For any aircraft a parachute is necessary for many reasons. When it comes to drones a parachute is necessary for a crash landing or an unharmful drop-off from high altitude. In this instructable I will show you how to create a paper parachute that can be taped together and released from a drone. With an airplane-like-drone the parachute should be released from the back to avoid collision with the propeller. With a quadcopter type of drone the parachute should be dropped from the bottom of the drone to also avoid collisions with the propellers. This project requires materials that most of you already have and less than two hours of your time. Have fun!!
Step 1: Materials
- At least 6 sheets of paper
- String of some sort
- Ruler / Straight-Edge
- Hole Puncher (not required)
- X- Acto Knife
You also need something to cut on like a mat to put on your desk so you don't cut the desk. I used a old notebook and changed pages when they got too cut up.
Step 2: The Math Behind It
The parachute in this tutorial has 12 separate parts. Each part has a base length of 6cm meaning that the circumference of the base of the hemisphere is 72 cm or 28.3465 inches. Working backwards with the formula C = d x π the diameter of the hemisphere is around 9 inches (the diameter of a basketball).
If you want to adjust the diameter of the hemisphere to your liking just choose your diameter (d), multiply by pi (π), and divide by 12. This will give you the base length of each of the 12 pieces of the hemisphere.
While the base length of the example pieces that I provide in the next step are 6 cm, the height of these pieces are 19 cm. This is the ratio of base to height for these pieces, however, the problem with drawing out each piece by yourself if the angle of the curve. This problem is solved in the next step...
Step 3: The File
The file attached below is a document containing two pictures of the component. If you want to keep the diameter of your parachute at 9 inches (basketball size) then print 6 copies of the file below.
If you wish to change the size parachute then open the file in word or any other text editing app that can change the size of the picture. Once the file is open and you have determined the new diameter of your parachute, determine the base length of each component with the formula, B = (d x π) / 12. Now in the text editor create a straight line drawing the length of your desired base length. Then, adjust the picture of the component using the corner dots to keep the ratio of height and length the same until the base length of the drawing is the same as the length of your line drawing.
Once you are done print as many copies as you need (the size of the component might change to take up an entire page) to have 12 separate components.
Now that I read over this it seems more complicated that it is so I am going to create a youtube video an attach it so that you can just copy what I do.
Step 4: Putting It Together
Once you have printed out each of the components, use your x-acto knife and ruler to carefully cut out all of the twelve components. After they are all cut out set aside 2 pieces of tape that are about an inch long. Get two cutouts of the hemisphere and line up the bases of them keeping the side tabs inside. Tape the bottom together. Work your way up the cutouts by infolding the tabs together and taping it in place.
Repeat the instructions above for all of the cutouts and add supporting tape if necessary. In addition, add tape to avoid any air leakage to maintain enough air draft.
Step 5: String It Together
Depending on how strong your string is, choose how many strings emerge from the parachute. Label each cutout component that will connect with a string. At the edge of the hemisphere tape the edges where you are going to create a hole to attach the string. Using the hole puncher, punch a hole where you had just taped.
Then cut as many equal lengths of string as the holes that you punched. The tie loops into each string and loop the string around each one of the holes, and then tie the other end of the strings together.
Step 6: Putting It to Use
If you wish to drop-off something from your drone then tie whatever it is you wish to drop off to the end of the strings. Using a servo, pin the end of the parachute to some part of the plane and control the servo with one of the channels of you R/C system. When you wish to drop of you item move the servo to release the parachute from the drone and watch it descend from the sky.
If you wish to create a safety parachute system for you drone then tie the end of the strings to your drone. Then get another piece of string and tie some sort of small and somewhat heavy object to one end (like some quarters) and tie the other end of the string to the top of the parachute. Then carefully fold up and store the parachute to an open part of your plane. Using a servo, pin your small and heavy object to some part of the plane so that if you get into a sticky situation you can move the servo to drop the quarters which pull out the parachute and open it. Your falling plane will slow down to a safer speed and save some of you components from breaking.