Prop Bike Trailer - Suggestions?

GoldenMotor.com
A air propeller driven bike - actually, I'm considering a trailer.
The Wright Brothers were bicycle mechanics before they were airplane mechanics,
so the concept has been floating around for a while.
(Previous discussion in this form is meager.) Endless Sphere thread


There are prop venders.

  • I plan to use a cowling around the prop as a guard and to channel the air.
  • Since the bigger the prop, the better, the limiting factor is unwieldiness. I'm thinking the prop can be a meter in diameter.
  • I plan on using the Harbor Freight Predator 79cc engine. I'm familiar with it, and it's cheap (US$80. with coupon and tax exempt).
  • Direct drive: the prop will attach to the shaft of the engine.
  • Trailer hitch will probable be a swivel universal joint at the seat post.
  • Kill switch wires and the throttle cable go from the trailer to the handlebars.
  • I'll use 26" wheels spaced as wide as I can to the sides of the cylinder cowling.
A big objection is that air drive is inefficient contrasted to a drive using the friction of the surface for traction.
True, but an air drive, particularly a detachable one, has advantages to compensate for the lack of efficiency, simplicity, for starters.

Yes, I'll surely peg the dork meter on this one, but, you know, they laughed at Robert Fulton. Fulton's folly

Yes, I realize pushing bike trailers are reportedly problematic at higher speeds. I'll deal with this by making the point of attachment as far forward as possible, and I don't expect to go fast, anyway.

Since the the Prop-Pusher-Trailer is transferable from any bike to any other, I can't see this becoming a waste. But if it's worthless, I can use the engine elsewhere and I'll have a trailer.

Criticisms, Suggestions, Comments, etc.?
 
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maniac57

Old, Fat, and still faster than you
Oct 8, 2011
4,484
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0
memphis Tn
A air propeller driven bike - actually, I'm considering a trailer.
The Wright Brothers were bicycle mechanics before they were airplane mechanics,
so the concept has been floating around for a while.
(Previous discussion in this form is meager.) Endless Sphere thread


There are prop venders.

  • I plan to use a cowling around the prop as a guard and to channel the air.
  • Since the bigger the prop, the better, the limiting factor is unwieldiness. I'm thinking the prop can be a meter in diameter.
  • I plan on using the Harbor Freight Predator 79cc engine. I'm familiar with it, and it's cheap (US$80. with coupon and tax exempt).
  • Direct drive: the prop will attach to the shaft of the engine.
  • Trailer hitch will probable be a swivel universal joint at the seat post.
  • Kill switch wires and the throttle cable go from the trailer to the handlebars.
  • I'll use 26" wheels spaced as wide as I can to the sides of the cylinder cowling.
A big objection is that air drive is inefficient contrasted to a drive using the friction of the surface for traction.
True, but an air drive, particularly a detachable one, has advantages to compensate for the lack of efficiency, simplicity, for starters.

Yes, I'll surely peg the dork meter on this one, but, you know, they laughed at Robert Fulton. Fulton's folly

Yes, I realize pushing bike trailers are reportedly problematic at higher speeds. I'll deal with this by making the point of attachment as far forward as possible, and I don't expect to go fast, anyway.

Since the the Prop-Pusher-Trailer is transferable from any bike to any other, I can't see this becoming a waste. But if it's worthless, I can use the engine elsewhere and I'll have a trailer.

Criticisms, Suggestions, Comments, etc.?

BE CAREFUL around any engine driven prop.
They can easily maim and kill instantly!
I would not attempt this due to safety concerns....
(and my nickname is Maniac!)
 

WightBoy

Member
Aug 30, 2012
271
0
16
Michigan, USA
Regarding the danger, I plan to completely enclose the prop inside a large cylinder.
I looked at a wheelchair today.
Maybe I could mount a engine mount, a cylinder, and a central tongue.
Too funny! But at least if S***hits the fan you will already be in a wheel chair!
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
4,484
22
0
memphis Tn
A shroud would have to be quite heavy duty construction to contain a spinning prop.
Be aware of the dangers and do your homework on design first.
In order for a shroud to improve thrust, there has to be super precise tolerance on the blade to shroud clearance.
 

Maxvision

New Member
Jun 13, 2009
551
1
0
San Diego, CA
Kinda like sticking your head in a blender if you ask me!

but then...you didn't ask me...

There's a guy in San Diego who owns Rusty Spokes bike shop. He built a prop driven bike with an electric motor. Normally I'm an adrenaline junky myself and willing to try most anything. I took one look at that bike and all I could see in my mind's eye was blood, guts, flashing lights and ambulance sirens.
 
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A shroud would have to be quite heavy duty construction to contain a spinning prop.
The prop spins without touching the shroud. Are you saying the shroud should be bullet-proof, able to withstand a catastrophic failure of the prop?
Be aware of the dangers and do your homework on design first.
In order for a shroud to improve thrust, there has to be super precise tolerance on the blade to shroud clearance.
Actually, the ducting-trust-improvement was a secondary possible benefit of the shroud, but I'm certainly interested. Do you have any information on the effect of varying the size of the margin between the inside shroud diameter and the prop diameter?