---------------------------------------------------------- Europa-List Digest Archive --- Total Messages Posted Thu 05/03/18: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:46 AM - Re: Metallurgy and undercarriage legs (tennant) 2. 01:30 AM - Re: Metallurgy and undercarriage legs (clivesutton) ________________________________ Message 1 _____________________________________ Time: 12:46:00 AM PST US Subject: Europa-List: Re: Metallurgy and undercarriage legs From: "tennant" Hi Jonathan, Without knowing the material and the heat treatment condition it is difficult to give any advice. The important property for a spring leg is the yield strength, as stresses above this Level will bend the leg permanently. Assuming that the legs are quenched and tempered to increase the yield strength (probably SAE4130 as they are made in the US), any extreme heating of the metal will reduce it again so that the next "not so hard" landing will bend the legs again. I remember some years ago that the nose wheel legs of the RANS were regularly bent here in Germany, and we did an Analysis on one and changed the material to something slightly stronger, but not so that the structure would be damaged instead of bending on a hard landing. Sorry I cannot help any more, but I would suggest that a set of new legs is probably the way to go. Best regards Barry -------- Barry Tennant D-EHBT At EDLM - Germany Read this topic online here: http://forums.matronics.com/viewtopic.php?p=479804#479804 ________________________________ Message 2 _____________________________________ Time: 01:30:02 AM PST US Subject: Europa-List: Re: Metallurgy and undercarriage legs From: "clivesutton" Hi Jonathan, My two-pennarth is that there really may only be a handful of experts in the whole World who could give a fully informed answer to your question. Phase diagrams, microalloy additions, stress intensity factors - it's another world . . . However, general steel industry knowledge tells me that as per many spring steel grades, susceptibility to fatigue-cracking is made worse by the introduction of surface blemishes induced by e.g. corrosion, dents/local impacts and even factory surface hardening treatments like carburisation. So the risk of creating surface stress-cracks during a local bend repair for the typical grades used (AISI 6150 et al), is high. But your S6 friend may find the following EAA article more informative and authoritative and save themselves a lot of grief . . . https://www.eaa.org/en/eaa/aviation-communities-and-interests/homebuilt-aircraft-and-homebuilt-aircraft-kits/resources/building-articles/landing-gear-wheels-and-brakes/spring-steel-landing-gears Quoting here from a paragraph within it:- "You may as well face it, rebending and heat treating a spring steel gear leg in your own work shop, with a single welding torch, is not practical. You simply cannot get enough uniform heat on it, over a wide enough area, to allow you to bend the metal without inducing stress cracks. Countless builders have tried to anneal and straighten, or rebend, the gear legs themselves but only a few have succeeded while many have thoroughly botched the job" I hope useful regards, clive. -------- Live as if you were to die tomorrow. Learn as if you were to live forever. Mahatma Gandhi Read this topic online here: http://forums.matronics.com/viewtopic.php?p=479805#479805 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message europa-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Europa-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/europa-list Browse Digests http://www.matronics.com/digest/europa-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.