---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 10/20/21: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:37 AM - Re: Vacuum pad shear couplers (Christopher Cee Stone) 2. 03:18 PM - Re: Fw: Aero Electric Post (Neal George) ________________________________ Message 1 _____________________________________ Time: 08:37:53 AM PST US From: Christopher Cee Stone Subject: Re: AeroElectric-List: Vacuum pad shear couplers Another response to accessory drive couplings https://www.kitplanes.com/disintegrated-drive-coupling/?utm_source=ActiveCampaign&utm_medium=email&utm_content=KITPLANES+Weekly&utm_campaign=KP+Weekly+2021%2F10%2F12 ...chris On Tue, Oct 19, 2021 at 3:56 PM Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > So the idea that a plastic shear coupling can > be 'overstressed' by some anomaly in field > excitation simply has no foundation in physics. > It is far more likely that material or a process > used to fabricate the coupling is deficient. > > I found some exemplar shear couplers from a > vacuum pump pad. The two disks at each end > are engaged by pins on hard, drive parts. > The cylinder of plastic between the disks > is the shear section. > > Being plastic, it is not a trivial matter to > craft a well calibrated part for shear strength. > B&C went through some iterations of materials > before settling on a production configuration. > > I'm pretty confident that Plane Power is having > difficulty with their present batch of parts. > > Bob . . . > > Un impeachable logic: George Carlin asked, "If black boxes > survive crashes, why don't they make the whole airplane > out of that stuff?" > ________________________________ Message 2 _____________________________________ Time: 03:18:39 PM PST US From: Neal George Subject: Re: AeroElectric-List: Fwd: Aero Electric Post Gentlemen - A new Tempest-branded alternator coupler was installed and tested yesterday. New graph and comments from Gregg follow Neal The graph below was from the test flight yesterday, 19 Oct. The gray line is normalized rpm (actual rpm/150) from the left mag, blue line is volts, amber is amps. Takeoff power was applied around 22:13:13. The alternator field was turned on at around 13:31. The dips at 11:25, 12:55. 14:25, 16:49, etc are curious. This graph is from =9Cblack box data=9D which is recorded at 16 Hz. The one Hz data shows similar results. The flight to Gainesville today was uneventful on all counts. I=99m now thinking material failure due to heat and possibly bad stock, as Bob mentioned in his email to you yesterday (thanks for passing that along). ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-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/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-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.