---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Tue 01/04/11: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:34 PM - drop of rpm on take off (georg.stiller@arcor.de) 2. 03:55 PM - Re: drop of rpm on take off (Simon Lancashire) 3. 06:33 PM - Re: drop of rpm on take off (ruruny@aol.com) ________________________________ Message 1 _____________________________________ Time: 02:34:11 PM PST US From: georg.stiller@arcor.de Subject: RotaxEngines-List: drop of rpm on take off Hi all, I just subscribed to the list. What a great forum! I have trouble with my 80 hp 912. Maybe someone has a good idea and can give me some help. Background: 912 with 150 hrs. in a Kitfox, no troubles so far, 98 octane auto fuel, alcohol test negative, aircraft parked in heated hangar, properly drained and engine run up, fuel always filtrated, filter visually clean, carbs freshly pneumatically balanced, mag drop ca. 200/300 rpm (has recently deteriorated). What happened: Very cold outside temperature, about -15 centigrade. Max. ground rpm ca. 5000 rpm (should be 5100, has deteriorated somewhat - under cold conditions?), acceleration and take off normal, a couple of seconds after take off sudden drop of rpm to ca. 4500-4600 rpm. After another couple of seconds and the engine catches up and returns to 5000 rpm. At least, so far it always did. No problems in cruise with 4300 rpm. I usually take off and cruise also under these cold conditions without carb heat. I tried a take off with carb heat and a couple of seconds after take off: rpm drop as obove! All this happened four or five times. Next I plan to change the spark plugs, although they still look good and the manual says change after 200 hrs. Any help would be highly appreciated! Thanks, Georg Kitfox, 912 80 hp Germany ________________________________ Message 2 _____________________________________ Time: 03:55:41 PM PST US From: "Simon Lancashire" Subject: RE: RotaxEngines-List: drop of rpm on take off Georg, I am new to this forum and have a Pulsar with an early 912. My aircraft is low wing and has a boost pump as the fuel tanks are below the engine. Is it possible that your problem may be due to low fuel pressure due to the angle of incidence at the point of takeoff in the kitfox? (very nose high) The standard Rotax pump can only suck so hard and may be o0n the limit without help. Fuel boost pumps are inexpensive and easy to fit and i use mine always for take-off, landing and fuel tank switching. Good luck! Simon, UK Pulsar XP G-BUZB -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of georg.stiller@arcor.de Sent: 04 January 2011 22:30 Subject: RotaxEngines-List: drop of rpm on take off Hi all, I just subscribed to the list. What a great forum! I have trouble with my 80 hp 912. Maybe someone has a good idea and can give me some help. Background: 912 with 150 hrs. in a Kitfox, no troubles so far, 98 octane auto fuel, alcohol test negative, aircraft parked in heated hangar, properly drained and engine run up, fuel always filtrated, filter visually clean, carbs freshly pneumatically balanced, mag drop ca. 200/300 rpm (has recently deteriorated). What happened: Very cold outside temperature, about -15 centigrade. Max. ground rpm ca. 5000 rpm (should be 5100, has deteriorated somewhat - under cold conditions?), acceleration and take off normal, a couple of seconds after take off sudden drop of rpm to ca. 4500-4600 rpm. After another couple of seconds and the engine catches up and returns to 5000 rpm. At least, so far it always did. No problems in cruise with 4300 rpm. I usually take off and cruise also under these cold conditions without carb heat. I tried a take off with carb heat and a couple of seconds after take off: rpm drop as obove! All this happened four or five times. Next I plan to change the spark plugs, although they still look good and the manual says change after 200 hrs. Any help would be highly appreciated! Thanks, Georg Kitfox, 912 80 hp Germany ________________________________ Message 3 _____________________________________ Time: 06:33:50 PM PST US Subject: RotaxEngines-List: RE: drop of rpm on take off From: ruruny@aol.com Carb float bowl vents run to bottom of firewall? ------------------------------------------------------------------------------------- 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.