Does anyone make Aileron Spades for models?

[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...