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Need help motorizing a 1963 Schwinn with a DC motor
My name is David Lunde. I am looking for a motor that, in a thus far
fruitless attempt, I have been unable to find. PLEASE TAKE THE TIME TO READ THIS, AND ANY SUGGESTIONS ANYONE HAS WOULD BE MUCH APPRECIATED. Bio: I am 16 years old and I love outboards, bikes, cars and anything that moves. I wanted to embark on a project that would be cool and overall silent - meaning I wanted to make something electric. So here is what I started... My project: I have a 1963 Schwinn world traveler (it was my father's) and I want to hook a DC motor to it. I did some calculations (thanks to my physics class) and according to my calculations I produce about 2/3 hp on my bike. Here are my numbers if anyone is interested. You can do the calculations THE CALCULATIONS: 1 hp = 33,000 ft*lbs/min my ft*lbs/min = my weight (224lbs) * length of the peddle from rotation axis to end of peddle (7 in. or .58ft) * number of times I peddle in one minute (50 revolutions/min under uphill conditions and at slowest speed, full weight on one foot) = 6,533 ft*lbs/min The rear and front sprockets have a gear ratio of 3.06:1 which means I am actually peddling with 19,991 ft*lbs/min This then means that I produce about 19,991/33,000 = .65 or almost 2/3 hp (I don't know if this is realistic. I remember reading someplace that humans are capable of producing 1/5 hp or so, but this is what I got. -I would like speed and power, so I decided on a 1 hp DC motor. This would be more than enough for me, especially considering two special features on this Schwinn bike. First of all, it has a transmission. Meaning there is a 17 tooth sprocket sticking out of a cylinder. Inside that cylinder are three different gears. Lowest gear just engages the outside sprocket and 2nd and 3rd gear engage gears inside the transmission. So if I get this thing working I would be able to shift gears by disengaging the motor and shifting (pretty cool). Second of all, (this isn't really a function of the bike but...) I can gear down the sprocket so I would need less than 1 hp but I want power. Mounting the motor and future 12VDC car battery holder will be no problem. Procuring a motor is my problem. My Project PROBLEM: -I can't find a flippin' 1 hp 12VDC motor for less than $400!! I don't have that money! My first thought of solving this problem was to use a starter motor from a V8 engine. If it can turn a fly wheel in winter I would hope it could push me up a hill. So I went to a junk yard and found many starter motors, but the motors (or all the ones I've seen) have the bendix and the motor cast as one piece of aluminum. Because of this I can't remove the bendix for fear of there being no bearings left for the motor (I believe the bearings are cast into the aluminum). Not only that, but the starter motors are NOT made to run continuously. If they heat up it can melt soldering, casting and whatever else is near. So that ruled that out... The great thing about finding it at a junk yard was it was cheap. What I need: I NEED A 1HP 12VDC MOTOR THAT WILL RUN CONTINUOUSLY FOR CHEAP. I am not very rich. If there is an older style car that someone know about where the bendix and motor are separate I would be willing to look at that, but I would rather have a continuous running motor instead. So if there are any suggestions, please please please e-mail me or respond back to this. All would be much appreciated. Thank you for reading this and for your time. There are a lot of good brains to be picked on the Internet. Any questions just e-mail me or respond to group. I will look daily for responses. Sincerely, David Lunde |
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#3
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"Cal Dia" wrote ..
........I'm not sure where the battery pack goes. Or maybe they use small gas engines - I can't remember. There was a kit available after WWII whereby a very small 2-cycle engine attached to the handlebars and ran against the front tire. Called a Whizzer. These made a brief comeback during the gas shortage in late '70s (?). A competitor engine was also available and even a complete Whizzer bike. The market went to minibikes instead. |
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Hi David
I've had several electric bikes over the years, most of them used what we call Pancake Motors, but they can be changed to drive the gear instead of using friction against the tire. Although the newer Hub Motors sound good, they eat way to much juice which makes them basically worthless. You sounded like you were wanting to drive the bike by using the pedal gear as the connect, that's not a good idea. My best bikes used pancake motors, but instead of driving the tire, I installed a regular small pulley on the motor and a very large pulley to the bicycle wheel, the large pulley measured two inches less in diameter than the bicycle wheel excluding the tire and actually attaches to the ferrules the spokes screw into. Uses a belt instead of a chain so you can use the existing drive system, only in reverse of the way it was meant to work. I have fooled with various starter motors, they draw a lot of current and get real hot real quick, but salvage ones are cheap! You don't have to worry too much about the Bendix just lock it in the engaged position either buy using a spacer or a spot weld to keep it in place. If you keep your eye on yard sales, often you will find motorized kids toys on sale, usually broken, for real cheap. These are often only 250 watt motors and you need about 400 watt motors for a good bike. But two of them mounted such that the belt can run across both of them will give you just under a full horsepower and sometimes more, depending upon the toy it came from. Just for grins we collected several cordless screw drivers once and after removing the gearboxes and installing small pulleys we mounted 8 of these things in an arc over the back wheel. We were quite surprised, that bike would climb a hill like a mountain bike. We probably could have gotten by with only 4 of these little motors. Our rheostat was bad so you had to lean over the handlebars to take off or it would dump you over backwards. When working with more than one motor, theres no using a slipping belt clutch system, hi hi..... Good luck with your adventure! TTUL Gary |
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"Cal Dia" wrote ...
Here is a great article that discusses the "comeback" and the companies that produced/sold the "strap-on" motors, and why they no longer do so. http://www.users.globalnet.co.uk/~pa...cc/arc0394.htm Thank you thank you thank you. When I was a youngin I wanted to put a motor on my bike so bad I lost sleep trying to design it. A friend of my father mounted a conventional horizontal 4-cycle single cylinder engine on his bike and was having a ball. During the gas shortage I was walking to work and would see a swarm of these Whizzers and related types buzz by sounding like steroid mosquitoes. Envied them much. |
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