SonexBuilders.net

On landing, I experienced a heavy shimmy that resulted in the airplane ending up in the grass. Inspecting the hydraulic brake and wheel pants mount, I noticed that it was free to rotate.

So I removed the axle assembly, and this is what it looks like. Did this start as a circular shape? It's not clear in the plans.

Can a sideload on landing cause this kind of damage?

Hi Hambone,
I can't comment on what might have caused that damage, but I do believe those were originally round holes. Here are some pictures of my SNX-L01-05 axles that I have yet to install:

Thanks for that. I see how this could have been a tab with a circular hole before the damage, and some force opened it up. I'll see what Sonex has to say about it.

Those holes that the pin goes through takes all of the braking force. Probably should be checked often.

There are lots flying successfully out there but I beefed mine up because I'm a fraidy-cat!

I can see how that one bolt and tab take the rotational wheel braking force. I only have 10 hours in the Sonex, and have never used heavy braking. I believe the damage could have been caused by getting sideways on landing and almost ground looping. Or they could have already been damaged when I bought the airplane, or in the 2000 mile UHaul trip.

Murray Parr wrote:There are lots flying successfully out there but I beefed mine up because I'm a fraidy-cat!

How did you beef them up? I'm considering just taking it to a local machine shop to fix it. It's critical that the hole is exactly in the right place to match the hole in the brake assembly and wheel pants mount.

Are you using the Sonex hydraulic brakes, or Something Else?

Something Else might require a different attachment to the axle.

It looks to me like you need a new SNX-L01-05 axle, (https://www.sonexaircraft.com/eshop/car ... SNX-L01-05 $112) or to take the axle assembly off the gear leg, cut and grind the remnants off, and use the plans to cut a new tab out of 4130 steel, perhaps the next size up, and have a skilled welder weld it on.

karmarepair wrote:Are you using the Sonex hydraulic brakes, or Something Else?

He has Sonex hydraulic brakes. We were discussing outside of the forum. My thoughts would be to weld on a new tab and skip the mounting bolt hole matchup to the axle. I'm also posting here to see if there is any agreement or contrary experience to share.

Tracy O'brien had a better idea.
He also made/makes axle assemblies that install the same as the Sonex unit with the four-hole plates.

It seems to be asking a lot of a single attach point to stabilize the wheel pant as well as absorb the torque from braking.

Hi all, Randy,
Thanks for bringing this up. Sonex orig.designed the axle with the single small tab. To be used with
the cable operated azusa shoe brakes. After the sonex hyd. brakes came out it put more load on this tab.
There were some failures . Where the whole brake assembly and wheel pant rotated.
Before our Waiex first flew in 2014, we modified our axles with the square plates we purchased
from tracey obrien. He sold the square plates seperately, i had posted on here, a few people
also installed these. Tracey also sold the complete axle as randy has pictured.
What was nice about the square plates was the holes lined up with the tab hole and the holes in the red brake
assembly. They also had the center axle hole drilled. We simply bolted up the sq. plate with the axle assembly, took to a local welder in tucson,
and had them welded on. You can then use 3 out of the 4 holes to bolt up the red brake assembly.

I was reading this thread last nite, and then was searching the web for tracey obrien . I couldnt find anything.
Does anyone know, is he still in business? on another winter trip to the warmer south of US?

In anycase suggest people modify their axle assembly with a steel sq plate with 4 holes . Keep the tab . Use it to hold the sq plate for welding. Maybe sonex could modify their axles to have a bigger sq. steel plate to bolt up to.
added: i found on the web www.Tracyobrienmarinedesign.com
on webpage they indicated they produce aircraft axles landing gear and motor mounts.
i messaged them asking if they making these parts for sonex. awaiting reply.
WaiexN143NM
Michael.