model came off the board. The ribs being about 4 or 5 inches apart and a strong covering being used. WIth the sag the shape away from the ribs is actually quite airfoil like with noticable ridges at the rear of the ribs. The trailing edge curve being a simple down curve of about 2 inches in length.
As you can imagine this is a very fast wing to build this way. It's all flat, tapers are super easy and the ribs are simple to cut off long strips of wood. I tend to cut them to length as needed and then stack them all together with the trailing edges flush, notch for the trailing edge stock leaving about 1/2 inch of trailing edge protruding and then build the wing and slide in the trailing edge stock. Lift the wing, use the handy template to adze the curve at the rear of the ribs and yer done.
The RC sport model I built this way flew well but that was because of low weight and lots of power. The glide is also decent but certainly not up to soaring level. About as good as any other sport model. Really tight loops tended to result in a high G stall and the model sort of stalls, turns, stalls, turns, etc around the loop in little bobbles when pushed really hard. Make it big and light for the power and your's will fly well enough to please you as well.
