HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old May 30, 2012, 04:21 PM
Registered User
San Francisco Bay Area
Joined May 2001
332 Posts
Discussion
Can RDS slip? How to fix??

After a rough landing with the flaps down one of my flaps has shifted as shown in the attached photo.

Could the RDS hardware have shifted somehow? Or bent?

Or could the RDS hardware have shifted on the servo output shaft?

Any suggestions on how to fix this would be greatly appreciated.

John
John Webb is offline Find More Posts by John Webb
Reply With Quote
Sign up now
to remove ads between posts
Old May 30, 2012, 04:26 PM
Registered User
Joined Jan 2008
4,190 Posts
John:

RDS can slip, for sure. But, there are two possibilities, I believe.

One is that the servo is stripped. That's the easy way out: remove the servo, and install a new one.

The other is that the wiper is indeed rotated inside the carbon torque tube that couples with the servo output. That's the hard way out, but still fixable.

The wiper on your particular installation (if I see it correctly - it looks like the RDS kit from RCBuilder) is a stainless steel rod inside a carbon torque tube. You must remove the wiper and torque tube, pull out the stainless steel rod and re-glue with new epoxy. Then, re-assemble the thing, just as if for the first time.

The best instructions are on the web site for www.RCBuilder.com

It's fiddly, but doable. I speak from experience.

Yours, Greg
glidermang is online now Find More Posts by glidermang
Reply With Quote
Old May 30, 2012, 04:52 PM
Registered User
San Francisco Bay Area
Joined May 2001
332 Posts
thanks Greg

It's actually a 6 servo Vandal.

I'll start by removing the servo and go from there. I guess this is where having the hands of a surgeon would come in handy.

John
John Webb is offline Find More Posts by John Webb
Reply With Quote
Old May 30, 2012, 05:42 PM
a.k.a. Bob Parks
Glendale, AZ
Joined Jun 2008
2,083 Posts
It sure looks like the servo is rotated differently then the other wing. I would check the servo mechanics, especially for stripped gears, by trying to move the shaft.

I did have one of my rcbuilder RDS wiper shaft installs slip on an early Lighthawk. Once it was out I just cleaned off the shaft & re-glued it, make sure there is a flat spot on the steel shaft for the glue to bind.

To remove the servo just set the servo arm flat, push away from the servo on the yoke & pry the servo out from the opposite side so it slips off the yoke pins. You should be able to get the wiper out of the pocket after you remove the servo.

I made a tool for removing glued in servos using one of those computer slot covers you find on the back of PC cases. I narrowed the bent end on a grinder so it slipped right under the servo & gave some leverage.

BP
bbbp is offline Find More Posts by bbbp
Reply With Quote
Old May 30, 2012, 10:56 PM
G_T
Registered User
Joined Apr 2009
5,531 Posts
Whenever I've built an RDS system, I've taken a dremel cutoff wheel and cut a key slot lengthwise in the wiper where it inserts into the torque shaft. Then it is installed with West Systems epoxy possibly with something like milled fiberglass added. The slot does not extend quite to the edge of the torque tube, to prevent a weakened wiper.

Additionally, try to clean the inside of the shaft with some denatured alcohol before gluing it up. Of course, also clean the wiper and don't touch it after cleaning! Skin oils do negative things to epoxy bond strength.

After this type of install, even if the glue bond fails between the dissimilar materials (stainless steel and carbon fiber composite) the keying will keep it functional.

Gerald
G_T is online now Find More Posts by G_T
Reply With Quote
Old May 31, 2012, 10:51 AM
Hey was that a Thermal ????
Joined Nov 2009
2,448 Posts
Great advice especially what GT said. That key slot is a life saver. The last couple of RDS installs I did I used Hypo tubing as per Drella's original design. The bond seemed to hold mnuch better when compared to the carbon tube system. The natural lubricity of carbon makes it more difficult to get a good bond.

paul
The_Builder is offline Find More Posts by The_Builder
Reply With Quote
Old May 31, 2012, 01:05 PM
Time for me to Fly...
Mr. Wiz's Avatar
United States, MI, Fenton
Joined Jan 2000
8,201 Posts
You guys ever tried JB Weld on stuff like this? It's incredibly strong and available at just about any hardware. I use it to bond titanium pushrod ends into CF pushrod tubing on giant scale stuff. Just a little sanding is all it takes and it never lets go. I actually used it to reattach an outside rear view mirror on my sons Grand Prix. The mirror housing is a black plastic material. It's now held for two years.... car washes, bumpy roads and all. It's good stuff.
Mr. Wiz is offline Find More Posts by Mr. Wiz
RCG Plus Member
Last edited by Mr. Wiz; May 31, 2012 at 01:26 PM.
Reply With Quote
Old May 31, 2012, 03:03 PM
Jim C
ShadowFalken's Avatar
Joined Sep 2009
1,473 Posts
Quote:
Originally Posted by Mr. Wiz View Post
You guys ever tried JB Weld on stuff like this? It's incredibly strong and available at just about any hardware. I use it to bond titanium pushrod ends into CF pushrod tubing on giant scale stuff. Just a little sanding is all it takes and it never lets go. I actually used it to reattach an outside rear view mirror on my sons Grand Prix. The mirror housing is a black plastic material. It's now held for two years.... car washes, bumpy roads and all. It's good stuff.
Various formulas of JB Weld. I like the slower versions for best bond. I too used it for carbon/Titanium push-rods. Then I found Hysol. Application specific formulas and stellar results.
ShadowFalken is offline Find More Posts by ShadowFalken
Reply With Quote
Old May 31, 2012, 06:26 PM
Original Bloody Spadder
proppy jon's Avatar
phoenix
Joined Jul 2004
1,129 Posts
back to the topic look at the coupling it definately has turned 1 stripped or jummoed gear train
2 the coupling came off and turned then was clock wrong when it was put back on alot of builders dont put the screw in on the servo i had sevral vandals with that prolem what i would do is clock the coupling correct and see if it happens again i bet the servo gear stripped or jumpped teeth
hope this helps john
proppy jon is offline Find More Posts by proppy jon
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Curving relative wind, how much slip is ideal in turns, yaw strings videos aeronaut999 Modeling Science 7 Jun 19, 2012 10:58 PM
Discussion **Update** Fixed my busted plane - now it's forgotten how to fly! - Fixed! kenzietech Beginner Training Area (Aircraft-Electric) 7 Apr 05, 2012 07:29 PM
Help! How can this be fixed..weld, JB Weld...etc? ABADGTP Fuel Plane Talk 20 Nov 06, 2011 07:07 PM
Discussion Quad yaw response. How can I fix it ? oded mazor Multirotor Talk 4 Sep 24, 2011 07:15 AM
Discussion How to fix t-rex tail belt input gear slip? delamar Mini Helis 9 Jul 11, 2006 01:47 AM