Peter The idea of on board electric starter for restarts in the air is a very expensive. There was a company a couple of years ago that sold a system for this purpose but it would add unessary weight to the airplane. The fuel that i use has 10% nitro methane added as oxidizer. I believe in Eorupe and other places that dont use nitro. And as far fuel econmy i get about a 15 minute flight on an 8oz tank. These engines are classified as high compresson disels. Mike Johnston ----- Original Message ----- From: "Peter L. Peres" To: Sent: Saturday, May 18, 2002 3:09 AM Subject: Re: [EE]: Update - Spark ignition for model engines > On Fri, 17 May 2002, Michael Johnston wrote: > > >Can I ask the gentlemen who started this thread why he wants to convert a > >glow engine to ignition. I guess gasoline is considerably cheaper than model > >airplane fuel. But when you look what you have to do to convert to gas it > >wasn't cost effective for me. Clarence Lee the engine guru in rcm magazine > >wrote in one of his columns "That most model engines will lose some power > >converting to gas ignition. > >just a thought. > >Mike Johnston > > Besides guru points and money there are a number of applications that work > better if you have spark ignition. Among them very economical running and > in-flight restarting, as well as throttle range and high end power output > (remember the glow has nothing resembling spark advance so it runs > sub-optimal all the time). You can't run a glowplug very lean, it will go > out. If you want high endurance you need a spark or a direct injected > diesel. The latter is not available in model sizes (yet). I do not know > for sure but I suspect that a correctly implemented spark ignition (with > proper advance curves) could produce the extra power that would put it on > par with or beyond glow operation on the same engine because of proper > ignition timing. And last, the energy carried by gasoline is higher than > for alcohool so you gain some 30-50% in energy contents in the same tank > by just changing the fuel (and you can't do that by staying with glow). > This will give an engine with lower idle, higher maximum output, that runs > leaner and responds better and more precisely to control. > > Peter > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.