Rudder pedal reinforcement KF-5?

[SilverFox5]

Hi,
I see many threads about the rudder pedal reinforcement for the KF-4.
Was there ever a SB for this issue on the KF-5?
My kit was supplied in May of 1994 and it does not have the gusset's welded on in the corners from the horizontal torque tube to the vertical pedal tube. I see the the S7 manual on line at Kitfox shows these gusset' s. Are these gusset reinforcements required for my KF-5? Attached is a picture of my tubes.

Joe Leeman
KF5
Rotax 912uls

[Dave S]

Joe,

Yup - you want to do that. There have been some that have snapped off. Fortunately a friend of mine had a pilot in the other seat when one of his pedals broke.

[alexM]

Can someone post up a pic with the gussets? I'm at the perfect spot to deal with this now

[DesertFox4]

A friend just had this happen on his model 5 while on short final. Got his Kitfox stopped with no damage. He has a flying buddy with a model 5 and had the same thing happen to his rudder pedal recently.

24535

[Cosmofly]

Anyone has a picture of a reinforced pedal with gusset?

[alexM]

I just went and looked at my pedal assemblies and they do not have the gussets. Then I looked in the KF7 manual and they are shown in most of the diagrams. Lousy picture shown here.
24536
I looked in the service bulletin section of my KF5 manual but there is nothing on this issue. If anyone has a copy of the SB, or at least the recommended change (sheet metal thickness, size, etc) it would be greatly appreciated. It's going to a a little tricky dancing around the rivets that are already installed.

[SomeDay7]

Alex, All the service bulletins are on the Kitfox website. Click on the home button and go to the technical facts button. They are listed for all Kitfoxes.

[Cosmofly]

Thanks... I am currently stripping a model IV, for a rebuild project. Maybe something I should consider...

[airlina]

When I built my Series 5 '99 thru '03 the problems had not yet been occurring . When the Service bulletin came out I didn't want to pull the rudder pedal torque tubes to weld gussets so I used another method that allowed me to accomplish a fix with the pedals staying in place. I will get to the hangar tomorrow for some pictures and an explanation. Coming up on 1000 hrs with no problems. Bruce N199CL

[alexM]

Alex, All the service bulletins are on the Kitfox website. Click on the home button and go to the technical facts button. They are listed for all Kitfoxes.

That's a gold mine, thank you. I'm seeing SB38 which only indicates Vixens, and I'm not finding a different one.

Thankfully the fix does not include welding. That reinforcement looks straightforward enough.

[Russell320]

Model 4 rudder pedal.

[Jcard]

Well dang.
Guess I have been looking for an excuse to tear into it and install those nice dimple die mudscraper pedals anyway.

[Kitfox Pilot]

A friend just had this happen on his model 5 while on short final. Got his Kitfox stopped with no damage. He has a flying buddy with a model 5 and had the same thing happen to his rudder pedal recently.

24535
That could have been a bad day.

[airlina]

OK , here was my fix done in 2003 without removing the rudder pedal torque tube assembly. Made up 4 stainless steel straps that were bent to the same tube size as the rudder torque tube, then riveted and bonded with a bunch of 3M scotch weld , which was the our old Hysol with a vintage kit from skystar. I really laid the scotchweld on thick with proper prep of both surfaces (the tube and stainless) to form an adhesive gusset effect.

[alexM]

That is exactly what is shown in SB38. I compared it to my KF5 pedal assemblies and saw where I would have to account for one pop rivet directly in the way and dance around one more (I don't see those rivets on your pedals above). I thought about it later and it would make more sense for me to drill those two rivets out and then use longer ones that go through the strap (along with hysol).

[jrevens]

OK , here was my fix done in 2003 without removing the rudder pedal torque tube assembly. Made up 4 stainless steel straps that were bent to the same tube size as the rudder torque tube, then riveted and bonded with a bunch of 3M scotch weld , which was the our old Hysol with a vintage kit from skystar. I really laid the scotchweld on thick with proper prep of both surfaces (the tube and stainless) to form an adhesive gusset effect.

In my opinion that's a very good alternative, Bruce. The design probably adds more than adequate strength, although I haven't tried to calculate that for sure. There is a lot of contact area and the shear strength is quite good - ScotchWeld 2216 is a very good structural epoxy and, again in my opinion, superior in some ways to the 9460 used currently. The only disadvantages to using it are a higher price and a little less convenient mixing ratio, since it isn't 1 to 1 like the Hysol.

[Jerrytex]

I welded the gussests on my KF 5 project. Epoxy primer and mailbox blue single stage urethane paint. Fairly simple modification.



2456424565

[SilverFox5]

Hi Bruce, thanks for posting the pictures. I like the idea. I think we will do something similar except i will try to get a couple rivets in the horizontal torque tube along with the 2216 adhesive. I will post pictures of mine when I get it done. But might be a while before we get to that project. Am concentrating on getting the Wings 100% complete and ready for Oratex so we can get them stored out of our way. Our kit did not have the fast build wings so we have a lotnhours invested. Only need to finish fitting the wing tips and epoxy on and fit the light standoffs. Picture attached with wings attached.

Joe

[alexM]

This is what my rudder torque tube assemblies look like. When I looked at the manual diagram it looked like I have extra rivets, but when I read the rivet call-out it clearly states 2 on top, 3 each side and 4 on the bottom.
A little tricky to weld around. I'll be fabricating the stainless strap and replacing some of these with appropriate length replacements for sure.
24567

[PapuaPilot]

This seems like a good thread to put this in.

Has anybody else had cracking on the rudder torque tube at the pulley brackets? If so, what did you do to repair it?

33376

[Dave S]

Hi Phil,

I have not had that happen; however, when I got my kit from the previous company (prior to John) both of the brackets welded to the fuselage botton for anchoring the rudder pedal adjustment arms were defective. One of the ears broke off with a little push - all of them were burned almost through the bracket. A little careful and judicious work with a small tip oxy/acetlyene torch cured it. OXY/Acet work is quite versatile and in this case, all the the metal was 4130 alloy so no particular issues.

If it were me, I'd pull the part, sandblast it, V-out the crack if necessary to assure complete weld penetration and do the repair with the torch, prime, repaint and go fly. The torch can also be used to normalize the welded area to stress relieve the area - commonly done in antiquity with airframe welding before everyone went to electric welding.

Most work today seems to be done with TIG or MIG systems which would not be my first choice (particularily MIG). Doesn't seem to be many people who are up on oxy-acet as in the past A competent OA welder would make short work of the repair.

[airlina]

This seems like a good thread to put this in.

Has anybody else had cracking on the rudder torque tube at the pulley brackets? If so, what did you do to repair it?

33376

You got my attention Phil, I have my plane home for some winter maintenance , will take a close look tomorrow. Bruce N199CL

[Eric Page]

Phil -- if you're willing to mail them for work, there's a guy near me, in Chehalis WA who does excellent welding and knows what's required for aircraft. He's made hundreds (thousands?) of engine mounts for Vans and does a PA-12 replica fuselage that's a work of art. He did the rudder tube reinforcements on my Series 5 (see my build thread). His name is Steve Furjesi (fur-jessy). Phone number on his website: https://super-12.com/

[PapuaPilot]

Hi Phil,

I have not had that happen; however, when I got my kit from the previous company (prior to John) both of the brackets welded to the fuselage botton for anchoring the rudder pedal adjustment arms were defective. One of the ears broke off with a little push - all of them were burned almost through the bracket. A little careful and judicious work with a small tip oxy/acetlyene torch cured it. OXY/Acet work is quite versatile and in this case, all the the metal was 4130 alloy so no particular issues.

If it were me, I'd pull the part, sandblast it, V-out the crack if necessary to assure complete weld penetration and do the repair with the torch, prime, repaint and go fly. The torch can also be used to normalize the welded area to stress relieve the area - commonly done in antiquity with airframe welding before everyone went to electric welding.

Most work today seems to be done with TIG or MIG systems which would not be my first choice (particularily MIG). Doesn't seem to be many people who are up on oxy-acet as in the past A competent OA welder would make short work of the repair.

I have a friend at work who does incredible welding. He usually does TIG. I made up some pieces today from 4130 steel to weld onto the pulley arms and the torque tubes. That will provide a little more support. I will post some pictrues after the repair.

This all started becuse I found a crack starting on the pilot's right rudder pedal tube in a preflight . . . I don't have the gussets welded on my pedals yet. I have been monitoring them and sure enough a crack started. I pulled out the rudder pedal assemblies to do the gussets and decided to start the condition inspection a couple months early.

Today I began installing my latest upgrade, the streamlined lift struts! I'm looking forward to having them and being back flying again. :D