Portable Propeller Engine

About: Hi I'm Michael! I love all things Science, Engineering, & 3D Printing. If you've enjoyed my work then I've love to hear from you!

Have you ever had a rubber band powered balsa wood aircraft? I did, and i was mad when it broke. So i came up the the Portable Propeller Engine, I call it the Porta-Prop.

It is a self supporting rubber band powered engine shaft and blade. It is designed to fit a specific type of balsawood aircraft sold at Michael's craft store, but im sure it will fit any old thing you strap it to. Now you can play with the r-band powered craft as much as you want, and when it breaks, you can simply switch the prop over to a new plane! Here's how to make it....


1 proconstructed balsa wood airplane (I got mine from MIchael's crafts for $1)

1 long and one small rubberband

1 or 2 Lego propellers (the bigger the better)

a small paperclip

less than a foot of 1/4" dowel rod (use poplar or pine)

certain common Legos, pictured below


a ruler

a dremel tool or something with simiar drilling and sanding capabilities


needlenose pliers

silicone spray makes it much faster

remove the nose weight

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Step 1: Making the Rotary Shaft

It is pretty hard to give a good verbal description of what a lego looks like, so there are ample picture given.

1. get out your long rubberband and the three other legos pictured. A black ridged rod about an inch long, a gray friction nut, and a cylindrical hollow uni-bumb.

2. cut your rubberband and slide the ends through the top of the black uni-bumb.

3. slide the black uni-bump with the band in it onto the black ridged rod in such a way that the rubberband is also attached to the rod. Slide the gray friction nut onto the shaft, and put superglue between the nut and black uni-bump to help permanently attach these items to the black ridged rod.

4. (note in the photo i used a cylindrical unibump for this part, you should use two cubic unibumps)
get two cubic uni-bumps. you can lego lock them and glue them together to that the holes are facing the same direction.

5. Now get your propellors ready, and assemble the whole thing as shown in the first photo.

Step 2: Assemble the Balsa Airplane

The package has instructions on it. Assemble the plane like normal.

the plane has a weight on the nose, take it off and keep it until the end. If your finished plane isnot balanced right and adjusting the main wing doesnt fix it. You can use this nose weight to rebalance it.

Step 3: Build the Support Shaft

we have to use a dowel rod to support the force of the rubberband. If we were to attach the rubberband directly to the plane it would not be protable and it would create a lot of force in the plane.

1. cut the dowel rod to 4.75 "

2. use your dremel tool and a cuttoff wheel to cut a groove to half the depth of the rod, for the entire length of the rod. I set my rod onto a boxtop with a corner to help support it.BE CAREFUL. at one end cut a little deeper for about a 1/4"

3. use your dremel small sanding bit to make the groove wider. Choose a sanding bit which will allow the plane to fit into the groove. Also sand the 1/4" deeper end out so that it has extra room for the next part.

4. get your paperclip nad make it straight first. Now bend it around the rubberband (the one you glued to the propeller rotor earlier) and back onto itself. Now twist the two free ends together a bit and superglue it to the inside of the 1/4" deeper groove. Make it strong, glue it twice if you have to, but make sure you leave enough room for the plane to fit in behind it.

5. when that dries bend the paper clip into a hook or 90 degree angle. This is to bring it away from being too close to the shaft, you want the rubberband to stretch from the loop to the propeller without touching anything else.

6. Now just slide the dowel rod through the gray frame pieces you glued together earlier. It happens to be the perfect size to keep the gray pieces from sliing around on the rod.

7. When everything is dry you should be able to wind up the propeller and watch it spin when you let go. Use the silicone where the spinning rotor rubs against the gray frame pieces.
you can bend the paperclip to achieve this desired affect, you want the rubberband to be almost loose when it is not wound up at all.

now your porta-prop is done. To attach it to the plane, just push the plane up to the groove as close to the prop as possible. Take off the propeller and put a small doubled up ruberband over the shaft and plane to attach them better. Also, slide the main wing towards the tip of the plane, this will make up for the addition of the weight. your done have fun!

Step 4: Video

hopefully this vieo will give you better viewing angles and explanation!

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    23 Discussions


    9 years ago on Introduction

    i'v got a tip:
    make better (cleaner) pictures.

    but i like the instuctable!!!


    9 years ago on Step 1

                              Hi,man i need serious help frm u, i have been given a project on making a glider plane which are not operated by any set of batteries or fuel allowed to use small pastic propellers on their planes.And i couldn't get to know frm ur presentation how to build a propeller?? ... plz help

    1 reply

    Reply 9 years ago on Step 1

    Do you mean the blades themselves? On my little plane, those were legos. They are ideal because they are lightweight, strong, and seamless, and because it would be hard to make your own propellers.  The rest of the model is simply attaching one end of the rubber-band to the prop axle and the other end to a fixed point of the plane.  Hope that helps.

    By the way, It would also be helpful if your message did not have spelling errors, for future reference.


    10 years ago on Introduction

    Good job, but sheet pics... Hard to understand, no offense


    10 years ago on Introduction

    Do I have to use a propeller, can't I make one out of cardboard or sumthin, cuz I don't have time to buy one. Cuz with my friends we all make one of these instructables people make, then have fun with the things we make. So is there I way I can make a simple propeller out of household items

    2 replies

    well my advise is that it would save more time to buy one somewhere, check your local stores for lego packs that have propellors or a hobby shop. IF you really wanted to make one, keep in mind, it should be as symetrical as possible to avoid misalignment of weight problems. I would suggest making a model of the propellor out of modeling clay, bake it to harden it. Then stick your model into some JB stick weld or Mighty Putty to make a mold. Then when the mold hardens, use more mighty putty with the mold and make a propellor, you can always sand down imperfections later too. but all that is very involved...


    10 years ago on Introduction

    hahah lol i saw this on the berenstein bears.


    10 years ago on Introduction

    I know it is good to encourage people, but there are some glaring issues here with me. So, please take this as some constructive criticism please. The pictures are easy to fix really. Most camera buttons on the digital cameras are actually 2 buttons in one. Most will focus and lock on half a push, then snap the photo on the full push. Take advantage of this by holding your hand flat at about the distance the object is away. Half press and hold the shutter button to focus on your hand, then swap your hand with the object and snap the photo. Also most cameras have a "close up" mode. Look for a flower symbol or something. My main issue is this setup will not fly any different than if you glued a weight to the nose. If you use Legos it will be too heavy and accelerate rapidly into the dirt. Lego props are heavy, not cheap, and they are designed for play, not practicality. I just don't want to see a kid glue all his precious legos together, just for it not to work. Make sure to use the propeller the plane came with or another hobby/light weight one. You might need to modify it though. I love legos and I've been building things that fly for over 2 decades. So that little issue hit a soft spot with me. ; ) Other than that, the format was pretty rock star : ) . Keep up the good work and we look forward to seeing more!


    10 years ago on Introduction

    From a private real plane flyer...good to go.


    LOL !!! I was a terrible 'ible photographer. Blurry, badly framed, you name it. Finally I started propping my cheapo camera on a bag of beans and some books. And using the self-timer - that is key I think. Anyway I can see your pictures just fine and the explanations are clear.


    10 years ago on Introduction

    You've got my vote. Nice job and good explanations.


    10 years ago on Introduction

    darn, I just came up with this but you already did it. only i was going to add the whole "build a plane from scratch" business


    10 years ago on Step 3

    Great instructable! But dude, get a better camera


    Reply 10 years ago on Introduction

    yea, you just have to wind it up a lot. If you dont wind it enough it rewinds itself and starts spinning the otherway! wich creates a cool nosedive. It creates a totally different flight pattern when it is powering itself. Once ive thrown it and the propeller flew off after flying a few feet, and it actually made the plane fly farther! perhaps thats a thought for a future project.