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Wing Tips (no, not the shoes!)

captainron

captainron

Well Known Member
This must have come up at one time or another, but has anyone ever tried wing and elevator tips a la Mooney style on a Vans?
Or, going another route, has anyone tried winglets?
 
I've seen winglets on a Glasair IIFT that used to be local. It looked pretty silly. My concern would be what kind of loads are the winglet imparting to the wingtip and will the pop-rivets or #6 screws be strong enough. I kind of think it would be ok but who knows.
 
Wing tips

I have to think that a simple flat aluminum tip would weigh much less and have less drag than the fiberglass tips.
 
Yes

Hi Ron,
The Air Tractor factory deducts 40 % spar life when owners install winglets, or just multiply your 8000 hour wing (on my AT502) by .60 for 4800 hour spar life due to the twisting loads imposed by the winglets. They're supposed to reduce vortices and allow for less chemical drift. Leland Snow (owner of Air Tractor) has been fussing with the FAA for years now regarding spar life. BTW, my airplane is now at Southeastern Aircraft, just west of Ft. Pierce, getting new (used ) wings since mine have 7820 TTSNEW on them. FWIW, the PT6 on the front also has 7820 TT with no overhaul yet!! ;)

I'm sure that at 200 MPH speeds, there'd be even more twisting loads even tho' our little stubbies are stiffer than my Air Tractor's 50 foot wings. As you well know, wingtip design is still somewhat of a black art and I'd doubt you'd see any difference with or without (square ala Mooney) wingtips. I recall a guy out west with no tips....well, square ones and a reported faster cruise. Less span maybe?

Regards,
 
Here, let me help you solve this question, once and for all.

Here's a Lancair Legacy with tiplets.

DSCN0944.sized.jpg

DSCN0947.sized.jpg


Now, let me get this out of your head. Those tips, unless you can fly in the FL's are a *speed penalty*. Test have been made on Lancair 4's, and they cost you about 3kts down low and really only gain you maybe 2kts when *way up high - like above 20K*.

The Commercial guys use em to reduce the drag from the wing tip vorticies, but we'll never be able to go fast enough to make that happen for us, unless you want to test VNE.

They look cool, but are useless and a penalty.
 
pierre smith said:
(square ala Mooney) wingtips. I recall a guy out west with no tips....well, square ones and a reported faster cruise. Less span maybe?

Regards,
Click to expand...

This is more what I was pondering than the winglets. Each bare wingtip weighs 6 pounds before any additional glass, filler or paint. I don't think I'm nuts-this idea worked for Mooney! I was just questioning if it's been tried on a Vans! If someone has tried it and indeed shown a faster cruise, I believe it's in the realm of plausible ideas. What are we building experimentals for anyway?
 
captainron said:
This is more what I was pondering than the winglets. Each bare wingtip weighs 6 pounds before any additional glass, filler or paint. I don't think I'm nuts-this idea worked for Mooney! I was just questioning if it's been tried on a Vans! If someone has tried it and indeed shown a faster cruise, I believe it's in the realm of plausible ideas. What are we building experimentals for anyway?
Click to expand...
Good point, Ron - Outside of maybe looking funny, a flat aluminum plate on the end of the wing would save a lot of weight. I can't imagine the glass tips add anything to structural integrity.
I'm looking forward to hearing how this turns out! When I get to that point, the flat plate option would sure save a lot of time and weight!
 
N674P said:
Good point, Ron - Outside of maybe looking funny, a flat aluminum plate on the end of the wing would save a lot of weight. I can't imagine the glass tips add anything to structural integrity.
I'm looking forward to hearing how this turns out! When I get to that point, the flat plate option would sure save a lot of time and weight!
Click to expand...

Thanks Johnny, This seemed like a normal inquiry, and after seeing endless discussions on induction, plasma, 90K Garmin panels, car engines running at 5000 rpm, I get blasted for questioning a simple, proven, easy concept that does work on some fast "spam cans". It might look funny, but when you're in the driver's seat and going fast, can you see it?
 
Nemesis

Search winglets on you will find posts by a few aero engineers on the subject. Basically, a performance penalty on most a/c ours included.

I have been thinking about something like the tips on the Nemesis. Have not seen them in person, so it may be "unfeasable pipedreaming" as well, but the theory of impersonating an elliptical planform seems sound. Seems like mother nature got it right a long time ago (shark fins, tuna, ect.)
 
Wingtips

My reasoning for the Mooney comparison is only that it is an airplane of comparable speed and power to what we are building, but they have always had a speed edge over similar competition in the "spam" world. Think about the older models: Lycoming 180 hp, no fancy engine stuff, simple as a rock! I have heard stories that the wingtips were done this way for speed, and also heard that they were done this way simply for economics of build. If the truth is that this design is faster, as well as being way simpler and faster to build and finish, who wouldn't be interested?
 
RV8RIVETER said:
Seems like mother nature got it right a long time ago (shark fins, tuna, ect.)
Click to expand...

Maybe, but the '59 Cadillac and the Cessna 310-B disappeared from the market
at about the same time-almost a half-century ago!
 
Wing tip Fence

captainron said:
My reasoning for the Mooney comparison is only that it is an airplane of comparable speed and power to what we are building, but they have always had a speed edge over similar competition in the "spam".
Click to expand...
This was a while back but this couger builder/pilot claimed slower Stall/landing speeds and slightly higher cruse at altitude- I think you're question is really on to something. I don't think there has been enough experimentation in this area with our non-laminar flow/short constant cord wings. I do believe the Mooney comparison is out of wing catagory but in the speed range. But still, your on to something- black art that needs further study :rolleyes:

http://www.chlassociates.com/Aviation/n93140.htm

Brad
RV6A
Finishing & Panel
 
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It just seems to me that if I don't have to power another 37" of wing span through the air, why should I do it just for style's sake? I'd rather haul the same weight in fuel, but without the drag penalty.
 
experiment

I hear ya Ron!
But that loss is a loss of wing area, and the tip design is (as everything in the aircraft endeavor) a compromise. But for me, reducing stall speed without affecting weight, cruse speed, safe flying characteristics, etc: is the name of the game- But this would mean a change of a flying surface that can affect everything- (including spin recovery :eek: !!) I think Vans has tested and tested and tested-
Intuition tells me there is something here- (but maybe my time would be better spent in a Sam James cowl??) Don't know, but I just wanted to say again- I think this an area that could use more study....Thanks for bringing it up!
Brad
 
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captainron said:
It just seems to me that if I don't have to power another 37" of wing span through the air, why should I do it just for style's sake? I'd rather haul the same weight in fuel, but without the drag penalty.
Click to expand...


If you're talking tip fences, it really wouldn't be very hard to fabricate a set that replaces the wing tips (assuming your wingtips are removable) - just for experiment's sake. But remember that along with that drag reduction comes a loss of about 15 square feet of wing area (a 15% reduction?), and that will raise the stall speed some - might be offset by the tip fence!

Reducing the wing area can also have some stability and control/ weight and balance effects, so you'd want to be pretty cautious in flight testing - but its probably in the realm of reasonable experimentation.

I'm a well-known hard-boiled skeptic, so I still think you'd be doing it for the fun of experimenting though....it's pretty hard to beat the optimization of Van's design (or the number of testing hours behind it!

Interesting idea.

Paul
 
Wing tip fence

Resurrecting an old thread to see if anyone has experimented with a wingtip fence or flat wingtip similar to Mooney? Years ago there was some discussion about a simple wingtip fence but never heard if anyone has tried it. If so, please share.
Thanks,
Cj
 
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