---------------------------------------------------------- Europa-List Digest Archive --- Total Messages Posted Fri 09/04/20: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:15 AM - Re: Nose Wheel Shimmy (Paul Hawkins) 2. 08:47 AM - Re: Re: Propeller? Gearbox? "Wow-wow-wow" resonance (D McFadyean) ________________________________ Message 1 _____________________________________ Time: 01:15:28 AM PST US From: Paul Hawkins <1963paulhawkins@gmail.com> Subject: Re: Europa-List: Nose Wheel Shimmy To kill shimmy 100% of the time full rudder preferably into wind but either way the will break the nose-wheel swinging from side to side, in the past I=99ve tried everything replacing parts raising the nosewheel and gen tly let down / slamming it down the only thing that works is catching it early with full rudder the shimmy will stops immediately straighten up and continue down the runway. The key to not getting shimmy in the first place *never ever* pull the power off just over the runway on short final, you=99ve got the speed right leave the power where it is until you land then kill the power or glide onto the runway from height. Cheers Paul G-ROOV 914 XS On Thu, 3 Sep 2020 at 22:30, Jeff B wrote: > > A little swipe of Nyogel 774VH on both sides of the fiber washer then > torqued to spec will solve the problem. > > Jeff > > "I believe that forgiving them is God's function. Our job is to arrange > the meeting." > > -Gen. Norman Schwarzkopf > > On 9/3/2020 11:58 AM, Matt Dovey wrote: k > > > > > > When landing on a hard runway I always get nose wheel shimmy. I've > checked the friction on the on the nose wheel fork and found no problem. > Has anyone else had similar problems? > > > > > > > > > > Read this topic online here: > > > > http://forums.matronics.com/viewtopic.php?p=498144#498144 > > > > > > > > > > > > > > > > > > =========== =========== =========== =========== =========== > > ________________________________ Message 2 _____________________________________ Time: 08:47:07 AM PST US From: D McFadyean Subject: Re: Europa-List: Re: Propeller? Gearbox? "Wow-wow-wow" resonance Can also be a worn propshaft bearing(s), where the shaft is rotating in the bearing (as normal) and simultaneously orbiting around the centre of that rotation (allowed by radial play). Duncan McF. > On 19 June 2020 at 14:58 clivesutton wrote: > > > > Hi Jonathan, what you describe is 'Heterodyning' or 'Beat-frequency' created by the difference between two noise or vibration frequencies very close together. > > Do you have a recording on e.g. a mobile phone that i could listen to - along with the engine speeds in play at the time? And what about:- > > 1) How the frequency of 'wow-wow' change if you speed up or slow down the engine a bit? > 2) How does the 'wow-wow' effect change with Airspeed? > 3) the CS mode idea is viable too - does it occur when that is turned off/the prop is not trying to hunt for optimum speed vs pitch? > > It's impossible to say from just the description given, but assuming the above items make a significant difference, my initial suspicions would be one prop blade with a slightly different prop pitch to the others and/or blade tip tracking differences between blades. Both of those parameters should be quite easy to check on the ground (no engine running needed) and reporting any variation you find? > > Clive > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=496930#496930 > > > > > > > > > ------------------------------------------------------------------------------------- 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.