If you don't plan on using flaperons or anything like that, is there really any advantage to having a servo in each wing vs one for both? Seems that it would just be that much more to trim and mess with during building... It will be on a Stinger .60 if that makes any difference.

Thanks all

Reasons for 2 servos:
More power to each aileron (more torque).
Easier to adjust trim using radio, rather than messing with control linkages (if you have a computer radio).
Easier to install, uses standard control horns, control rods (instead of torque-rods which have to be built in at construction time).
Can play with flaperons, etc (if you have computer radio).
Typically have shorter control rods, reducing the amount of slop in the linkages.
Is "cooler" than one servo.

Reasons for 1 servo:
less weight
less cost.
Typically all that is needed (for most non-3D non giant-scale planes).
Mechanical coupling of ailerons is advantageous because you trim both at the same time.
no need for expensive computer radio
no need for 5 or more channels / y-harness.
If the instructions will call for this setup, it will most certaninly be adequate.
Simpler interms of trims, centering, and everything else.

Basically, if the Kit says "One servo", then the chances are good that is all you need. If you need two servo's for you flying style, then you are probably exceeding the planes capabilities in other respects.

If the instructions call for 2 servos, then it is probably because the additional control sensitivity (less slop, more torque, shorter rods) is required to suit the flying style of the plane.

There is no need to have a computer radio, a Y-Harness will work just as well.

This does not answer your question directly, other than to say that there is more reasons than just "to have flapperons" that you want one servo per aileron.

gus

Makes sense...
I do have a computer radio - sorta. Its the JR XF631 6 channel so I can do a little more than the standard 4 channel Quattro. The instructions really only call for one servo but do give instructions on using two so I guess thats what I'll do. The ailerons are the full length of the wing but it also has fairly meaty rudder/elevator. I have two high torqe servos and the rest are JR 537's. Would the high torqes be better on the rud/ele or the ails? I'm going pull/pull on the rudder for whatever that's worth...

Put the hi-torque servos on rudder and elevator if you have a two aileron servos. That gives the best torque to each control surface.

Another advantage of duel aileron servos on planes with long wings and strip ailerons that the ailerons will twist less. This results in less flutter problems and a better roll rate.

In reality, I can not believe that a 60 size craft needs the torque provided by a "high-torque" servo. Standard servos should be sufficient for all your surfaces. When I say standard, I mean "ball-bearing" style servos (the JR537's). This is basically the all the literature I have found on the Stinger suggest that standard servos are fine.

If you have the high-torque Servo's already, put them on rudder/elevator because those typically have the largest torque requirements, but remember, they are still overkill for the task at hand.

gus

On the stinger 60 standards are fine but I do have a couple of 40 sized 3D models with high torque servos on them. If you got the money to spend on the servos you will feel the difference in the air.

One good reason for two servos is if one fails. You can still have some controll with one aileron working. Anyway, one is better than none. this is especially true if you're flying something that does not roll couple with rudder inputs, meaning that you couldn't turn just with rudder and elevator easily.

I can notice better aileron response with my planes that have dual aileron servos. Also, you don't have those pesky torque rods that always seem to work themselves loose in the aileron after a while.

MadScientist
yes... glad i read this, i was just about to post that.
if the kit says you can use 2 than use 2, the advantages out weight the disadvantages (wich there really arent any) more power is always better right ?

also, if your plane is being built to go faster tha nthe original kit was intended to go, do the dual servos so you dont lock up the surfaces at hig hspeeds. as well as reduce fluter. also, whats teh torgue on those servos and are you using 4.8v or 6v?

gus, I do already have the servos. I was already considering putting two on the wings and figured I would need at least one more sooner or later anyway so I bought two of them from a buddy. He bought them for an Extra 300 but decided to go with some different ones so he sold me these for $45.

Balsa, they are 77oz torque (Hitech HS-605BB) and to start with I'll prolly just use the stock 4.8 that came with the radio. I hope to upgrade later as funds allow though. Especially if I find heavy battery consumption to be an issue. I don't think there will be much problem with response times but I'm sure the 6 would be allot more stout.

As for the overkill, well the whole plane will have / may need some overkill. I ordered heavy duty control arms, heavy duty servo arms, pull/pull rudder cables, soldier clevises etc. As Balsa's sig states, I fly em hard (hope to avoid the crash for a while though). Afterall, I did fly the elevator clevis off of my Hobbistar lol. The clip that sticks through the control horn folded back after a high speed dive/loop. Guess thats what I get for using the stock plastic clevis or over flying a trainer.

I love full speed fly by's and sharp turns, and often sharp turns at full speed. I figure I better do everything I can to make sure something doesn't fall apart in the air again. I didn't specifically buy the high torques for this plane, but they were cheap and available... It will have an Irvine .72 with a Pitts slimline on it using a 13x9, 14x8 or 15x6 prop depending on the clearance so it should still move pretty good. The range is 60 to 91 so I'll actually be in the lower middle I guess.

I like to fly hard I guess. I tried the low/slow/float plane concept with a friends plane and it just isn't the same. I guess for now I still feel like the teen just learning to drive and having a muscle car to play with. I'm just trying to hedge my bets as best I can for my flying style (or lack therof). Any other suggestions are MORE than welcome.

Thanks,
Rik

Seeing as how you're asking, I have a suggestion.

You mentioned full speed, sharp turns.... I'm going to assume you also like to pull out of high speed dives fairly quickly.

I'd highly recommend that you beef up the center joint of the wing. If the Stinger is a kit, add carbon fiber strips to the top and bottom of the main spar, start one end about 1/3 span out, come across the center, and out to about 1/3 span on the other wing. (Just apply them with epoxy while building.)

If it's an ARF, beef up the center joint at least. Use epoxy thinned with alcohol, and fiberglass strips.

It also wouldn't hurt to add triangle stock to the joint of the horizontal and vertical stabs, where they meet the fuselage, and some of that same triangle stock to the back side of the firewall to fuse joint.

The 2 to 3 ounces (75 grams) added weight will be well worth it.
Dennis-

If you are doing lots of high speed stuff, be sure to make the aileron pushrods as short and heavy as possible. Use 4-40 hardware and NO ZBENDS; use ball joints if possible. Also, put the control horns out at 2/5 to 1/3 the span of the aileron to minimize flutter possibilities (1/2 span is the worst possible location). Use stiff material for the ailerons.

Rodney

I am finishing a cloud dancer 40 in which I installed separate servos for the ailerons and mounted them center span. Please tell me why this is the worst location.

Thanks Russ

Yes it is a kit with a foam wing core and balsa sheeted wings. Is carbine fiber better than plain ole glass or would glass work? Depending on the price and availability of the fiber I may or may not be able to get it. Would it go on the foam or on the sheeting and would I use the Zpoxy that I sheet the wings with or regular epoxy? I've never heard of carbine fiber. All I've used is different thickness of glass. As for the triangle stock, I agree, that would probably be a good idea. As I stated in my least message I plan on doing allot of overkill on the plane just for my flying style. All the rods will be 440 and like I said pull/pull on the rudder with cables.

As for the dual servo locations, should they be in the middle of the wing chord (chord-new word I learned recently :-p) about 1/3 from the end or nearest the root? They are full length ailerons on the stinger. I too am curious as to why the middle of the span is worst, I hadn't heard that before... Also, why no zbends? I would think they would be as good or better than a ball joint that can pop out of place?
Thanks all,
Rick

If they are full length ailerons just put them about 1/3 of the span not the chord. The reason why not put it 1/2 of the span is: a full lenght aileron experience a slight twist at high aerodynamic loads. That is, given the force to deflect the surface is applied near the root then the aileron tip will measure a lower angle at that point. This is acceptable in our sport. Now if you place the servo, force to deflect the aileron, at midspan then both of the aileron tips will register a different angle of deflection than the one at midspan because of the twist created by the aerodyamic load. That configuration creates a lot of turbulance and unnecessary drag. Think of it as if the wing is a propeller, the higher pitch should be close to the root while the smaller is at the tip. This is to balance out the displacement of air mass while its rotating.

As for where on the wing chord to locate the servo, as close to the aileron as possible is good. That keeps the aileron rod as short and stiff as possible.

The "no z bends" thing, I suspect, is because some guys thing that a rod will have a tendancy to flex a bit at the Z, and the bending of the Z can weaken some metal rods (depends on the hardness of the metal, etc), which can result in the rod breaking at the bend. This kind of failure is most likely if you encounter flutter, as fultter puts a huge load on the pushrod and servo, and does it as a hard, rapid vibration that is murder on linkages, gears, etc. Also, I've never seen a size 4 rod bent in to a Z, just size 2 rods. If you're going with 4-40 hardware, why use a 2-56 bent rod at the connection, stick with quality 4-40 stuff from end to end.

Good point on the zbend, sounds logical.

I've heard that flat edged and tapered ailerons help to reduce flutter. These will have a flat/straight TE, but it would do me any good to slightly taper them off at the ends or would that just degrade the efficiency of them? Also, assuming a 4.8 battery will work fine, would I gain any major benefit by using a 6v?

As for hinges, Robart hinge points are the ones they say to use but I've heard several talks about either CA or pinned , metal/plastic hinges being just as stong. Any thoughts ?

I got the kit today and it looks like the elevator is only 1 3/8 wide, would it hurt much or negatively affect anything to use a bit wider piece? Also, the turtle deck and most of the top side of the plane are ABS. Can you monokote that or should it be painted ?