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Building a Better Motorized Bicycle
toyotaboy writes "Saw this in 'design news' magazine. It's a bicycle using an engine that looks like something pulled off of an R/C airplane. He uses a gear reduction system as well as a overrunning clutch to keep the engine running while stopped. Claims to get 20 mile range from its 1/4 gallon gas tank (80mpg). If you figure most engines like that are 30k rpm with 1:100 gear reduction, and an average bike rim is 26", you should get potentially 1,458,000 inches per hour, or 23mph! He goes on to say that similar devices in electric form (segway) fail because of their heavy 80lb weight and limited 10-15 mile range (and where do you recharge?) This thing can be filled back up at any gas station."
I fly rc planes... I know about this stuff... The engines that turn 30k rpm are tiny glow fuel powered engines, NOT weedeater gas engines (max of around 10k) Glow fuel runs from $15 to $20 per gallon, not very cost effective! Also, the picture isn't clear enough to really show anything of the engine!
Of course this situation is produced by the knee-jerk reactions of the "moral green majority" out there.
The most efficient internal combustion engines ever made are infact 2-stroke diesel engines, often used in ships and the like, these are large engines and it's well worth replacing them if a more efficient design exists.
The US killed off the 2stroke at about the same time a number of companies were readying very clean and efficient engines for market, given a uniflow design (has exhaust valves at the top) and fuel injection a 2stroke engine can be made cleaner than a 4stroke for the same power.
Of course this particular application uses a rather crappy little engine by the look, but please don't tar all 2strokes with the same brush.
In the good 'ole USA they ban 2strokes without ANY form of emission testing, it doesn't matter if you can pass emissions tests - 2strokes are banned. Of course it is fine to go and buy a new "Recreational Vehicle" that averages 9MPG, after all, how could THAT cause polution??
Ahh, the joys of politics..
http://www.giant-bicycles.com/us/030.000.000/030.0 00.000.asp?lYear=2003&bikesection=8828&range=127&m odel=10594 [URL Giant-bicycles.com]
"You win again Gravity!" -Futurama (Zapp)
There's all kinds of 2-stroke engines for yard and other uses out there.
s tore/pages/lawnmower-26.html s tore/pages/lawnmower-27.html
Try some links on for size:
http://www.mowdirect.co.uk/acatalog/600i-2_2.htm
http://www.shophutt.co.nz/sites/lawnmower/online_
http://www.shophutt.co.nz/sites/lawnmower/online_
http://www.epinions.com/content_70547902084
In the first three, I reference not one or two, but three different 2-stroke lawnmowers that are in current production and sales. The last link is for a rather popular home and garden tool, the Ryobi Trimmer Plus- a modular system that allows for spin-trimmer, blade edger, pole pruner, tiller and other attachments to the power head, a 2-stroke engine.
Just because there's stricter emissions rules doesn't mean they've gone away. Check your facts next time.
I am not merely a "consumer" or a "taxpayer". I am a Citizen of the State of Texas
Well, you could shut it off... The pedals still work! Personally, I like this idea a whole lot more than the $2500 electric jobs that are good for a spin or two around the block.
I don't imagine the noise would be that loud anyway, the engine on this bike would be very small. Think of a weed eater, or perhaps smaller. Modern ones aren't that loud. This thing isn't going to sound like your average motorcross bike.
For more style-conscious people, there is a company (can't remember the name) that sells cruiser-style bikes with a small gas engine mounted in the main frame triangle. It's chromed out, and looks like some kind of special-ed Harley for children/old folks.
Modern two smokes run fairly clean. Oil is injected instead of mixed with the fuel in the gas tank. A well designed naturally carburated engine will expell most of the exhaust gasses. Larger 2strokes will use a supercharger to get the same effect. A 4 stroke will still be cleaner then a 2 stroke though. 2 strokes also tend to be louder as you need an unrestricted exhaust.
While two strokes are inefficient, pound for pound a 2stroke engine will be more powerfull then a 4 stroke engine (the common type). A 2 stroke cylinder has a power stroke every revolution of the crankshaft. A 4 stroke only has a power stroke every second revolution.
Grand Prix motorcycle racing until last year was all 2 stroke engines. What used to be the class of 500cc motorcycles is now the MotoGP class which allows 1000cc 4 strokes to compete with 500cc 2 strokes. Dirt bike racing is still dominated by the 2strokes, but that is changeing as manufacturers introduce new 4 strokes. From a racing technology point of few it has only been very recently that a 4 stroke engine has been able to compete with a 2 stroke engine that is half the size.
Why isn't it a 4-stroke? Weight. Size. Power. 2 cycles like this one will produce gobs more power with smaller weight than 4 strokes. Plus they are simpler, easy to rebuild, and can be mounted in different positions because they don't have an oil sump
Obviously you haven't looked at the latest four-stroke model airplane engines.
These things operate in any attitude (heard of aerobatics?), are not much heavier than a two-stroke of equivalent power, and offer much better fuel economy, less polution and less noise.
Check out this engine which produces more than two horsepower from just 32 ounces (900g) of weight and 1.2 cubic inches (19.7cc) of displacement.
Or this one which manages to extract 3.5ps (2.6hp) from an engine that weighs under 1KG and displaces just 23ccs.
What's more, small four-stroke glow-plug engines run on methanol, a renewable fuel that is far more environmentally friendly (and cheaper in some places) than gasoline.
Hmmm, choices, choices.
I could spend extra money to add this polluting loud (presumably) engine to my bicycle. This would allow me to go slower [1] than I already go, albeit for little effort. Hmmm.
Or I can continue to bike to work and around town on my nice comfy road bike, and fuel myself with extra chinese and french pastries, or lunches with my co-workers at asian restaurants.
Hmmm, buy gas or pastry? I know which I pick.
[1] I've hit 49 miles an hour on a nice downhill on my normal commute, and I regularly sprint to ~ 25-27 mph just screwing around. My cruising speed is 21 mph (1 mph faster than this thing)[2].
[2] On the flat, no wind, long distance pacing etc.
He should redesing this to take advantage of one of the most efficient and enjoyable forms of transport: the modern roadbike.
Essentially this would mean dumping the engine and all the other crap he's added.
It's not a motor--it's an engine
lets format this a bit better
... fuel
cell bike similar specs as the gas powered except without the stink. I guess the only problem would be getting the hydrogen for it. Very neat though
>I'm holding out for a Hydrogen powerd rocket bike!!
Not exactly a rocket but
There are active groups dedicated to such vehicles. One such is the power-assist elist on yahoogroups (formerly egroups.com).
/. editors thought this particularly newsworthy.
http://www.power-assist.org/
The list has both ICE and EV partisans.
Most of the commerical and homebrew systems strike me as more clearly thought out than the "headline" design. I don't see why the
Sir Clive Sinclair invented a "bike with an engine" in 1992. First came the Zike, which was an electric bike. Two years after that came the Zeta (check out the Zeta II) which was a electric motor that you could fit on your regular bike, converting it to an electric bike.
Need I say that both were commercial failures? Anyway, the history now repeats itself with SEGway. The difference between the Zike/Zeta and Stephen Katsaros' IC motor driven bike is minimal...
Motor Assisted Bicycles are a Good Thing[tm] ...
( unless one's Gov't has decided to destroy one's possible choices, for the benefit of their authority, OR for the benefit of their preferred lobby-groups )
... compared with many alternatives...
BUT:
MX5 Super Bike Engine seems to be the one that works best ( though I gather it requires a bit of break-in/tuning ), and unfortunately, it's a 2-stroke, and
( halfway down the page ) Honda 4-stroke 31cc Bicycle Engine, while it is a 4-stroke, it boshes one's ability to stack stuff on the rear rack...
Also, I'm told that Small Engine Care & Repair is the best book to get with 'em.
/dev/motor-assisted-bicycle(random||forum) can be found here
Messages to/for me ( in me journal )
Exactly and all for what? 23mph, 80mpg! I had a little motorbike that did 80mpg and 45mph. Why not put the effort into improving a conventional motorbike, it has room for a larger fuel tank and big silencer. Much easier route to tackle the problem. I bet if you developed this model engine mountain bike into something people would buy in volume it would end up looking like a conventional motorbike. Alternatively pedal the damn thing and get fit as well.
Actually, it's entirely possible to create a quiet-running RC engine. I've got an HPI Nitro MT that is many many times quieter than the quietest lawnmower. Been doing this RC thing for a little while, see.
Noise from these engines all has to do with the tuned pipe design.
the "Spartamet" is very popular amongst older people. It is regarded as extremely uncool to ride one, as only elderly women are seen using them. They are very helpful for them riding against the strong winds that blow in the flat lowlands. check out some info about them from here where some guy gives instructions on how to modify them to get more speed & power (which is always cool)
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