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Slats and other mod questions

bda said:
I have been hearing rumors of someone building helio style slats for a cub wing - does anyone have real intel on this?

Or am I going to have to build them myself?
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That would be me......................... Unless there is someone else that I'm not aware of. If so, I would love to work with them. I have been working on this for years.

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"Southern Aero" Please post pics and details here so we don't have to subscribe to a Facebook group and search through endless group posts to find relevant data. Thank you.
 
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Perhaps it's just the picture angle. The gap at the slat trailing edge appears to be much greater than the leading edge gap. Is this the same ratio which the Helio uses? In my mind this will slow down the exit velocity, increasing the turbulence over the upper camber, when it ought to be speeded up in order to hold the boundary layer tighter to the wing trailing edge. Won't this increase the wing's stall speed?
Southern Aero said:
View attachment 107301
Click to expand...
 
brownbear said:
Skywagon, I am not sure but I think ratio on the Helio courier is four or 5 to one.
The largest gap on the bottom.
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That's what I was thinking. The whole idea is to accelerate the air flow over the upper camber by changing high pressure volume to low pressure velocity.
 
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bda said:
southernaero.net
Click to expand...
Better Picture, thanks.

img-1680.jpg
 
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skywagon8a said:
Perhaps it's just the picture angle. The gap at the slat trailing edge appears to be much greater than the leading edge gap. Is this the same ratio which the Helio uses? In my mind this will slow down the exit velocity, increasing the turbulence over the upper camber, when it ought to be speeded up in order to hold the boundary layer tighter to the wing trailing edge. Won't this increase the wing's stall speed?
Click to expand...
The slats are just "stuck" on there for the pic, I had just hung the wings for the first time to make struts. The target for the slot seems to be about 1.25% - 1.5% chord, there is not a lot of info on this ............................. you just have to go measure existing wings. I did copy Helios's travel of 12° - 13°. The theoretical radius is about 26" below the wing. They are adjustable for testing/tweaking purposes. With slats out the effective wing area is increased +/- 10% , depending on how far they are extended, and the wing NOW becomes a highly underchambered section WITH a slot. Combine this with a good set of flaps and I would expect Helio type characteristics or slightly better with less wing loading. Pic below is when they were first fitted, again nothing adjusted. I am after flatter, tail high, safer approaches and still being able to "tote the load".

I grew up around the Helio and even flew some with Larry Montgomery ................. for some of you old guys to remember. I always wanted one but figured I could never own one so decided to modify a Piper which is what Helio started with.

1720882085844.jpeg
 
That trailing edge gap def (looks) too large, but I am excited to see this!! Good work!

What do we need to do to get it flying??

What flaps are you planning to use?
I have found that the slats on my SuperStol push my AOA so high that it takes a HUGE flap to flatten it out - so big I had to re-engineer the wing to brace for it. My 3rd version flaps are over 30" chord(extended) - double slotted for articulation so that when up, there is less added chord.

I believe it was Skywagon that posted the Abbot Aero library link for slat testing. Very good info.
https://www.abbottaerospace.com/dow...d-full-span-slots-with-ailerons-and-spoilers/

Another good one is:
commons.erau.edu/edt/301/
 
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bda said:
That trailing edge gap def (looks) too large, but I am excited to see this!! Good work!

What do we need to do to get it flying??

What flaps are you planning to use?
I have found that the slats on my SuperStol push my AOA so high that it takes a HUGE flap to flatten it out - so big I had to re-engineer the wing to brace for it. My 3rd version flaps are over 30" chord(extended) - double slotted for articulation so that when up, there is less added chord.

I believe it was Skywagon that posted the Abbot Aero library link for slat testing. Very good info.
https://www.abbottaerospace.com/dow...d-full-span-slots-with-ailerons-and-spoilers/

Another good one is:
commons.erau.edu/edt/301/
Click to expand...

I am familiar with those. My problem is I do not want to use the USA 35B or the similar Clark Y that both these links use as they are already high lift airfoils. I want something that is better for generating high lift with the slats and flaps and then cleaning up for speed (relatively!) and efficiency. Originally I was going to use the 23012 as the Helio uses but if that was used I would have to raise the front attach point over an inch to accommodate the AOA needed for that section with the drooped nose radius. An engineer friend suggested the 2412 modified over the 23012. He laid this out for me on a spread sheet (from TWS) comparing the the USA35B and the 2412 and the numbers were real close, so I ended up going that direction. I only have one airplane with my wing flying and it is not slatted but proves that this can be a "bolt on" for a Piper type. No W&B change, no strut change, no trim change ................ just less trim was needed. As most of you have experienced, the faster you go in a Cub the more you crank down trim.................... to the point you run out of trim, especially in the higher HP versions. The only thing that has to be changed is the birdcage and the root fairings. Badlands also uses this section with great success so I believe I'm on the right track.
 
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Cessna's 2412 works well, should be a good wing. The 23012 can have a LE discontinuity but slats/VG's help reduce that. Plus, it takes more incidence to perform as noted.

Gary
 
Bill Rusk said:
Welcome to the SC.org forum, Flyboy8.

Slats and/or slots can be great things depending on your mission. Slats tend to extract a speed penalty at cruise and slots tend to be heavy. Both work well at high AOA and do seem to add a safety factor.

Experimental Cubs may have awesome quality or "not so much". It depends on the builder. Also the quality of the paint job is not always indicative of the quality of the rest of the build. I have seen some wonderful paint jobs but what was under the paint was a trainwreck. I have seen some paint jobs that looked like they were done with a latex house paint roller but the structure and all that really mattered was great. The Buyer Beware" sign applies to all aircraft but perhaps more so to experimentals.

There is a lot more flexibility to modify and tweak an experimental. You can do your own maintenance if you are so inclined. Be sure you get a knowledgeable guy, like Sean Tubbs, from Caldwell Idaho to help you with a pre-buy inspection.

Best of luck
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Bill,

Your statement isn’t correct. If you buy an experimental you can’t do your own maintenance any more than you can do on a type certified airplane. The builder is issued a repairman certificate for the particular airplane otherwise it takes an A&P.

Charlie
 
Charlie Longley said:
Bill,

Your statement isn’t correct. If you buy an experimental you can’t do your own maintenance any more than you can do on a type certified airplane. The builder is issued a repairman certificate for the particular airplane otherwise it takes an A&P.

Charlie
Click to expand...
I thought the owner can do any maintenance or modifications on an experimental, the only thing that requires an A&P or repairman's certificate is to do the annual condition inspection.
 
One of the keys to the Helio Courier is the Stabilator and anti serve tab system. I think without this type system, the likelihood of stalling the tail at high angles of attack capable due to to the Slat/flap combination becomes likely. I also think that without the roll control offered by the differential spoilers, it is likely that the ailerons will stall...

I have owned and flow Couriers and emulating their performance, in my mind is not easily done. Dr. Otto Koppen designed a pretty unique airplane that fit certain missions. My fat cub has slatted wing and I like it...it flies similar to the Helio, but not the same.

I guess what I'm saying is be certain to think through exactly what you are designing and make sure it ticks off all the boxes you want. The Courier is a lot more complex to own and maintain and a handful to push around on the ground at times...but it is amazing.

Steve
 
FatCub300 said:
One of the keys to the Helio Courier is the Stabilator and anti serve tab system. I think without this type system, the likelihood of stalling the tail at high angles of attack capable due to to the Slat/flap combination becomes likely. I also think that without the roll control offered by the differential spoilers, it is likely that the ailerons will stall...

I have owned and flow Couriers and emulating their performance, in my mind is not easily done. Dr. Otto Koppen designed a pretty unique airplane that fit certain missions. My fat cub has slatted wing and I like it...it flies similar to the Helio, but not the same.

I guess what I'm saying is be certain to think through exactly what you are designing and make sure it ticks off all the boxes you want. The Courier is a lot more complex to own and maintain and a handful to push around on the ground at times...but it is amazing.

Steve
Click to expand...

I have been working on this in one form or another for well over 20 years, it has evolved, and I 100% agree with you on the stabilator. I have given it much thought and actually have it drawn up with the monocoque tail also. BUT I eventually decided to go with the "Stretched Pacer" configuration as it is close(r) to where the Helio started. The early Helios were fabric covered aft of the cabin and I have always been a "tube and rag" guy.

Spoilers are a necessity as with the Helio ........................... that is what in C in C/STOL stood for. ..................... controllable. This wing will have them too, just trying trying to cram all these features in a Piper style wing has been quite a chore.
 
One of the things the original Helioplane taught, was the need for an unusually tall vertical stab and rudder, due to a normal sized one being blanked out completely at high angles of attack.

The lightest Courier I owned, which was a 391B, was a delight to fly. It did everything well, except go fast.

What you are doing looks like it will be a fun and worthwhile project in the end. I understand how it all sounds easy in the beginning, but by the time we complete a real project, we've earned our stripes in the art of making all the simple stuff actually work in the real world.

I don't see spoilers or "interrupters" as Helio coined, as being overly complex, but they will pay dividends in a crosswind one day.

Now if you could just sort out a 108" aeromatic prop, belt reduced to your engine, you'd almost have a Helioplane!!!

Good luck and enjoy the ride!!!

Steve
 
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FatCub300 said:
One of the things the original Helioplane taught, was the need for an unusually tall vertical stab and rudder, due to a normal sized one being blanked out completely at high angles of attack.

The lightest Courier I owned, which was a 391B, was a delight to fly. It did everything well, except go fast.

What you are doing looks like it will be a fun and worthwhile project in the end. I understand how it all sounds easy in the beginning, but by the time we complete a real project, we've earned our stripes in the art of making all the simple stuff actually work in the real world.

I don't see spoilers or "interrupters" as Helio coined, as being overly complex, but they will pay dividends in a crosswind one day.

Now if you could just sort out a 108" aeromatic prop, belt reduced to your engine, you'd almost have a Helioplane!!!

Good luck and enjoy the ride!!!

Steve
Click to expand...
The original fin is hanging on the fuselage at the moment but not yet mounted. I have given some thot to taller versions and also fin offset and zero thrust engine mount. I have a Maule mount just in case! To do that I would most likely have a fin that was not sharing covering with the fuselage. TBD.

I have the "spoilers" worked out but not yet built. I do have the bearing mounts made and the rest planned for. I just removed the wings from the fuselage for more work on them including spoilers. The spoilers can't work as on the Helio because of the internal wing structure. I have that worked out and will be able to use them for "parking" in windy conditions and possible descent control.

I know the bigger the prop the more efficient it is but I have to draw the line somewhere. No geared engine! Well, not now anyway.
 
Cessna's Caravan employs spoilers. Inboard of and raises up with aileron. Roll actuator works both.

Gary
 
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BC12D-4-85 said:
Cessna's Caravan employs spoilers. Inboard of and raises up with aileron. Roll actuator works both.

Gary
Click to expand...
That's kinda like the Helio. The Helio's is on a rotating "drum" that works continuously with the aileron. I don't have room for that in this wing with the brace wires. Wish I did.
 
Check out the SuperStol spoilers, they are connected directly to the ailerons, and work great! I have "aileron" control in the low 20s.

As for the Vert tail - Yaw is what determines how slow mine can go. I can keep adding power and keep slowing down (pulling the nose up) but when I run out of rudder it's time to land. Mine needs more vert tail.
 
I flew a Superstol last year and I agree...yaw is a weak point. I will say that I have seen two landings with a Super Stol that seriously got my attention...watching from a distance, they both looked like the tail stalled, as the airplane pitched forward drastically, as the power was brought back, right on short final

Fortunately they were close enough to the ground that the result was just a good smack on big tires, but it did get me thinking about tail's stalling.

Again, the Stabilator solves the high angle of attack problem, as regardless of how steep the wing angle is, the horizontal tailplane is nearly directly into the relative wind. It is also huge on a Helio and super effective and a pretty long moment-arm.

I tufted the tail on my Super Chubby...and it's pretty surprising what the air is doing at high angles. I know on my ship there is a point where it really makes no sense to raise the nose higher, as all that does is reduce the sight picture and jeopardize the tailwheel. If you can't see your spot, it sorta makes it hard to hit it...so even though the plane will slow down further...much below 38 or 39 and I can't see over the nose.

( of course I'm short....maybe if I grew, I could slow down more).


Steve.
 
The flat tail on the SuperStol does stall too early. I made a 21% thickness symmetrical airfoil for mine, no more tail stall.
Then I had to put lexan floorboards in.

Hopefully the larger flaps will fix that.

I would like to build a Javron 4 place with helio style slatted wings next.
 
I've tried the slats full span with my chubby and I can't see any difference, so have mine configured with about 3 feet non-slatted, inboard...the slats took an absolute beating being behind the prop wash and the biggest pain in the rectum is re-fueling with the slats inboard. I didn't notice any difference over the tail. So practically...they leave a lot to be desired putting them all the way to the root. ) The Helio was a pain to fuel also , for the same reason. (slat's making you wish you had monkey arms. )

I added BLR styled strakes at the horizontal stab and that's made a huge improvement in keeping flow attached. Mine are probably bigger than needed, but I've tried to induce stall/spin...which is almost silly, as the nose is up so high that you'd have to have your head on wrong to not notice....but even slow, turning and a solid pull to a shudder and a heavy boot to try to get it to break and it just keeps on mushing till you run out of up.

All in all...to my way of thinking, slats are amazing safety devices. kinda like bush wheels and all the other goodies. In a pinch they might save your bacon. Assuredly they give more options than less capable aircraft.

The only criticism I have with big slotted flaps, throwing off massive turbulent flow aft...I closed the gaps on mine and it is nice now...Again...good luck with your project. I think it will be an awesome performer.

I'm so glad to hear the symmetrical horizontal and elevator made a huge difference...I did not like the SuperStol burble and stick pump...but I liked everything else about it.


Steve.
 
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