Rubber-Band Powered Balsa Wood Glider

I am Rohan Inampudi, a 9th grader at USC High School, Pittsburgh, PA.

I created a glider using Balsa wood and 3D-printed parts that I designed. This glider is rubber band powered and will glide pretty far. I did not post the launcher on this instructable as the launcher design is variable. Feel free to make your own launcher and use it as the rubber band notch on the glider works with any rubber band.

NOTE TO JUDGES: Some of the pictures in the preview on the webpage have been cropped, so please click on each picture to see the full picture. I have noticed some of the previews limit some info on the pics. This can apply to everyone else as well.

You will need 6 items to make the glider:

• one long balsa rod
• a 24" balsa plate
• the 3D-printed airplane head
• the 3D-printed airplane tail
• masking tape
• a rubber band

You will also need:

• scissors to cut the tape
• an X-acto knife to shape the wings.
• access to a 3D printer
• PLA or PETG filament (I do not recommend anything else, but definitely no flexible filaments like TPU)
• Fusion 360, Inventor, or some other CAD editor

A ruler is also preferable for measuring balsa and tape.

Below are the STL files for the 3D prints.

Print the airplane head and tail. I designed these using Fusion 360 and what you see are the STL files. Download the STL files attached to the SUPPLIES SECTION and 3D print them. It will take approx. 1 and a half hours. These are the bases for the balsa wood.

The head comes with a notch that is used for launching. The notch holds the rubber band on your rubber band launcher. It is a pull-back design.

Note that the letters are my initials as a design watermark. Feel free to change them or remove them when you are editing the model(which you may have to, more on that later).

Get a long balsa rod. This will hold the 3D-printed head and tail. The size is indefinite, but it cannot be shorter than 24".

Find a balsa plate as well. It is preferred that the plate is exactly 24" long. The width can be anywhere around 2". That length is great for flight and it is what I used. I used balsa because it is soft and will slide onto the 3D-printed pieces easily. It is also lightweight, promoting flight.

Mark the balsa at 16" and 22". Cut along these lines. You should end up with a 16" piece, a 6" piece, and a 2" piece.

The 16" piece is for the front wing. The 6" piece is for the back wing. The 2" piece is for the rudder/vertical stabilizer.

Shape the peices. I used these shapes, but it is up to you and your preferences. Any shape will work as long as the middle of the wings are full length(based on the balsa plate). Try to shape your wings for optimal flight. I aimed for long distance, but you can shape them for best speed.

An X-acto knife will work best for cutting balsa as it is soft.

Optional:

You can color these wings in if you want, and I did that at the end. This is completely your preference, paint the wings however you like!

There is a hole in the head made for a balsa rod. Slide the balsa rod into the head for a tight fit. Not all balsa rods will work as I designed my 3D print for the rod that I have. You may have to edit the 3D print using the STL file to fit your balsa rod.

Slide your balsa rod into the bottom hole of your tailpiece. This should be the hole that is fully surrounded by material. The rod should slide freely around i.e. the fit is not tight. Slide the piece exactly 3.5" into the rod. Like the head, you may have to edit the STL file for the hole to fit your rod for a free fit.

Gather 2 pieces of masking tape(for a secure fit). Each should be around 2.75" long, but no shorter than 2.5". Wrap each piece on either side of the tailpiece to secure the tailpiece. Make sure not to slide the tail around in the process as the tail will not be 3.5" into the balsa rod. This will secure the glider's tail.

Using the above pictures, attach the balsa plate pieces to your glider. The back wing should slide into the space between the top and bottom of your tailpiece. The rudder(vertical stabilizer) will go into the vertical wedge on the top of the tailpiece(the hole that has only 3 sides surrounded by material).

The front wing will be attached to the balsa rod using a rubber band. Do this directly in the middle of the head and the tailpiece. Place the front wing on top of the balsa rod and wrap a rubber band tightly around it for a secure fit. How this is done is up to you based on how stiff you want the front wing to be. I wanted it to be flexible but not flimsy so I did a double wrap, but if you want something else, go for it!

I did not have a picture for launching because this step is optional. I also do not care how your launcher is built because there are many designs. Just note that the notch at the head of the glider was designed for a pull-back design using rubber bands. The size of the rubber bands does not matter, but if you want the plane to go far use long, strong ones. Thin rubber bands will easily break due to tension as the plane is long.

In combination with the lightweight nature of balsa wood, the design of this glider should allow it to fly pretty far(around 40 feet, give or take). I designed the plane this way so no matter your artistic skill with shaping the front, back, and rudder wings, the glider will still be enjoyable. Note that designing the wings with skill will make your glider go faster, farther, or both.

You can use your throwing power to launch the glider.

It is not necessary to use a rubber band. If you do not want to spend time building or getting a launcher, the glider will work perfectly if you just throw it with your hands. However, this method does require you to shape your wings well, as bad wing shapes will make your gilder plummet. Strong throwing power is also needed as a weak throw will not suffice for a glider of this size.

This was most definitely a fun project for me, and I assure you it will be fun for you as well! Playing with the end product is also very gratifying!

Thank you!