Wings? Square vs. Round tips.

[BSEC]

Wings? Square vs. Round tips.

Hey Folks,

A few of us will soon be ordering wings for projects and the square vs. rounded wings debate has started. I remember seeing the topic batted around here a few times but after searching I?ve come up empty handed. Does anyone remember when or in which threads this was discussed? I could?ve sworn someone had made a thorough comparison but I can?t find it for the life of me.

In talking around here, the general consensus seems to be that no one wants to get away from the standard round tip wing. However? Since folks are talking about going on amphibs. The extra wing / flap area seems to be the logical choice. Does anyone have experience flying both stock wings and Dakotas extended flap / aileron square tips on the same plane? I?d be interested in hearing what folks have to say.

Once again, any input is appreciated!!!

[pzinck]

Years ago Jerry Burr sent me some very nice test data on the various wingtips.I think hendricks ,demers,ferguson were all included.I will look for thre info.Maybe Jerry will chime in he has done lots of research and knows what all those things mean.The wing is a funny thing and changing it is like changing the weight of a supercub,it will have drastic effects on the way your cub feels.The cub i have now is drooped,squared,extended,aileron extended and vortexed.Boy she gets out real short when heavy.You would think this is the ultimate for a supercub right? Wrong. It all depends what you want.The piper stock wing is light on the controls turns nice,the visibility is good and gets off damn good heavy.The roll rate is much better with a stock wing in my opinion. I think the heavil modified wing makes your cub feel like a heavy 185 on the controls.It is so hard to reccomend any changes.You may gain a little something,but then you lose a little something.Try to fly both setups so you can decide whats best for you.Good luck, i have agonized over all these mod descisions at one time or another. I love my plane,but i just sold a stock wing cub,and i loved that one too.They felt like 2 different planes though.Too much mods and weight and you will lose the super out of the cub.

[RedBaron]

Great points pzinck and you're absolutely right.
I've got stock wings with little VG's glued on, and if I was to rebuild that's what I'd do. My buddy's got the leading edge cuff on his and VG's, but he's going to take the cuff off this winter during rebuild.
All that stuff just adds weight anyway....
My opinion on the wing works for me anyhow.

--RB

[T.J.]

If you want to go slow, long wings help. Do sail planes have short wings? No. Does the U2 have short wings? No.
Any increase in wing area decreases the wing loading. That has to help short takeoffs/landings. Unless, the increase in weight from the extended wing negates the decrease in wing loading.
I think I understand what I just said, I think.

[Crash]

I have to agree with pzinck on this one. I had extended flaps and wings for years and upon rebuild, sold the wings and purchased new stock ones. I like flying the Cub a lot better with stock wings. Lighter feeling all the way around. Plus they just look better. Crash

[Luke_theDrifter]

You could put ALL the do-dads ever made on a set of Cub wings, and you could make the longggggest Cub wings ever......and maybe, just maybe, you could slow it down a little more.

HOWEVER, the tail on a Cub ALWAYS starts to sink first at slow flight. That said, WHY do ALL of this work to the wings when nearly every aspect of a Cub's slow-flight performance revolves around the tail? (besides, its always nice to be thinking about tail )

I've seen the "square" tail feathers, can't remember what the claim to fame on them was, but I'm sure they're suppose to do something.

This is a slippery slope. If no one ever tried new and revolutionary stuff we'd still be in the stone age. On the other hand it is VERY rare that some mod truly makes the plane perform better. With modern technology it seems hard to accept that an airplane designed over 50 years ago still can NOT be significantly improved on from a flight performance view point.

Believe me, I've thought long and hard (for many years) about how to make the tail fly better at slower speeds. Of course for ever action there is a re-action. Its always a trade off. If you made a great big tail you'd solve the problem of the tail being the first thing to sink at slow flight. However then what would happen to the wonderful flight characteristic's of the famous Cub wing? Would the venerable Cub still have the traditional "mush", versus a break-over stall? Would there be some new, nasty, flight characteric's as a result.....probably yes.


Its hard to beat stock wings on a Cub. During short take off, landing, and slow flight contests you can see this time after time.

I do realize, and have seen, a very dramatical landing flare in a Cub w/ droop tips & extended wings, right to the point of stalling both wings and then quickly leveling off-thrusting forward, right before you tear the tail off by hitting the ground, however this is NOT an everday practical manuver, this trick is used to win the short landing contest.

I think its about 85%-95% more about who's driving, versus what type of do-dad you got straped on the wings.

Good Flying...>Byron

[Michael E. Butterfield]

I like the long wing on floats. The darn thing needs all the lifting surface that can be mustered to drag those things out of the water. Just my opinion, and we've all got one.mb

[Jerry Burr]

Hi Luke. You have an interesting observation of the Cub tail. I suppose two people can look at the same rock and see different things. When you slow a Cub down a bit and apply flaps and then have to apply forward trim to relieve the pressure, is that what you mean by the tail sinking? And do you mean that the wing is still flying and the tail is not? The only time I have ever seen a Cub tail stall (while lifting up and not down) was when it was loaded 500+lb over gross and loaded clear to the tail post. On short final the tail did in fact sink with full down deflection of the elevator. It was recovered with full power, but it was close. He was just a tad too slow. I have never seen this in a normally loaded Cub. Jerry.

[ground loop]

A very experienced, respected bush pilot told me that he was certain that the bigger flaps help.
I find it very difficult to intellectually defend that a wing with less lifting surface, less flap and and same amount of aileron with less leverage because it is closer to the airframe is the superior entity.
Can anyone form a credible theoretical argument why the stock wing has better flight characteristics?
As far as appearence, look at a bunch of older wings and see how the rounded ones look after years of use. Quite a few show dents and worn paint far more than the squared ones. They seem to survive wing cover wear and trees better.

[pak]

I was told, some years ago, by a well known cub pilot, that a lot of the benefit of the extended wing is lost due to the flex, in the wing, beyond the strut attach points. How's that for a run on sentence.
pak

[kase]

I fly around with a guy that has ext wings with plane booster tips. At lower elevations we are close to the same performance wise but above 5000 MSL or so he can really get off allot shorter and out climb me. Both have 160 hp with the same prop.

[BSEC]

I find it very difficult to intellectually defend that a wing with less lifting surface, less flap and and same amount of aileron with less leverage because it is closer to the airframe is the superior entity.

I'm somewhat in the same boat as you ground loop. From an academic standpoint it seems the square Dakota wings should give the best performance. That said I'm having a hard time finding a comparison where all things were equal.

I suspect the difference square wingtips /extended flaps and the added weight make to a light 800 pound plane would be much different than the difference noticed on a 1200 pound plane. Like anything else my question is probably mission specific and if there was any one "right" answer everyone would have the same gear.

From where I sit now it looks like...

Possible upside of the square tip wing is;
Improved short field performance.
Improved float operation.

Possible downside of the square tip wing;
Heavier feel.
Doesn't have the same look.
Could reduce useful load by as much as a case of beer.

To me the major downside is the possible heavier feel second to weight increase. However, if one was to assume the aileron had the same travel and was exposed to the same air, could you argue the control pressure should be the same with both wing types?

I really don?t want to deviate from the look and feel of the stock ?18 and I?m thinking a stock wing with VG?s will be close in performance to the square wing, but because the potential upside seems to outweigh the potential downside it requires consideration.

[Gunny]

BSEC - I have Dakota's square extended wing with leading edge slots and I love them. Slots vs. no slots I can't comment because I have never flown a no slot extended wing.

I will make this comment. If you are going with extended wings I would choose the Dakota's because you are not cobbling an extension on the wing but rather getting a wing that is built as a squared off wing from the git go - i.e. full length spars etc.

I don't notice any difference between my roll rate and the roll rate of my cub before the rebuild when it had stock wings and vgs. But then maybe I don't have enough experience to be able to notice a difference.

If you can get out this way you are welcome to fly my cub and see what the wings feel like. It doesn't feel heavy to me - it feels real solid especially slow on short final. Now some of that (maybe all of it) is the slots which I think are a massive safety enhancement - the stall/spin resistance is remarkable and if you fly the airplane you will easily notice that.

My best suggestion would be to fly the wings before you make a final decision. Good luck with your project.

[cubunltd]

If the ailerons are extended out to the wing tip on the extended wing, the roll rate does not suffer very much at all. it is when the ailerons aren't extended to the tip (like the Demers wing) that the roll rate sucks.



John

[Gunny]

If the ailerons are extended out to the wing tip on the extended wing, the roll rate does not suffer very much at all. it is when the ailerons aren't extended to the tip (like the Demers wing) that the roll rate sucks.

.....and incidentally, the ailerons are moved out to the wing tip on Dakota square wings.

[Jerry Burr]

Hi cubunltd. I think Ferguson's hot tips would be a better example of a bad situation. Demer cuts the spars and only has about 4 inches to the tip, while Ferguson has a whole bay plus the tip. Check the STC's. Jerry.

[cubunltd]

Yea, you're right Jerry. I forgot about those.

John

[ground loop]

I heard Penny Nixon (spin tester extrodinaire) say it is exceptionally difficult to recover a PA-14 with extended wings from a spin. So, spin recovery of an extended wing without a slot may be a disadvantage, but it may only be with 14's. Any spin expertrts have any comments.

[skysigns]

as far as long wings it all depends what you are going to use your plane for i had 2 cubs 1 with stock wings 1 with long wings the 1 with long wings i could pull a larger banner do to i could fly slower
the best way to gat a cub to perform is keep it light

[750XL]

any possible way to extend the ailerons and flaps out width wise and have them sticking out farther back

[Erik]

Typically people eliminate the wing root faring and extend the flaps to the fuselage. I think any extended wing should have extended ailerons. Yes it's possible as I have seen it. Cub Crafters use to have a modification to extend the ailerons back with the flaps. I here people that put that mod on end up taking them off.

[mvivion]

Erik,

I think the mod you are referring to is a kit to droop the ailerons with flap deflection. I didn't like this on the two Cubs I flew with the kit. It seems they tried to copy the Robertson concept as applied to a lot of aircraft, but they didn't do it quite like Robertson did, and it didn't work as well. It also made for some sporty stall characteristics.

I agree that if you are going to extend the wing, by all means extend the ailerons as well. For years and a couple thousand hours I flew a Cub with wings extended one full bay and droop tips, but stock ailerons. This was in Kodiak, and in turbulence the airplane was less than fun to fly. It did teach me to rely almost strictly on rudder for roll control, though .

On the other hand, that airplane would yard a load out of the water as well as any Cub I've ever met, and I'm sure the difference was the wings. That Cub eventually got stock wings, and it didn't get out of the water as well as before, in my opinion.

Floats and high density altitude are the real tests for wing area. Those are the venues where wing area really makes a difference.

I wouldn't argue stock wing vs long wing, but if you're doing long wings, by all means extend the ailerons as well.

I also disagree that the tail stalls in these airplanes. Now, there is some turbulence that can be sorted out with either the Boundary Layer strake or the VG's on the Micro kit, but this simply improves the airflow over the tail, some of which is disturbance coming off the flaps, I suspect.

MTV

[pzinck]

On the cub i have now i have droop ailerons.I will leave them on when rebuilding.I hated this mod for about 15 hours.At first i landed longer ev ery trip.Now that i am experienced with em(7 years or so) i kinda like em.When flying this mod your approach has to be real real slow.The sink rate is incredible.If you come in hot,you just float down the runway.The key with this is to set up a real slow final and you have to give it a burst of power right before the flare or you will hit kinda hard.I dont beleive you could judge this mod in flying it for just a few hours,and v.g.'s are a must. You dont have much aileron authority with full flaps on this one in a crosswind.I just adjust accordingly in strong gusty crosswinds.2 notches are doable in bad crosswinds.On final i may take a notch off if roll control is compromised.I always dump flaps immediately when i hit the ground.Lots of people dont like robertson stol as well,but i like it on the cessna.Once in a while if i am in practice and i fly real slow approaches other pilots have just watched and shook their heads and ask how do you fly that thing so slow.One said from a distance that thing looks like a spider coming down a web.You can actually fly this thing real slow kick the rudder and you have done a 180 in about fifty feet if turning into a head wind.

[Yard Dart]

I think it still comes down to your mission. If going to fly heavy or floats out of short lakes maybe extended wings are the way to go. But don't complain about roll rate or you may think you are flying a husky ! Yard Dart

[T.J.]

zinck:
Does your Cub have a seperate handle for the ailerons? Most I've heard about were connected to the flap handle. I'm putting a seperate handle for droop ailerons on the right side of the seat.
Along the same line.......Why does a Cub have Ailerons stops? With the droop ailerons, why not extend the aileron travel by adjusting or removing the stops?
Thanks:

[S2D]

any possible way to extend the ailerons and flaps out width wise and have them sticking out farther back

check with Wayne Mackey

[Jerry Burr]

TJ. Before you start on two handles send me your e-mail address. Trust me, it's not a good idea. Jerry.

[pzinck]

T.J. my aileron droop is controlled by the flap handle.The pulley system is pretty simple,all it does is loosen the top aileron cables and tighten the lowers.My buddy was working on a homemade system for an experimental cub,i dont know how he is making out.I ended up getting a good deal on mine years ago from a canadian that sold some of cubcrafters parts for them.I dont understand why people are so hostile to this mod? My cub definitely flys slower than the average cub.Maybe people are scared of it like some are afraid of robertson stol.I love robertson stol as well and dont find it all that difficult to fly in crosswinds.

[mvivion]

pzink,

It may have to do with the way they're installed. The ones I flew had really nasty stall characteristics. On one of those, they removed the kit, and the stall became normal. It could have been the way the kit was rigged, though.

The one thing I don't like is that the ailerons keep deflecting more with more flap deflection. On the Robertson kits, when you go to max flaps, the ailerons actually reflex some, giving you more aileron control at max flaps.

MTV

[pzinck]

My Plane has very docile stall characteristics,in fact it mushes more than anything and you have to work to get it into a stall.This could be because of the combination of the other mods though.Was the cub that you flew equipped with other mods,or just the droops? I have a suspiscion that bigger horsepower helps these stol mods as it helps overcome some of the drag incurred by longer drooped ailerons and such.I know this wouldnt help on power off situations,but on takeoff it is able to pull the plane harder and thru the extra drag.My plane is almost impossible to stall power off with the extra weight up front.It seems like you have to give it power to get high enough angle to get her to drop.