---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Fri 12/26/14: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:16 AM - Re: Engine boosting (rampil) 2. 07:41 AM - Re: Re: Engine boosting (William Daniell) ________________________________ Message 1 _____________________________________ Time: 07:16:47 AM PST US Subject: RotaxEngines-List: Re: Engine boosting From: "rampil" William - Merry Christmas! It is not wear on moving parts that would be of concern, it is instead the added stress on the crank, the rods, the pistons and the cylinders/heads. Remember the rotax gets its performance from light weight alloys which are designed to just meet expected stress, not the added stress of running at an MP 10 - 30% higher than design. The 914 is not just a 912 with a blower bolted on, some moving parts were also upgraded. In experimental aviation fooling around with your engine is certainly permissible, even encouraged, if you know what you are doing. There is even a Rotax-designated service center in Mississippi that does all kinds of mods to stock engines for the Highlander / SuperSTOL crowd. All I said in my initial comments is that for my aircraft, I would not markedly diminish the reliability of my engine for a small gain in power and an even smaller gain in speed. Your mileage will vary. I use my 912s Europa for 1000 nm cross country trips from 0 - 1000' MSL airports. I like a reliable engine! -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=436284#436284 ________________________________ Message 2 _____________________________________ Time: 07:41:11 AM PST US Subject: Re: RotaxEngines-List: Re: Engine boosting From: William Daniell Ira likewise Merry Christmas. Yes I had the same thoughts about stress hence keeping the boost to 33" and reduce power to 30" within 3 minutes of take off. I cruise at 27". Also I suppose my need taking off at 8500' is slightly out of the normal operating range and requires extraordinary measures! However the local mechanics tell me that the internals of the 914 are the same as the 912 and certainly the anecdotal reliability "stats" would suggest that the mod doesn't over stress the engine. At 27" I am burning 4 gals and hour. The downside of the mod in my opinion is weight, complexity and heat albeit this is less complex than a 914. If I were flying at sea level I would choose a 912s as an excellent balance weight simplicity and power. Interestingly enough the only major issue that I have heard of with rotax here was a 912s on mogas. Even the premium mogas here is of very poor quality and in a friend's aircraft this caused detonation which cracked a piston. Quality gas is a must in high compression engines. Will William Daniell LONGPORT +57 310 295 0744 On Fri, Dec 26, 2014 at 10:16 AM, rampil wrote: > > William - Merry Christmas! > > It is not wear on moving parts that would be of concern, it is instead > the added stress on the crank, the rods, the pistons and the > cylinders/heads. > > Remember the rotax gets its performance from light weight alloys which are > designed to just meet expected stress, not the added stress of running at > an MP 10 - 30% higher than design. > > The 914 is not just a 912 with a blower bolted on, some moving parts were > also upgraded. > > In experimental aviation fooling around with your engine is certainly > permissible, even encouraged, if you know what you are doing. There is > even a Rotax-designated service center in Mississippi that does all > kinds of mods to stock engines for the Highlander / SuperSTOL crowd. > > All I said in my initial comments is that for my aircraft, I would not > markedly > diminish the reliability of my engine for a small gain in power and an even > smaller gain in speed. Your mileage will vary. I use my 912s Europa for > 1000 nm cross country trips from 0 - 1000' MSL airports. I like a reliable > engine! > > -------- > Ira N224XS > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=436284#436284 > > ------------------------------------------------------------------------------------- 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.