Need a good airfoil for a foam wing
02-21-2003, 08:14 PM
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Need a good airfoil for a foam wing
Hello all,
I'm at it again. This time I need a good airfoil for a foam wing to be tape covered. I'm scratch building a v-tail sailplane and will be used as a HLD thermal plane.
I first tried it with meat tray based foam shape with flat bottom and found that it has way too much drag. Once airspeed drops off the sink rate is not acceptable at all and I can not maintain good forward speed without nosing it down a bit. (not good for a sail plane so back to the drawing board)
A freind will cut me a solid foam wing, I just need advice an a good airfoil for this type of application. Planning on 8" cord X 60" + or -, three pannel polyhedral wing. Does not have to perfect, but I would like somthing better than the clark Y.
Completed all up weight on the plane now is 13oz. I expect a pretty good weight increase by going to a solid foam wing. (Probably to about 15 - 16 oz.) but hope to make up for it with good lift.
I'm at it again. This time I need a good airfoil for a foam wing to be tape covered. I'm scratch building a v-tail sailplane and will be used as a HLD thermal plane.
I first tried it with meat tray based foam shape with flat bottom and found that it has way too much drag. Once airspeed drops off the sink rate is not acceptable at all and I can not maintain good forward speed without nosing it down a bit. (not good for a sail plane so back to the drawing board)
A freind will cut me a solid foam wing, I just need advice an a good airfoil for this type of application. Planning on 8" cord X 60" + or -, three pannel polyhedral wing. Does not have to perfect, but I would like somthing better than the clark Y.
Completed all up weight on the plane now is 13oz. I expect a pretty good weight increase by going to a solid foam wing. (Probably to about 15 - 16 oz.) but hope to make up for it with good lift.
02-21-2003, 10:46 PM
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Need a good airfoil for a foam wing
What type of spars (size and material) are you planning to use? Most of the small, lightweight HLG's are using thin airfoils these days. Your foam/tape wings wouldn't last long without a strong spar design.
Check out the Terminator at the CRRC site:
http://www.charlesriverrc.org/articl...minatorhlg.htm These guys have been there & done that!
Also look at Dr. Drela's Apogee on the same site:
http://www.charlesriverrc.org/articl..._apogeehlg.htm
Good luck!
Check out the Terminator at the CRRC site:
http://www.charlesriverrc.org/articl...minatorhlg.htm These guys have been there & done that!
Also look at Dr. Drela's Apogee on the same site:
http://www.charlesriverrc.org/articl..._apogeehlg.htm
Good luck!
02-21-2003, 11:17 PM
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Thanks fot the links Dickey
I can't use a real thin airfoil for that very reason. I can do a spruce spar though and plan to for at least the center section of the 3 pannel wing. Pretty easy to put in. The tape reeally does a great job as long as you are not using a bungie or a winch. You can high start them gently or HLG OK.
My hop is fo an ultrlight HLG that I can take anywhere and not worry about all the rigging for a launch and a decent flight or two. The durability of the foam is alos a big plus.
My hop is fo an ultrlight HLG that I can take anywhere and not worry about all the rigging for a launch and a decent flight or two. The durability of the foam is alos a big plus.
