Pietenpol-List: Weld cracks found

matronics · Post by **matronics** » Mon Jan 08, 2007 9:38 am

Original Posted By: "Dick Navratil"
Subject: Pietenpol-List: Weld cracks foundHi Piet'ersAs of late I have been fabricating my straight axle landing gear. I elected to use .120" wall thick 1 1/2" O.D. 4130 tube for the axle. There has been a lot of debate on this subject, of what is sufficient wall thickness for this axle. After the misfortunate forced landing of Iccarus Plummet a coupleof years ago there was substantial discussion on this site on the subject. The BHP Flying and Glider plans call for a 12 gauge tube, which equates to .109" wall thickness, so I figure I'm a little thicker, plus a stronger alloy. Anyway, I welded onto my axle two 1/2" dia. tubes to act as anti-rotate devicesso the axle can't rotate when the brakes are applied (a-la-Mike Cuy). I then took it over to the local engine shop on the other side of the airport herein Poplar Grove, with instructions to Mag-na-flux (magnetic particle non-destructive test) the welds. To my surprise they found two cracks! It wasexplained to me that when the weld cools, sometimes the weld area shrinks and"pulls" away from the base metal, thus causing the crack. I had to go back andgrind-out the cracks, and re-weld, then re-inspect.________________________________________________________________________________

matronics · Post by **matronics** » Mon Jan 08, 2007 10:31 am

Original Posted By: "Phillips, Jack"

matronics · Post by **matronics** » Mon Jan 08, 2007 10:54 am

Original Posted By: Ben Williams

matronics · Post by **matronics** » Mon Jan 08, 2007 4:20 pm

Original Posted By: "Jack T. Textor"

matronics · Post by **matronics** » Mon Jan 08, 2007 5:52 pm

Original Posted By: "walt evans"

matronics · Post by **matronics** » Mon Jan 08, 2007 6:43 pm

Original Posted By: "gcardinal"
Subject: Re: Pietenpol-List: Weld cracks foundWalt,You are absolutely correct in your assumption. I TIG welded this axle. Dan HelsperHelsper Sewing Corp.8186 Commerce Dr.Loves Park IL 61111PH (815) 885-4365FAX (815) 885-4366________________________________________________________________________________

matronics · Post by **matronics** » Tue Jan 09, 2007 1:46 am

Original Posted By: Clif Dawson

Brodhead Pietenpol Association