Do spoilers (such as on sailplanes) work the same as ailerons or flaps?

Hm this is only a guess.

If you had individual control of the spoilers on each wing and moved them differently (eg. one at a time or with different amounts of deflection)
they could I think in theory act somewhat like ailerons but if they both are actuated by the same amount simultaneously then they would likely do two things

1) slow the plane down
2) possibly cause a bit of a drop in altitude

where as flaps can act to slow a plane down and help with lift

Yes. You can use spoilers to roll a plane if you lift only the side you wish to bank towards. I believe that is how the B-2 bomber does it. They function as spoilerons if triggered independantly (and proportionally vs. up or not) and can be thought of as 100% aileron differential. Note that you'll also be setting up some odd lift & drag differences in the wings and you'll probably need to compensate with rudder. I wouldn't be surprised some models (with non-dihedral symmetrical wings) might get some adverse yaw and dutch roll on you.

I have several models set to raise the ailerons on a slider switch to act as spoilers. It kills lift and allows the model to settle at a steeper angle. In this case they function both as ailerons and spoilers.

Flaperons are just the opposite - the ailerons can be mixed to drop together.

Spoilers Used on full scale sailplanes are not normally at all like what most modelers call flaperons.

Mid chord spoilers do not impart much pitching moment like trailing edge surfaces that reflex up.

What that means is mid chord spoilers cause virtually no tendency to dive or climb on deployment. The airplane will remain in the same attitude but just lose altitude at great rate. Trailing edge surfaces when used as spoilers will demonstrate pitch changes and the need to retrim.

Here is my original Quad Kaydet (it was lost on flight 29 to a midair) and you can see mid chord spoilers that I built into the airplane just for kicks. The results were rather dramatic, when deployed from level flight power at cruse the airplane would remain in the same but be falling flat at a very alarming rate and when retracted would instantly be right back at cruse with not pitch change instantly. There was no real purpose to then and it was just for fun, shock and awe. I did not set them up to function differentially as the airplane roll control was/is excellent. QK #2 was soon flying but I did not bother with the spoilers.

If one build mid chord spoilers they should always be inboard of the ailerons. The last thing one would want is to disturb the airflow over the ailerons on deployment.

John

I do have spoilerons set up in one of my Extras, just for fun too. Sometimes I will be too high for a landing and hit a switch and the plane will start to drop instantly!! At the same time I do have aileron control, kinda sorta. I just snap the switch back up and have full alieron control again and swoop in for a landing. It's fun but I can see a lot of surprised people running into trouble with them if you don't know what to expect. Same thing goes for flaperon. I have used them both on fun fly planes with good effect, the set up is not good for everyone though, sometimes it can cause a stall and bite you.

OK, I don't like the idea of spoilers on my sailplane. How about ailerons? Is there any point in having ailerons on a sailplane? Can ailerons be built into a sailplane that does have them as an option?

Spoilers on sailplanes is actually a very good idea. If it is a hot day and you have a good sailplane, you might have trouble getting it down without spoilers.

When you try to get a sail plane without spoilers down on a hot day with boomer thermals, you come to really appreciate them, even if they are rarely used. The one or two times they save your plane from a fly-away you'll say they where well worth the effort.

Ailerons will work on some sail planes, not on others. If you're working with a polyhedral wing, ailerons aren't really necessary, just a good size rudder. If you have a wing with dihedral or a straight wing, then ailerons will be more effective. For thermal flying, unless you are going into competition (then you'll want a competition specific plane, but that's a topic for another day), a rudder/elevator/spoiler sailplane is going to be as effective anything else.

I've always flown my sailplanes 2 or 3 channel, 2-meter and standard class, preferably 3-channel.

Hogflyer

So elevator, rudder, spoilers?

How do the spoilers work? One separate gimble stick (is that what they are called on the TX?) for each spoiler with 2 separate servos? Or one servo and one gimble stick operating the two spoilers like flaps?

Spoilers do what the name implies. They "spoil" the flow of air over the top of the wing which causes a loss of lift in that portion of the wing. Without lift that wing drops relative to the other wing. If both wings have spoilers deployed both wings lose lift and the plane requires more speed to maintain a constant altitude. In the deployed position they can also function as "air-brakes" during descent causing the plane NOT to speed up as much while descending. How much depends on a number of factors. Spoilers tend to be less effective in roll control at lower speeds than ailerons.

http://www.rcuniverse.com/forum/forumid_231/tt.htm
http://en.wikipedia.org/wiki/Spoiler_(aeronautics)
http://en.wikipedia.org/wiki/Air_brake_(aircraft)
http://www.youtube.com/watch?v=MljPRTtJHhU&NR=1 F-15 video of airbrake deployment

Here's the way I like to set mine up: Aileron stick controls rudder, so elevator/rudder on the same stick (right stick for mode 2), and the throttle to control the spoilers.

I prefer to hook my spoilers up directly on a single servo to both open and close - not rely on a rubberband to close them. A bit more complex with bellcranks, but I like to have positive control over them. Some spoilers, when the rubberband return gets weak, can lift up a bit on their own and possibly spoil some lift. With direct servo contol that will only happen with a servo failure.

I know some who use a toggle switch or rotary switch for their spoilers, but I find the throttle stick easier. I've seen some guys with 2-meter gliders use the Hitec Focus 3 radio - the gimbal for rudder/elevator and the slider switch on the back for spoilers.

Hogflyer

Can the spoilers be set up with two servos as you would ailerons? Then have the linkages go straight to the spoiler like an aileron would? What kind of Y-harness would you use for the two-servo setup to have the servo go the same way, instead of opposite like ailerons.

Flaps can be setup with two servos so why couldnt spoilers be hooked up the same way as flaps?

Spoiler installation photos and graphics would be great.

You could just have a regular y harness, just point the servos the same way instead of opposite ways when you do ailerons.

So you are saying yes, spoilers can be setup with 2 servos and standard pushrods, instead of one servo with the fishing-line-in-a-tube hookup that I hate?

I don't see why not. It would add a little weight, but it should function fine.

How bout micro servos for the spoilers as they don't really need any pressure to open/close them, with standard servos for the rudder and elevator?

That would barely add any weight.

A Sailplane w/o Ailerons is a beginners plane.

You WANT ailerons for full control.