Tailwheel Spring Clamp Failure

[jdmcbean]

Does this mean John is ready to start selling the Aluminum leaf and brackets? Previously when I checked it was in development undergoing "testing"

Yes.. it is available.. We have not done an official release of the new tail wheel spring and it has been tested on the 5-7 aircraft. While I suspect it will work fine on the IV the angle of the spring may be an issue with some tail wheels. Works great with the 8" pneumatic Maule, ABI-3200, Scott 3200, and Matco's 8" and 10". (most of the testing was with the ABI-3200 and the Matco)
$349.00 for the spring and mounting hardware.
$59.95 for the draw spring, clips and chain.

[Paul Z]

That is a nice looking tail spring, very clean.

[Danh]

I like it, this is real clean

[Flybyjim]

I hope this is in the kits being sent out now

[jrevens]

That's very nice looking! How does it compare in weight? Also, my experience with solid aluminum springs is that they are usually stiffer than steel leafs. Is that the case here?

[jtpitkin06]

At some point all this strenghtening becomes a moot point because a large impact on the tailwheel assembly will then cause the whole fuselage tail structure to bend; which is much harder to repair. Maybe a bolt that shears before that happens is not such a bad idea. Just thinking.

How about making the tailwheel attachments and the fuselage so that neither part breaks under hard landing impact?

There is a lot of torque on the springs if impact occurs while the rudder is fully deflected and the tire/wheel is off centerline. It appears the AN3 size bolts are a bit too small for the anticipated loads. In addition the bottom plate under the springs may be a bit bit too thin. A thicker bottom plate and AN4 bolts seem warranted. These are simple mods that might limit potential failures. The rear of the fuselage is pretty beefy at the tailwheel attachment area so I doubt it needs any new bracing.

Jp

[kitfoxnick]

I've broken two so far. One off airport j turning to take off and tail wheel hit a hole. The other was when I was on skis.

[jiott]

Nick,
What broke? Was it the AN3 bolt shearing off?

[Paul Z]

According to what I read it was the bolt. "The AN3 broke just beyond the grip length in the threads. AN3-12A is the origional bolt length. AN3-13A would be a better solution." The shear strength at a cross section of the threads is significantly less than the shear strength at the full diameter of a cross section of the full bolt diameter.

[n85ae]

My support plate is .125 4130, and my bolts AN-4 it fit together just as well
with that hardware as with the AN-3's so to my mind, the AN-3 debate is
silly, and pointless. Use AN-4's.

Jeff

How about making the tailwheel attachments and the fuselage so that neither part breaks under hard landing impact?

There is a lot of torque on the springs if impact occurs while the rudder is fully deflected and the tire/wheel is off centerline. It appears the AN3 size bolts are a bit too small for the anticipated loads. In addition the bottom plate under the springs may be a bit bit too thin. A thicker bottom plate and AN4 bolts seem warranted. These are simple mods that might limit potential failures. The rear of the fuselage is pretty beefy at the tailwheel attachment area so I doubt it needs any new bracing.

Jp