Decathlon tailwheel leaf springs

J

John Kempton

New member
I am unable to get my 8KCAB tailwheel pivot pin set up vertically, I think because the leaf springs have sagged a little with age. I can get the springs reset locally, cheaper than buying new ones. The parts are listed as 3-1543-3 down to -1, -1 being the lowest and longest spring, but I can't find any specs such as angles for each spring.
Rather than just bend them all 10 degrees and hope, does anybody here know what the actual angles should be?
Has anybody else done this before (rebending) and was it a good idea or a bad one?

Any info appreciated, i am in Australia and there is not a lot of Bellanca knowledge.
 
I had the same problem a couple years ago and ordered a new spring set from ACA(I don't remember them as being expensive). We took the old sagging springs and had them rebent to the same angles as the new ones. We kept the old ones as a spare.
During our most recent annual in March we discovered that the new springs were twisted. How they got that way we haven't a clue, but we put the old rebent set on and they are working fine. We will have the twisted set straightened and set aside as a spare.
I would suggest that if you rebend your springs, you bend them so that the pivot post is actually past vertical with no load in the airplane. Ours is set so that when no load on the airplane we have approximately a 5 - 10 degree angle to the pivot post with the bottom being farther forward than the top. When 2 people are inside, the post is almost vertical, still with the bottom ahead of the top.
We haven't had a t/w shimmey since setting up this way.

Ron
 
Hi Ron,

Could you explain what you mean by "twisted" in your post above? I installed new springs too, it stopped the shimmy problem. I installed them a few months ago, and now it seems (by eyeballing--no measurements taken yet) that my tail wheel is canted a few degrees to the left when viewed from behind---the weight seems to be borne by the left side of the tail wheel tire. It may have been that way before and I didn't notice it.

Thanks!

bill
 
Same thing here, I was standing behind the aircraft and noticed that the tailwheel was not straight up and down(vertical). Ours was twisted the opposite direction than yours, we were running on the right side of the tire.
We removed the leaf springs and set them on the floor and could see they were clearly twisted. No idea what caused it. We replaced the leaf spring and our wheel is now square, vertical or whatever you want to call it.

Ron
 
I have successfully had the springs rebent.
Before we removed them, the off vertical angle was measured/guessed as 15 degrees, so I guessed that bending the springs down 15 degrees would give a vertical pivot. Had a skilled engineering shop do the job and it worked out well, though the centre spring needed to be replaced.
One problem is that with three x thirty year old springs, how do you know which if any are the original and correct? That is where the skilled engineer is an asset.
Anyway, it all worked out and once fitted the aeroplane was easy to ground handle with only one hand and little effort; also less stable to taxi. I had just become accustomed to a gradual change in things, much happier now I am back to normal.

If I lived in the USA I would just buy new ones, but as I am far away the freight would be very painful on such heavy items and the rebend became a good option.

Also cured a major fuel leak by fitting new tank filler caps. An old cap had developed an air leak via a cracked seal, looked very like a holed tank.
 
I bought new tailwheel springs a few years ago - freight to Australia wasn't too bad.
John - your airplane went well at Parkes.
 
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