Does anyone make Aileron Spades for models?

[IMACmike]

We are also working to get a "feel" to the human arm. Our ability to move our arms fast, stop fast or on center is based on airleron weight and feel. The servo will do that based on mechanics every time. (at least a Futaba servo will!! zing!)

with JR you really can feel the difference!

[kjkimball]

OK, Matt. I'll chime in on this one.

Why spades? Early ailerons such as on cubs, Pitts S1S, Buckers, etc. are Freise style. These had light forces. Rol performance was increased by sealing the leading edge of the aileron to the wing trailing edge. Later, ailerons changed to symetrical style that are round nosed with the hinge line in the center of the radius of the nose. This allowed easier sealing of the aielrons to wing gap but with very high stick pressures. This is the S1T Pitts style aileron and eal monoplane ailerons. From what I can recall, the Zlin monoplanes of the late 60's or early 70's had spades first. When the S1T wing and new aileron came to be too heavy, the idea from the Zlin was used and the forces were reduced. Rumor has it that this idea came during a discussion between the manager of the pitts factory at the time and a friend of our from Texas. It worked.

As it has been pointed out, spades are tuned to the airplane and pilot. Each unique. Yes, the mass of the spade being forward of the hinge line can be used as some portion of the required mass balance of the aileron system. If it is as on the SP95 and a few other designs, do not fly with spades off or the ailerons will flutter and flutter is bad...

Spades can be thought of as additional aileron area. This added area is forward of the hinge line of the aileron and forward area can be used to lessen the stick forces for the pilot. In the 20's the Travelair 2000 had 'elephant ear" ailerons which had a rounded forward section at the tip that resembled that of the mammal's ear. This area reduced stck forces.

Note how the spades on the extra are mounted on a slope relative to the wing, lower inboard. This allows these spades to do 2 jobs. One, lighten the roll stick forces and two, allow the extra to comply with FAA certification of having to be able to lift a wing with the rudder (no dihedral in the wing so needs this). The tilted spade catches the air in yaw and deflects the ailerons to allow rudder/roll coupling.

It is possible to build ailerons that do not require spades. It takes many tries to get it right. Even at that, it is only right for one person on one airplane. We did get it right on the python. The ailerons are much larger than the model 12 that we kit yet hae no spades. There are many other factors that played into getting a spade free set up. Hinge point is only one. Simply changing an aileron from 2 hinges to 3 can change the aerodynamic stick forces.

The idea of using spades on a model would be tricky to sort out. It is very easy to have spades that are too large and over drive the controls. In this case, you could actualy end up with tension loads on the linkage instead of compression loads. It would be possible to have the ailerons stick at full deflection. Setting the pitch angle on the spade is critical and if it is off from optimum, the ailerons may have zero centering or get snatchy in some flight attitudes.

So, to be more direct to the original poster's questions of are model spades available? I don't think so. Should they be? Nah,....most likely not for the many reasons pointed out in this thread. Knocking them off in wing bags, in the grass, etc., would be a real problem.

Kevin Kimball
www.pittspython.com

[Matt Chapman]

Kevin,
Thats a great response! Thank you.
I'm working on trying to get my ailerons better this coming season. I'm going to have to make up a set of new arms as the new Extra arms don'f fit my older style wing. I would also like to try the tilt to the plate as well. We'll see how that goes.

Take care!
Matt

[rdgood]

Matt and Kevin,

Do you think that there would be any advantage to adding any sort of aerodynamic counter balance to take some of the load off of the servos?? From what it sounds like the only way to tell (with the current info) is be able to feel the forces during flight. I am wondering if a person could set up some kind of rig with an ammeter and detect the deflection forces??

Probably more work than its worth but hey its what we modelers do!!!!


Ronster

[asleep]

We had a crack at spades about a year back. Indeed, they did lighten the torque on the servo's but they made everything so 'twitchy' as when their angle of attack came to an incidence that would put a moment on the control surface, it was like running +ve expo. And making things worse their efficacy is different at different speeds.

The Red Bull lads are fine as their flying as fast as they can all the time and hence, the spade config is more predictable.

My $0.02??? 3M IMAC will happily run with 2 x ganged (or separate) 8511's. Unless you're Mark Leesburg who would need about 4!!

cheers
sleeping

[yak55x]

I have been studying the possibility for a while as well. I've come to the conclusion that the angle of the spade arm effects it in that the up aileron spade digs at a higher agle of atack than the aileron that goes down. This would be the effect of the spade arm forward sweep angle.

I sold my Yak 55M so I can't take picture to show you but it is very obvious when you see it. And the Yak has HUGE double spades. The up aileron spade really digs hard. Hence the name of spade? Makes sense. I don't know who invented them.

This causes more down lift and drag than the opposing aileron which pressures that aileron to deflect farther up. If the ailerons were not connected via cable or pushrod this would be an unstable condition but when interlinked there is still a positve neutralizing force - but less, which to the pilot is a lighter stick force.

I think it would be easy to set them up with an eagle tree e-logger recording the amps from the Rx pack. It would be easy enough to compare pre and post amps while flying mostly roll manuvers.

Better yet would be to use the more advanced eagle tree systems that record servo position and isolate the aileron servos amps. The catch is that the ailerons have to be mechanicaly interconnected for them to balance out the forces.

The added bonus of static balancing would increase the aileron flutter evelope speed as well.

None of this is rocket science - somebody will do it and then everyone will jump on board knowing that spades are a lot lighter than servos and batteries. who want's to be the guy? haha

The aggressive hinging techniques may be better suited for models and easier to set up but I fear the gap created would lead to less roll performance in the end. Most full size mounts are using both aft hinging and spades but the latest designers are realizing that they can just use 25% hinges on the outboard side of the aileron and 35-40% on the inboard hinge to lighten the forces. But again - aileron gap sucks. More the suckier. But how much roll can you use anyway?

I just got back from the Red Bull air races in Monument Valley and the roll rates are blinding. Mush faster than you'll see at an IAC contest. It's amazing - I love those planes so much it makes my eyes water.

Servo tabs are interesting too, allthough not very scale and may not give a very "tight" feel. Just an intuition - may be allright on models though. I was thinking of trying it.

Why nobody does all this? It's easier to buy another servo - or three

I'll get around to trying it and post the amp reading ect.

[yak55x]

One correction I thought about. The angle attack of the up and down spades are probably the same. But the angle of the spade arm creates a mechanical advantage for the up aileron spade whose lift and drag both try to lift that aileron farther up and have a longer moment in relation to the hinge line.

The other spade which is closer to the wing now on the down aileron has up lift but it's drag which may be more important is nearly in line with the hinge line so it has much less mechanical advamtage than the other spade. This would explain the use of low aspect ratio planforms which create a lot of drag per degree of angle of attack. I'm just trying to reverse engineer these things but so far it would be easy to quantify my theory.

Anyway, we know they work But It can't be just that thier area is forward of the hinge line because they are way too small to have such a large effect.

Personally, I think for some reason they have been very mystified. I'm not really sure why. I know that there are a lot of mystics about things that are really simple but haven't been explained well or people just don't take the time to understand. Spades are a little different in that there may be only a few IAC-type aerobatic aircraft designers in the world right now and probably less of them have really taken the time to study aileron spades or write it down for the rest of us knuckeheads. So no wonder they are not mentioned in aerodynamic texts ect.

I've seen average joe's like me do some pretty amazing things so if someone out there want's to try spades - just go for it. Practical experience and experimentation can trump a genius in a chair. When it gets done right I bet it would be worth it. I'll sure the heck try it but I'm rather busy and slow to build so somebody will probably beat me. Salright -it's all good. I have some eagletree stuff on order....


If Jim Kimball finds them to be hard to set up - they probably are - at least on a full size airplane where "aileron catch" would be pretty risky and I'm sure would scare the crap out of anyone messing with thier spades. But I think the key would be to emulate the full size methods closely and start with small spades while checking the amps to that servo and making small changes. Wouldn't it be worth it to get rid of 3 to 7 servos, power managers, battery weight ect?

[asleep]

	Quote: Originally Posted by yak55x
	Wouldn't it be worth it to get rid of 3 to 7 servos, power managers, battery weight ect?

I think if you're looking to save some weight, this probably isn't the right area. You'll always need a power manager of some sort, against the - dry - weight of the model, servo's weigh next to nothing and given their torque output (even at 4.8v, better yet at 6v) I'd be very nervous of control surface flutter. I've got 2 x ganged 8511's on each aileron on my 40% Extra 3M. Hypothetically, if you took that back to one servo because of your 'spade' you're asking for confetti. A spade significantly increases the potential of control surface flutter and if you don't have enough output torque from the servo/s to combat this, you could use your spades to dig your crankcase out of the ground. Battery weight? LiPo's / NiMH are so much lighter than good old NiCads and again, to forgo a battery that will satisfy potential amp draw from xx number of digi servo's in a snap or whatever - that's just crazyville. No???

The effectiveness of control surfaces is determined by so many things, no need to list. If you're really hung up on making a more efficient aileron, start to get your head around the different shapes of a wing's cross-section, cord thickness, leading edge shape and so on. Upon understanding how differently shaped wings disturb airflow and produce lift you could start messing around with aileron design.

You might decide to design a assymetrical mirrored concave aileron. That would seriously have an effect on airflow and subsequent control inputs - and could turn out to be a complete waste of time.

Why not investigate mixing in differential elevators to assit on the rolling axis?? Easy to put in / out, vary the %'s... You might find you've created a smoother roll - now that's worth investigating? yes/no?

Even going for a lesser pitch prop (eg. 34 x 12 to a 34.5 x 11), to increase the area of the thrust cross-section.

And list goes on forever. Next year, it will be variable pitch props (already investigated over 20 years ago by your US legend, Hanno Prettner)

But I do have to admit, spades do look pretty cool!!

Best of luck!

Sleeping

[Flypaper 2]

This is my first post on this forum so go easy on me. I put servo tabs on my old 1/4 scale Corby Starlet. On the trailing edge of the aileron, they're 1/4 of the area of the aileron. To find the right throw, I moved in one hole at a time in the tab. When I hit the magic spot, it was as if you'd put the next size bigger, faster servo on the aileron.

[Zee]

Servo tabs works on models well. Servo tab is like trim tab on aileron/elevator, just like Flypaper 2 is showing in the picture. I try those on model of Extra 230 elevators.

The spades do not work on models for one simple reason, you have no way to set it up properly.
The angle is critical and on full scale, way to set it up is go fly it and feel the stick pressure and if need shim it up. You do not feel the control pressure on your TX stick, so how you know that you actualy not adding load to your servo?
You could matematicaly figure out the angle of the spade, but until you test fly it and see what the controll pressures are doing you don't realy know.

I used the aileron and elevator servo tabs on my full scale design with good sucess.
Weight counter ballance, like on aileron is also good thing.

Zee

[btomlinson]

There was a fella selling them on RCU... I saw the ad but cant seem to locate it now..

[flyingklown]

You do not need them for our planes. Only Full scale. There would be no difference on an RC. I was told anyway by a full scale pilot that flies RC. But who knows? This would be an interesting topic to explore..

[GremlinX]

I think there are spades on that 70% Staudacher that just flew.... check it out...

[wcc963]

well here is a video of RJ Gritter flying an MX2 foamie at the 2009 ETOC "he has spades" do they do anything? i dont know, but they definetly look cool. if anything they can be on there for a visual effect... it could be just something different that we havn't seen in RC

http://flightpass.higherplaneproduct...udio-H264s.mov

[sensei]

	Quote: Originally Posted by Biff
	Spades are HYPER critical to set up properly. Being as we can't "feel" them in flight, they would be potential trouble in an RC aplication. When setting these up on a full scale ,they are shimmed to get the right feel. Perhaps I'll drop Matt Chapman a PM and have him jump in here. He should be the best guy to answer this one.

What he said.

Bob