---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Sun 06/15/08: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:05 PM - Re: Engine Vibration (Guy Buchanan) 2. 01:51 PM - Re: Engine Vibration (Roger Lee) ________________________________ Message 1 _____________________________________ Time: 01:05:59 PM PST US From: Guy Buchanan Subject: Re: RotaxEngines-List: Engine Vibration At 03:14 AM 6/13/2008, you wrote: >It seems the bolts attaching prop to engine were fractionally too >long so that torquing them up wasn't tightening them properly. We >are talking microns here but enough to allow a resonance on certain >days given certain conditions. A little wear on the washers reduced >the tension causing the sudden change. Temperature may have been >expanding or contracting various bits such as hub and bolts to make >more or less tension as well. A little wear on the hub and "smoke" >on the back of the hub suggested that things were moving. Geoff, Thanks for posting this. I believe I have the same problem, but couldn't figure out the "smoke". Guy Buchanan San Diego, CA K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar. Do not archive ________________________________ Message 2 _____________________________________ Time: 01:51:26 PM PST US Subject: RotaxEngines-List: Re: Engine Vibration From: "Roger Lee" Hi Guys, If you have smokey bolts, rivets or whatever it usually means something is lose and rubbing. It may not look or feel lose to the touch, but it is under stress or vibration. We just had a Lightening aircraft crash here in the Tucson area. The Lightening is a low wing ELSA homebuilt. It was fairly new with about 30-40 hours or so. It lost the prop in low level flight and from what I have been told second hand was that he tried to turn back toward a landing site with a 180 degree turn. He was way too low and went in hard. It was a fatality. He would have been better off staying straight and stalling into the low ground cover bushes. He may have turned over, but he would have walked away. I won't make a 180 turn less than 400' in my FDCT and you better be doing things right at that altitude. Sometimes a messed up plane is imminent, but picking the lesser of the evils for a landing site and saving your skin is a better choice. It's sad when anyone dies enjoying what they love. -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Service Center 520-574-1080 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=188003#188003 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rotaxengines-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RotaxEngines-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/rotaxengines-list Browse Digests http://www.matronics.com/digest/rotaxengines-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.