---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Mon 05/18/09: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:14 AM - Re: alternative carb for 912 (Dave Austin) 2. 04:36 AM - Re: alternative carb for 912 (Thom Riddle) 3. 07:28 AM - Re: alternative carb for 912 (Roger Lee) 4. 07:34 AM - Re: alternative carb for 912 (Thom Riddle) 5. 08:47 AM - Re: Re: alternative carb for 912 (Gilles Thesee) 6. 01:42 PM - Re: Re: alternative carb for 912 (Ken Arnold) ________________________________ Message 1 _____________________________________ Time: 04:14:24 AM PST US From: "Dave Austin" Subject: Re: RotaxEngines-List: alternative carb for 912 Thom, I couldn't help seeing the trailer item you put on your messages AFTER you had asked about a carb change!!! Could I ask why you would want to change the carbs to something else? Dave Austin 601HDS - 912 Just kidding.. do not archive ________________________________ Message 2 _____________________________________ Time: 04:36:27 AM PST US Subject: RotaxEngines-List: Re: alternative carb for 912 From: "Thom Riddle" Dave, I'm interested in adapting a single carburetor to the 912 with manual mixture control to replace the two expensive and complex Bing 64s. I'm just curious if anyone else has done this. I have no problems with the current set up and just finished cleaning, inspecting, replacing seals and synching both carbs at about 700 hours. Rotax 912 engine is a great engine but the carb setup is overly complex. I'm looking at the Aerocarb as a possibility. There are cheaper ones available but this one is about as simple as a carburetor can be. http://www.aeroconversions.com/products/aerocarb/index.html I spent most of my career as a mechanical engineer doing machine design and keeping it simple has always proven to be a virtue, hence the quote in my signature line. -------- Thom Riddle Buffalo, NY http://riddletr.googlepages.com/sportpilot-cfi http://riddletr.googlepages.com/a%26pmechanix A complex system that works is invariably found to have evolved from a simple system that works. - John Gaule Read this topic online here: http://forums.matronics.com/viewtopic.php?p=244490#244490 ________________________________ Message 3 _____________________________________ Time: 07:28:44 AM PST US Subject: RotaxEngines-List: Re: alternative carb for 912 From: "Roger Lee" Hi Thom, Typically you lose some HP going to a single carb. That's why so many 2 strokes and 4 strokes over the many years went to 2 carbs from the earlier days of ultralights. They wanted to get more HP out of their engine. -------- 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=244510#244510 ________________________________ Message 4 _____________________________________ Time: 07:34:52 AM PST US Subject: RotaxEngines-List: Re: alternative carb for 912 From: "Thom Riddle" Roger, "Typically you lose some HP going to a single carb." Not if it is sized correctly. -------- Thom Riddle Buffalo, NY http://riddletr.googlepages.com/sportpilot-cfi http://riddletr.googlepages.com/a%26pmechanix A complex system that works is invariably found to have evolved from a simple system that works. - John Gaule Read this topic online here: http://forums.matronics.com/viewtopic.php?p=244512#244512 ________________________________ Message 5 _____________________________________ Time: 08:47:09 AM PST US From: Gilles Thesee Subject: Re: RotaxEngines-List: Re: alternative carb for 912 Thom Riddle a crit : > I'm interested in adapting a single carburetor to the 912 with manual mixture control to replace the two expensive and complex Bing 64s. I'm just curious if anyone else has done this. I have no problems with the current set up and just finished cleaning, inspecting, replacing seals and synching both carbs at about 700 hours. > > Rotax 912 engine is a great engine but the carb setup is overly complex. I'm looking at the Aerocarb as a possibility. There are cheaper ones available but this one is about as simple as a carburetor can be. Thom, Of course, the Aerocarb is simple, but like any other throttle body injector, it needs manual inputs (mixture) to perform what float or diaphragm carbs do automatically. You just can't provide adequate mixture over the full slide range with a slide moving across a circular throat and just a needle. Also, those devices are very dependent on fuel delivery pressure. That's what float or diaphragm carbs were invented for. If simplicity is key, then changing a system that works is best avoided. How many work hours for an adequate intake manifold and filter box design ? How many test hours to ensure correct working over the entire flight envelope ? How much fiddling with needles, to end up with a one of a kind system that probably won't work in another airplane ? > > http://www.aeroconversions.com/products/aerocarb/index.html > > I spent most of my career as a mechanical engineer doing machine design and keeping it simple has always proven to be a virtue, hence the quote in my signature line. Nice quote indeed. Also "If it ain't broke, don't fix it". Best regards, -- Gilles http://contrails.free.fr ________________________________ Message 6 _____________________________________ Time: 01:42:45 PM PST US From: "Ken Arnold" Subject: Re: RotaxEngines-List: Re: alternative carb for 912 There are a bunch of NASCAR guys here in NC that know all about big carbs. You might have to cut a hole in top of your cowl but that might look awesome! Good Luck, Ken ----- Original Message ----- From: "Gilles Thesee" Sent: Monday, May 18, 2009 11:37 AM Subject: Re: RotaxEngines-List: Re: alternative carb for 912 > > > Thom Riddle a crit : >> I'm interested in adapting a single carburetor to the 912 with manual >> mixture control to replace the two expensive and complex Bing 64s. I'm >> just curious if anyone else has done this. I have no problems with the >> current set up and just finished cleaning, inspecting, replacing seals >> and synching both carbs at about 700 hours. >> >> Rotax 912 engine is a great engine but the carb setup is overly complex. >> I'm looking at the Aerocarb as a possibility. There are cheaper ones >> available but this one is about as simple as a carburetor can be. > Thom, > Of course, the Aerocarb is simple, but like any other throttle body > injector, it needs manual inputs (mixture) to perform what float or > diaphragm carbs do automatically. > You just can't provide adequate mixture over the full slide range with a > slide moving across a circular throat and just a needle. Also, those > devices are very dependent on fuel delivery pressure. That's what float or > diaphragm carbs were invented for. > If simplicity is key, then changing a system that works is best avoided. > How many work hours for an adequate intake manifold and filter box design > ? How many test hours to ensure correct working over the entire flight > envelope ? How much fiddling with needles, to end up with a one of a kind > system that probably won't work in another airplane ? > >> http://www.aeroconversions.com/products/aerocarb/index.html >> >> I spent most of my career as a mechanical engineer doing machine design >> and keeping it simple has always proven to be a virtue, hence the quote >> in my signature line. > Nice quote indeed. Also "If it ain't broke, don't fix it". > Best regards, > -- > Gilles > http://contrails.free.fr > > > ------------------------------------------------------------------------------------- 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.