Balloon Powered Single Cylinder Air Engine Open Chassis

Balloon Powered Single Cylinder Air Engine Open Chassis is an open chassis version of Balloon Powered Single Cylinder Air Engine Toy Train (https://www.instructables.com/id/Balloon-Powered-Single-Cylinder-Air-Engine-Toy-Tra/). This vehicle has the same drive train as the train engine, but is significantly lighter in weight. The results are it has traveled over 70 feet on smooth surfaces, and over 55 feet outdoors on concrete into a slight headwind, on balloon power.

We race these vehicles for longest distance. One part of the racing strategy is to inflate the balloon as much as one dares, while of course wearing safety goggles just in case "fuel tank" (balloon) failure occurs. Me, being the "professional balloon powered single cylinder air engine racing champion" that I am (did I really just say that ?!?!?), would like to offer a hint to all up and coming balloon powered single cylinder air engine racers....., "give your old balloons to your competition and use a brand new balloon", but please don't tell anyone.

You will need to purchase 4 "AS568" #219 o-rings (1 5/16" I.D., 1 9/16" O.D, 1/8" section) for the tires and at least 1 "punch balloon" (I found mine at a local party supply store, but they also are available on line).

I probably forgot a file or two or something, so if you have any questions, please feel free to ask.

Designed using Autodesk Fusion 360, sliced using Cura 2.3.1, and printed in PLA on an Ultimaker 2+ Extended and an Ultimaker 3 Extended.

Step 1: Print, Purchase and Prepare the Parts.

As mentioned in the introduction, you will need to purchase 4 "AS568" #219 o-rings (1 5/16" I.D., 1 9/16" O.D, 1/8" section) for the tires and at least 1 "punch balloon" (I found mine at a local party supply store, but they also are available on line) for the "fuel tank".

I printed my parts on an Ultimaker 2+ Extended and an Ultimaker 3 Extended using .1mm vertical resolution and 100% infill for "Cylinder.stl", "Rod Balloon.stl", "Rod Balloon Coupler", "Rod Balloon Hook", "Journal Crankshaft 4mm 1.stl", "Journal Crankshaft 4mm 2.stl", "Journal Crankshaft 10mm 1.stl", "Journal Crankshaft 10mm 2.stl", "Gear Journal Crankshaft 4mm 2.stl" and "Bushing Journal Crankshaft 10mm 1.stl", 20% infill for the remaining parts, and no supports.

This is a precision print and build and as such requires a clean and level build plate (to eliminate warping) and trimming, filing and/or sanding (to remove edge oozing). Prior to assembly, test fit and trim, file, sand, etc. all parts as necessary for smooth movement of moving surfaces, and tight fit for non moving surfaces. Depending on the colors you chose and your printer settings, more or less trimming, filing and/or sanding may be required. Carefully file all edges that contacted the build plate to make absolutely sure that all build plate "ooze" is removed and that all edges are smooth. I used a flat jewelers file and plenty of patience to perform this step.

Study "Assembly.stl", the cad output of Autodesk Fusion 360 and the photographs carefully noting the locations and positions of the various components as assembly proceeds.

Step 2: Assemble and Test the Air Engine.

Slide "Rod Piston.stl" into "Head Cylinder.stl" noting the orientation of the hole in "Rod Piston.stl".

Press "Piston.stl" onto "Rod Piston.stl" positioning "Piston.stl" exactly 28mm from the end of "Rod Piston.stl". This is the cylinder head assembly.

Slide "Valve.stl" into "Cylinder Center Top Port.stl" noting the orientation of the valve holes. This is the cylinder assembly.

Press the cylinder head assembly onto the cylinder assembly. This is the air engine assembly.

At this point, as shown in the video, you should be able to easily and smoothly move the valve and piston rod in and out of the cylinder. If not, disassemble the air engine assembly and lightly file until they do.

Step 3: Assemble and Test the Crankshaft.

Slide "Journal Crankshaft 10mm 2.stl" into the hole in "Arm Piston.stl" noting the orientation of "Arm Piston.stl".

Press "Journal Crankshaft 10mm 1.stl" onto the octagonal pin on "Journal Crankshaft 10mm 2.stl" noting the orientation of each.

Slide "Journal Crankshaft 4mm 2.stl" into the hole in "Arm Valve.stl" noting the orientation of "Arm Valve.stl".

Press "Journal Crankshaft 4mm 1.stl" onto the octagonal pin on "Journal Crankshaft 4mm 2.stl" noting the orientation of each.

Slide "Journal Crankshaft 4mm 1.stl" into the hole in "Chassis Front.stl".

Press "Journal Crankshaft 10mm 2.stl" onto the octagonal pin on "Journal Crankshaft 4mm1.stl" noting the orientation of the two journals. This is the crankshaft assembly.

Press the air engine assembly into "Chassis Left.stl".

Press the crankshaft assembly onto "Chassis Left.stl", noting the orientation of each.

Press "Chassis Right.stl" first into the crankshaft assembly, then onto the air engine assembly.

Slide "Bushing Journal Crankshaft 10mm 1.stl" into the crankshaft hole in "Chassis Left.stl" then press into "Journal Crankshaft 10mm 1.stl".

Slide "Gear Journal Crankshaft 4mm 2.stl" into the crankshaft hole in "Chassis Right.stl" then press into "Journal Crankshaft 4mm 2.stl". This is the chassis assembly.

At this point, as shown in the video, the crankshaft should rotate freely with no drag or catching and "Arm Piston.stl" and "Arm Valve.stl" should swing freely on the crankshaft journals. If it does drag or catch, or the arms do not swing freely, carefully examine the entire crankshaft assembly making sure it is "true" (meaning all journal surfaces are parallel to each other and the chassis surfaces, and no journal, bushing or gear rotates out of true) and clear of all extraneous plastic.

Step 4: Connect the Air Engine to the Crankshaft, Then Add the Front Wheels.

Using "Pin Arm Piston.stl", attach "Arm Piston.stl" to "Rod Piston.stl". Once attached, rotate the crankshaft to ensure no drag or catching occurs as shown in the video. If it does drag or catch, the air engine piston chain (includes the parts "Rod Piston.stl", "Head Cylinder.stl", "Piston.stl" and "Cylinder.stl") needs to be carefully filed until no drag or catch occurs.

Using "Pin Arm Valve.stl", attach "Arm Valve.stl" to "Valve.stl". Once attached, rotate the crankshaft to ensure no drag or catching occurs as shown in the video. If it does drag or catch, the air engine valve chain (includes the parts "Valve.stl", "Head Cylinder.stl" and "Cylinder.stl") needs to be carefully filed until no drag or catch occurs.

Place o-rings onto "Wheel Left Front.stl" and "Wheel Right Front.stl", then slide "Wheel Right Front.stl" into the front axle holes in the chassis assembly from the right (gear) side of the chassis assembly. Press "Wheel Left Front.stl" onto the octagonal pin on "Wheel Right Front.stl". The wheels should rotate freely with no drag or catching. If they do drag or catch, check both "Gear Journal Crankshaft 4mm 2.stl" and the gear on "Wheel Right Front.stl" for build plate ooze or extraneous filament.

With no drag or catch occurring, you should be able to blow into the top port of the air engine, give the front wheels a nudge, and the air engine, crankshaft and front wheels should all move with ease.

Step 5: Final Assembly.

Place o-rings onto "Wheel Left Rear.stl" and "Wheel Right Rear.stl", then slide "Wheel Right Rear.stl" into the rear axle holes in the chassis assembly from the right side of the chassis assembly.

Press "Wheel Left Rear.stl" onto the octagonal pin on "Wheel Right Rear.stl". The wheels should rotate freely with no drag or catching.

Press "Adapter Balloon.stl" into the top air engine port.

Press one "Rod Balloon Coupler.stl" onto one end of a "Rod Balloon.stl".

Press the second "Rod Balloon Coupler.stl" onto the remaining end of "Rod Balloon.stl".

Press the two remaining "Rod Balloon.stl" into the remaining ends of the two "Rod Balloon Coupler.stl".

Press "Rod Balloon Hook.stl" onto one of the remaining ends of the balloon rod assembly.

Press the balloon rod assembly into the small square hole in "Chassis Front.stl".

Hook the punch balloon onto the balloon rod assembly hook.

Place the balloon open end onto the balloon adapter.

To run the engine, I use "Adapter Balloon.stl" as a mouth piece to inflate the punch balloon, after inflating I press my thumb onto the balloon end of the adapter to seal the air, then press the adapter into the air engine upper port and off it goes!

Congratulations, you're done!

Hope you like it!

Comments

[Spencer98]

Hi, my dad and I are trying to re create your design as a home project and are having a problem with the power on the backwards stroke. The engine still works just off the single front stroke alone but not strong enough to move the car weight. Any helpful insight on why this may be happening?

Love the design,

Thanks!

[gzumwalt]

Hi Spencer98,

I'm sorry for the delayed response as I've been dealing with medical related issues.

This model is most certainly an intricate print, sand, polish and assemble model which requires a good 3D printer, 3D printing skills and intricate sanding and polishing. Have you checked the videos I published showing how smooth this model must rotate in order to operate?

I am sorry for the delayed response and for the problems you've encountered, hopefully we will get them solved.

Greg

[Spencer98]

Thanks for getting back!

Yes we spent a fair amount of time reviewing every video we can find on YouTube and instrustables you have posted about the car. Our model seems to be polished, sanded, and frictionless as yours.

We have used a UPrint SE plus printer with ABS print material for most of the parts. For the cylinder and front end crank assembly we used a Formlabs Resin printer for maximum accuracy.

If you’d like I can email you some videos of our model to show you?

Thanks!

[ThomasD260]

Hello, i recreated this as a fun at home project. I am having some trouble with the punch balloon not being able to power/push the cart. Have any tips on how to fix this problems?
Thanks

[gzumwalt]

Hi ThomasD260,

The problems that could cause this are friction, crankshaft journal timing, piston located wrong on the piston rod, and the valve plate installed upside down.

This model will operate by blowing into it, so check the videos I posted to make sure your model operates as easily and smoothly as those in the videos.

Best wishes!

Greg

[ThomasD260]

I am trying to recreate this and I am wondering if your measurements are to scale?
Thanks

[MatthewN85]

You have another air engine vehicle that you made before the train that you said went about 40 feet. I am curious as to why this travels further when geared for torque. Do you think this would still go as far with a party balloon.

[gzumwalt]

Hi MatthewN85,

The original design (before the train) directly drives the front wheels putting which makes it run faster, but puts more "strain" on the air engine. The gear reduction of this design increases the torque at the expense of speed, but it also places less strain on the air engine thus making it operate more efficient (while small, there are air losses on both ends of the piston rod and around the build plate).

Party balloons may work, I used the punch balloon for it's thickness and the small hook on the end.

Greg

[MatthewN85]

So you increase torque so it has less strain and therefore gets more cycles of the piston. In theory it doesn't seem like it should make so drastic of a difference but it does make sense. I was just wondering because I am doing a balloon car race as a school project and, with access to a 3d printer, there is no reason to do it the normal way.

[gzumwalt]

Think of it this way, with air loss being a constant, achieving a higher air engine RPM with a gear reduction increases torque in this design and running time. The additional distance achieved by the second model over the first was only 10 feet, and the earlier model got there quicker, but the later model could do so over rough terrain thanks to the increase torque and runtime.

I'll check my backup files to see if I still have the Autodesk Fusion 360 files, and if I find them, I'll post and/or send them to you. Keep in mind, these engines require meticulous printing, filing, sanding and assembly to attain the performance shown in the videos, so please don't expect to print, assemble and run to achieve the results in the video.

Thanks for you interest!

Greg

[fisho1]

this is so cool. thanks

[LauraMelnik]

Love it!!!!

[gzumwalt]

Thank you, I'm glad you liked it, we race them and they kids and grandkids love them!

[CG2002]

I have been trying to make your original version of the car, what did you change the cylinder to ( I noticed it was different)

[gzumwalt]

There are a few changes to this open chassis design versus the previous open chassis design.

First, there's the addition of a 4 to 1 gear ratio to increase torque. This required both chassis and drivetrain changes.

Second, I changed the design of the crankshaft journals and printed them at 100% infill.

And finally, I moved the engine intake port to the center of the engine to help stabilize the vehicle.

I believe that is all, if you have any further questions or difficulties with the models, please feel free to ask.

[random_builder]

This is cool! I think I like your train better, but this is still pretty nice.

[zposner]

I agree, this would be cooler with a car body

[gzumwalt]

Hmmmm.....

[gzumwalt]

Thank you!

I like the looks of the train much better, but a few complained it would take too long to print and require too much plastic. So, I used the same engine, drive train components and wheels, just changed the chassis for a lower center of gravity. It does travel much further than the train thanks to its lighter weight.

Thanks again, I'm glad you like it!

[random_builder]

I didn't think about that! If I was building one, I probably would build this, because it uses less plastic.