Bicycle Dynamo powered by model I.C. engine

[sasquatch]

Thanks again Brian, great thread!!

[Jon Heron]

A thing of beauty, Brian!
Good job!
Cheers,
Jon

[brian Rupnow]

Thanks Guys.--That little project went very quickly, but it wasn't very complicated either. Jim Dunmyer off this forum gave me the dynamo, and I think I spent about $10 on aluminum and lightbulbs. My time was free and I was setting around the house going a little squirelly from boredom, so it all came together just right.----Brian

[alanganes]

Nice work, as always.

I'm curious as to what would account for the generator binding up when it turns in one direction but not the other. Any idea what is going on there?

[darryl]

I found that 'anomaly' interesting also- turns freely one way but not the other. These things have sleeve bearings and are designed to be permanently sealed. Most likely they have a sort of 'lubricant pump' designed into the bearing, which is basically some spiral grooves put in such a way that lube gets pumped inwards from both ends of the bearing. Having nowhere to go, it sort of pressurizes the bearing and creates a fluid film to keep the shaft from touching the surfaces of the bearing. In a modern rendition of this, the lube is a silicon oil and basically stays in the bearing and lasts a lifetime.

Turning something like this in the opposite direction draws the lube out of the bearing and makes it begin to act like it's dry.

Some of my 'facts' may be off a little, but this is how I understood it anyway. I found it fascinating reading about hydrodynamics.

[brian Rupnow]

I may have learned something here about the Chuck Fellows carburetor which I built and installed on this engine. The carb works great, and I recommend it to anyone looking for a simple, easy to build carburetor with a "throttle" on it. The carb I built is from one of Chuck's early designs, with a #8-32 screw acting as the throttle. By turning the screw in, it closes off the 1/8" diameter main air passage, and by unscrewing it, the air passage is opened, thus letting more air (and venturi induced fuel flow) into the engine. I took matters a step farther, and made up a little handle to clamp on the head of the #8-32 socket head cap screw, so that with an arc of about 180 degrees swing I can go from idle speed up to a much higher engine speed.---And that works fine, as long as there is NO LOAD on the engine. However, when the engine is under a load, it doesn't want to rev very high. I thought about this for a while, and come up with the following theory---An 8-32 thread only advances (or retracts) 1/32" for a full 360 degrees of turn. The 180 degrees of arc I am limited to with my "throttle handle" only advances (or retracts) the screw 1/64". Now on an engine running under "no load" conditions, that 1/64" is enough to go from idle to quite a respectable "high" rpm. However, in an engine running under a load, that 1/64" simply isn't enough to feed the fuel and air the engine requires to overcome the "load" and rev higher. The main air passage on the carburetor I built is 1/8" diameter. To really feed the engine the fuel and air it needs to rev higher under a load would require that the screw be unwound possibly a full turn or even 2 or 3 turns. This is all just theory at the moment, but tomorrow I will do a practical test and remove my "throttle handle" and see what happens when the engine is running under the load of the generator and I unwind the screw more than the 1/2 turn I am currently limited to. In the video I posted, the engine is running with the throttle "wide open" within the limits imposed by the swing of my throttle handle.

[JRouche]

Great project Brian. Loved reading all the posts and watching the idea come to light Loved the video also, I was hoping there would be one. Your voice works for recordings, easy listening.

Cant wait to see the next project, I always tune in when I see a thread of yours. JR

[mickeyf]

Looks great!

Behind and to the left of the engine in your video, that looks an awful lot like a rear view of an arbor press like the one I have... ?

[brian Rupnow]

Looks great!

Behind and to the left of the engine in your video, that looks an awful lot like a rear view of an arbor press like the one I have... ?

It is Mickey. Nice bit of kit when you need one.---Brian

[brian Rupnow]

For what it's worth--after spending some time adjusting the carburetor, I ended up with the following results. The top engine rpm with no load on it is 1900 rpm. When the slack belt is in place, it puts enough frictional load on the engine that the rpm drops to 1780 rpm. When the belt is fully tightened and the generator is lighting the light very brightly (2.9 Volt bulb), the rpm drops off to 1467 rpm. The finished diameter of the driving and driven pulleys is 2.0" and 0.845", giving a ratio of 2.367:1----So, the dynamo is turning at 3472 rpm. That is without factoring in any belt slippage. If we allow 5% for belt slippage then the dynamo is turning at 3300 rpm, and that gets pretty darn close to the "best guess" calculation I had made originally, that based on a 28" diameter bicycle tire, with the "rub contact" diameter at 26" , the dynamo with a 1" friction wheel on it would be turning 3000 rpm. when the bicycle was going 10 miles per hour.

[brian Rupnow]

--Back when I was a kid, a neighbor had a "wind charger" mounted on his garage. As I remember, it had 4 or 6 "blades" made out of old car license plates, and was about 30" overall diameter. The "blades" were attached to a center hub that was mounted on a car generator, and he must have had a voltage regulator wired into it somewhere. He used it to keep a spare battery charged up. That would have been in the 1950's. Then in the 1960's when they ran the hydro line into Kaminiskeg Lake near Barrys Bay I was in high school in Bancroft. I got a part time job with Ernie Byers, a local electrician, wiring and doing some plumbing in cottages in on the Lake. One place sticks in my mind, because it had a fast flowing stream coming down the hill from the northwest side, right beside his cottage. He must have been a pretty resourceful guy, because he had a Pelton wheel in the stream, hooked up to a car alternator and had the whole cottage wired for 12 volt electric lights. One of the funny/crazy memories I have from that time---Ernie had a little wee car, I think it was a Mini Cooper or an Austin Mini. We went to the hardware store in Bancroft and picked up six 10 foot lengths of 1/2" copper pipe to take up to Kaminiskeg. He didn't have any roof racks, so he had me roll down the passenger window and stick my arm out the window and hang onto the pipes. They didn't weigh very much, and he taped the ends together so they wouldn't all come apart while we were driving. About half way up to the lake, we ran into an absolutely ferocious thunder and lightning storm. i was scared right to death that I was going to become a human lightning rod, hanging onto all that copper pipe, but Ernie said "Don't worry Brian, we are up on 4 rubber tires, the lightning won't bother us!!!" I don't know if he was right or not, but I didn't get struck by lightning. I was awful damn glad to get to the end of that trip, anyways.

[jdunmyer]

Brian,
I've seen model engines that were running a generator like your setup, but the lamp was a miniature of a street light.