A 3D Printed Balloon Powered "Jet" Car With Inflator.

I designed "A 3D Printed Balloon Powered "Jet" Car With Inflator" for our grandkids. The inspiration for this model was from a YouTube follower of mine who asked how I thought a version he had seen worked. Well I'm not sure how the model he saw worked, but this one certainly entertains the grandkids (a "driver" is in the works, I wonder who that could be?)!

My design uses a 67mm ID silicone "hemisphere", that I carefully removed from a silicone baking mould, as a bellow and 3D printed TPU95A valves and gaskets to create a balloon inflator. As seen in the video, the car's nozzle plugs into the inflator, the car's balloon is inflated by repeated presses on the inflator red button, and the car is released by a single press of the inflator green button.

As usual I probably forgot a file or two or who knows what else, so if you have any questions, please do not hesitate to comment as I do make plenty of mistakes.

Designed using Autodesk Fusion 360, sliced using Ultimaker Cura 4.9.1, and 3D printed in Ultimaker PLA and Ultimaker TPU95A on an Ultimaker 3 Extended and Ultimaker S5s.

Silicone adhesive.

Thick cyanoacrylate glue.

I acquired the following parts:

• One Compression Spring (7.14 by 19.05mm).
• Four R22 O-Rings (28mm ID, 3.5mm section).
• One silicon hemisphere (67mm ID, 1mm thick, removed from a silicon baking mould).
• One 9" balloon.

I have included a PDF file which includes the 3D printed part names, quantities, material, layer height and infill settings I used to 3D print this model. I 3D printed all PLA parts using the Ultimaker Cura 4.9.1 "Engineering Profile" on my Ultimaker S5s which provides a highly accurate tolerance requiring minimal if any trimming, filing, drilling or sanding. However, prior to assembly, I still test fitted and trimmed, filed, drilled, sanded, etc. all parts as necessary for smooth movement of moving surfaces, and tight fit for non moving surfaces. Depending on your slicer, printer, printer settings and the colors you chose, more or less trimming, filing, drilling and/or sanding may be required to successfully recreate this model. I carefully filed all edges that contacted the build plate to make absolutely certain that all build plate "ooze" is removed and that all edges are smooth using small jewelers files and plenty of patience.

This model also uses threaded assembly, so I used a tap and die set (5mm by .8, 8mm by 1.25 and 10mm by 1.5)) as required for thread cleaning.

To assemble the Bellow, I performed the following steps:

• Using a small dot of thick cyanoacrylate glue on the valve mount pad (the pad to which the valves are connected), I attached "Intake, Valve.stl" to "Intake, Gasket.stl", build plate sides touching, making sure the valves were centered over the valve holes.
• Spread an even layer of silicon adhesive to the inside of "Bellow Base.stl".
• Pressed the intake valve assembly into the bellow base such that the valve side of the intake valve assembly was facing up and making sure the valves were aligned over the holes.
• Cut one hemisphere from the sheet of silicone moulds.
• Filled the outer track in the bellow base assembly with silicone adhesive.
• With a slight rotating motion, pressed the hemisphere into the bellow base assembly carefully rotating it to make sure it was completely seated, then set the assembly aside to cure.
• Using a small dot of thick cyanoacrylate glue on the very end of the arm on "Exhaust, Valve.stl", I attached the exhaust valve to "Exhaust, Gasket.stl" such that the valve was centered over the exhaust valve hole and the arm pointed to the center intake hole.
• Spread a thick bead of silicon adhesive around the rectangular hole in "Exhaust, Manifold.stl".
• Pressed the exhaust valve assembly onto the exhaust manifold such that the valve side of the valve assembly was inside the rectangular hole.
• Spread a thick bead of silicon adhesive on the exhaust valve assembly around the outline of the rectangular hole in the exhaust manifold assembly.
• Pressed the exhaust manifold assembly onto the bellow assembly making sure the mounting holes aligned. I temporarily secured the bellow onto "Case, Bottom.stl" using four "Bolt (M8 by 1.25 by 9.6mm).stl" and allowed time for the bellow assembly to cure.

To assemble the retainer, I performed the following steps:

• Using silicon adhesive, I glued "Washer, Cone.stl" to "Spring Clip Mount.stl" with the chamfer facing outward.
• Pressed "Spring Clip.stl" onto the retainer assembly flat side down.
• Positioned "Release Knob.stl" into the retainer assembly such that the elongated pin on the knob slid between the spring clip and the knob handle was to the left as viewed from the rear of the assembly.
• Positioned "Release Knob Retainer.stl" onto the assembly and secured in place with two "Bolt (M8 by 1.25 by 9.6mm).stl".
• Spread a thick bead of silicon adhesive around the exhaust hole in the retainer assembly.
• Pressed "Spring Clip Mount Gasket.stl" onto the retainer assembly.
• Spread a thick bead of silicon adhesive around the exhaust hole in the bellow assembly.
• Pressed the retainer assembly onto the bellow assembly, and secured in place using two "Bolt (M8 by 1.25 by 9.6mm).stl".

To assemble the top, I performed the following steps:

• Positioned "Plunger, Bellow, Handle.stl" into "Case, Top.stl".
• Threaded "Plunger, Bellow, Pad.stl" into the plunger handle.
• Positioned the compression spring over ""Button, Release.stl".
• Slid the release button assembly into the top assembly.
• Secured the release button assembly in place using "Button, Release, Retainer.stl".

To assemble the car, I performed the following steps:

• Placed one O-Ring onto one "Car, Wheel.stl", then repeated for the remaining three wheels.
• Attached one wheel assembly to "Car, Chassis.stl" using one "Car, Axle.stl", then repeated for the remaining wheel assemblies.
• Threaded "Nozzle, 7mm.stl" into the rear of the car assembly.
• Rolled the lip on a 9mm balloon all the way up the balloon neck.
• Placed the balloon onto the car assembly balloon mount.

For final assembly, I performed the following steps:

• Loosely attached the bellow assembly to "Case, Bottom.stl" using four "Bolt (M8 by 1.25 by 9.6mm).stl".
• Attached "Case, Side, Nozzle.3mf" to the case assembly using two "Bolt (M8 by 1.25 by 5mm).stl".
• After attaching the nozzle side to the base assembly, I carefully adjusted the position of the bellow assembly in relation to the nozzle side to make certain the seal between the car nozzle and retainer assembly was air tight by repeatedly adjusting the position of the bezel assembly closer to or further away from the nozzle side. This step is important for successful operation of the retainer mechanism. After accurate positioning, I fully tightened the four bolts holding the bellow assembly to the case bottom.
• Attached "Case, Side.3mf" to the case assembly using two "Bolt (M8 by 1.25 by 5mm).stl", then repeated this process for the remaining two sides.
• Positioned the case top assembly over the case assembly such that the release knob is over the release lever, then attached the top assembly to the case assembly using eight "Bolt (M8 by 1.25 by 5mm).stl".

After assembly, I simply plugged the car nozzle into the retainer hole, repeatedly pressed the bellow plunger until the balloon inflated, then pressed the release button and the car took off!

And that is how I 3D printed and assembled "A 3D Printed Balloon Powered "Jet" Car With Inflator".

I hope you enjoyed it!