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Old Jul 11, 2012, 07:44 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
North AL, USA
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Winglets - What Have You Guys Found?

Hey,

As promised from my last post, a question. A lot of the airliners people have interest in building have winglets (K's MD-11).

What kind of information have you uncovered in your research about winglets? Are there any best practices on how to make these in the RC-size arena? I'm curious as to what you guys have done so far.

I haven't had a chance to look at any commercially-available models like the WindRider 737 to even get an idea how they are shaped. I would think you better know what you are doing alignment-wise otherwise you'll be trimming-out unwanted yaw if not getting into an out-of-control situation.

WHOOP WHOOP! Thread diversion... I'm a ways-off from building an airliner, but maybe a year or so from now. If I get lucky I can work on one over the next winter, I have several in my club that can fly her if I'm not ready (I probably won't be!) Still interested in the Caravelle SE210. No winglets there, but there are vanes...
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Old Jul 11, 2012, 08:13 PM
Sittin' on my hands
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United States, WA, Seattle
Joined Jan 2005
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I honestly dont think they'll do anything for an RC airplane. There just wont be any wing-tip vortices to cancel out because our foam planes are going only like 50 knots. But they look cool. I could be wrong though. Maybe they'll produce happy side-effects. Might be worth experimenting on a glider.

as far as build is concerned.. perhaps a spar cut like an "L", glue foam on both sides, and sand-to-shape probably.
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Old Jul 11, 2012, 10:52 PM
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Winglets help reduce wintip vortacies which reduce drag which helps any aircraft. . . . . .plus they look cool!
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Old Jul 11, 2012, 11:01 PM
RC = Empty wallet
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Australia, VIC, Melbourne
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^^+1 On rc aircraft, they would do next to nothing, more for looks than performance. They come in many shapes and sizes
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Old Jul 12, 2012, 06:28 AM
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Originally Posted by InvalidUsername View Post
^^+1 On rc aircraft, they would do next to nothing, more for looks than performance. They come in many shapes and sizes
Wow!. . . . now those are what you call winglets Lol
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Old Jul 12, 2012, 07:17 AM
was geht , müssen unten kommen
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United Kingdom, London
Joined Dec 2010
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if you get them outta line the case a lot of drag and will stall the wing Quicker however the advantage of having winglets on an RC model is the improve take-off/landing performance... (due to winglets increasing the span) and for that very same reason you can fly at 1 maybe 2% lower throttle when Cruising which means slightly longer flight times..
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Old Jul 18, 2012, 12:44 PM
Avoid The Ground!
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I get more gas mileage... XD
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Old Jul 22, 2012, 11:39 AM
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United States, AZ, Mesa
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I've only used winglets on one airplane for 3 build comparisons. It's a scratch build from Eastwind Models Gemini Twin plans. This plane does outstanding touch and goes and for some crazy reason I just love trying to fly it on the ragged edge of tip stalling. Sometimes I get bit and she falls out of the sky.

#1 build was with tall winglets as seen on most airliners and flew pretty good. This first one was completely destroyed in a trip and fall (don't ask).

#2 one was also done with the high winglets This wing was damaged in a crash from stupid flying. (Stall turns at 12 feet AGL )

#3 was rebuilt from what was left from the crash of #2 and has Horner style tips. These gave the plane a different feel. Just seemed all around smoother. There is a definite decrease in tip stall tendency. Much more stable at super low speeds.

I think the high winglets look the coolest and may possibly have some affect on yaw stability but the Horners made the most noticeable overall improvement. I doubt the Horners have any tip vortice affect as on a full size aircraft. They most likely act as added washout on our smaller planes. In any case I'm working on a 50% larger version and it will have the Horner tips. As soon as I sell off some more planes to make room I'm going to drag the bigger one out and finish it up. Another 2 months or so and it'll finally be cool enough to fly again.....

Joe
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Old Jul 22, 2012, 08:57 PM
A Day @ a Time - Matt. 6:25-34
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Horner tips... never heard of them, but these look like what is on my Sensei.
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Old Jul 22, 2012, 09:52 PM
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Horner tips... never heard of them, .
Because I misspelled it as usual. It should read Hoerner. Mine are probably better described as a drooped Hoerner. I got the idea after seeing a GWS E-Starter wing. It looked cool so I figured what the heck. They work well for me.

I'm posting a .pdf file I found that gives a brief look at the different kinds of wing tip devices in use. There is a TON of info out there on wing tips and STOL devices. I'm sure you'll find something that you want to try. I had a book around here on STOL R/C aircraft. I believe it was by Andy Lennon. Don't know where the heck it might be but I'll have to see if I can dig it up sometime. It had a lot of cool stuff in it.

Joe
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Old Jul 22, 2012, 10:44 PM
A Day @ a Time - Matt. 6:25-34
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Outstanding information, thanks for the presentation.
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Old Jul 22, 2012, 11:01 PM
M0unt@in M0del$ minion
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You're welcome. Hope it helps a bit. Don't forget to check some of the links on the last page of the .pdf.

Joe
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Old Jul 22, 2012, 11:05 PM
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Outstanding information, thanks for the presentation.
I totally agree. . . thanks Joe!
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Old Jul 23, 2012, 01:00 AM
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Tennessee
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Winglets do work but only at one speed. For transports, winglets are set for crusing speed and can increase drag if the speed is too far off the design speed. In 1979, I conducted extensive flight testing on a low aspect ratio sailplane and found up to 10 percent increase in glide time from a fixed altitude when the winglet toe out angle was set for minimum sink airspeed. I wrote an article that was published in the May, 1980 issue of Model Aviation about the experiment that contained a lot of the data. I concluded that winglets work for model airplanes but aren't usually worth the extra effort.
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Old Jul 23, 2012, 09:02 AM
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Originally Posted by ChuckA View Post
Winglets do work but only at one speed. For transports, winglets are set for crusing speed and can increase drag if the speed is too far off the design speed. In 1979, I conducted extensive flight testing on a low aspect ratio sailplane and found up to 10 percent increase in glide time from a fixed altitude when the winglet toe out angle was set for minimum sink airspeed. I wrote an article that was published in the May, 1980 issue of Model Aviation about the experiment that contained a lot of the data. I concluded that winglets work for model airplanes but aren't usually worth the extra effort.
Amazing work Chuck! Nice glider!
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