Cessna 120-140 Association

Some time ago I read the suggestion that hollow axles should be replaced with solid axles on my 1946 Cessna 140, N89297 S/N 8323.
Well, I checked, and I do have hollow axles. We may put skis and/or floats on this aircraft in the future.
An inquiry to Aircraft Spruce resulted in a request for a part number!!!
Of course, we did not find a part number in the Aircraft Spruce catalog.

Requesting pointers to the solid axle article, or a part number and discussion about this.

Thank you for your consideration.

Jer/ Eberhard, Colorado

I just put Grove axles on my 140 solid aluminum. There is a thread on here with my approved 337. Make sure you call Grove to order the correct P/N as Spruce doesn't list it.

Grove doe make several iterations on the bolt patterns, and there is the ability to 337 them. IIRC Randy Thompson made an argument that solid axles may not be as strong as you think. Also, were the axles for skis aluminum or steel? I'm sure someone will chime in....

Yes, still looking for more data... "solid axles may not be as strong as you think", ok, please tell me!

Are "the axles for skis aluminum or steel"? Please chime in. We are considering skis and floats on this Cessna 140.

Thank you for your consideration.

Jer/ Eberhard, Colorado Mountain Flying CFII, Airplanes & Gliders.

Yeah, sorry to stir the pot, a lot of the steel/aluminum/hollow/solid discussion I see on the 170 website regarding skis and floats. I recall on the old 140 website before it went down that there were comments along the same line with the 140's. There is a link for hollow steel axles for 170's, however there are probably bolt hole patterns and paperwork legalities so I mention it only for discussion. There are several 337 examples you can use for the Grove installation if you go that route.

https://www.airforms.biz/index.php?rout ... uct_id=780

For the Grove information http://www.groveaircraft.com/5016.html

For the Grove axle bolt patterns http://www.groveaircraft.com/axletemplate.pdf

IIRC, the only difference between the 140 and 170 axles are the diameter of the bolt holes.

6643 wrote: ↑Wed Feb 20, 2019 1:20 pm IIRC, the only difference between the 140 and 170 axles are the diameter of the bolt holes.

I believe this is correct. Early 170's had 120/140 gear legs, sans the mid level step holes.

I looked into this and was active on the threads that were lost.

The aluminum that was used on the early axles, (aircraft s/n 8800 and earlier) 6064?? comes to mind(not sure if that is correct) was discontinued and Cessna went to 2024 T3 which is what Grove uses.

A. I find it very hard to believe a solid axle would not have more strength than a hollow one.
B. You can find steel axles for 170's and 180/185's.
C. Steel certainly would be stronger.

If you can get a field approval for the Groves, by all means that is the way to go.

I recall there was a ski plane axle made by P. Ponk, I think...

Oh, I also recall that a hollow axle is stronger than a solid one of equal mass, due to the fact that it will have a much larger diameter, and the strength is carried mostly in the outer portion of the part. However, given two axles of the same diameter and material, one hollow and one solid, the solid one will be stronger (and heavier.)

I'm looking to do the Grove axles on my annual this year. Looking at the 337s that other members have used, there is a note on the back, *See attached previously approved 337. Anybody have a copy of the mysteriously previously approved 337? Or is this a case of a long line previously approved 337s, approved with a previously approved one that was approved on the basis of another previously approved one that had also relied on a previously approved....whoa, I totally got lost there.... Where is 337 001?

Actually, aren't you looking for "337 zero"?

What you need is one with all the pertinent data, even if it isn't the first.