Compressed Air Airplane Launcher

Hi, my name is Lincoln Clarke and I'm a grade 11 student at the Toronto French School in Canada.

In this Instructable you will learn how to make and airplane launcher that operates on compressed air, with launch speeds of up to 26.6km/h (7.4m/s) and acceleration of about 70m/s²! I will also show you some physics analysis of the plane's motion.

Not much specialized equipment is needed either!

• Air compressor
• Trigger handle for air compressor
• Ideally Mastercraft
• Other similar models work for the purpose as well, but the 3D printed parts are made specifically for the Mastercraft one linked above
• 3D printer and filament
• Superglue

First, I took a picture of the trigger I would be using and added it to my Fusion 360 design as a canvas. Then I scaled it and began tracing the profile of the attachment. After extruding it, I swept a circle along the tube's path to cut out just enough room for the trigger's nozzle. Then I made a new sketch for the acceleration chamber and extruded it, joining it to the attachment.

The first step is to design the chamber insert, which will transfer the air's kinetic (originally potential) energy to the plane.

It took me two design attempts to get a plane that worked decently well. In my first design, I was inspired by the F-117. However, this design was very unstable in the air, and would just do about 10 flips after being launched rather than flying and covering ground. Although it looked sort of cool as well, I wanted something that flew a bit better, at least for the first portion of the flight.

I decided to redesign it more like a commercial jet–with less area under the wings and an actual fuselage. First, I made a cylinder and lofted the end to a point. Then, I cut slots for the wings. Next, I made the wings to fit in the slots. Finally, I cut a hole in the bottom of the plane for the chamber insert. This insert is what accelerates it out of the chamber.

This iteration worked much better, as you can see in the video in the following section.

I printed the plane's body as well as the trigger attachment upright. The trigger attachment does require some light supports, but not many and they're easy to remove. For the fuselage, I printed at 0.3mm layer height because there aren't any fine details.

1. Glue the wings to the plane fuselage using Superglue
2. Glue the chamber insert into the fuselage with Superglue
3. Let the glue set

1. Connect the nozzle attachment to your air compressor trigger
2. Connect the trigger to the air compressor with the regulator set to a low pressure (10 PSI)
3. Insert the chamber insert (square rod) into the launcher's air chamber
4. Fire!

You can increase the pressure for more speed, but do wear safety goggles and don't aim it at any living things!

Using Logger Pro by Vernier, we can analyze a video of the plane being launched. After calibrating the video (telling the software the scale), we can just add a dot where the plane is and it will move it forward 1 frame. This will create an arc of points as seen in the second picture. Logger Pro will convert these points into a data set from which we can make graphs. I chose to analyze the plane's speed and acceleration. To do so, I created new calculated column for the speed of the plane. This column simply adds the magnitudes of the x and y vectors of velocity together to get the plane's speed. Graphing the speed allows us to calculate the acceleration of the plane when leaving the launching chamber. It accelerated at a maximum of 70.4/s²! Looking at the data set, we can also see the maximum speed: 7.4m/s!

I am quite happy with these results, especially the acceleration.

It is interesting to think of potential real world applications of such a device. Compressed air is commonly used in industry to power machinery, but isn't generally used to launch aircraft. Currently, most launching systems for aircraft use powerful electromagnets, but compressed air could be an alternative in some scenarios. For example, drone gliders used for surveillance could be launched this way in order to gain a lot of energy without having to consume its battery life. With longer tracks and higher pressures, this could be a great option.