Front Donuts for nose gear CTSW

[procharger]

I need to replace shock bumpers or donuts on nose gear where to order??

[procharger]

polyurethane dampeners where to order.

[Tom Baker]

Which airplane? Roger Lees has them, but they are the larger size for the CTLS, but in my opinion they will work on the SW. Flight Design USA has both sizes.

[procharger]

CTSW

[procharger]

I have Tundra nose I don't see anything but spring is that correct? polyurethane dampeners

I may not need not sure. Front end does move up and down like a spring.

[Tom Baker]

The polyurethane dampers were part of a free suspension upgrade for the nose gear. The original was a very heavy spring. 

[Roger Lee]

The CTSW started with springs in the front suspension, but they moved up and down too far and wore out the slot with the pin and would bang and bottom out up and down. So FD replaced the spring with 6 red polyurethane dampeners. Now the front end should be fairly solid with no up and down free play when you pick up the front end an 1"-2" and and let it down firmly. There should also not be any side to side motion. A quarter inch side to side is fine, but much more than that and the front suspension pin should be replaced.

 

If you need either dampeners or pin I have them. Just let me know.

I also have door lift struts and the CTSW (16) rubber engine mounts.

[BravoFoxtrot]

The attachment is the Flight Design procedure to replace the spring with the polyurethane pucks. They will sell you a kit with all the recommended parts to do this. That is mostly the pucks, washers, new nuts, and the 2 pieces described as "Support - DKA4010171". Roger or Tom would know if these pieces are required. If so, I believe the only source is from Flight Design. I think this is a good upgrade to do. My understanding is the concern is if the nose should come down hard, it can do damage to the strut assembly. If you order from FD, you might want to order a new pin (KA4010101) at the same time. If you take this apart and find it worn, you can replace it at the same time. Otherwise just keep it as a spare. Good luck.

Nose Gear Damper Exchange Procedure.pdf

[Roger Lee]

The stock pins are 11mm tall and 8mm wide. I make mine 11mm tall and 8.2mm wide. If the front slot is worn like the majority get then using a stock pin allows side to side wobble which you don't want. The slightly fatter pin allows you to hand fit the pin to make the front suspension solid. You could sand or file it down to be a perfect fit. Many front ends I do just take the 8.2mm because of normal wear. If you have wobble it will get worse and get get to the point of front suspension replacement. This should be a pre-flight check and is very easy to do. Takes all of 10 seconds.

The old red polyurethane dampers were 20mm tall and 20mm wide. Mine and I believe FD's are now 20mm tall and 25mm wide. They just last longer and do a better job.

[Tom Baker]

Flight Design has two different sized for the dampers. 20mm for the CTSW and 25mm for the CTLS or something like that. I just went through this trying to get the parts for the upgrade on a CTSW.

[Roger Lee]

I have used 25mm for years on both. 20mm get crushed to easily. 

[Mike Koerner]

I thought (probably a mistake) that the spring was more likely to cause PIO if you brought the nose down first, whereas the plastic discs would eat up some of that energy, and that Flight Design made the change to reduce the calamity associated with a botched landings.

Mike Koerner

[procharger]

I will check when I pull it apart going to do hose job first of the year, if pin needs replacing

I will fix,  if spring is still in there I will leave it, after 13 years I see no need to change it with

no real problems. You would think spring would do better on a hard landing than solid

dampers or what ever they are called. I have a lathe I guess I can make a pin when needed.

[Roger Lee]

The pin is very hard molychrome steel. You'd need a mill and not a lathe. 

[cdarza]

I had a pin made couple years back.  (not sure what the material was) Just recently, had shimmy on my last landing when I would brake hard..  The pin is a little loose again so am gonna give it  another try and fabricate another one.  I do worry I am doing damage to the shaft and might need to replace that if the gap gets wider.   

[Roger Lee]

If the gap were to get too wide for any pin then it can be welded on each side in the slot then file it back down to the correct width. I've done it 3 times with good success. 

[procharger]

Are you hand filing  or can you use end mill to keep everything flat

and square.

[Roger Lee]

Most don't need to reduce the pin width because they have already worn the slot wider. If you do need to reduce the width you can use a file or sander. Just pay attention and keep the side you're working on flat. This is hard metal.

[Tom Baker]

I have replaced a few using Roger's pins. I adjusted the thickness using a belt sander. I went slow, and it took a while because they get hot while sanding. I was able to adjust pressure to keep the true.

[Roger Lee]

I usually use a belt sander to if I need to trim any. About 70% of the time I don't need to trim.

[Vic]

How is the rotation axle and fork connected? Does that pin connect the fork to the upper axle somehow. I have not taken the gear apart and curious how this gear is assembled 

[Roger Lee]

A bolt down the center top to bottom and the pin keeps the two parts from turning. This project is fairly easy to do.

[Vic]

Thanks Roger

[Hans Gj]

To disassemble the leg, just loosen the bolt sitting on the underside and pull it apart?