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Jan 11, 2011, 09:22 PM
Thread OP

A little EZ spoiler linkage review

OK, so I bought a new Topaz S V2 and thought I'd use the "EZ spoiler" linkage layout. Not as easy as you may think. So, I thought I'd display a couple diagrams of the EZ spoiler pitfalls you may encounter. I drew these in autocad to scale in an effort to figure out what I was doing wrong.
This is a Hitec HS65 servo in the spoiler bay of the Topaz S V2.
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Jan 11, 2011, 11:02 PM
Hot Dawg Glider Pilot
schrederman's Avatar
So... it appears that the length of the rod holder and the placement of the slider on the spoiler are critical. Thanks for posting that. I have been saying I'm going to put servos in the wing for a long time... but I thought the servo belonged in the nose... sorry, couldn't help myself... I'm old...
Jan 11, 2011, 11:25 PM

EZ Spoiler Linkage

Chip Ė In my original description in RC Groups it appears I didnít stress the need to cut off the forward servo mounting lug. Cutting off the lug would allow the servo to be located further forward than your drawings show. While I did say it is not necessary to locate the servo arm pivot point exactly under the spoiler hinge line, getting the servo pivot point Ďnearí the hinge line is.

Looking at your bottom picture in the first column (First Try) the interference would not occur if that front servo lug was removed. I just re-looked at the RC Groups pictures showing the mock-up installation photos (black servo) and the installation photos in my blue Topaz - S. The servo lugs have been removed in the mock-up photos and the front servo lug has been removed on that blue HS-55 servo in the wing of my Topaz. While I have received many reports from modelers who have successfully used this EZ Spoiler setup, yours is the first one showing the need to cut-off the servo lug. I now realize I should have described the need to cut-off the servo lug. Please accept my oversight and apology.

On a more positive note, I know youíll love the performance of your new Topaz S-V2.

Jan 12, 2011, 06:49 AM
Thread OP

Re Response


I don't think the front lug of the servo needs to be cut off but, you do have to do some home work / geometry to get it right on the first try. The servos in my wings are mounted in between blocks with a ply plate hold down and the lug is needed to position the servo. It's still a super way to link up the spoilers, this was just a heads up to those about to use the EZ method.

I am ready for some warmer weather so I can give this plane some air time.
Jan 12, 2011, 12:59 PM
WINS - Winch In Nose Sailplane
jaizon's Avatar
Thanks to all for the mini-lesson on this setup. I tried before and failed. Now I see why. RCGroups at its best!
Jan 12, 2011, 11:51 PM
life long racing nut & modeler
granada don's Avatar
I just saw a very neat way of mounting the spoiler servo , the builder just cut a rectangle servo slot in the wing rib no exta mounts wood etc.

The airplane is in the Electric Sailplanes under ' show us your plane ' by cebola, the builder is recordcap posted today the plane is grey & clear with a bit of orange a very nice build job.

Jan 13, 2011, 01:21 AM
Bone Breaker
Lammergier's Avatar
I have trying to figure how I want to install spoilers on my Sky 1.7
I have had this picture for awhile. Not sure where I got it so I could give credit. Looks simpler...or is it?
Jan 13, 2011, 02:32 AM
life long racing nut & modeler
granada don's Avatar
It looks like that rod might bind in the servo arm without a ball end , or set the servo in 90 dedrees to what it is in the pic and have the servo run inline with the rib.
My 2 c. worth

Jan 13, 2011, 08:17 AM
winds light to variable
Kookaburra's Avatar
Here's my adaptation of Ray's mechanism using E-Z connectors shown in half-opened position [as fitted to 2.6m Habicht].

Process of trial and error to get it to work. Forward lug left intact. Servo mounted as high as possible in the bay to bring it towards hinge axis; rod goes below horizontal with spoiler blade in closed position. Used servo disc instead of arm so that rod could be anchored either side of servo axis and leave maximum sliding room for spoiler blade connector.

Works fine on bench [aircraft still under construction] and locks closed securely without stalling servo.

Thanks Ray.
Last edited by Kookaburra; Jan 13, 2011 at 06:12 PM.
Jan 13, 2011, 10:09 AM
agony sweetns the victory
atjurhs's Avatar
Ray, I too have had difficulties using your method.

I do have it installed on one of my planes, but the problem I have with that install is that the spoilers don't go all the way down (closed) as if they don't have enough closing power, but the servos are not whimpy. So I'm confused? Do you have any idea what I'm doing wrong in the install's geometry?

Also what do you mean by "front servo lug" ? You state that the front servo lugs have been removed in the mock-up photos and the front servo lug has also been removed on the blue Topaz. What I thought to be the front servo lug is shown in both photos, so again I'm confused?

Thanks, Todd
Jan 13, 2011, 10:16 AM
agony sweetns the victory
atjurhs's Avatar

I've used that method before on a RES with a single "unibrow" spoiler, except I had the servo rotated 90degree from that shown in your pic. It works very well, BUT the issue I had with it is that I had a very thin airfoil and in order to get the spoiler in a near 90deg deployment the metal pushrod connecting the servo arm to the the spoiler tube had to be so long that when the servo was closed the servo arm extended below the bottom of the wing surface into the fuselage. Maybe I didn't get the geometry right to keep the pushrod short, I don't know, but it worked really well.
Jan 13, 2011, 01:08 PM

Spoiler Links

Todd - Without seeing your installation I can only guess as to why your spoilers wonít close properly. I suspect you might have: 1) a mechanical interference between the servo arm and the spoiler arm when reaching the closed position or 2) the lower wire rod end might be hitting the spar. Take a good look at CHIPGIBBS diagram in Post #1. The three bottom drawings clearly show the relationship of these two items when the spoiler is closed (I copied Chipís excellent diagram for my own future use, thanks Chip).

To answer your other question Todd about removing the servo lug. The pictures also show that I removed the forward servo lug from the blue HS-55 servo. This particular servo is the same servo I originally used in the Topaz and is shown in the 2008 article. The black HS-56 servo shown with the blue HS-55 has not had any of the lugs removed Ė itís my unused contest spare.

Since my original RCGroups article in 2008 Iíve updated the system slightly by replacing the blue HS-55 servos with HS-56 servos to take advantage of the HS-56ís multiple (three position Horizontal and Vertical) mounting lugs. The actual operation of the spoilers remain unchanged. Using the HS-56 servo I can now attach the servo with one mounting screw (horizontal lug) and a bit of servo tape along the rib. I made the change to permit quick replacement at a contest if needed. In my favor, I havenít had the need to replace the servos. Once again, note how close the servo is located to the spar (my reason for removing the servo lug to get the servo pivot point near the spoiler hinge line).

KOOKABURRA shows great use of a servo wheel instead of an arm to place the EZ links on both sides of the servo pivot point Ė very nice (Iíll file that one also). Thanks ĎK.

I hope this helps.

Jan 13, 2011, 01:21 PM
Registered User
Wrench's Avatar
I've used the "sliding rod" install before, you don't need 3 easy connectors, you only need 2.

The one on the servo arm away from the spoiler can be deleted by a simple 90 degree bend in the wire to protrude down through the servo wheel. There is no real force on that end and only needs to hold the rod centered to the servo wheel. Lighter and cheaper.
Jan 13, 2011, 05:42 PM
It's gonna be YUGE!!!
LVsoaring's Avatar
Originally Posted by Wrench
I've used the "sliding rod" install before, you don't need 3 easy connectors, you only need 2.

The one on the servo arm away from the spoiler can be deleted by a simple 90 degree bend in the wire to protrude down through the servo wheel. There is no real force on that end and only needs to hold the rod centered to the servo wheel. Lighter and cheaper.
Wrench, could you post a pic or diagram? I'm having trouble creating a mental image of what you mean.
Jan 14, 2011, 12:46 PM
Registered User
craigrrr's Avatar

I prefere simple

On most of my RES planes I use an HS55 servo with a long arm that pushes directly against the bottom surface of the spoiler.

Spoiler is retracted by a rubber band segment attached from spoiler surface to surface that servo is mounted on.

I have found that if servo is placed properly and arm is long enough, the spoiler will deploy approx 90 degrees (if desired).

I like this method because:

1. Adjustment is not critical; results in no pressure on servo in the non-deployed position.

2. Weight is minimal.

But I am only a sport flyer and I realize that competition flyers might need something more sophisticated.


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