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Update Instructable with test ride video at link below.

https://www.instructables.com/id/Free-Propeller-Bike-Mod-Update/

Video of Bike and Propeller test.



I wanted to put an electric motor on my bike. I didn't want to mess with a chain and sprockets so I build an electric propeller bike. It is easy to install and remove. It sounds cool and its easy to use the pedals, the prop or both.

I used a free car electric motor that I fixed, free laptop batteries that people threw out and a home carved propellor.

Step 1: Parts Needed

Parts needed
Electric motor (car rad fan, AC compressor)
Battery 100Wh + (laptop batteries work best)
Switch (door bell switch over 10A works)
Wires (I used 14 gauge)
Some wood (to build the mount and prop)




Step 2: Carving the Prop

First I used excel to calculated the angles needed at the different prop stations.

I choose a diameter of 20 inches because thats about how wide I am. I don't want the prop sticking out and hitting stuff as I ride my bike.

I just want the propeller to push me around 20 to 30 km/h. So I want a pitch that work well at these speeds. I started with a 6 inch pitch. From my excel sheet a 6 inch pitch is about 27km/h at 3,000 rpm. Most large motors operate around 5,000 to 10,000 rpm. The prop will operate most efficiently at an angle of attach of about 3 degrees. The air will also accelerate as it is sucked onto the prop. So I am thinking that it might be more like 5000 rpm when the bike is doing 27km/h.

I used pine 4x1 boards to carve the prop. I decided to have a 2 inch tip width and 3.5 inch root width. I used the excel sheet to Calculate the drop every inch along the radius. I marked the drop with a marker. I then started carving using a box cutter and homemade draw knife. The motor side of the blade is curved and the other side is flat. I used 80 grit sand paper to get a very aerodynamic blade shape.

Step 3: Attaching to Motor

Every motor shaft is different. I found with the motor I used it was easiest to JB weld a wood mount to the shaft.

I cut 2 circles using the hole saw. I glued the shaft in the center and glued a 3.5x3.5 inch square of 3/8 plywood to it. I then used 4 screws at the corners to attach the prop to the motor.

Step 4: Batteries

If you use laptop batteries like I did you will need over 6 cells (one laptop battery).

Best would be 3 batteries or more (over 18 cells).

You can see how to build the battery pack below.

https://www.instructables.com/id/Free-lithium-Ion-Battery-Pack


Step 5: Motor Mount

You can make a sturdy mount out of wood for most motors.

I had to use a 3 inch hole saw to cut 2 half circles to hold the motor.

Step 6: Balancing and Testing

It is important to balance the propellor very well. The propeller is rotating very quickly so a small imbalance will cause a lot of vibration.

Vibration will damage the motor and steal a lot of power.

To balance, mount the prop to a shaft. Place the shaft on two objects of the same height. The heavy blade will rotate down. Remove some wood and balance it again. Also balance the hub.

Test run the motor/prop and made sure it pushes.

Step 7: Control Switch

For the control switch I used a 10 A doorbell switch.

I like this switch because it switches off when you stop pressing it (much safer).

I used 14 gauge wire to wire the positive to the handlebars and through the switch. The negative was directly wired to the motor.

A larger switch may be required as the motor can pull more than 10 A.

Step 8: Mounting to the Bike

In my first test I mounted the motor and propeller to my cargo crate. This was not strong enough.

I made a mount that uses hose clamps to fasten to my rear carrier vertical tubes. I drilled holes in 2 2x1s to put the hose clamps through. The motor mount was then screwed into the ends of the 2x1s. This was very secure.

I only mounted the motor here because I wanted to keep my cargo crate attached. The motor should be mounted so that the prop sees clean air if possible.
I'm doing something similar but on an old ATV. Its just a rolling chassis. No motor or plastics . Mounting a v-twin on the back sideways with an aluminum prop. The V-twin motor is a Yamaha 1100 cc. will put an instructable on here when completed and tested
Great invention bro. At first u pedal and than use the power of propeller. Great idea buddy and i think u must use a dc table fan which is complete and just fix and go..
Great!
I do appreciate the advice and I don't think its fair to drive by and hit someone with the tip of a propellor that doing 200km/h. <br><br>I am still improving the design and am now working with a larger battery and radiator fan motor. <br><br>Once my testing is complete and I have a perfected design I will try to build a large plywood duct. I am just worried it will be difficult to make it light and strong enough. If I am moving and I drop the bike I think the prop is hitting something regardless of how much protection I have.
Allow me to explain the irony of my comment. CARS are dangerous. PEOPLE are dangerous... propellors are VERY dangerous... but you have the choice to stay away from the danger if you wish. This person obviously does not wish to. Me? I stay away from HIS danger. I create my own dangers. The dangerous comments are somewhat humorous here, it is pretty clear that this is VERY dangerous. I didn't mean otherwise. Sorry if I ruffled feathers. It IS a pretty cool toy, though.
Abinc<br><br>Thanks for the great questions.<br><br>This bike has 55psi in the tires so friction is low. Going up hill you need to pedal to assist the prop. No gyroscopic effect.<br>Range with 2 laptop batteries maybe 15km.<br><br><br><br>
Motor is now held on with hose clamps. It was too powerful for duct tape.
About using RC plane motor. Yes they are small and efficient but also expensive. I like using broken car 12 volt motors I get for free. I think the one I am using is about 300 watts. The magnet was broken and I just glued it with JB kwik so I am worried about vibration and the motor getting hot.
With 12 cells (2 laptop batteries) its about 30 minutes at 30km/h (15km). But I am adding more batteries.
Update instructable with test ride video.<br><br>https://www.instructables.com/id/Free-Propeller-Bike-Mod-Update
<p>por que no, mejor usas el motor con una serie de engranajes o poleas, para mover tu bicicleta, esto se me hace peligroso para quien pasa a tu costado y para ti por si llegas a caerte, pero si tu idea es usar una h&eacute;lice, pues te recomiendo que uses una ya fabricada, las venden en tiendas de aviones a radiocontrol, las hay de madena y nilon, b&uacute;scate una con un buen paso de avance y que sea para empuje, para que puedas impulsarte (lo dudo), te recomiendo esto por que las fabricadas estan pensadas para que sean flexibles, no se desprendan en movimiento, esta balanceadas. Pero antes de tomar esta idea piensa un poco m&aacute;s en seguridad...</p>
<p>How far can you go on that batter pack?</p>
<p>How much thrust did you get from this setup (kg?)</p><p>How much kg/w ?</p><p>Have you considered to use brushless avia-models motor for it? I suppose it can be much more efficient, very small motors have power of 300-500W and i believe much better efficiency. Examples - <a href="http://www.hobbyking.com/hobbyking/store/__16232__NTM_Prop_Drive_Series_35_48A_1100kv_640w.html" rel="nofollow">http://www.hobbyking.com/hobbyking/store/__16232__NTM_Prop_Drive_Series_35_48A_1100kv_640w.html</a></p><p>Anyhow, bravo! And show us action and real life measurements!</p>
<p>PLEASE REMOVE THAT from your Bike before you hurt yourself or someone else!</p><p>other than that its a great instructable on how NOT to propel a bike!</p>
I'll echo the safety concerns. Just a brush with the blade tip would cause severe injury. I would go with building a ducted shroud. It would add safety and efficiency.
<p>utilizzando quelle piccole batterie, che &egrave; la gamma [km] di tua moto?</p><p>Imperio da Firenze</p><p><br></p>
<p>A fast-spinning blade on the back of a bicycle. What could possibly go wrong???</p>
<p>Video! Video! All We Want a Video of this AMAZING INVENTION in action!</p>
<p>+1!...+1!...+1!...+1!...</p>
<p>In my Rc airplane flying I have seen people get cut and need stitched from a 6&quot; prop. You may want to make some type of prop guard.</p>
<p>No way is this ever going to move anything but a little bit of air. If it created enough force to do anything, duct tape would not hold it in place.</p>
<p>Can you give us an idea of how well this works? A movie would be great.</p>
<p>Ha ha, pretty funny. My guess is it does little more than make plane noises. Prop and motor way too small to actually move the bike (maybe if nobody is on bike it'll move).</p><p>If you want the motor to actually move the bike, put a roller on it and have it rest against the wheel.</p>
<p>It needs a mesh cage around it to be safer.</p>
<p>I have to agree with the safety issue here.</p><p>Even at 3k rpm, that wooden prop will do major hard to anyone/thing unlucky enough to get hit by it.</p><p>I love the idea, and plan to play around with the concept, but PLEASE consider the safety of others when working with fast spinning blades!</p>
<p>I thought about this concept of bike propulsion some time ago. Glad to see that someone actually built a prop-prototype. I have questions: What is the impact of tire friction on rate of travel? Ditto gravity; specifically, how severe is the slow-down when attempting to climb a hill? Did you consider lighter weight materials to maximize cargo capacity and speed? Is there a gyroscopic effect (e.g. -- difficulty in changing directions)? What is the range? Is there a difference in braking as compared to conventional pedaling? Can you detail your riding experiences and what you would do differently next time?</p>
<p>Ah ! </p><p>At last a proper answer to those who propel their bicycles with rockets (yes ! I saw in on You Tube) : this will go slower bur farther !!!!&hellip;</p><p>Thanks of the real fun from this post !</p>
<p>Great work! Can you share your eXcel formulas?</p>
<p>Amazing work! Does it actually give you any propulsion?</p>
<p>Impressive how well You calculated important details. But how does it perform?</p><p>Also there is a risc of the switch getting stuck (600 Ampere initial surge not unsual for such a motor, could weld the switch stuck, not able to disconnect), I recommend some alternative emergency/security switchoff in serial.</p>
I'm wondering if instead of a guard do a cowling it would improve performance and provide safety
Can you post the exel doc pleas
<p>This is super awesome, and something I have dreamed of doing myself. I would definitely add a metal cage around the propeller to avoid injury though. Great instructable!</p>
Right now there is a hurricane here. I also need some more laptop batteries but then I will do a real road test.
<p>Let's see it in action - how fast can you go on prop power alone?</p>
an alternative to the switch might be a relay.
As long as the relay doesn't stick. Happened to me on a project.

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