Ok,I fly off a short paved runway with an equally short approach to it that requires loosing alot of altitude quickly making it hard to slow down for landing. You have to clear the tops of the trees first,then dive down and hope you can get slowed down enough to land on the pavement and not overshoot it into the rough(hard on cowls and props). So I want to experiment with either spoilerons or flaperons on my Big Stick .60,then maybe my little sukhoi 31,and if all goes well I could use is on my new edge 540. So, if I do decide to try this.....what would you pros recommend? I'm kinda leaning toward spoilerons because I heard the plane wont glide as far. Its easy to glide the whole length of our runway if your going too fast. But I'm not sure if spoilerons would slow me down as much as flaperons. I also hear flaperons can cause tip stalls more,but this is likely the least of my worries as I usually cant get slowed down that far if I wanted too,lol. So,what do you think considering my short approach and having to loose alot of altitude in a short distance?

Anything involving combining ailerons with something else is a bad idea. You lose aileron authority when you need it most, and that's during landing. You can still slow it down enough without them, it just takes practice and careful flying.

Anything that kills lift toward the outbound section of the wing first is always a bad idea. Inbound flaps are designed to both slow the plane, create additional lift at slower speeds, as well as create a condition where the wing will stall from the inside out. You can probably get away with it on the big stick, because they are so stable anyway. If I were going to do it, I would use flaperons and drop the ailerons, but only by about 1/2 of the total throw, so you at least have that much left for roll control. I would not use spoilers without combining them with some inbound flaps (as in a crow setup).
However, that being said, there is no way you will get by with it on the edge. If you drop both ailerons on the edge, you are going to tip stall that plane in a heartbeat.

what are tip stalls, or any kind of stalls? is it actually where the engine stalls due to some position of the plane?

Write to Ed Moorman at [email protected] or hit him with A PM here. He writes the FUN AEROBATICS article in RC Report and can tell all those that don't subscribe how to set up A plane. Better yet, subscribe!! He likes the spoilorns slaved into his throttle, I like my flaperons slaved to my elevator but plan to give his system A try.
My fun flying plane is A Hots 60 size with A YS 1.10 and I enjoy trying different things in it. I don't do this type of stuff to my pattern planes at all though.
I think it was last month he covered these two set ups.
Gene

It's when the plane or the air going over and under the wing is not moving fast enough to provide lift and the plane just becomes a rock. Not a problem if you have enough altitude to get some speed back up, but at landing it would be imminent death. Tip stall from what I can tell is one side of the plane loosing lift and rolling off to that side.

Let me know If I'm right guys, I have been around planes and done about everything you can do except fly a real one myself.

In our hobby, it's whenever the airplane stalls and "drops a wing". And they almost always drop a wing, no matter where the stall starts on the wing, tip or root.

Straight wings naturally stall at the root. It's how they do it. But stalls start at the tip on tapered wings. Almost never do our wings stall equally on both sides at the same instant. So what happens? One wing loses lift before the other and the airplane drops a wing.

And every time one of our models drops a wing everyone talks about it as a tip stall. An Ugly Stik did it the other day. Probability is close to 100% that straight wing stalled inboard first, but one wing went before the other. Everyone called it a tip stall. The term is great for describing the results, but sucks at describing more than that.

BTW, where the stall starts has a lot to do with how quickly the results show up. It's simple leverage or lack of it. When the lift toward the tip is lost, it has a more pronounced effect than loss of the same amount of lift would have closer to the fuselage. So you often see tapered wing airplanes drop a wing much faster or more violently than you see the wing drop on a straight wing airplane. It's also easier to stall the shorter chord wing tip. Shorter chords are less effective than longer ones and stall sooner. Which is why tapered wings stall from the tip. And why straight wings don't.

OK, you want to know if you're right or not.

A stall is caused by too great an angle of attack. That's it. Nothing more. It can happen at high speed or low speed. But it only happens when the AOA is greater than it should be.

But you pegged what a tip stall is. It's exactly what you said, "Tip stall from what I can tell is one side of the plane loosing lift and rolling off to that side. " Spot on.

Why one side only? Well, our models are almost never perfectly lined up. They're almost always "side slipping" or yawed. Full scale airplanes have instruments for the pilot to help him keep his airplane "straight". We don't have anything at all, and are strapped with the problem that we can't even see the very few degrees that are enough to cause problems. And we've got another problem with wind gusting. We for sure can't see the wind. And add the problem of wind direction and we're setup for the fall. Or our models are. How often does your model have the wind straight down the runway on it's landings? So almost every time our wings stall, one side is going to go before the other. And you're right. All of us will call it a "tip stall".

If you're trying to dump energy on landing, learn to slip. Nothing brings a plane down like a hard slip, and you have full control all the way through.

Slipping a warbird with a high wingloading isn't such a great idea, but the stick should do it great, and you can get a little slip going with the acrobatic planes, but you'll want to try it at altitude first, since you can slip yourself into a snaproll if you aren't careful.

Between the options of flaperons or spoilerons, go with spoilerons, you do loose some aileron control, but not as much, and you don't create the stall problems mentioned above, since spoilers lower the AOA of the wing, while flaps raise it.

If you don't mind doing mods on the plane, you could always install air brakes on the fuse or seperate spoilers on the top of the wing, that will get you stopped quick.

Another trick, put a little bit of fuel tubing on the wheel axles to add some drag. Just a little bit of pressure can really shorten the roll out.

On tricycle gear planes, you can also do some aerodynamic braking, where you touch the mains and then pull the nose UP, and hold it up as long as you can while you rull on just the main gear. This creates a lot of drag and slows you down faster than rolling on all 3 wheels will.

Montague's comments are right on the money.

I would try slipping it in, but learning to slip is tricky and some planes don't do it as well as others.

If it were me, I would try spoilerons. As Monty said, they will not cause a stall, in fact, just the opposite.

I used to fly full-scale sailplanes and the trick to a perfect landing was to stay higher than you needed to be, and pull out your spoilers to regulate altitude.

The nice thing about spoilers is that your plane will sink like crazy without gaining airspeed - the problem is regulating it. They would need to be controlled by your Tx in such a way that you could turn them OFF before you pancaked into the ground.

Ummm... could you guys explain how to go into a slip? [sm=49_49.gif]

I'd love to ('Cause I love doing them)

First off, the planes that seem to do them best are things like Cubs, Bipes, even the Chipmunk does them exceptionally well.

Picture that you're making a left turn to final approach. When the plane has turned about 45 degrees (with another 45 degrees to go before it's lined up with the runway) feed in some opposite (right) rudder.

The plane will stop turning, but will slip or "crab" toward the runway - flying sideways so to speak.

This creates a LOT of drag, so the plane usually slows rapidly and looses altitude quickly. For this reason - and the fact that it can be tricky to recover from - it's a good idea to practice this 2 mistakes high

Ah... how about 3 mistakes high for this old fart!!

Thanks for the info. Opposite rudder, eh? Ok. This looks like something I will try when I can finally head out to our field. Wind/rain today, tomorrow warm and sunny but 20 - 25 knots of wind. Blah!!! I want to fly the Skylark!!!

What's funny here is that I've been doing that without knowing it was a slip. Not necessarily when I was supposed to do them, but just playing around in turns seeing what happens when I do things with the rudder. Good stuff!! Now I know what it was I was doing up there.. Still... 3 mistakes high now that I know what it is I am practicing.

CGr.

A slip technically is any time you aren't in co-ordinated flight. Knife edge flight and flat "skidding" turns are both types of slip, though that doesn't help in this case.

I find it easier to do a normal turn, then line up on final, then apply rudder and some opposite aileron. If you do it right, the plane continues in the direction you started, but the nose is pointed to the side, and the plane is banked in the opposite direction.

Doing the slip in a turn as described above is pretty cool, and the plane can really come down in a hurry that way.

In a cross-wind, you use the slip to point the nose in line with the runway. You basically use the rudder to point the nose, and the ailerons to keep the plane from drifting sideways. This works out to rudder WITH the wind and ailerons into the wind. So if the wind is coming from the airplane's right, you use LEFT rudder and right aileron. The plane will be in a right bank, wings banked into the wind, but not actually turning.

Note that you're going to holding the rudder and aileron the whole time you're slipping, it's not like a turn where you center the controls.

Exiting the slip is best done slowly. If you release the rudder quickly before you release the ailerons, you set up a perfect snaproll situation, so ease into and out of any slip.

That's the tricky part no matter HOW you do it

Amen brother!

Seriously, it just takes practice. Most people find two things hard about a slip:
1. moving the hands in opposite directions at the same time (often, moving both sticks "out" is easier than "in" or vice-versa, but cross wind landings don't give you a choice, so work on both)
2. holding the sticks off center for a good length of time, and making small adjustments while holding the sticks off center.

I'll still botch a slip once in a while, but usually when I'm trying to do something extreme (like the one-wheel touch and goes, rolling most of the runway on one wheel before lifting off stuff), not when I'm just trying to land. Most landings don't require nearly that much slip, even short or obstructed fields.

(One of these days I'm going to out fit an LT-40 for serious STOL action.... As it is, we've marked out a 100' foot box on the grass runway, and I can get up and down and back up with out ever touching outside the box (sometimes))

Since my name has been mentioned, I'll jump in. I generally use flaperons and spoilers (spoilerons, as others call them) on all of my planes. At least all of the sport and 3D planes.

Let me dispell a few misconceptions. By and large, you don't lost aileron control when you use spoilers or flaperons. At least, I have never noticed any. I admit that I do like a lot of aileron movement, but I use a lot of expo to control it. Your ailerons will be less effective at a high angle of attack, which both types of control can lead you to. You can also get into a high angle of attack without either spoilers or flaps.

Flaps and flaperons tend to not be very useful to slow you down for landing on a sport plane unless you use a lot of flap, 45 degrees or more. They normally cause you to float on down the runway, way past your intended landing point.

Flaperons are great for turning tighter for more loops at your club funfly or just for messing around.

For landings, especially in high winds and in cross winds, I love spoilers mixed to the throttle. Having both full span ailerons up tends to wash out the whole wing, causing a loss of lift. This lets you descend steeper or get the nose up and slow way down. On a good windy day, You can nearly drop vertical. In a 3D plane, you'd call this an elevator. I use these on every sport or 3D plane.

Right now, I am down to 4 sport planes, an Ultra Stick 60 & 40, a Wild Stik 40 and a Tango (great little plane, by the way). All of these use both flaperons and spoilers.

As for slipping, I rarely do it on a model. I am very familiar with slipping in a full scale. I taught it for landings and simulated flame out patterns while I was a T-37 instructor pilor in the USAF for 4 years. Slipping with an RC model is fine if you have experience and know your plane. If you use a lot of rudder for the slip and also get the nose up to slow the plane, you have just put in snap roll controls. Pop the power in before you release these controls and you can get a snap. I have seen it. It just takes practice and experience. Some guys like it and use it a lot.

All of this brings me to a point I'd like to make. To progress in your RC flying, you need to learn to use all the controls of your plane. You can't say, "I'm going to use ailerons for turning all the time," for example. At harrier speeds, which is normally below stall or control speed, you are holding the plane at a very high angle of attack, increasing power to let the prop blow air across the wings for lift that you wouldn't be getting from forward speed. You are riding on a bubble of air and your ailerons are good for keeping the wings level. If you bank too much, you slide off the bubble and gain speed, so you yaw the plane around with rudder and level the wings with ailerons. If you use a lot of rudder, you may need to cross control the ailerons. What you are doing is using all the controls to guide your plane. If it takes rudder, you use rudder. If it takes power to create lift, you just got yourself a blown airfoil.

Now then, back to flaperons and spoilers and how I set them up.

First, you need to go to a Flaperon wing type (on JR, anyway). After you do this, you will plug your 2 aileron servos into 2 different channels. On JR the right aileron servo goes into channel 2 (ailerons) and the left one goes into channel 6 (flaps). For Futaba and Hitech, I believe it is channels 1 & 6.

After you set a Flaperon wing type, go to Elevator-Flap mix. This is normally a pre-programmed mix on 6 and greater channel radios. Hold up elevator and program in 50% down flap. Hold down elevator and program in 50% up flap. You should set a switch to turn flaperons on and off.

A side effect of setting a Flaperon wing type is you can adjust each side individually for centering (subtrim) and end points.

For spoilers (spoilerons) go to a free mix. On my JR radios, I normally use mix 3 or 4. These are the non-trim, single point, simple mixes.
Set throttle as master and flaps as slave.
Pull the throttle stick to idle and set the mix so both ailerons move up about 15 degrees. As you advance the throttle, the spoilers ought to drop down and be back to the normal aileron position at half throttle.
Set a switch to arm the spoilers. I normally use the Landing Switch.

Take your plane up and fly a normal landing pattern. Note the final glide angle. Next time, arm the spoiler switch. Cut the power to idle right opposite yourself and start turning final. You may need to point the nose down a little, but the plane will assume a steeper glide path. If you are going to touch down a little short, add power. Your plane speeds up a little and the spoilers also drop down some. Both will move you forward and slow the descent. Reduce to idle again and descend to touchdown.

You'll need to play with the spoiler angle to get what you feel comfortable with. At a certain point. you will get to where you are close to running out of up elevator to flare the plane. The max spoiler it the point where the plane is dropping like a rock and you get one pull to full up elevator to avert a hard landing. You have to time it right or it's curtains. I know from experience. A more conservative max spoiler deployment is where you get 2 pulls on the elevator, one where you mis time it and the other to finally touch down.

Spoilers are a ton of fun. Everyone with a computer radio should try them a few times. It feels great to get out on a windy day when someone had to carry your plane out and you get to do multiple touch and goes with a near vertical descent. Try it.

Thanks alot guys,that really helps and explains alot. I'm curious to see the effects of both spoilerons and flaperons. I beleive I will start experimenting with spoilers first on my big stick which I'm the most comfortable flying just to see how it works out. I will definetly start out with only very little at first and not use it for landings until practicing it alot up high. We'll just have to see how it goes. I wanna see for myself just how it works out. Wish me luck!!! lol

Good luck! And have fun!

Well, it seems my view of things is always a tad different. But here is one more idea from the certified oddball.

We used to fly at a community college parking lot. It was surrounded by trees. On the south side, 100 foot pines stood about 150 feet from the lot. We had the choice of making a tight pattern inside the tree line or coming over the trees, watching for our shadow to let us know when we had cleared the tree line and then decending. Either way, everone that flew there needed to be very proficient at slow flight. Slow flight is flying around at a very slow speed with the nose of the plane at a high angle of attack and carrying a fair amount of power. Suprisingly, when members of a nearby club came to visit us, they were unable to get their planes back into the field. Many were rescued by local pilots that were expert in the technique and very familiar with the field. (So, unless the situation demands it, most people aparrently don't practice or even know about the technique) I am reminded of that situation every time I hear a story like yours. The first thing I question is wether or not you are aware of the slow flight technique and using it to land in tight fields. Stiks in particular are very capable of slow flight and landing in extremely tight fields with short runways. It is possible that you might over come the situation with technique alone and no modifications. But if mods are ultimately required, my first instinct would be the addition of flaps, not spoilers. Although slipping is effective, (and fun), flaps will allow the aproach to be completed with greater precision. And flaps tend to make a plane feel rock solid at low speeds. And they effectively increase the washout of the wing by a factor of "alot", making tip stalls unlikely. Spoilers, generally aren't something you want deployed on short final. They are used enroute as speed brakes, to increase decent rate, and are generally deployed after touchdown to kill lift, avoid bouncing, and increase braking. But on short final, they can mislead you. Its difficult to sense how much elevator remains for round out and flair and they may overpower your ability to do either.
Anyway, another 2 cents worth.

I have a Hanger 9 Ultra Stick 60 ( like the Big stick) and I had a 3d friend program my DX7 for Quad flaps. He used all 6 mixes. At any rate it has a thing called "Crow" were the inside falps go down and the outside alerons go up. Almost stops it in the air. I can land like a helicopter in only a 5mph head wind.

Zif

PilotFighter, What you're describing is a "harrier" approach. Hanging the plane on the prop, and desending at a high angle of attack (alpha or AOA). While that "works" for some models, it's a really bad idea with others. Full scale pilots would call it the back side of the power curve. Anything with a high wingloading and lower power-to-weight ratio isn't going to do it very well at all, and any kind of gust at the wrong moment would easily result in a stall-spin-crash. Models with enough power to simply power up and pull out of that kind of thing will be fine, but I wouldn't do that with anything else. (yes, I can do it, sometimes I do it for fun, because I can. But I don't teach it as a normal way to land).

Nope, not quite a harrier. Imagine a harrier, then take it down a notch.

If you just mean slow level flight with the engine nearly at idle (just enough power to not descend), then yeah, that's just normal slow flight. You had experienced pilots who couldn't do that? (actually, now that I think about it, I know a few who seem to have binary throttles...)

I was reacting to your "fair amount of power" part, which made it sound like you were holding a high AOA, on the backside of the power curve.

I would imagine that anyone that is not experienced, trying that, with an aircraft that was not powered accordingly, in wind, especially a cross wind, no matter how strong, would be makng an approach to disaster... or at least a very serious moment or two of terror.

CGr.