Am I a weirdo? Just wondering....

Has Bike Guy Joe lost his marbles?


  • Total voters
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Kaos

Guest
Man that looks dangerous!!! the guy stops a liitle short at the end of the clip and it looks like it comes close to hitting him in the back of the head. I saw a guy loose a couple fingers once starting a model airplane using his finger to spin the prop instead of a chicken stick so i have seen the damage they can do. with out some kind of a guard around the prop I would'nt ride that thing, it's a accident waiting to happen
 


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DougC

Guest
Yea, I'd say somebody's tried it:
http://www.thrustpac.com/

......although it seems to make a lot of noise for what speeds they're getting.

You can make them work, but it's really pretty tough to make these things efficient--because what you need is a prop/fan speed that comes fairly close to the bike's speed, but no place out there makes high-efficiency fans for such speeds,,,, and all the little engines available have RPM curves that make them spin way too fast to directly drive suchy a fan, if you could even get one.
~
 
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Guest

Guest
Those look awesome! Too much money though, I could make one for under a hundred.

The "efficient" prop part is easy. I have all kinds of charts and ect. pertaining to how much pitch for any given speed. You could always use a reduction of some kind and make a larger, slower turning prop.
 
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Dennis Becraft

Guest
propellor prop power seems feasible, simple, fun

Here's a reduction drive for giant scale RC use.

http://www.rcgroups.com:80/forums/attachment.php?attachmentid=154765]

The builder says this is "a belt reduction unit for a 41cc "weedeater" engine that is turning a Topflite Powerpoint 24x10 prop."

My reading about this generally suggests you get 50% more thrust with a reduction drive. The guy in the vid here;

http://youtube.com/watch?v=RUwJRnc6uLo

says he gets 45 mph. I get no response from him by email. I was curious about his engine, prop dia. & pitch etc.

Playing with the numbers of my Honda GX31 & a prop I have (36' dia. & 16" pitch) leads me to a reduction of about 3.5 to 1 to get about 30 mph. It should give better acceleration & hill climbing than direct drive model plane props, designed for much higher speeds.

It seems you could use a lightweight bike this way. You could use rear suspension easily too.

I'd like to see it on a fully enclosed, streamlined recumbent with the engine/prop mounted higher to intercept 'cleaner' air.
 
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mopedjay

Guest
i built one of the backpack fans out of a leaf blower and a homemade prop out of plywood it didnt work out too well

i would think it would be better just to have the engine driving the wheels cause even friction drive would be better than a propellor drive unless your in the water
 

Tom Bartlett

New Member
Joined
Jul 29, 2007
Messages
24
Propeller Driven Bicycle (warning long Post)

Back in 2000, a Zipcycle customer (I've forgotten his name) in Ohio built a propeller-powered bike, and shipped it to us for evaluation. He used a 30cc string trimmer engine with a 22" RC airplane propeller and mounted the entire rig on the back end of the bike, and included a fan guard. Unfortunately, I cannot find the photos, but we kept the bike about a month, and all the guys at the plant (including me) rode it daily. The additional weight at the extreme rear took getting used to, but overall, it worked fairly well. The initial acceleration was not great, but we simply added human power to get it started faster. Once under way, the power continued to build until about 25 mph, then it sort of peaked. The noise was greater than a normal Zipcycle, but not unduly uncomfortable. We decided not to market the bike, but overall the power train worked, it was controllable (a little more balancing was required), and (relatively) safe with the fan guard. It is almost worth building another just to re-create the looks on the faces of those you have passed. It has to be seen to be believed.
On a side note about propeller-powered vehicles, the Lane Motor Museum in Nashville, TN has a propeller-powered tadpole trike driven by a Harley hung way up and out on front. I was there one Saturday when they took it out in the parking lot for a demonstration run. First, a very brave mechanic hand-propped the engine while the driver held the brakes. Then it was driven carefully around the parking lot (no one, absolutely no one got very close). The sight alone was worth the trip to Nashville.
Tom Bartlett
 
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mopedjay

Guest
i was thinking i could make a hat with the weedwacker engine mounted on the back with the prop then with it on my head it would be out of the way then it would power me on anything

and i think since the motor is attached to me and not the bike then it doesnt have to be registered right
 
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Sianelle

Guest
i was thinking i could make a hat with the weedwacker engine mounted on the back with the prop then with it on my head it would be out of the way then it would power me on anything

and i think since the motor is attached to me and not the bike then it doesnt have to be registered right
 
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