Ok, so I've seen a lot of new motor scooters and they seem neat: they can go a lot of places cars can't and get excellent fuel economy. For me, the drawbacks seem to be A.) they're loud and vibrate a lot because of the one-lunger engine B.) they smell because of the unburnt fuel in the exhaust and C.) almost all have carburators that require work to get the engine running. I think I can solve all these problems.
Radial engines have been used in anything from planes to cars, and although they never caught on with cars, they made a lot of sense for airplanes because they didn't take up as much space as inline or V-engines. I propose an upsidedown Y-shaped 3-cylinder radial engine for a motor scooter. It wouldn't take up much more space than a single cylinder, and with a 1in. bore and 1in. stroke it would only be 39cc, perfect for a scooter. It would be a pushrod design with the pushrods on the side of the engine to take up less space. There would be direct injection instead of a carburator to make it more efficient and less smelly, and the fact that there'd be 3 cylinders instead of 1 would make it an overall smoother and quieter engine.-- acurafan07, Jul 13 2007 World's smallest supercharged V8 http://youtube.com/watch?v=N8TXMUaC9OsLooks pretty neat to me. [acurafan07, Jul 13 2007] Like this but smaller? http://www.revopower.com/the_wheel.htmlI want one [Giblet, Jul 14 2007] Kneeslider http://thekneeslide...powered-motorcycle/ [Klaatu, Jul 14 2007] SMALL radial engine http://www.robart.c.../r780construct.aspxRequires RealPlayer to view video, but it gives a good scale shot as he;s running up the engine. [Klaatu, Jul 14 2007] This would be cool. Can you really get much power out of a 1" bore and stroke?-- nomocrow, Jul 13 2007 Thanks, I know I'd buy one if they made these.
Well I personally like the 1" bore and stroke because it would make for a "square" engine. I'm pretty sure that 1" bore and stroke x 3 cylinders would make for an as-powerful-as if not more powerful engine than a single cylinder. I included a youtube link to the world's smallest supercharged V8, with a 1" bore and .9" stroke.-- acurafan07, Jul 13 2007 [Giblet], I've seen that motor before, very neat. Although, I wasn't thinking of a hub motor like that, simply a 3-cylinder radial engine that would turn a chain and sprocket combination (just like other gas-powered scooters).-- acurafan07, Jul 14 2007 neat.
ever see those old radials with stationary pistons and rotating cylinders (attached to the prop)?
makes me wonder if you could just put the engine in the wheel itself?-- TIB, Jul 14 2007 Now that would be really cool. Unfortunately, while that probably would work ok on a motorcycle, most motor scooters have very small wheels (like less than 10"), so the engine probably wouldn't be able to fit.-- acurafan07, Jul 14 2007 Like the "Kneeslider"? <link>-- Klaatu, Jul 14 2007 Nope. I've seen radial engine motorcycles before, and they're quite different. Aside from the fact that that's a 7-cylinder radial airplane engine (probably over 150 times greater displacement than my idea) mounted perpendicular to the frame rather than parallel like I propose, it's also a motorcycle.
Thanks for the link, the bike looks cool. But is that why you boned it?-- acurafan07, Jul 14 2007 I boned it for not being an original idea. The only difference is scale. Smaller bike and smaller engine. How is your idea unique from the kneeslider? I guess I need a better sales pitch.
I'll look for the link for the small radial engine being produced.
update <link>-- Klaatu, Jul 14 2007 Well a 3-cylinder is different from a 7-cylinder radial (as I'm sure you won't find any motorcycle powered by a 3-cylinder radial), and a motorcycle is a lot different from a motor scooter (you wouldn't bone a radial-powered train idea just because radials have been used in cars before, would you?).
The original idea is that while a lot of motorcycles have a lot more than one cylinder, no motor scooters I've ever seen have had more than one (although vespas sometimes do). And this idea is to make a small and space-efficient engine package so that more than one cylinder could be used to power a motor scooter in a practical way (while solving some problems).
Also in my idea, the engine would actually fit on the scooter, unlike the kneeslider (which seems like it would scrape off a cylinder head or two on the pavement just from a short drive).-- acurafan07, Jul 14 2007 1" bore x 1" stroke = 12.8 cc per cylinder, = 38cc for your 3-cyl radial. You won't be able to wrangle much torque out of that, but with such tiny cylinders, you should be able to wind it right up to some fantastic revs, and gear it down.
@ [TIB] - the pistons weren't stationary, they went around with the cylinders and crankcase. The CRANK, however, was firmly bolted to the firewall, same as the prop was firmly bolted to the crankcase.
Fitting such a tiny engine inside the wheel could be done, but the engine would still have to be geared down before the wheel. Funny: the wheel turning, the engine within turning even faster. Fuel delivery and throttle control routing would be tricky, though.
"(as I'm sure you won't find any motorcycle powered by a 3-cylinder radial), " I found a site where someone had done exactly that, adding a cylinder to a Harley engine, which uses a common-end rod like a radial, so now they were driving a three-cylinder sorta radial. It was a big metal W instead of a Y.-- elhigh, Jul 16 2007 //I found a site where someone had done exactly that// Touche. I guess I kinda figured someone somewhere had done it, but even then it's still still a different animal than this idea. And I'm still pretty sure my idea here hasn't really been baked.
And if it could be fit into the wheel, that sounds neater and more efficient than anywhere else on the scooter (and with a more reliable drive transmission). As long as there'd be a way to also fit a clutch or torque converter in there, that sounds like the way to go.-- acurafan07, Jul 16 2007 random, halfbakery