Oleo Springs, again

captainpat · Post by **captainpat** » Fri Feb 22, 2008 09:39

It's been a while since the subject of spring quality from Wag and Univair has been discussed. N83806 has a decided list to starboard and I have determined that it is the oleo spring (thanks to all the good info earlier in this thread). Has anyone used a WagAero spring lately? Have there been any quality issues over the past couple of years?

Should I replace both springs and seals while I have it hoisted up?

Thanks for any info.

Pat

Mnflyer · Post by **Mnflyer** » Fri Feb 22, 2008 19:10

Hi Pat, the best thing to do is remove the oleos and check them to make sure its your spring thats bad, it could just be that the packing has compressed to the point that its letting the wing drop some or it maybe the spring. This happened on my Champ, I ordered a new spring and when I got the oleo out the spring was loose but after removing it it measured within 1/8th of an inch of the new one and afer installing new packing the spring was very tight and the installed assembly brought the plane back to level, I think all the bad springs are now out of the system.
Hope this helps some.

captainpat · Post by **captainpat** » Sat Feb 23, 2008 11:35

Mnflyer,
Thanks for the reply. I think I will do as you suggest and measure the old spring first. Somewhere on this topic someone posted the measurements for a new spring.

Pat

Mikek · Post by **Mikek** » Sun Feb 24, 2008 14:26

captainpat wrote:Mnflyer,
Thanks for the reply. I think I will do as you suggest and measure the old spring first. Somewhere on this topic someone posted the measurements for a new spring.

Pat

http://www.hangar9aeroworks.com/Aeronca ... hInfo.html

captainpat · Post by **captainpat** » Sun Feb 24, 2008 17:11

Thanks Mike. I knew I had seen the measurement somewhere.

Pat

CF-KYE · Post by **CF-KYE** » Tue Jul 01, 2008 11:53

The bad springs are not all out of the system yet. I just got myself another one and will be replacing it when I get home next week. Don't want to name the supplier as I haven't let them know yet and I'm sure they'll replace it. The replacement however is gonna get a bit of a mild workout in my press before I change it out.

Dan

Captgrumps · Post by **Captgrumps** » Tue Jul 01, 2008 12:54

If you know the wire size, type (oit temp?) number of coils and the ends (closed and ground, open or just closed) and length should be able to figure the max load if the strut compression length is known. That will tell if the spring takes a"set" which is what it is called when a spring is overloaded in stress. If I can find my old spring slide rule and wire info I could probably dust off my brain and figure it.
Years ago in my quest to get into aviation I worked for a spring company in spring design checking what engineeers sent us. Spring design wasn't big in engineering schools then.

Doug

Mikek · Post by **Mikek** » Tue Jul 01, 2008 17:32

Grumps wrote:If you know the wire size, type (oit temp?) number of coils and the ends (closed and ground, open or just closed) and length should be able to figure the max load if the strut compression length is known. That will tell if the spring takes a"set" which is what it is called when a spring is overloaded in stress. If I can find my old spring slide rule and wire info I could probably dust off my brain and figure it.
Years ago in my quest to get into aviation I worked for a spring company in spring design checking what engineeers sent us. Spring design wasn't big in engineering schools then.

Doug

Are they not able to have the "Set" removed during the making of the spring, by compressing it before grinding the closed ends of the .375 wire?

Mike

Captgrumps · Post by **Captgrumps** » Wed Jul 02, 2008 00:58

Mike--

They do not compress the spring after manufacturer. The spring is manufacturered to take a load at a certain deflection and certain weight with a certain type wire and wire size.. If the spring takes a set it is permanent and the spring loses its elasticity. When the spring ends are ground they are usually set between grinding wheels and the operator controls the grinding by not putting any real deflection in the spring. Set is PERMANENT and the intended elasticity of the spring is gone forever. If you compress a spring to your desired length and it stays there you have induced a set , shortened the spring and weakened it. Might as well trash it and go for the right length, diaameter, wire size and desired deflection within the wires limits.

I designed two springs for my old Stinson JR-S and Travel Air 6B (6000) . One was wound right and the other left so they would not bind each other.. One fit inside of the other and one was smaller/ longer and was a spring to take taxi weights thereby designed to be the taxi spring. The shorter larger spring was the landing spring. On landing the taxi spring collapsed to the height of the landing spring, but did not take a set and then the landing weight was absored by the landing spring.

Most springs like in the Aeronca gear are made of oil tempered wire.

Some spring makers will probably make a spring for aircraft, and some will not so some folks tell the maker it is for farm equipment. Afteralll there is not part number on a spring. Ever get a spring with a yellow tag?

Doug