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Tail wheel chain length

D

d_kandle

FRIEND
Idaho
Is there any way to adjust the length of the tail wheel chain? If I use 5 links on each side the springs are quite loose. If I remove one from each side there is no slack. Any way to add 1/2 a link (or the equivalent length)?
 
Do you have the AN eye bolts? Sometimes adding or removing them will make that small change you are looking for.
DENNY
 
There are different pitches of sash chain available-- check your local Ace Airmotive store.
You might be able to find a size that allows for your required mength.
Or you can set it up too tight, with the 4 links of the chain you have now as described,
then pinch some or all of the links flatter--that'll loosen it up some.
 
Thanks for the video link (very clear).
However, when I tried to adjust the chain length as shown I got very different results. My problem is that I've got the short pawl. This is the way the tail wheel came from the SQ2 kit. My wheel turns quite a lot farther before it engages the pawl.
Should I be using the long pawl?
 
d_kandle said:
Thanks for the video link (very clear).
However, when I tried to adjust the chain length as shown I got very different results. My problem is that I've got the short pawl. This is the way the tail wheel came from the SQ2 kit. My wheel turns quite a lot farther before it engages the pawl.
Should I be using the long pawl?
Click to expand...

I prefer the long pawl on an off airport use airplane. It allows me to unlock in less space and maneuver around things in tighter areas. Have seen no adverse effects in landing or take off. I know of two people who prefer the short pawl which unlocks in 45 degrees of rotation.
This is a short pawl.
2014-04-26-08-20-16.png
 

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I prefer no slack in the tailwheel chains. The chain adjustment shown in the video is too loose for me. It has a delay between rudder movement and tire movement, I have tried it that way and the steering response was poor.

So the question is what about steering don't you like?

If it is poor/delayed response you need to eliminate slack. Stiff turning/ won't pivot when pushing tail sideways by hand, make sure it is lubed properly (NOT OVERLUBED) and 3 springs not 5. Want it to unlock sooner, go to long pawl. Cuation!! Tight chains can cause issues also so I would error on the side of slight slack as mike said.

DENNY
 
DENNY said:
So the question is what about steering don't you like?
DENNY
Click to expand...
I didn't like the part where the steering arm was getting bent or not holding. I didn't fully understand the internals. I had compression springs and a short pawl. The springs were getting completely compressed before the pawl released the steering arm. With the lighter weight steering arm the result was bent arms. It was suggested that I upgrade to the heaver steering arm. Then the weak point was the internals of the steering arm. It got so that the arm would not hold at all for a turn to the left (it would take very little rudder pressure to break it free) but the pawl was never doing the release.
It appears that the more tension from the spring which is present when the pawl releases the steering arm the harder it is on the internals. Short pawl and compression springs seems to be a non-working combination (unless the chains are very loose). I've ordered a long pawl. I would like to have positive steering, so I don't want to have a lot of slack in the chain. Using a short pawl, it would appear that unless I want to have a very hard pull from the spring when the short pawl engages the release spring, the chains need lots of slack (to avoid stretchering them too much prior to the pawl reaching the release spring).
 
d_kandle said:
I didn't like the part where the steering arm was getting bent or not holding. I didn't fully understand the internals. I had compression springs and a short pawl. The springs were getting completely compressed before the pawl released the steering arm. With the lighter weight steering arm the result was bent arms. It was suggested that I upgrade to the heaver steering arm. Then the weak point was the internals of the steering arm. It got so that the arm would not hold at all for a turn to the left (it would take very little rudder pressure to break it free) but the pawl was never doing the release.
It appears that the more tension from the spring which is present when the pawl releases the steering arm the harder it is on the internals. Short pawl and compression springs seems to be a non-working combination (unless the chains are very loose). I've ordered a long pawl. I would like to have positive steering, so I don't want to have a lot of slack in the chain. Using a short pawl, it would appear that unless I want to have a very hard pull from the spring when the short pawl engages the release spring, the chains need lots of slack (to avoid stretchering them too much prior to the pawl reaching the release spring).
Click to expand...

compression springs is the answer to you problem... or I mean that's your problem!
 
I'd never heard of this before, and have looked at several different exploded parts drawings pof the Scott 3200 & 3400 t/w's from the spruce & univair catalogs as well as from ABW. I just checked the Airframes Alaska / ABW website and found a drawing where they ID both a short pawl & a long pawl. When did they start offering two different length pawls, and which one is the original part? (I posted this on the t/w castering thread also)​
 
I would do as Mike suggested and get rid of the compression springs. Rebuild/lube according to Steves video and throw in the long pawl. That should do the job. Grease plays a important role especially in the cold. I use AeroSchell 22 now, the motion of the tailwheel is not as stiff in the cold compared to some other red grease.

I don't know when the long pawl came out, but when I had my Cessna problem last year that was the fix. On a side note never grind the pawl to make it work smoother that is what caused my problem. Polishing the end on a buffing wheel is all that is recommended.
DENNY
 
I figured out that the compression springs were reaching their limit before the steering arm released. I replaced them with standard cub extension springs soon after I got the heaver steering arm.
 
This is a simalar disscussion to what the guys flying the squirlly little HOT LANDING acro planes have continually. Lot's of those guys start out with the springs loose till they get over thier "Happy Feet" syndrome. Then they move to get rid of the commpression springs and learn that the mount is much more controllable as well as more docile when they do !
Interesting bit of knowledge on the long or short paw, Always learning some knew!
 
flyrite said:
This is a simalar disscussion to what the guys flying the squirlly little HOT LANDING acro planes have continually. Lot's of those guys start out with the springs loose till they get over thier "Happy Feet" syndrome. Then they move to get rid of the commpression springs and learn that the mount is much more controllable as well as more docile when they do !
Interesting bit of knowledge on the long or short paw, Always learning some knew!
Click to expand...

What is the alternative to compression springs?


Sent from my iPhone using SuperCub.Org mobile app
 
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