---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Sat 09/20/08: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:43 AM - Re: Rotax 914 (jetboy) 2. 04:22 AM - Re: carb ice revisited (Thom Riddle) 3. 07:40 AM - Re: carb ice revisited (Roger Lee) 4. 07:56 AM - Re: Rotax 914 (Gilles Thesee) 5. 01:18 PM - Re: carb ice revisited (Thom Riddle) 6. 02:28 PM - Re: Re: carb ice revisited (Noel Loveys) ________________________________ Message 1 _____________________________________ Time: 02:43:52 AM PST US Subject: RotaxEngines-List: Re: Rotax 914 From: "jetboy" I would be cautious about grounding both ends of the cable shields because of what can occur to components of the ignition system when operating the starter motor. Depending where the battery is located and how it is grounded and connected to the starter motor frame there can be 1 or 2 volts appearing between parts of the engine casing and the rest of the airframe. During cranking there is a large current available here, certainly enough to vaporise any electronic parts that might be in the way. The point about earth straps across 2 or more lord mounts is a valid one too, I once had starting troubles on a C150 and discovered neither of the straps were present, meaning the entire 2-300 amps was going thru the throttle , mixture and maybe carb ht. controls! Ralph -------- Ralph - CH701 / 2200a Read this topic online here: http://forums.matronics.com/viewtopic.php?p 5239#205239 ________________________________ Message 2 _____________________________________ Time: 04:22:23 AM PST US Subject: RotaxEngines-List: Re: carb ice revisited From: "Thom Riddle" Roger, You are not a smart ass. You just live in a place where 50% humidity seems like a steam bath. Back east, where we have enough rain to allow trees to grow, 50% humidity seems down right arid. I've been flying since 1966 and I know the symptoms of carb ice. That is how I know I've had it. It is true that the Bing carbs are LESS LIKELY to ice up but they can and do under high humidity conditions. I've had it happen to me on two separate occasions, both of which were in conditions highly conducive to carb ice. Although it is rare enough that I don't bother with a carb heat system, it does happen here in the land of "normal" humidity :-). -------- Thom Riddle CFI-SP Power Plant Mechanic N1208P RANS S6S, Tailwheel, 912UL N197BG FS1/447 -------------------- Scratch any cynic, he said, and youll find a disappointed idealist. George Carlin Read this topic online here: http://forums.matronics.com/viewtopic.php?p 5244#205244 ________________________________ Message 3 _____________________________________ Time: 07:40:38 AM PST US Subject: RotaxEngines-List: Re: carb ice revisited From: "Roger Lee" Hi Thom, If you ever make it down to the Tucson, Az. area give me a call. I'll be happy to take you and whom ever up in my Flight Design CT for a flight around the area in some of that dry air. :D I have a friend that lives in New York that I'm sure he would be happy to take you for a cruise in his CT. Invites good any time. -------- 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 5278#205278 ________________________________ Message 4 _____________________________________ Time: 07:56:06 AM PST US From: Gilles Thesee Subject: Re: RotaxEngines-List: Rotax 914 Fergus Kyle a crit : > Hello, > I am assembling the wiring for the above model engine. In the > process, I wired the dynamo module wires to coaxial cable which runs to the > ignition switches, ensuring that the coax braid is exclusively connected to > nearby engine ground at one end and one pole of each switch at the other. > The switches are enclosed in small alum boxes attached to the panel for > interference protection. > I see, by Installation manual, page 75 [electric circuit, d/1996 05 > 10] that there seems to be an electrical ground connection to the switch > frame and thus to the metal panel on which it is fixed. If that is so, then > the engine frame ground extends into the cockpit via the coax. > Is this the intent? > Fergus, FWIW, I wired one 914 and one 912S engines as per the Rotax installation manual with good results. At the time I too was a bit puzzled by the Rotax suggestion to ground the shield at both ends, but after much reflexion decided to wire the ignition by the book. Worked flawlessly. Some info here http://contrails.free.fr/engine_rotax_mag_connect_en.php Best regards, -- Gilles http://contrails.free.fr ________________________________ Message 5 _____________________________________ Time: 01:18:19 PM PST US Subject: RotaxEngines-List: Re: carb ice revisited From: "Thom Riddle" Thanks for the offer, Roger. If I get down your way again, I'll look you up. -------- Thom Riddle CFI-SP Power Plant Mechanic N1208P RANS S6S, Tailwheel, 912UL N197BG FS1/447 -------------------- Scratch any cynic, he said, and youll find a disappointed idealist. George Carlin Read this topic online here: http://forums.matronics.com/viewtopic.php?p 5303#205303 ________________________________ Message 6 _____________________________________ Time: 02:28:13 PM PST US From: "Noel Loveys" Subject: RE: RotaxEngines-List: Re: carb ice revisited So true. But sho0rt of landing immediately and pulling off the air screens there is no other way to verify ice in the carb other than through symptoms. Noel -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of Roger Lee Sent: Friday, September 19, 2008 10:18 PM Subject: RotaxEngines-List: Re: carb ice revisited Hi Guys, Please don't take my next comment as being a smart ass, but how do you guys know if it was really icing without any confirmation and have you ruled out all other possibilities? Without confirmation it still is speculation. These are not standard carbs like the ones we were raised with during our life, but quite different. These are variable venturi carbs. That in itself makes them less prone to standard icing effects. -------- 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 5184#205184 ------------------------------------------------------------------------------------- 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.