Droop tips

[Ironman Al 35]

Can anyone tell me what the advantages to droop wing tips is? I see there are some for sale here from TJay. Why dosent every one use them?

[EDMO 1078]

The Avid kits come with a different style of tip which was non-removable, but they can use the Kitfox droop tip or the Hoerner style tips, and each style can be made removable.   The early Kitfox kits came with the drooped tips, but when they changed the ribs on the Model 4 or 5, they started including the Hoerner tips, the same as on their Speedster shortwing model.  One guy had both kinds of tips for his Kitfox - It may have been a model 4 - he made them removable, and reported that his plane performed the same with either kind of tips.  Kitfox does not offer the droop tips in their catalog now.

Cessna and others used some aftermarket huge droop tips, and some of the people who had them swore that they greatly helped takeoffs and slow-speeds - Others swore AT them because they blocked visability or they bumped their head on them!  I have flown a Cessna 182 with regular tips, and another with the drooped tips, but I can't make a comparison because the one with droop tips had the Robertson STOL kit and it really got off the ground quicker.

EDMO

Edited 27 Jan 2016 by EDMO

[Dusty 126]

Can't comment on the performance at this stage,but my 4 with std wing tips  gives a smaller blind spot in the pattern than my droop tip 3 

the droop tips definatly look cooler

[EDMO 1078]

Can't comment on the performance at this stage,but my 4 with std wing tips  gives a smaller blind spot in the pattern than my droop tip 3 

the droop tips definatly look cooler

The Cessna 210 tips I am using are what I would call semi-drooped - not as big as the ones on the Kitfox or  aftermarket 172/182.

EDMO

[Fly-n-Low 181]

Hype. How much weight does it weigh vs benefit?

[EDMO 1078]

Hype. How much weight does it weigh vs benefit?

I believe my droop tips off of the Kitfox 2 are heavier than the Hoerner tips, and probably about same weight as the 210 tips.   There is not a lot of weight differences between them.

TJay's droop tips look like they would be lighter than mine, and probably the same as the Kitfox Hoerner tips.

The benefits are about another 18 inches of wing on each side.  3 feet of wingspan is a lot, and also changes the aspect ratio of the wings...(span divided by chord)...which affects lift/drag ratio.

EDMO

Edited 28 Jan 2016 by EDMO

[EDMO 1078]

Being one who "seldom goes with the standard designs",  I have wondered if the droop tips might be more effective if you mounted them UPSIDE-DOWN?  Just look at the tips of the modern jets and you will see the winglet tips sticking UP from the wing, which increases the effective wingspan more without widening the plane, which makes a better aspect ratio, etc.

And look at the photo of the white plastic pusher that Larry posted in "Modifying a B model cowling" - all 4 tips point up!

OR - Do you think that I should call Rutan and Boeing and tell them that they are wrong? 

EDMO

Edited 29 Jan 2016 by EDMO

[lostman 198]

I have tips on my Teenie Two that are turned up for the same reason all the ones Ed mentioned above do. They are all low wing aircraft. 

From my studying of the NASA reports on tips the droop tips are the best you can do as far as they tested. There is a lot to it though. Things like the angle and amount of the curl, etc. When I built and installed mine I picked up 6 knots of airspeed, verified repeated. Plus lost almost 3 MPH on the stall. Pretty big difference if you ask me. The one thing I can't measure is the lack of yaw I have. I don't know if it's just that I think it's better or that it really is. That's a tough one to test on my little plane. It didn't need a lot of rudder to start with and now I can run the plane from 90 degree bank right to left with hardly any pedal input at all and no dutch roll whatsoever. It made a fun plane even more fun to fly.

Of course your results may vary but I intend to do the same thing to my Sonerai II when I get to that point. I personally like the looks of them better as well. 

My mom and dad's Cessna 172 has huge STOL droop tips on it. I fly it from a field elevation of 4650'. It has NO stall. I mean it will flutter all the way to the ground. Of course I wouldn't land it that way but I have consistently landed with three people at and indicated 45 MPH. It's a blast!

Just my experience with tips. 

[EDMO 1078]

Just throwing in a couple of tidbits to add to what Lostman wrote:   In design, the main two differences between low and high wing aircraft are, that low wings need more dihedral, and the vertical stabilizer has to be taller on a high wing plane.

I don't know that winglets can only be used on low wings - or why they couldn't be used on high wings, except for hitting things, like the top of hangers, etc.

EDMO

Edited 30 Jan 2016 by EDMO

[lostman 198]

I was thinking about this some more this morning. I realized that years ago the crop duster I flew (A Cessna 188B Agwagon), had droop tips. It was about the only low wing airplane I can think of that has them that droop down instead of turning up. It would land fairly slow as well, but it also had a STOL setup on it because we were routinely flying with a density altitude of around 7,500. The field elevation was 5,600. 

Basically it can be done, as long as you have the clearance. With the dihedral and wingspan of the Agwagon it had a lot of clearance still. Besides, it's not like we were landing it (intentionally) in rough terrain.