If you over torque the bolts , they will stretch and get thinner. Then they wear more easily.
The way the Ercoupe wings distribute the load, the wear of both wing lugs should be even, but if all upper lugs are wearing faster, that indicates more load along the top spar. However, Univair lines out the torque values for the wing bolts. Think of them as pins, not so much as bolts: The recommended method for tightening the nuts on the wing attach bolts is to draw nuts down tight and continue tightening as required to line up the nearest slot and cotterpin hole provided you do not exceed 100 ft-lb dry torque on the front bolts and 10 ft-lbs dry torque on the rear bolts. If a fitting lug is worn out, that's a problem. Univair does not have any replacement lugs and an oversized bolt would have to reamed in. I don't know if there are any over sizes available, but one can assume that the lugs will wear egg shaped, you'll have to ream the hole perfectly round first to assure a longer lasting fit. Hartmut To: [email protected] CC: [email protected] From: [email protected] Date: Mon, 30 Nov 2009 19:34:00 -0800 Subject: Re: [ercoupe-tech] Wing fitting wear ??? Eddie, I have found several Coupes that had main wing bolts with less than proper torque which allowed the wing bolts to ride up and dowm and wear the fittings. It always seemed to be the top bolt. After inspection and proper torque value, there appeared to be no further wear noted at the next inspection. It is very critical to have a calibrated torque wrench and the service manual if you are going to work on your own plane. If you can't find the torque for these bolts, contact me offline. Tom..............A&P/IA --- On Sun, 11/29/09, Eddie Wilson <[email protected]> wrote: From: Eddie Wilson <[email protected]> Subject: [ercoupe-tech] Wing fitting wear ??? To: [email protected] Date: Sunday, November 29, 2009, 6:48 PM Installing new Wing attach hardware for my Alon, got me thinking about the steel fittings on the fuselage. Being curious,I cleaned the bolts and the holes of all grease and oil and inspected the fittings. I noticed that when I slide the bolt into the lower attach fitting, it has a real nice close tolerance fit. But, when I put the same bolt in the upper fuse attach fitting, the bolt is much looser. Is this normal wear? Is there a min.- max. tolerance on the diameter and elongation of these holes? What is the fix when these holes get super "sloppy"? oversized bolts? Thanks again! _________________________________________________________________ Windows Live Hotmail: Your friends can get your Facebook updates, right from Hotmail®. http://www.microsoft.com/middleeast/windows/windowslive/see-it-in-action/social-network-basics.aspx?ocid=PID23461::T:WLMTAGL:ON:WL:en-xm:SI_SB_4:092009
