Dinky Propellor bike!

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JaxInsany

JaxInsany

New Member
May 6, 2013
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Portland, OR
Hello to the forums! Could a conventional 30-36cc weed eater engine spin a propeller fast enough to push a bike forward? I'm wondering if it is an idea I should even consider, seeing as there are lots of pictures of similar propeller motorized bikes out there on the interwebs! Possibly a gearing system to make the propeller spin faster?
 
maniac57

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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There is a name for people who put propellers on bicycles....they are called "amputee's"
 
F

fasteddy

Well-Known Member
Feb 13, 2009
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JaxInsanity,

Look on the radio controlled sites or just Google weed eater motors with propellers. They are used on some very large RC aircraft and there is one huge bomber that has 4 of them on it.
They are used as outboard motors as well.

You may want to consider a small chainsaw motor also. More bang for the buck. Check You Tube for more ideas than you need.

Make it happen.

Steve.
 
JaxInsany

JaxInsany

New Member
May 6, 2013
60
0
0
Portland, OR
fasteddy said:
JaxInsanity,

Look on the radio controlled sites or just Google weed eater motors with propellers. They are used on some very large RC aircraft and there is one huge bomber that has 4 of them on it.
They are used as outboard motors as well.

You may want to consider a small chainsaw motor also. More bang for the buck. Check You Tube for more ideas than you need.

Make it happen.

Steve.
Click to expand...
May I ask what the difference between a weed eater engine and a chainsaw engine is? I assumed they were similar CCs, or is it another factor that makes them more powerful? And thanks for the research ideas!
 
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fasteddy

Well-Known Member
Feb 13, 2009
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JaxInsanity,

Thank you and yes you can ask. The weed eater motors are for the most part of a lighter build than the chain saw motors. They are also built to be used for a lot lighter work. Considerable difference between cutting weeds and light brush and cutting trees down and then cutting them up.
You get what you pay for as well. A $100 weed cutter isn't going to be as heavily built as a $400+ chainsaw.
If the chain saw makers could get away with weed eater motors my guess would be that they would.

This is not to say that a weed cutter's motor isn't as usable as a chain saw motor but for swinging a prop that will move you and a bike you may want to look at a better motor if you are going to keep it for any length of time.

Just my opinion of course and your experience may very. You will most definitely need a cage around the prop and a solid one. Every time I see one without a cage I think of the operator losing control of the bike and landing under the prop or falling backwards into it.

Steve.
 
maniac57

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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memphis Tn
Aero motors are specially built for max power at a certain rpm depending on prop size.
They don't have to accelerate smoothly through a big rpm range like direct drive engines.
They are usually more powerful per cc than regular motors, but less flexible in running.
You can easily tune any engine for your rpm needs with a pipe and carb or porting mods so don't insist on a aero motor unless you get a good deal.
You want something as powerful as possible to pull a serious prop or your idea won't fly (snork) Chain saw would probably be the best bet for power vs, cost.
Make sure you have a SERIOUS safety cage too...high-rpm prop failures are NO JOKE!
I still think it's a bad idea, but as long as you approach it with the potential dangers in mind, it can be done safely.
 
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msrfan

Well-Known Member
Sep 17, 2010
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Southern California
Also most of the cheaper string trimmers use only one main bearing on the crank, leaving one end unsupported. A lot of them are direct drive, where a chainsaw always has a clutch.
 
JaxInsany

JaxInsany

New Member
May 6, 2013
60
0
0
Portland, OR
msrfan said:
Also most of the cheaper string trimmers use only one main bearing on the crank, leaving one end unsupported. A lot of them are direct drive, where a chainsaw always has a clutch.
Click to expand...
Do I really need a clutch for such a simple rig like this though? If I wanted less or no power, I could just let it drop to idling and that would be perfectly fine, I believe.
 
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