Darinh wrote:

The slats make the helio unable to stall and spin

Isn't this about like saying the Helio cannot crash? Pretty sure any plane will stall given the correct set of circumstances. Seems to me you need to qualify this statement by saying, as you eluded to later in your post, that above 28 knots, the Helio will not stall. Having said this, isn't stall more a function of angle of attack, relative wind, loading, air density and several other factors not simply airspeed? I am pretty sure the Helio won't fly below a certain speed and can't hover so it indeed will stall regardless of the leading edge slats if you get too slow or too steep. It may not enter a spin but it will stall, right?

I think the Helio is an awesome airplane and it will do some pretty amazing things with the right pilot but it won't defy the laws of gravity.

No the helio will crash. like all things that go up they also come down! But they are very safe, you are really flying in a 14g roll cage.

Reuben

The Erco Ercoupe and the Helio Courier use the same method for preventing the stall from happening. The deflection of the elevator is limited so you can not achieve an angle of attack sufficient to stall.
The Ercoupe's inner portion of the wing will buffet a little (Stall) but the outer portion of the wing stays flying. Aileron control is maintained all the way through this angle of attack. This is done with a twist in the wing. The Ercoupe Ailerons are a little different because they travel up far more than the down. If I remember right it was like a 60 degree upward and only about 10 degree downward deflection. This helps with controlling the yaw produced with the downward deflected Aileron. More lift more drag. This was done so the Ercoupe could be flown without rudder pedals. The rudders (along with the nose wheel )is connected to the control wheel and also moves the rudders (and nose wheel) when moved. The ball stays centred quite well, although if you get slow and ham hand the plane around you can get it to slide one way or other
The Helio Courier also has the elevator limited but instead of twisting the wings they use the slats to control the boundary layer. The Ailerons are effective but they have help with interceptor blades (spoilers) that move up into the airflow on the upper surface of the wing you want to lower. These interceptors work very well to control the Courier at the lowest of airspeeds. The Ailerons on the Courier also pass into the airflow on the bottom of the wing to help with yaw.
Both the Courier and the Ercoupe have the same problem when the power is off and the airspeed is low. They descend like a rock! Wing still flying but descending fast.
So with power on the Courier will fly at 28 but your engine had better keep turning or you had better hold enough air under you to recover if the cooling fan stops turning up front.
G.J.

Limited elevator travel? It don't need as much travel as a cessna because they have horizontal stabilizer/elevator.

Vx climb out pretty high AOA






Horizontal stabilizer





Reuben

What I am saying is if you had more deflection on the elevator you would be able to stall the wing.

Semantics:
The word "semantics" itself denotes a range of ideas, from the popular to the highly technical. It is often used in ordinary language to denote a problem of understanding that comes down to word selection or connotation.

Why are we trying to stall a heliio?


Back to Zs question, and then away from it... IMHO Flaperons are tantamount to drooping ailerons... learn to fly them right, and you will likely love them, fly them like a cessna wing, and you will likely cry about low speed roll issues.... The stohlest of the stohl, let it all hang out.
If I were looking for a new airplane, and really looking at the experimental market (and even some certified) I would be paying attention to one more thing past the trailing edge... The leading edge Notice anything in common between these two stohl monsters:



Now, there can be good installs and bad, hence the removal on lost of Zeniths... but if your starting at ground zero, it just might be one more consideration

Why would more deflection on the elevator cause the wing to stall?

Another way of looking at this is this way.
If you do an engine change and decide to put a larger heavier power plant up front some planes will not have enough trim on the plane to slow the plane down to a minimum speed.
If you were to take this a little farther you could get the nose heavy enough that you would not have enough trim and elevator to stall the plane with no power. If you take this farther you could get to the point where a stall would be impossible even with power.
So now if you take your plane and limit your yoke or stick to travel half of the normal distance. (Same as limited deflection.) You would essentially make your plane stall proof. You wouldn't be flying very slow but without that travel you would not be able to stall your plane.
G.J

I can agree with here a little, more weight up front will make you not be able to fly slow. But if I am getting what you are saying right, you are saying that if you get so much weight up front you won't stall! after so much weight being up front you won't be able to climb or fly. The helio has an airfoil that is very bad for stalling but with the LE (leading edge) slats it is not able to really stall.

Reuben

What I mean is when you pull back or push forward on the stick or yoke you are basically changing the C of G fore and aft. You are just doing it with the elevator instead of the load position put in the plane (Payload).
If you have weight in the nose you counter act the forward shift of the C of G this by trimming back to balance the plane.
If you place the weight in the back of the plane you counter act the rearward change of the C of G by trimming forward on the trim.
The Courier was designed so the ability of the elevator (Stabilator) is limited. Because of this it is not able counter act the forward C of G to stall in a properly loaded plane. I would think if you load a helio to the most rearward allowable C o G you might be able to get the wing to buffet indicating a stall. You would definitely get it to stall if you loaded outside of the envelope rearward.
G.J

Ok I see what you are saying now! And it makes a hole lot more sense!

Reuben

Do flaperons result in more adverse yaw? A wing-long aileron seems like it would produce more adverse yaw than a 1/3 length aileron, even more so when the flaperons are lowered like "flaps."

Perhaps it's a wash, as the most adverse yaw is produced by the section of control surface furthest out on the wing, and the more inboard section doesn't affect yaw as much.

Thoughts?

Zane wrote:Do flaperons result in more adverse yaw? A wing-long aileron seems like it would produce more adverse yaw than a 1/3 length aileron, even more so when the flaperons are lowered like "flaps."

Perhaps it's a wash, as the most adverse yaw is produced by the section of control surface furthest out on the wing, and the more inboard section doesn't affect yaw as much.

Thoughts?

Yes. Kitfox deals with it with aileron differential in the flaperon rigging . The up flaperon goes up about two times as far as the down flaperon goes down. I transitioned to my kitfox from a Cherokee. The kitfox seems to me to have about the same amount of adverse yaw as the Cherokee. Not very much.

Zane wrote:Do flaperons result in more adverse yaw? A wing-long aileron seems like it would produce more adverse yaw than a 1/3 length aileron, even more so when the flaperons are lowered like "flaps."

Perhaps it's a wash, as the most adverse yaw is produced by the section of control surface furthest out on the wing, and the more inboard section doesn't affect yaw as much.

Thoughts?

Look at the advanced glider wings. My all-time favorite was the beloved AS-W20 (an earlier cousin to Bumper's AS-H26E). It has a 15 meter (49.2 feet) span. The '20 had flaps and ailerons which functioned as differential flaperons.

Move the main flap lever back and forth through the "normal" range, and the entire trailing edge of the wing (flaps and ailerons) move up or down tip to tip to change the airfoil's camber for high or low speed flying. At any position within this normal range (positive or negative flaps), moving the stick left or right gives "differential" AND "sequential" aileron movement. Meaning with left stick movement, the left aileron moved up a lot, the left flap moved up moderately, the right flap moved down moderately, and the right aileron moved down only a little (to minimize adverse yaw).

The amounts of the "differential" (more up than down) also changed with + / - flaps, because the speeds and angles of attack were different, so adverse yaw was different. But at any flap position, moving the stick left or right gave you full-span aileron control, that was tailored to minimize drag and adverse yaw at the appropriate AOA and speed.

Then when you moved the flap lever out of a gate and into the "landing" range, the flaps came down 40 or 55 degrees, but the ailerons went back UP. The model airplane people call this the "crow" flap position. When you moved the stick left or right, one aileron went way up and the other aileron only went a tiny little bit down.

The control "mixer" that regulated these functions was a strictly mechanical, ball bearing gimbaled device which would be a mechanical engineer's master's thesis even today 35 years after Gerhard Waibel designed it..
The net result of all this was an aircraft that had a 43 to 1 glide, two finger sportscar handling even with a huge wing, and UN-MATCHED short-field landing performance. With flaps down and ailerons up, you had full crisp aileron control through and after the stall (which occurred in the low 30 mph range). A slick world class racer that could land in 250 feet even at 9+ pounds per square foot loading.

The reason for putting this detailed description here is that many of the control system features of this glider would be very very useful and increase both safety and performance on a STOL powerplane. Guys like Wayne Mackey and the people building the Sherpa should look into this stuff. The application is different but the principles hold valid.

Zane wrote:Do flaperons result in more adverse yaw? A wing-long aileron seems like it would produce more adverse yaw than a 1/3 length aileron, even more so when the flaperons are lowered like "flaps."

Thoughts?

Yes,
that is why the Helio has interceptors (spoilers). Savvy home builders and mechanics also take advantage of this route. Here are a couple pics of an experimental PA12 clone. It uses Slats and Drooping ailerons (again tantamount to flaperons) and also uses spoilers to deal with the adverse yaw. A sharp cub guy will also notice the deeper chord in the tail feathers.



Here is the best shot of the slats. The drooping ailerons are also Wayne Makeys set up, that allows for use of flaps independent of ailerons if desired.



Here are the spoilers, you have to look really close as they blend in with the sky.

.
I know this is an old thread, but boy what great information. The Pros & Cons of flaperons in Small Aircraft makes for a great read.

I just wanted to mention an update regarding another aircraft recently introduced in tail dragger form. It is the Savannah S . It, like the Kitfox S7 Super Sport and many others, boasts flaperons. The airfoil design on the Savannah's horiz stab is an interesting development as well, and the prop clearance is not half bad either.

KitFox S7 Super Sport with Flaperons



Recently Introduced Savannah S Taildragger with Flaperons

Ugh! As much as I want to like it...the taildragger version just doesn't work with that airplane. At least aesthetically....

bart wrote:Ugh! As much as I want to like it...the taildragger version just doesn't work with that airplane. At least aesthetically....

It is unfortunate how truly treacherous they look in the conventional configuration. *Shivers*

.
I think I could....over time...get to like the tail dragger version of a Savanna S or a Zenith 750. It sort of vaguely reminds me of a Porter.



The problem is, the Savanna fuselage is a tad too short and I'm not sure the tail feathers are enough to control the yaw and other control issues, which in part are further aggravated by a fat stubby STOLish wing having to slice through the air. Sort of the same for the Maule. Other thinner and less STOL capable wings such as on a BH Patrol may offer a better compromise IMHO.

Savanna Length 6.6 meters (21' 8" ) and wing length 9 meters ( 29' 6").

Anyway, I'm sure flaperons will continue to work for some folks, and not for others. Some planes like the BearHawk LSA or Aeronca Sedan dump the flaps all together, and just run ailerons, and they seem to do just fine.