Scott 3200 Arms

[yerich109]

Guys,

Of the troops that have a 3200 on their machines, has anyone had problems with the arms bending upward? Last year the right side arm on my 3200 bent up, so I bent it back down. About a month later it happened again. I had been having some other problems with it such as steering (it had been operating as full swivel, with no steering), so I had it broken down and rebuilt.

We found out that the fork casting had broken on the inside, the thrust plate was bad, and the arms were also replaced.

Everything worked great for a few months, but now the right arm is bent upward again. Probably about 40 degrees. I hate to just bend it back because I know it will make it weaker.

Anybody have any ideas????

[NY86]

OK, I'll bite. First thing I'd do is figure out why it's bending. The pull on the arms should be pretty close to straight on. It takes a lot of force to bend the arms. Sounds like, at least, something's very out of line. (You do have springs between the rudder and the tailwheel, right? It would seem impossible to exert enough force through the spring to bend the arm...)

WadamI missing?

[jgerard]

What about putting a slight twist at the end of the arm where the hole for the steering spring is. The idea is to have the vertical centerline of the hole perpendicular to the load applied by the spring. If I remember correctly the steering bar on the rudder that the rudder cables attach to has a slight twist at the end where the cable bolts attach for the same reason.

Jason
N43643

[Forrest Barber]

The force is not in alignment.... the Cessna 180 does the same. I think the correct tailwheel for them is the 3400?? In any event the ears are already bent up at the tips about 90 degrees to get the proper alingment. I use the 3200 , but the springs are very light and appparently do not force the ear up at any time in operation. Put her on a saw horse and move things about & see if you can find the problem.

[NY86]

forget I mentioned alignment. Red Herring. The spring should not be able to exert enough force to bend the arm given the limited travel of the rudder bellcrank. And, if it's pulling that hard, why isn't the wheel just turning to relieve the strain? (What's preventing it from turning?)

Any way this could be happening while the plane is tied down?

[Forrest Barber]

OR not kicking out when it is supposed to do so. WE had the same arm bending problem on a 1929 Waco CTO here that had a 3200 on her. One side was getting too much pressure. we extended the arms up a bit and adjusted the swing do it would allow the free swivel to take palce without bending things.....that is why some testing needs done prior to approval of these items being installed on the older aircraft..... the previous picture shows the extreme angle of the spring to arm. plus my tow hitch of course...

[jgerard]

Forrest-

How come your tailwheel steering tiller a welded steel plate instead of a cast aluminum tiller that bolts into the bottom of the rudder?

Jason
N43643

[yerich109]

I noticed that the picture shows the non-compression type springs. Mine has the compression springs. I think that it may be bending when I am taxiing to the left, then apply right rudder. Now that I think of it, it feels like the spring is bottomed out in this scenario. Eurika, that sound like a valid explanation doesn't it?

So, how do I keep this from happening, should it even happen at all?

Can I just make the switch to the spring type in the picture? Will the tension wear the lower rudder hinge point?

What say you?????


Thanks for all of the responses,

[Forrest Barber]

The welded steering arm is used later on at Taylorcraft to prevent the cast ones & spring steel ones from breaking off!!
the compression springs should not be used on this type system unless you have a Maule , then one of each is the recommendation.... sure that could be the reason for the bending.

[yerich109]

Thanks Everyone. This is one of those things that I have just assumed were correct, since it was on the aircraft when I bought it two years ago. I'll get the tension springs put on, and hopefully fix this problem forever.

Blue Skies,

[NY86]

Yeah, compression springs can bottom out. That would explain how enough force gets applied to bend the arm. Scott has a special spring for the 3200. I'd go for that if I were you. It's a heavy tailwheel and needs a heavy spring to keep it in line...

PN 3239, NOT PN 2151

[jgerard]

Hey Forrest-

Is there a drawing or and parts available to modify the older rudders to the newer "welded steel" type tail wheel steering arm? Or should I just get a Piper one and have the machine shop turn the shaft down?

Jason
N43643