DownUnderFlier Posted August 26, 2021 Report Share Posted August 26, 2021 IMG_4489.MOV Our CT2K's Trim Tab hinges were worn, giving a vibration through the airframe at certain speeds. Didn't want a fluttering Trim Tab, so replaced all the Trim Tab hinges with new FD ones and now there is no slop in the Tab's hinges. But discovered that there is slop due to due to wear in the Control Rods themselves .. Now waiting on new Control Rods. 8-) IMG_4491.MOV Quote Link to comment Share on other sites More sharing options...
Mike Koerner Posted September 10, 2021 Report Share Posted September 10, 2021 My CT2k tab hinges have a lot of play as well. I damp the oscillations with tape, but I'm worried that the pin in the outer piano hinge might wear through someday. How did you position the new hinges for riveting? And why does the pushrod have an extension riveted on to it? Why didn't they just use the right length rod in the first place? Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted September 10, 2021 Report Share Posted September 10, 2021 Those rod end shafts are two piece, the slop is probably coming from that rivet securing the two parts becoming loose over time. You could replace the rivet (maybe use an oversized rivet, which is a thing that is sold for this purpose), and/or fill the gap between the shaft parts with high-strength epoxy (JB Weld in the states, not sure the equivalent in Oz). You could also get a welder to put a bead of weld around the gap and really remove the issue...probably dissimilar metals though (main shaft Aluminum, end steel), not sure if welding could be done. Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted September 10, 2021 Report Share Posted September 10, 2021 4 hours ago, Mike Koerner said: My CT2k tab hinges have a lot of play as well. I damp the oscillations with tape, but I'm worried that the pin in the outer piano hinge might wear through someday. How did you position the new hinges for riveting? And why does the pushrod have an extension riveted on to it? Why didn't they just use the right length rod in the first place? Mike the typical pushrod in an aircraft is made from a tube that can be cut to any length, with ends installed similar to what is shown above. Think of it as an adapter from the tube to the rod end. It also allows for a lighter weight pushrod. Quote Link to comment Share on other sites More sharing options...
Runtoeat Posted September 10, 2021 Report Share Posted September 10, 2021 I went thru looseness on this system a few years ago. I found that tightening all components in the system stopped the flutter. Need to go into the complete bracketry of the horizontal stab and trim thru to the trim wheel at the console. This means removal of the elevator to get to these parts. If the trim hinges are loose, these must be replaced. Not an easy job and must be done by someone who knows how to do this. This was done on my CTSW to comply with the horizontal stab trim tab reinforcement SB issued for some CTSW's. Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted September 10, 2021 Report Share Posted September 10, 2021 The hinges are not to bad to replace aside from drilling out the stainless steel rivets. A pneumatic rivet puller for installation is a must. Quote Link to comment Share on other sites More sharing options...
DownUnderFlier Posted September 11, 2021 Author Report Share Posted September 11, 2021 19 hours ago, Mike Koerner said: My CT2k tab hinges have a lot of play as well. I damp the oscillations with tape, but I'm worried that the pin in the outer piano hinge might wear through someday. How did you position the new hinges for riveting? And why does the pushrod have an extension riveted on to it? Why didn't they just use the right length rod in the first place? Definitely replace the hinges ASAP. My process: For Stabilator rivets, hold rivet tail with vice-grips to ensure the rivet doesn't spin when drilling the head off - can't do that for TrimTab rivets as the tails are inside the TrimTab. Use 5mm cobalt drill bit & lubricant with very slow drill speed till almost through the head. Use stiff, sharp spatula/chisel to pry head off the rivet - easy for the TrimTab hinge-wing as you are working against the stainless steel hinge surface .. be careful with Stabilator hinge-wing as you don't want to damage the surface or structure of that. Position the new hinges using 5/32" Cleecos for riveting. I only had one rivet that spun in the TrimTab (examining the tail of that rivet, it was a pre-existing condition caused by a slightly too large hole during assembly) .. in that position a new rivet, the next size up was used. Rivet away ! Notes: Most stressful - carefully drilling the rivet heads Most time-consuming - jiggling the TrimTab to get all 12 rivet tails from inside the TrimTab out the 6mm holes at either end. Most physical - installing the new rivets by hand rivetter (gave more feel than an pnuematic one) ControlRods: The hours of wobbling TrimTab caused wear between the ControlRod aluminium tubes and the steel ends rivetted into them. I decided to replace these and get snug-fitting steel/aluminium ends rather than try and fix what was worn (53Euro each). Hope this helps keep your CT2K (and you, Mike) happy and flying for many more hours ! Cheers, David Quote Link to comment Share on other sites More sharing options...
Mike Koerner Posted September 11, 2021 Report Share Posted September 11, 2021 David, Thanks for the description and photos! Tom, Thanks for explaining these pushrods. Dick, I hope I don't have your problems. It's not flutter in the control system I see, just the tab vibirating and the hinge pins wearing. Andy, If my rod ends are lose, I think I'd go the 53 Euro route, like David, rather than try to glue them together (and no, you can't weld aluminum to steel, or a thick part to a thin part either). Quote Link to comment Share on other sites More sharing options...
DownUnderFlier Posted December 16, 2021 Author Report Share Posted December 16, 2021 Our new TrimTab ControlRods finally arrived. FD have dramatically changed the design. 30grams heavier but eliminated the wear-points. Happy Christmas ! David Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted December 16, 2021 Report Share Posted December 16, 2021 Hmm...I wonder if new hinges & rods might be a good idea for a CTSW as well...? I'll check the amount of play in mine and see if it makes sense. Quote Link to comment Share on other sites More sharing options...
DownUnderFlier Posted December 17, 2021 Author Report Share Posted December 17, 2021 No unwanted movement in the TrimTab at all, now. Happy Christmas. David IMG_4907.MOV Quote Link to comment Share on other sites More sharing options...
Runtoeat Posted December 20, 2021 Report Share Posted December 20, 2021 Nice report. The new rods are really improved. Did you re-balance the stabilator assembly? Thanks David. Quote Link to comment Share on other sites More sharing options...
DownUnderFlier Posted December 23, 2021 Author Report Share Posted December 23, 2021 On 12/21/2021 at 3:58 AM, Runtoeat said: Nice report. The new rods are really improved. Did you re-balance the stabilator assembly? Thanks David. Hi Dick, No, haven't re-balanced the Stabilator assembly. Flys well and vibration has gone. Happy Christmas. David IMG_4907.MOV Quote Link to comment Share on other sites More sharing options...
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