Mackey Slats on Round Tip Wing
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Dave Calkins
Registered User
Anchorage, Alaska
Not sure if I'm logged in.
But I'm sure that if you put slats on that round tip, it will do things that other round tip wings won't/can't.
If you haven't flown slats, you oughtta find somebody who'll let you fly their bird. That goes for anyone reading this.
With slats, the wing keeps flying at very high angles of attack that are unbelievable. They are easy to fly once you figure out that getting the nose up high and adding power is a "new normal" regime.
Dave Calkins
Registered User
Anchorage, Alaska
I don't know of any round tip Cub wings with slats, but if I had a round tip experimental Cub I would not hesitate to install slats on it, even if it was only half the wing, say, from the lift strut out to where the tip bow starts.
Seriously!
Seriously!
Olibuilt
MEMBER
Montreal, Canada
I bought a used set of slats for my square tips super cub project. A few weeks ago, I tried putting them on my white cub (round tip). But they are too long for the wings. The last bracket would end up in the round tip.... Will wait untill the project is completed, and the white cub will not have 100 holes in the leading edge...
Dave would there be any "cantilever" problems associated with a half wing solution? I have heard shouldn't put lightening holes inboard of the lift struts because of downward pressure between the strut attach and the fuselage. If the outboard section was producing lift to a much greater degree than say washout (in?) would that/could that over stress the inboard end when it (inboard end) was stalled?
Dave Calkins
Registered User
Anchorage, Alaska
cantilever problems? No, not in my opinion.
Our Cub wings stall progressively from root to tip, hopefully.....especially if we have the flaps deployed..........so, though in theory a loading problem of the outboard portion could be a problem with outboard slats alone, my gut feeling is it's a non-issue. Maybe some engineer can jump in and tell me how it'll never work
Dave Calkins
Registered User
Anchorage, Alaska
.....and then I'll mention the Stinson 108's and all the other fabric wings with an outboard slot or slat
I have a round tip 13 rib cub wing with leading edge slats and performance STOL flaps, it is a very stable and forgiving combanation. Landing speeds in the low 30's on the mains. I still need to experiment by pulling the slats off to see what they are really doing for the performance of the wing.
Thanks for the input...I would be interested in knowing the landing benefits... I am also interested in the safety element in terms of spins and such...
Dakota Coyote in Spearfish has the slat on his wings and they are one piece on each wing....
Wingwrench
Registered User
Lakeland, Fl
I'm finishing one up but it will be a couple months before it flys. Round tip Smith Cub w/ I0-360.
Little_Cub
MEMBER
Palmer, Alaska
Has anyone placed slats or slots on a J-3, PA-11 or other light bird?
Also curious about (like Dave said) >if it was only half the wing??
Also curious about (like Dave said) >if it was only half the wing??
If you happen to have any pictures of your wings and flaps I would certainly be interested....or some link to ones like yours.
Thanks!!
We're thinking of building an LSA Sport Trainer and my son and I have been talking about buying Zenith 750 slats and incorporating them into the wing during construction using some type of bracket attached to the spar extending thru the leading edge. I'm pretty sure I want to build a wood wing for weight savings and if I use the slats I may feel safer using an aluminum spar that I can rivet to rather than wood with bolts...just not sure yet.
The concept is sound and that is proven technology, I'm just not exactly sure how to attach them or at exactly what angle they should be set at to achieve best lift at high angle of attack to keep the air on the top of the wing. My son thinks the right answer is to just buy the 750 wing and slats a put it on the Cub fuselage. It would save time and effort but I don't think weight....and a Cub wouldn't look right with flaperons but it would probably work pretty well.
We've also considered VG's on the wing behind the leading edge running maybe 1/3 of the wing from the root out.
I can't afford a helicopter but I'd like to get close.
The concept is sound and that is proven technology, I'm just not exactly sure how to attach them or at exactly what angle they should be set at to achieve best lift at high angle of attack to keep the air on the top of the wing. My son thinks the right answer is to just buy the 750 wing and slats a put it on the Cub fuselage. It would save time and effort but I don't think weight....and a Cub wouldn't look right with flaperons but it would probably work pretty well.
We've also considered VG's on the wing behind the leading edge running maybe 1/3 of the wing from the root out.
I can't afford a helicopter but I'd like to get close.
I have not flown this wing without the slats and Performance Stols flaps but have over 9,000 hours in a standard cub. This wing is very stable, when stalled it will not try to spin at all and will just fall out in front of you, stall speeds are reduced considerably, airspeed does not work correctly at the angle it stalls but GPS will show between 23 and 25 mph. Wheel landings are very easily made at 33 to 35 mph with great visability. Not an expert but it is my feeling the flap helps the leading edge perform better as it did with my SQ2. Long story short the added weight is worth the added safety if you are working your airplane low and slow as I often do.
About 25 years ago I had a Horton STOL kit with stall fence and leading edge cuff put on my 172 and while it did not produce numbers like your Cub it did make it a lot safer plane and it did the same "break straight forward" stall and was well worthwhile. I'm looking to duplicate that on an LSA Cub that will be fun and safe to fly slow. I'm pretty impressed with that wing set up.
courierguy
MEMBER
Inkom, Idaho
I saw this trailer full of wing parts along with some slats recently. A collection of different parts owned by a guy who has welded for various kit plane companies over the years, and has made a few one offs that are somehwere inbetween a Cub and a Rans S-7, sort of....not really either though.
How they fit on the bird called "The Outlaw"
The Outlaw: 164 sq ft wing on a 700 lb airplane, never made it into production but it flew pretty sweet.
Playing around with the slats on my S-7... they failed the lightness test though: When I dropped one it fell to the ground, so they are not going on my plane, I'll continue to keep it simple and light, I can already get into places i have a hard time getting out, so unless I go with more power (mre weight and money) AND slats I see no big advantage, I already see numbers like BRQ1 reports.
I got to fly that plane a few times when we were over in Douglas, it was a pretty cool little airplane. It was hard to get in and out of but it was quick and nimble. Sombody put Wayne's slats on it at one point but I never flew it in that configureation.
Dave Calkins
Registered User
Anchorage, Alaska
Courierguy. "....AND slats I see no big advantage, I already see numbers like BRQ1 reports.".
I have to say to you that slats aren't about "...the numbers...".
Have you flown them? If you have, then your choice to not purchase them is informed.
I have to say to you that slats aren't about "...the numbers...".
Have you flown them? If you have, then your choice to not purchase them is informed.
courierguy
MEMBER
Inkom, Idaho
No, just going by what the head honcho of Backcountry Cubs, who flies a S-7 for coyote hunting. He said they required more power (to fully exploit what they can do) then the stock 100 hp Rotax delivers, so he took them off. It just seems that most with slats have a lot of hp to play with, probably why the J-3 and types isn't seen with them much. Even the lsa types using them are going with a souped up (140 horse) Rotax along with cs props. Thus my statement: more money, more weight., I don't need them for low ;speed handling as the micro vg's take care of that. I was "slat happy" until actually laying eyes and hands on them. 14 lbs. and lots of extra hardware. As others here have mentioned " nothing flies better then a LIGHT cub" and "how come they aren't winning Valdez?"
O
O
Dave Calkins
Registered User
Anchorage, Alaska
Well, I hate to be a smart aleck, but I'd love to point out that maybe you should fly them.
Also, I'll bet you a piece of pie that I know of 5 slatted birds that will turn 180 degrees in a span and a half.........while at minimum controllable airspeed.
......I've never flown a Courier, but I know a couple of guys who know a guy who has flown one. Maybe I'll ask them if the VG'ed Courier can turn sharper and safer.
I'm Mostly joking here.......
but let me add............Slats ARE winning Valdez, as I recall, from standing there and watching them.
.......but slats on a heavy or loaded airplane REALLY show what they do.
........and horsepower showcases them in only one regime (super high angle of attack drag-it-in approaches)
I love 'em.
Also, I'll bet you a piece of pie that I know of 5 slatted birds that will turn 180 degrees in a span and a half.........while at minimum controllable airspeed.
......I've never flown a Courier, but I know a couple of guys who know a guy who has flown one. Maybe I'll ask them if the VG'ed Courier can turn sharper and safer.
I'm Mostly joking here.......
but let me add............Slats ARE winning Valdez, as I recall, from standing there and watching them.
.......but slats on a heavy or loaded airplane REALLY show what they do.
........and horsepower showcases them in only one regime (super high angle of attack drag-it-in approaches)
I love 'em.
Dave Roberts
MEMBER
Eastern Montana
After getting a ride in a slat equipped cub with Wayne Mackey a couple of years ago I would definitely put slats on my cub if it were experimental. Maybe not so much for the numbers but for the safety factor. And like Dave said,"180 degrees in a span and a half", that really gets your attention.
Dave
Dave
68Papa
FRIEND
Chugiak, Alaska
BR; Are your Keller flaps on your 13 rib Cub standard length flaps? Extended to the fuselage? I'm assuming the flaps (keller) on your SQ2 have been lengthened as well as your ailerons??? I know it's apples to oranges, but if everything is extended on your SQ2, I'm wondering what the performance differences are between the two wings. How noticeably different are the two wings? I would also be interested in hearing the differences in performance once you pulled the slats off. I don't claim to be anything except a guy who drives a cub every now and then, but it would seem to me that Kellers flaps and Mackeys slats counter-act each other?????? I'm not sure if I'm accurately putting my thoughts into the correct wording, but the flaps are reported to give you a flatter deck angle, better visibility and slower landing speeds. The slats seem only to be effective once the nose is pointed up into the air and some power is added, thus allowing the plane to manuver / land and depart at much lower speeds as we see in the videos. Am I wrong? Somebody please feel free to educate me on the subject. Thanks.
Roger
skywagon8a
MEMBER
SE Mass MA6
My 2c, I have not flown a Cub with slats or with Keller double slotted flaps, however I have many 1,000s of hours with bigger airplanes which have both devices.
Slats do not increase lift. Slats change the air flow over the wing in a manner which causes the air to remain attached to the wing at a lower speed. Thus supporting the same weight with less air flow. Since there is less air flow the wing bending moment will not increase thus will not increase the bending loads on the spar. An engineer can likely explain this more clearly than I.
The slats complement the slotted flaps. The Keller flaps are flaps with a slat on the leading edge. Separate the two devices in your mind momentarily. Think of the Keller flaps as a small wing with a slat on it. Then combine the two. You must think about the angle of attack of the wing not the attitude (deck angle) of the fuselage. With both of these devices in use, the attitude of the fuselage will be more level at the same time that the angle of attack is high. The use of both of these devices will minimize pitch trim changes. Perhaps even cancel each other out. My guess is that a Cub with both of these devices will land at the same attitude as a unmodified Cub albeit at a much lower speed.
Slats do not increase lift. Slats change the air flow over the wing in a manner which causes the air to remain attached to the wing at a lower speed. Thus supporting the same weight with less air flow. Since there is less air flow the wing bending moment will not increase thus will not increase the bending loads on the spar. An engineer can likely explain this more clearly than I.
The slats complement the slotted flaps. The Keller flaps are flaps with a slat on the leading edge. Separate the two devices in your mind momentarily. Think of the Keller flaps as a small wing with a slat on it. Then combine the two. You must think about the angle of attack of the wing not the attitude (deck angle) of the fuselage. With both of these devices in use, the attitude of the fuselage will be more level at the same time that the angle of attack is high. The use of both of these devices will minimize pitch trim changes. Perhaps even cancel each other out. My guess is that a Cub with both of these devices will land at the same attitude as a unmodified Cub albeit at a much lower speed.
So, there would be no reason to increase the angle of incidence of the wing with the Keller flaps?
I'm just a poor retired guy trying to build a light weight cub that will perform well and I keep coming back to fix leading edge slats and a wing set at maybe plus 4 degrees and hope to be able to see the ground and land at <30 mph in ground effect. Is that possible with 40* standard flaps?
I'm just a poor retired guy trying to build a light weight cub that will perform well and I keep coming back to fix leading edge slats and a wing set at maybe plus 4 degrees and hope to be able to see the ground and land at <30 mph in ground effect. Is that possible with 40* standard flaps?
skywagon8a
MEMBER
SE Mass MA6
In my opinion, the stock unmodified Cub wing has the ability to function very well if mounted at plus 4 degrees without any other modifications whatsoever. If I were to add just one modification it would be the slotted Keller flaps.
A round tipped stock 13 rib wing with standard flaps or should it have extended flaps and ailerons and maybe a little bigger horz. stab.? IF I'm building the wings anyway, I might as well take advantage of the larger surfaces. Does that make sense?
skywagon8a
MEMBER
SE Mass MA6
I like extended long flaps with the ailerons going out to the squared off wing tip. This makes for better low speed lift with minimal drag increase. I have not found a need for larger horizontal tail surfaces. Perhaps more vertical tail area would be good, for floats anyway.
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