hollow aluminum axles

[8475]

My plane has hollow aluminum axles. Are these at risk of cracking? What's the current wisdom on reliability for these? Thanks.

[5115]

I don't see any problems with them if you are doing only wheels and no skis.
Like any axles at annual we inspect the circular part of the root for cracks. They do recommend solid alu or steel axles when you do skis (I have solid alu for years and doing skis), but if i'm not mistaking, that was for C170, for C140 it was just a suggestion.

John or others may have the actual paperwork mentioning those recommendations

[6898]

At next annual have them removed and dye tested. Or do a field approval for Grove there really good looking that is what we did.

[6597]

Yes, dye check them. Grove has drop in replacements but make sure you have the right bolt size pattern. They will provide you with a copy of a 337 and I understand they can provide a letter from a DER. Here's a thread you can read... viewtopic.php?f=8&t=622&hilit=grove

[5115]

David, please highlight mer on these pictures. I have never seen before some die penetrant pictures.
Are those with all the red spots discovered cracks???

[6597]

The one on the left shows a faint trace of penetrant at the juncture of the cylinder/axle and base. The one on the right is just sloppy on my part. The base portions that have red blotches are just slop. I was specifically interested in the cylinder/axle junctures. Both axles I scrapped.

Something like this process if you are not familiar... https://www.magnaflux.com/Magnaflux/Blo ... ting-Video

[5115]

Thank you David, this is very instructive

[8475]

Yes, dye check them. Grove has drop in replacements but make sure you have the right bolt size pattern. They will provide you with a copy of a 337 and I understand they can provide a letter from a DER. Here's a thread you can read... viewtopic.php?f=8&t=622&hilit=grove

David, thanks for the advice. This is good information. I'll get the dye-pen done this next annual.

[6643]

David:

You say you rejected both axles. Were you able to confirm cracks in either of the ones pictured? The one on the left doesn't seem to exhibit a pattern indicative of a crack; it looks more like a little pitting in the radius where the axle joins the base.

[6597]

John,

My IA and I waffled a bit but the dye activity we noticed on both seemed to be in essence the lower/forward areas of the axle/base interfaces, what we might expect from 70 years of landings. These were a few I found locally for 'just in case', grubbing thru a box at the old Columbia Airmotive facility. Now that you've got me curious I'll probably re-check them.

I can tell you that Groves weigh 1# 5.1oz each and the old ones I found weigh 11.9oz each FWIW.