Any idea why winglet type (raised tips) devices aren't used on many (if any) small GA aircraft. My Grandfather always had a sour taste in his mouth about droop tips for some reason, and he thought it was great when he saw the lazair ultralights and their raised tips. They should theoretically, also hinder the tip vorticies. Any merit to this? Any aeronatical types, please chime in...

First thing that comes to mind is how bad it would suck trying to pull the covers on over winglets.

A true Whitcomb winglet is an airfoil section of wing turned up and at an angle of attack that takes advantage of the air moving inboard near the leading edge that is trying to fill the low on top of the wing while directing the air that would be going spanwise outboard at the trailing edge and directing it aft. There still is a vortex but it is at the top of the winglet and much smaller because the tip has a smaller cord. That captured and directed airflow by the winglet can have a lift vector that points forward in the direction of flight. Whitcomb Winglets on the Long Eze are effective at certain wing angles of attack and as you reduce that angle of attack when going faster the winglet lift vector moves aft creating drag. Long Ezes wont win at Reno. I think the style upturned wing tips would be more aesthetic than functional. With the Cessna droop or super droop I believe that it is only capturing the air that would travel spanwise outboard. The high pressure air would still rush inboard on the top of the wing but from a lower waterline. That air would have to travel further and the vortex would be delayed recovering a section of wing for lift. I also believe the function of the Horner style tip squirts the high pressure spanwise flow out away from the tip moving the vortex out and recovering wing area.

avgas wrote:Any idea why winglet type (raised tips) devices aren't used on many (if any) small GA aircraft.

No comp class glider is without them, and of course they are used on a lot of small GA planes.

I used CFD (SW Flow) to look at what a winglet would do for a C182. Way too much time invested in it, frankly, but I was able to simulate a drag reduction of around 9% at Vy. This was pretty exciting- it worked out roughly the same as having 8 hp more available climb power in the 182, which adds up to 95 fpm more climb rate at a 2800lb gross.

Unfortunately, at cruise, the simulation also inevitably showed a reduction of 5 mph or so. Perhaps some noodling could reduce the cruise penalty, but this seems a bit less than real-world results with sail planes as it is, so the cruise penalty could be higher in reality. For short flights, estimated flight times were pretty much a wash (4000' climb, 100 nm dist). For longer flights, the cruise penalty starts adding up.

The wing moments were also quite a bit higher...not as bad as adding span like the WingX mod, but still significant. For all the expense of creating and certifying winglets, you could probably just as easily hang a larger engine up front at overhaul time and come out ahead price-wise,cruise-wise, and headache-wise.

For low wing loadings operating at high AOA (sailplanes), or for high wing loadings where the design can be tweaked to raise the induced/parasitic crossover drag speed to reduce the cruise penalty (large biz planes), it seems to work. I'm just not sure yet that it makes sense for most of us in between.

I have seen Winglets for the Cessna 188 and 337s Always wondered how well they did. Couldnt find any info on them and wished I had something for my Skydiving 206s that spend 90% of their time climbing.

In my Long eze I wanted to, but never did, create a winglet rudder reflex system for flights at lower wing AOAs and at higher speeds. After the initial test flights in that aircraft one winglet was making more lift than the other pushing the ball to one side. The book fix is to shim the opposite winglet rudder out pushing the aircraft straight. I had 1/4 inch deflection on the winglet rudder and on those glass surfaces you cut the rudder from the winglet that deflection really caught your eye. Dick Rutan flew in one day and I was looking at his Blue Long Eze and noticed he reflexed one and deflected the other. Sanding block and 5 min later 1/8 out on both sides and it wasnt noticeable. That gave me the idea.

courierguy wrote:

Battson wrote:

courierguy wrote:I am installing Hoerner type tips when I pull my wings to put in larger fuel tanks in a week or so. They seem to work, at least I've never heard them dissed real bad... but mostly they look cool, don't block viz like droops, don't hurt obstacle clearance, and I know a guy making them for my type plane.

Plus my factory supplied ones (non hoerner, non droop, more just cosmetic to pretty up the end of the) are trashed, some one keeps sneaking into my hangar at night and working them over.

Got a photo?

Not that I can find right off, I'll opost when I get them on, plus any difference if any in performance.

Or did you mean pictures of my boogered up ones? Ain't pretty......

Hey Courierguy. Just wondering if you have flown the hoerner's yet. Very curious on the results