---------------------------------------------------------- RV-List Digest Archive --- Total Messages Posted Tue 02/11/14: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:03 AM - Re: Empennage SBs SWAG (Tracy) ________________________________ Message 1 _____________________________________ Time: 01:03:15 AM PST US Subject: Re: RV-List: Empennage SBs SWAG From: Tracy GV, the only point I would disagree with you on is that resonant vibration i s the horse rather than the zebra. Tracy Sent from my iPad > On Feb 10, 2014, at 21:48, vanremog@aol.com wrote: > > Charlie- > > You misunderstand me. I would love to see the evidence, even if it was ex traordinary. Neither am I arguing against dynamic balancing, as mine was dy namically balanced by Dave Morss before it even flew the first time. > > It could be aerobatic motor mounts, the horizontal stab going into resonan ce, flutter or any other dynamic force. As with Occum's razor, I am looking for the most likely causes. Horses, not zebras, although I admit it may tu rn out to be zebras... > > -GV > On the other hand, there appears to be zero evidence of *any* cause, at le ast from Van's A/C, yet the cracks are there, on some airframes. And Tracy i sn't the 1st to mention it as a possible source of the problem. What's so ex traordinary about the assertion? Many have commented about major 'tail shake ' at startup & shutdown > -----Original Message----- > From: Charlie England > To: rv-list > Sent: Mon, Feb 10, 2014 6:23 pm > Subject: Re: RV-List: Empennage SBs SWAG > > On the other hand, there appears to be zero evidence of *any* cause, at le ast from Van's A/C, yet the cracks are there, on some airframes. And Tracy i sn't the 1st to mention it as a possible source of the problem. What's so ex traordinary about the assertion? Many have commented about major 'tail shake ' at startup & shutdown. > > Charlie > >> On 2/10/2014 8:01 PM, vanremog@aol.com wrote: >> You could propose that, Tracy but, aside from there being zero evidence f or that assertion, we would need to see more than just your word on it. As t hey say, "Extraordinary claims require extraordinary evidence". ;o) >> >> -GV >> -----Original Message----- >> From: Tracy >> To: rv-list >> Sent: Mon, Feb 10, 2014 4:03 am >> Subject: Re: RV-List: Empennage SBs SWAG >> >> Might I propose (with tongue only slightly in cheek) that the problem is o n the other end of the airplane. The only conceivable root cause of HS / E levator spar cracking is a resonant vibration of these parts excited by that throbbing thing at the nose. Possibly primary engine frequency during ope ration (aggravating factor being prop imbalance) or the tail shaking violent ly during startup and shutdown, in which case problem may be related to numb er of start/stop cycles rather than hours or aerobatic stress. >> >> RV-4 1850 hours >> RV-8 220 hours >> (Both - Mazda rotary engine powered) >> >> Sent from my iPad >> >> On Feb 10, 2014, at 1:57, Jack wrote: >> >>> RV7A 781JG >>> 466 hrs >>> No aero >>> No cracks HS or E >>> >>> Sent from my iPhone >>> >>> On Feb 9, 2014, at 10:41 PM, vanremog@aol.com wrote: >>> >>>> Might I suggest as you all go about your SB inspections, that you repor t back to the lists with your a/c type, TTA, inspection results (no cracks, c racks, extensive cracks) and your flying profiles (no aero, mild aero, hard a ero) to help us understand the overall fleet condition and assess the airfra me life of these designs under the normal range of conditions. Some of you a re quite easy on these airframes while others I'm sure are yank and bankers. >>>> >>>> As for my RV-6A situation at 1130 TTA, no cracks or distress found in e ither the horizontal stab or elevator, with a history of mild to no aerobati cs, a few dozen hours in mountain wave conditions during cross countries and only one time to +6gs during botched maneuver. >>>> >>>> -GV > > > > t="_blank">http://www.matronics.com/Navigator?RV-List > tp://forums.matronics.com > _blank">http://www.matronics.com/contribution > > > 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rv-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RV-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/rv-list Browse Digests http://www.matronics.com/digest/rv-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.