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Old Jul 05, 2006, 09:44 PM
hot air rises...
jfinch's Avatar
Pleasant Grove, UT
Joined Jul 2005
7,715 Posts
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Help me design a small fast wing

I've got a few design questions I hope you can help me with. Please bear with me if I ask a stupid question... I'm still learning . I would like to build a very fast and small low drag e-powered flying wing (i.e. break 100 mph under 20 amps ). I plan to power it with a Razor 400 or custom wound high Kv outrunner with TP1320 batteries. I have a hot wire cutter and have cut a few wings so cutting cores should not be too difficult. Oh, and the wing will be made from epp or eps, covered with henry tape and ultracoat.

First question. What airfoil would you suggest? My fastest wing right now (96 mph @ 23 amps) is a 30" wing with a hybrid airfoil of an SD-7032 top and SD-6060 bottom. I think it might be too draggy for really high speed. Searching around I've found that the MH-43 is a pretty popular foil for F5D wings. Would it be suitable to a tailess design? The Rafi #30 foil has been suggested but my google ended empty handed. Does anyone know where I can find this foil?

2nd q. How much sweep should I design into the wing? I'm not completely sure what effects sweep has? I think in increases drag during turns (bad) but also increases stability (good). Is a plank wing going to be the fastest? I'm not sure I'm comfortable with a plank (I have zero experience in that arena). What are the effects to flight when comparing sweep at the LE to sweep at the TE (deep V vs. delta wing)?

Also, what wingspan should I shoot for? I'm thinking 24". Anyone flying a wing smaller then that at over 100 mph?

What else should I be thinking about?
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Old Jul 05, 2006, 11:10 PM
Nucking Futs
I'm Rick James's Avatar
Southern Killafornia
Joined Jan 2005
1,626 Posts
I'm guessing the electric forum or the flying wing forum would be a good spot for this thread.

Sorry I can't help you more.

RJ
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Old Jul 05, 2006, 11:49 PM
hot air rises...
jfinch's Avatar
Pleasant Grove, UT
Joined Jul 2005
7,715 Posts
If anyone knows airfoils and wing design I'd think it would be you guys. I'm asking in the flying wing forum too though .
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Old Jul 06, 2006, 12:05 AM
blah...
THUREN's Avatar
United States, OR, Bend
Joined Jun 2005
2,932 Posts
Get THIS , chop the center out making the span you want, slap a motor on an pin it...

I bet it would haul!
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Old Jul 06, 2006, 12:34 AM
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Joined Jan 2003
6,934 Posts
If you can find a "Wedgie" they haul with a lipoly and an outrunner. A friend of mine carbon bagged one and it screams.
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Old Jul 06, 2006, 01:12 AM
by ZIPPER
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East Kurrajong Sydney Australia
Joined Aug 2004
5,707 Posts
The PW51 foil, is a good fast foil for a plank. We have had our Drongo up to 132mph using the PW51.


Glenn
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Old Mar 11, 2007, 01:02 PM
sloper dude
Jeffrito's Avatar
L'Étoile du Nord
Joined Jan 2005
200 Posts
Here's what you want to start with; an Aeromod Passaj.

The Passaj, like all Aeromod designs, is molded (in this case fiberglass) in a female mold over high-density foam. Not only is this the fastest wing around, but it's as tough as a bagged wing. Electrifying it shouldn't be very hard, but it would do 100 mph on the slope, without motor power. The wing separates for access to the electronics. Price is about $150 + shipping, and it's far less work to put together than a foamie.

Jeff
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Old Mar 11, 2007, 01:43 PM
The sky is my playground
flyboyjimi's Avatar
Near the Ocean in Hunt. Beach Calif.
Joined Apr 2006
999 Posts
I took a scrappy from WW and put a hacker B20 brushless motor with a ten amp speed controller on it and Mr Chang up on Fairview hill in Costa Mesa used to clock me regurlarly at 95 mph this was very shallow dive but the thing was just about maxed out I tried 4 by 3 prop and that seemed to do the best overall changing the pitch and length either made it faster or more power I used a 3 cell 1500 battery and the most amps I could get before it heating up was around eight good luck from a HACKY flyer in H.B. Jim
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Old Mar 11, 2007, 01:46 PM
The sky is my playground
flyboyjimi's Avatar
Near the Ocean in Hunt. Beach Calif.
Joined Apr 2006
999 Posts
And by the way the scrappy is a foam wing with little carbon flat strips located throughtout the wing and the length is 25 inches hope this helps Jimmy in H.B.
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