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NOSE WHEEL STEERING NOT A GREAT SYSTEM


MileHighCTLS

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This year's annual revealed bent rod ends (in the tunnel) on the ends of both nose wheel steering rods!  It is clear that this came from moving the nose wheel while stationary or moving at a crawl. The design seems pretty flimsy and lends itself to excessive forces on the rods.

Now the challenge is changing the rod ends inside the tunnel, without losing my religion!

Does anyone have any techniques for reaching the bolt head and nut running thru the rod ends?  It seems rather impossible to maneuver inside that tunnel with two hands. Do I need to remove the whole upper instrument panel to get better access? (BTW, the same access problem for getting to the fuel line going out to gascolator)

I am sure someone has already done this and I am hoping they can shed light on the topic.

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This would be very rare. This isn't a flimsy design and there are over 1800 Flight Design's that don't have this issue. It's fairly common on may aircraft. I have never seen or heard of this unless there was some kind of impact. Pushing it backward or forward should never have done this. That said there is an SB out for some CTLS's that did not have a stop inside that area for the peddles and it could be tweaked. The lack of the stop caused peddles to be depressed too far. Check to see if your plane fits in the serial number range and if the upgrade was done.

To get inside the lower tunnel it is usually by feel only and one hand. Someone on the engine side can be a big help by turning the rod end or rod. It is a PITA, but can be done.

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In my experience bent rod ends come from using a tow bar or tug to move the airplane on the ground. Unless there is something seriously wrong with the rotational unit for the nose gear there is very little stress on the rod ends. The force you feel in the rudder pedals is from the centering mechanism not the nose wheel.

I'm not sure what vintage your airplane is, but the one I have in the shop access is through the left panel and the switch panel. You might want to take the centering mechanism out, so you don't have to deal with the tension. Other than that it should be straight forward. Remove the rod from the bell crank, and pull it forward through the firewall. Replace the rod ends, tighten the jam nuts, and slide them back in and reinstall. It is not a real easy job, but just work slow and patiently and you will get it. 

IIRC the fuel line to the gascolator is on the front side of the firewall, and access is best achieved with the mount removed from the front of the airplane. I normally do this hose while doing a rubber replacement and I have the mount off anyway. If you take the muffler off you might get enough access. The hose from the fuel valve to the fuel flow is pretty straight forward. The fuel flow transducer should be mounted on a block just inside the firewall, with the nipple for the hose to the gascolator passing through the firewall.

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Thanks to both of you! BTW, my CTLS is 2011. I bought it with 30-hours on it 5-years ago. I do have the pedal stops installed. It was not like that when I bought it, as I was in on all inspections and we've never had an impact or "extra" hard landing. I believe improper use of the tow bar could be the cause. 

As far as design goes ... the steering rods on all of my other past and present planes have been way beefier, including other light sports. And the manner of moving the push rods seems odd. The plate actually pushes on the bolt!

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There's an alternative to the rudder stops if you have the old style push design. If you look into the foreward tunnel and see a large stainless steel cage, you have the integrated stops and spring design. If it's just a couple PVC blocks and a spring, you have the old design and should have stops up on the front.

I prefer the later cage design. Significantly more robust and despite using bolts for the steering horn, I haven't had bent rods or anything like it despite everyones love to try and force the pedals over at anything more than a walking pace.

By the way, as I tell everyone else: if your pedals are stiff, you're probably going too fast, and you're gonna bend something. Slow down and it gets a lot easier to turn.

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7 hours ago, Anticept said:

It's in a safety directive. One of the first for LSs

Absolutely! Thank you so much. That SB also calls for marking the nose wheel, to keep tow-bar use within a specific steering range. Now, after reading this and talking to the factory, I realize how easy it is to bend the rod ends or damage the pedal stops. And I am certain, I am responsible for this.

I pride myself, after years of aircraft ownership, of familiarizing myself with the idiosyncrasies of particular aircraft by reading all ADs, directives, alerts, bulletins and service letters regarding the plane. Somehow this particular one eluded me!

There is no doubt that this forum is one of the best owner forums I've ever been part of. The knowledge base in incredible!

The saying, "There is wisdom in much counsel" has never been more true than here.

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  • 4 months later...
14 hours ago, gorilla said:

Can anyone please confirm that the rod ends at the nosewheel end are 6mm bore with a 8mm right-hand male thread?  Thanks. 

Just replaced the nose gear rod ends on mine a couple of months ago and it definitely was a 8 mm bore with a bushing inside.  Was having trouble finding the FD part(s), but was able to get an exact match through an online retailer, but I don't know what your regulations allow.

 

Edit:  Looking at the FD parts catalog, I would not have known there was a bushing.  That is left out of the picture in it.

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3 hours ago, garrettgee2001 said:

Just replaced the nose gear rod ends on mine a couple of months ago and it definitely was a 8 mm bore with a bushing inside.  Was having trouble finding the FD part(s), but was able to get an exact match through an online retailer, but I don't know what your regulations allow.

 

Edit:  Looking at the FD parts catalog, I would not have known there was a bushing.  That is left out of the picture in it.

I've seen a couple different set ups from the factory over the years. Different bushins, spacers, and attaching hardware.

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8 hours ago, Tom Baker said:

I've seen a couple different set ups from the factory over the years. Different bushins, spacers, and attaching hardware.

On that note then, and I have asked myself this before having helped work in a shop on certified aircraft, does FD not publish updated parts catalogs based on serial number or year, or is it just "here is a parts catalog, you figure out what is different" type of approach?  I have found several things on mine that are sometimes very different than the IPC I have.

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I know it is semantics, but I think you mean standard category aircraft rather than certified. The issuance of an airworthiness certificate makes it certified, but it is what the certificate is certifying that is different.

For the most part Cessna, Piper, Beech, and some other mainstream standard category aircraft have really good parts manuals. In the case of some of the older fringe standard category aircraft the Flight Design manual is levels above what they have. Taylorcraft for example would make changes mid year on how they did things. There is not really any parts manual to document the change. At best there may have been an internal letter that no longer exist now. for them there is nothing that you can really say was standard.

 

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I think a lot of maintenance issues on light sport need to be resolved with common sense and experience. The current manuals have a lot to be desired. Back in the 40's and 50's it was expected that the mechanic knew all the basics and the manuals were there for model specific info. The j3 cub maintenance manual is 11 pages and half of that is rigging info.

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2 hours ago, Tom Baker said:

I know it is semantics, but I think you mean standard category aircraft rather than certified. The issuance of an airworthiness certificate makes it certified, but it is what the certificate is certifying that is different.

For the most part Cessna, Piper, Beech, and some other mainstream standard category aircraft have really good parts manuals. In the case of some of the older fringe standard category aircraft the Flight Design manual is levels above what they have. Taylorcraft for example would make changes mid year on how they did things. There is not really any parts manual to document the change. At best there may have been an internal letter that no longer exist now. for them there is nothing that you can really say was standard.

 

Yep, standard category was the word!  Cessna has good stuff for their early 2000s and beyond.  Use there software almost daily.  FD does ok with documentation, but definitely a lot to be desired.

 

51 minutes ago, Madhatter said:

I think a lot of maintenance issues on light sport need to be resolved with common sense and experience. The current manuals have a lot to be desired. Back in the 40's and 50's it was expected that the mechanic knew all the basics and the manuals were there for model specific info. The j3 cub maintenance manual is 11 pages and half of that is rigging info.

Common sense and a little bit of experience definitely goes a long way with these aircraft.  I have not found an issue yet that could not have been resolved without a parts manual, but it does occassionly take a little trial and error with parts to get exactly what you need.  I was getting ready to spend a small fortune on a rod end bearing for the nose wheel, until I realized there was a bushing in it.  They don't really make an 8mm rod end with a 6mm bore, which is what FD depicts in my parts catalog.  Was able to find exactly what I needed at McMaster once I figured out the bushing.

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BTW ... I just went thru an annual and replaced steering collar on strut, bolts, rods, rod ends and space bearings. The system works well when used properly but is weak overall. The main problem is you can overpower the left and right limits (stops) because the rod ends easily bend. When you're standing outside the plane using a tow bar you cannot easily "feel" the stops. It's easy to go past the stops and do damage.

Once I saw how the system works, I paid careful attention to the tow bar feedback and when I felt the slight stopping pressure, I marked in on the cowling as a reminder. I suggest others do the same.

Another note of caution ... do not attempt to use rudder pedals while standing still! That too can cause damage. Use rudder pedals only when moving forward. 

As a comparison, my 1946 Ercoupe is built like a BSH! There's nothing you can do to bend the steering mechanism, which is connected to the yoke (since there are no rudder pedals). 

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