Spoiler construction tips?
 

Anyone have a good link to tips on the construction and actuation of spoilers? I intend to install them on my Dynaflite Daydreamer.

RE: Spoiler construction tips?
 

Sorry I don't know of any links right off the bat.

I put them on my BOT ARF that I got from Tower.

I just sort of made it up as I went along. I made the bay from scrap balsa that was as deep as the ribs are and the width of the rib bays. I used trailing edge stock in the size you want from the LHS and I simply cut it to as many bays as I wanted it to cover and marked the ribs. I used a dremel to cut the rib down (right behind the spar) and kept test fitting the trailing edge stock to make sure it was as flush as possible. I did this before I boxed in the back of the boxes in each bay. You want to make the fit as flush as possible obviously. THen I ran a servo in each wing. I just used a micro servo and built a small platform for the servo to rest on and I boxed the servos in with scrap balsa and glued them inplace. I bought extra long control arms. Then rather than try and come up with an elaborate way of pushing the spoiler up and down, I simply let the arm push it up and some elastic pull it back flush.
You may want to glue in a bar under the bottom of the spoiler where the arm will push it up higher as it actuates.

Doing this I made them 4 bays wide for that 118" span plane which was plenty. THey actuated up about 80% which is overkill. THrow a mix on the radio to compensate for the nose dropping and your good to go.:D

Good luck!

RE: Spoiler construction tips?
 

Very cool, Liberator....simple and easy to visualize. It's going on a 2M bird, so should work without a prob. Thanks!

Kirk

RE: Spoiler construction tips?
 

You might want to look at this, I don't know if I'm to the part you're interested in yet, more work tonight.
http://www.rcgroups.com/forums/showthread.php?t=535065

RE: Spoiler construction tips?
 

Another cool tip is to use Radio Shack Rare Earth Magnets to get the spoilers to close and stay closed. They are dirt cheap, and also work great for things like canopy latches. The magnets are only about 3/16" in dia and about 3/32" thick.

RE: Spoiler construction tips?
 

I've put spoilers in a Gentle Lady and a RIser 100. The GL was one servo in the middle of the wing with golden rod connecting the servo and spoilers. The Riser was a servo in each wing connected to the spoiler by a piece of thin piano wire. I have full control over both sets of spoilers, no magnets or rubber bands.

RE: Spoiler construction tips?
 

On your GL, do you use 90 degree bellcranks to actuate the spoilers?

RE: Spoiler construction tips?
 

No bell crank, just golden rod from the servo to the spoiler. The spoilers are pulled open and pushed closed. I crashed a few weeks ago (wrong model on TX, controls reversed). IF I get to tear into it this weekend, I will take some pics and post them.

RE: Spoiler construction tips?
 

I just put a .mov of my sailplane landing with spoilers full open, with no pitch change and no mixed elevator. Put them at 60% and outside of the stab's span.

There's a link to my thread on my last post.
Rich

RE: Spoiler construction tips?
 

Ever get any pics?!?

RE: Spoiler construction tips?
 

No, sorry, I didn't get a chance. I will try sometime this week, weekend.

RE: Spoiler construction tips?
 

I installed spoilers on an Oly II eons ago using the Airtronics system...

The spoilers are made from 1" TE stock and the cord that activates the spoilers runs thru a nyrod outer tube to where the spoiler servo is installed in the fuselage. The spoiler cords exit the wing inside the fuselage and are connected to opposite sides of the spoiler servo disc.

The spoilers are hinged with Monokote, and retract with weights attached to blades. Actuating cord is braided fishing line or dial cord...

For gliders with conventional stab/elevator placement, spoilers should be located ouboard of the stab/elevator span to minimize turbulence across the stab... For a "T" tail, spoiler spanwise location is less critical.

Simple, cheap, light and reliable... never had a problem with 'em..

Cheers!

Jim

RE: Spoiler construction tips?
 

Direct linkage from a servo(s) will stall the servo and drain the battery. The pull cord with rubber band return is the safest for most spoiler activations. You can use linkage but like landing gear, the servo has to unload after the spoiler is closed. As many will use the spoilers progressively and not just pop them open and leave them open, you will need a positive linkage in that direction of travel. The pull cord tensions against the rubber bands. I've used a small music wire torsional spring along the hinge line is some applications. In others I mangaged to find some very small extension (screen door) springs.

RE: Spoiler construction tips?
 

I agree %100 with jmmbbo. I had a Sagitta 600 I put spoilers on as per plan option. They are simple, work perfect, really kill lift dramatically. Lee Renaud knew what he was doing.

Unless you plan on flying upside down a lot, use this design.

With all that said, I probably will never put them on another glider. I was always trying to keep the glider up as long a possible and really only used them once or twice to test them. They will make that glider sink like a rock.[sm=drowning.gif]

You could use rubber bands to close but it's really not necessary. And any current drain caused by them is small since you will only use spoilers for very short periods. You probably will not use the spoilers much, if at all.

Keep 'em light keep 'em high.

RE: Spoiler construction tips?
 

Not sure I understand how/why direct linkage will stall the servo and drain the batt. I have installed spoilers and actuated them this way with no trouble. I can adjust the amount of travel of the servo so that when the spoiler is down, the servo is at the end of its travel. It's not pulling against a mechanically stopped spoiler panel. Can anyone clarfy, or is my setup a road to disaster?

Rick

RE: Spoiler construction tips?
 

You've got it right. IF you didn't adjust the endpoint and the servo sat there trying to pull the spoiler after it went to the end of it's travel it would drain you battery, but you don't have that so you good to go! ;)

RE: Spoiler construction tips?
 

I've done my spoilers the direct linkage method with no problems. Using the thread method, spoilers can pop open on launch just because of the air traveling over the wing unless you have rubber bands as already stated, or magnets holding the spoiler down. WFIW, I think there's more control with the direct linkage method (sounds like a birth control method :D)

RE: Spoiler construction tips?
 

As was stated you must have end point adjustment on the servos for direct linkage. Nice when you have the high end transmitter and two channels you can devote to the spoilers. Many starting out in two meter or even three meter inexpensive sailplanes don't have those high end transmitters so the pull string with one servo in the fuse or wing root is the way to go.

As to spoilers popping open on launch; happens when there is "disturbed" air going over the wing -- high speed and high angles of attack. Nothing to worry about unless you are involved in some serious competition and demand everything from a winch and zoom launch. Then you most likely have that high end transmitter and the two dedicated servos and channels!

While the drain from a small stalled servo may be insignificant when the battery is fresh and charged; it's not so toward the end of the flying day when one is determined to get that last thermal.

RE: Spoiler construction tips?
 

No deep pockets here, just a Futaba 6T6XAs bottom end computer radio.

RE: Spoiler construction tips?
 

Was worried about uncommanded spoiler deployment on my OlyII, but the "thread drive" weighted spoilers worked great unless I dumb-thumbed the launch and pitched the nose up too much, at which time their deploying was a non issue since I had stalled the wing anyway... ;) They stayed put on a normal launch, and I suspect you could tailor the amount of weight to provide an indication of imminent stall. In addition to being simple, light and cheap (er... low cost), thread drive requires no adjustment to keep the spoiler servo from hitting a mechanical stop and draining power from the batteries.

Thread drive spoiler response is predictable and their effect on the flight path is immediate either extending or retracting... Flew the OlyII from some relatively small fields, so the spoilers were a necessity, and more than once kept the glider from being strained thru a cyclone fence or stuck in the trees :D

RE: Spoiler construction tips?
 

When it comes down to it, it's do what you are comfortable with, right? One area that I would not be comfortable with, is no spoilers on my planes. I was way up with my Riser 100 and needed to "bail out" because of an approaching storm. I could have spun it out but chose to use the spoilers and just kill the lift. Much easier on the airframe. I've also been on final approach and hit some lift. Not enough to "go around," but enough to screw up the approach and line me up with disaster ( a rocky road). Spoilers deployed, no further problem.

RE: Spoiler construction tips?
 

Here is a link to a discussion on RC Groups about spoilers with some pics...

http://www.rcgroups.com/forums/showthread.php?t=438178

I am building a Gentle Lady with spoilers right now and will be installing HS55's in each spoiler bay. I'll post some pics later.

RE: Spoiler construction tips?
 

As promised, here is a small video of my Gentle Lady Spoiler Mod...

Since I can't upload videos here, I've posted a link to it on RC Groups...

http://www.rcgroups.com/forums/showt...78#post5833060

RE: Spoiler construction tips?
 

You betcha!! In addition to controlling the flight path into a tight field, have also used the spoilers to keep the glider in sight and under control during extreme lift conditions - an enjoyable problem to have ;)