Finally a question I'm somewhat qualified to answer! I used to build model planes as a wee young boy, and I've had several of these little engines. Here are my thoughts on their feasability as power sources: * They are loud as hell. Even muffled, they are generally WAY louder than you'd think they could possibly be. Running one indoors on a test bench is painful without ear protection. * They burn gas relatively fast. They're not very efficient at all, mainly because making a working ICE that small requires a fairly simple mechanical design. All the ones I've seen are very much like deisels. They have a small glow plug on top of the piston, which is initially heated up by applying current across it. The fuel is pulled in by suction from the piston stroke, and usually is a fuel/oil mixture for lubrication. So to start the thing, you pop the battery connector on top of the glow plug, and either flip the prop manually (a bad idea, usually), or use a spring or electric device to turn the prop. This turns the shaft, moving the piston, and sucking fuel in. Pretty quickly, the fuel ignites, and the burning fuel keeps the glow plug hot, which ignites the next batch of fuel, etc. And viola, your engine is running. (I just found a good page that explains this as well-- http://www.gbso.net/Skyhawk/TwoCycl.htm. They point out that the glow plug's glowing element contains platinum, and it's kept glowing partly by a chemical reaction between the platinum and the fuel). * The fuel is not normal gasoline, but a mixture of methanol and oil (usually castor oil. See the page mentioned above for more on this). There are some restrictions on what you can use as fuel, and IIRC it produces some fairly foul exhaust. Running indoors is not recommended. All that said, I think this would be (as mentioned by Brain Boy) a great way to produce power outdoors, perhaps as a way to charge a battery (or just run your gear) on a camping trip. I don't think running one of these things on your body would be practical (they get really hot too-- even hotter than pentiums! ;-)). Wearing one of these things would be... unpleasant. Not to mention you'd need a pack of some sort to carry the fuel. Nifty idea though, anyway. --Rusty Charles J Knight wrote: > > > > (OK, > > > so it may or may not be practical...it's clever!) > > > I'm sure a model airplane engine attached to a small generator would > > produce much more power than a battery of the same weight. The only > > I had a feeling that it would. Just a weird little thought. Like I > said, > it may or may not be practical. > > > problems I can think of are related to the idea of carrying around a > > running internal combustion engine. > > I already had those thoughts -- in addition to the noise, there is the > exhaust, the potential danger of carrying around a flammable fuel > source, and a few others. But, if you take a look at a lot of battery > technologies, they don't inspire confidence either. > > But, as an off the cuff idea, it might be workable. > > > But you'd probably be one of the few people who could jump start a > > car with what they're wearing. > > That much power? That would surprise me! > > > But it could have it's uses as a small, self-contained, muffled(!) > > (those motors sound like angry mosquitos piped through Marshall amps) > > I haven't even tried to start the thing yet...just a little purchase that > I got at a flea market. > > > emergency power source for outdoor use or in case of extreme > > power load from large peripherals (like flash tubes). > > If the whole thing is appropriately built into a tiny aluminum alloy > > box, tank and all, it could in fact produce large amounts of power. > > Any ideas as to the amount of power? I know that it will run as long > as there is a source of fuel, so it's not a simple matter of watt-hours. > > > The main problem that cannot be bypassed though, is the outdoors-only > > nature of the gazoline-oil exhaust...unless you alter the engine to run > on pure > > hydrogen or to burn other hydrcarbons (butane, natural gas, etc...) > > *perfectly*...thus producing only CO2 and H2O. > > It should be possible to run it on vapors from almost any > petrochemical, including gasoline... > > But a truly clean burn is practically impossible without rather > significant control of the burn ratio, which in a retrofit will reduce > its output tremendously. > > Alternatives? > > > ...hmmm...how hard would it be to convert to butane? > > It's real cheap and available in good-sized containers for refilling > > lighters... > > As I understand it, conversion of an ICE (any ICE) requires only > a means by which the fuel can be introduced...new carburetor, > and a means to adjust the fuel-air mix. Occasionally the timing > needs to be adjusted. I haven't taken a close enough look at this > thing yet, to even FIND the carburetor. > > Butane is vapor at operating temperatures, right? > > Thinking about it, in this engine, I believe it uses a fuel-oil > mix for lubrication. I wonder if a simple conversion is possible > with a system like this? With separate fuel and oil it seems > simple... > > -- Chuck Knight > ___________________________________________________________________ > Get the Internet just the way you want it. > Free software, free e-mail, and free Internet access for a month! > Try Juno Web: http://dl.www.juno.com/dynoget/tagj. > > -- > Subcription/unsubscription/info requests: send e-mail with subject of > "subscribe", "unsubscribe", or "info" to> Wear-Hard Mailing List Archive (searchable): http://wearables.blu.org -- "You can never entirely stop being what you once were. 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