National Aeronca Association Bulletin Board

Gus,
Right you are regarding the Maule compression springs, although I still don't like those screen door chains that come with the setup. I haven't had a lot of time to work on the problem lately but am going to go back to my Maule wheel and compression set up with a 'loose' setup once things get back to normal. Right now I'm up to my neck getting ready for our breakfast/flyin next weekend. After that we have annuals on all three Champs. Hopefully things will slow down after that and I get to working on the situation.

Mike

I've been told, and am running 45 lbs psi in my Scott 3200 8 inch pnumatic wheel. Not having a problem.
The wheel has to be able to hit the ground turned to any angle because you are using your rudder untill the wheel can control your direction.
Any loose bushings, or bearings must be fixed first, then fix the angle of the king pin, then your problems will go away.

I did not like the control when I had slack in the compression spring set up. I had to use a lot of rudder (too much in my opinion) to get any turning movement at all. Especially at lower speeds. With the springs having a bit of compression built in, the control respnse is immediate. And much better to my likeing.

However it seems impossible to have the same amount of compression on the two springs. Because they are both of different length and different strength. That being the case, it would seem impossible to get the tailwheel to "center up" or align perfectly when the tail is off the ground and the rudder cetered. if they both had 1/4 compression the weaker spring would be pulling a lot less than the stronger one and thus result in the tailwheel to be off alignment.

I believe the Maule instructions state that each compression spring should have about 1/4 inch compression in each. However I find this nearly if not completely impossible and secondly, they do not state if this 1/4 should be with the airplane resting on the tail at empty weight, Gross weight of with the tailwheel free of contract with the ground as in flight? Since the leaf spring will change the length between the rudder horns and the tailwheel in each of these configurations it is hard to know what to do.

In my case, the previous owner told me he had just rebuilt the tailwheel with new bushings etc. While I have not taken the wheel apart to verify, everything the previous owner told me he has been honest.

At this point, I think I need to deal with the kingpin alignment as I can see that the top leans forward a few degrees. I think I need to evaluate if I need a new tail leaf spring. Or to get it re-bent. The problem is, if I go to a truck place that bends leaf springs, I have no idea how much and where to tell them to bend it.

It sure would be easier to just have some shims made to adjust the kingpin. I can't beleive these are not commercially available! I may have a source at a High school that has a milling machine so that I could have a few shims made for me. I will still have to make an estimattion as to the degrees of shim I need. Also what type of steel material to have them made from etc..

Always aired the 10" tailwheel tires to 50#. They are so small and firm that they can be nearly flat or flat and you won't know it without checking them. (I know it is a pain) or until you tear the valve stem. I always made a habit of checking them--had them on a 180/185 and Stearman. If you don't keep them aired the tire will spin on the rim and rip the valve stem out. Same thing happens when people don't check the air in 8:00x4's on Cubs. I once sold tires and tubes -- sold more tubes than tires in all the above.

Doug

the leaf spring is not that hard to re arch a few degrees. Three small blocks in a large vice can do it. Better equipment, better job of it, but not that hard to "get-r-done"

Holcombe wrote:the leaf spring is not that hard to re arch a few degrees. Three small blocks in a large vice can do it. Better equipment, better job of it, but not that hard to "get-r-done"

Does bending cold that not take the temper out or otherwise leave the spring weaker each time you bend it? As any metal once you exceed its yield strength it bend easier next time. And repeated bending further weakens it.

I thought in order to rebend a spring leaf correctly, the leaf spring should be heated to take the temper out, re-bend, and then retempered to put the spring back into it? If that is the case, it seems like a lot of work and I may end up paying 50% of the cost of a new tailspring from Wag which is listed as $145 or so.

But i also don't "need" to spend $145 right now if I can avoid it.

One thing I absolutely do not want to happen is to have the leaf spring fail. That ends up with rudder damage and possible wayward aircfart into the weeds with God knows what other damage.

I'm sure that if the spring bent once, it will bend again. Re arching might get another season out of it, or simply to the next time you really whack it down again or beat it up on rough grass.
If the new part is an option, I'd order it and fly with the re arched one till you are ready to install the new one.

Tail wheel shimmy can do real damage. Never let that condition go un fixed.

Remember, Free advice is worth exactly what you payed for it. Especially mine.
richard

I have a C85-12 with about 275 hours since major. The guy I bought it from built it up with Chrome cylinders which were a son-of-a-gun to break in... It took over 100 hours for oil consumption to get where I wanted it to be. Along the way I noted the reduced oil consumption running the straight grade.

As to the Camguard <http://www.aslcamguard.com/index.php> my engine has the 0-200 crank and etc. installed under the Aircraft Specialties STC. The folks at Aircraft Specialties strongly recommend the use of camguard and I went along with it. Only time will tell if it does any good...

The main thing is to use an oil appropriate for the season and change it regularly (along with the filter if you have one.)

Tim