Rubberband Helicopter Challenge

My group of three includes Dan, Mike, and Jason. Our goal is to design a helicopter that flies in the air as long as possible. Our helicopter does not need to look like a traditional helicopter, but it has to fly like one. My team wants to mount a camera on top of our helicopter so we can get an above-ground view of Mars.

Supplies to create the helicopter:

Balsa wood ( 2 18cm by 1cm by 1cm pillars and 4 5.5cm by 1.75cm by 0.5cm bases), hot glue, superglue, 2 3d printed blades, brass (tig welding), rubber band, and 2 3d printed bearings.

Tools that we used

X-Acto knife, drill (both large and small), hot glue gun, rulers, lube bottle, and a chopping block

My group got inspiration and other ideas from YouTube videos. The videos provided a variety of different helicopters and how they functioned. The videos helped us design our first prototype. Here are the links to the videos:

https://images.app.goo.gl/9vYP469z3joyFCRY7

How to make Flying Rubberband Powered Helicopter| Full tutorial

https://www.youtube.com/watch?v=DiJIvoHvGk4

https://www.youtube.com/watch?v=cIbGWDM3F6o&feature=youtu.be

We built a traditional helicopter. We wanted to use two blades that were connected to one rubber band. When one blade was charged up, the other one was too and therefore they would spin together in opposite ways. In addition, we used balsa because it is a light but sturdy material meaning that our helicopter will not be super heavy. My group used a mix of hot glue and superglue because if we just used hot glue, our project would become heavy and using hot glue was time-consuming. In addition, my group used 3d printed blades for several reasons. Initially, they bring variety. 3D printed blades are also extremely sturdy but provide lightweight. Finally, my group used bearings to help the blades stay in place and increase the spin of the blades. When the blades were attached to the wood, there was too much friction, resulting in no spin from the blades. My team drilled a hole in the wood and then put a bearing in. Once the bearing was attached, we put lube in it so the blades would spin.

Initially, my group started with cutting out the Balsa pillars. We cut two of these and they were both 18 cm by 1 cm by 1 cm. In addition to this, my group began cutting out the rectangular pieces that would hold the balsa pillars in place. We then put holes in the bases and super glued the balsa pillars into those holes. After, my group noticed that the balsa pillars were not sturdy and connected with the rectangular pieces which measured 5.5cm by 1.75 cm by 0.5 cm. To solve this problem, we created more rectangular pieces that went about 0.5 cm above the other rectangular pieces and the balsa pillars were also connected to it. After this, we began designing our blades. One blade was 9 by 3 cm and we drilled a hole through both pieces of wood. To make the blade fit in the hole, we got a small brass piece that measured about 4 cm and put it through the center of the blade. Then, we put it through the wood but unfortunately this created too much friction. Dan, then designed a bearing for the blade to go into. This bearing was about 3 cm long and 1 cm wide. We superglued the bearing through both pieces of wood and then put lube in it so that the superglue inside of the bearing would not stick to the blade's brass connector. When putting the blades in, we needed to find a way to make it spin, so we glued a rubber band to both of the brass pieces. When we tried to spin it, it would refuse to, resulting in a fail. My group did not have time to test multiple designs. Overall, we got our ideas from the YouTube videos above and trial and error.

This helicopter had many modifications along the way. There were many difficulties attaching the rotor to the balsa wood base of the helicopter. This was solved by attaching another piece of balsa wood that the tig metal welding logs would go through. Holes needed to be drilled through the new piece of balsa wood. These holes needed to be even so that the metal tig welding log would go through each hole straightly. These new pieces of balsa wood were the same size as the original 6 cm by 1 cm by 0.3 cm rectangular piece. There were many modifications to what the hook style would be in which the rubber band would be attached to. The hook design was originally going to be done by using paper clips. However, it was decided that the new hook design would be done by 3D printing. This was made for the rubberband to go through. The method of attaching the pieces of balsa wood together was also modified. It was initially done using a hot glue gun, but the use of hot glue guns decreased as the building process went on because it was very time-consuming. Metal wire was then going to be used to connect the pieces of wood, but it was difficult to attach the wood straight to the other pieces. For these reasons, the balsa wood was attached mostly using super glue. The 18 by 1 by 1 cm pieces of balsa wood were made and there were two 6 by 3 by 0.3 cm rectangular pieces of balsa wood that the tig welding logs were attached to, however, these dimensions were changed to 5.5 cm by 1.7 cm by 0.5 cm. These rectangualr pieces of balsa wood were attached to the welding logs using super glue. Super glue was used to attach the 5.5 cm by 1.7 cm by 0.3 cm pieces of balsa wood to the 18 cm by 1 cm by 1 cm pieces of balsa wood. However, with all this in mind, the helicopter rotors would not even remotely spin when the design was initially complete. For this reason, the tig welding logs were only glued from the edges of the holes that were drilled. This is also why the 3D printed pieces were attached to the tig welding logs which is where the hooks went. 

The modifications were completed in a variety of manners. For example, instead of using paper clips, tig welding logs were used to attach the blades to the base. These welding logs were attached to the 5.5 cm by 1.7 cm by 0.3 cm pieces of balsa wood by using a drill to drill a 0.3 cm diameter hole through the rectangular pieces. The tig welding logs were super glued by the edges of the holes to each of the two 5.5 cm by 1.7 cm by 0.3 cm pieces of balsa wood. The 18 by 1 by 1 cm pieces of balsa wood were attached to both of the rectangular pieces. The holes that the 18 cm by 1 cm by 1 cm pieces of balsa wood went through were made using X-Acto knives to cut one 1 by 1 cm holes through the 5.5 cm by 1.7 cm by 0.3 cm pieces of balsa wood for each of the 18 cm by 1 cm by 1 cm pieces of balsa wood. There were 3D printed pieces that were made that were attached over the tig welding logs. These pieces had a height of 2 cm, a diameter of 0.5 cm, and a 0.3 cm diameter hole through the pieces. The rubber band was attached to the end of this piece, which is also where the 4 cm long tig welding pieces ended.

These modifications helped to wind up the rotor when the trials were about to be done, since before the trials, the rotors would not wind up. This is because there was glue and welding logs that were attached to the balsa wood, and the rubber band could not rotate either for this reason. Therefore, the 3D printed pieces attached to the logs were used, and the process of gluing changed to make sure no glue prevented the welding logs from changing.

To conclude our project, we tested if our helicopter could fly, but unfortunately, the blades did not spin. Though our project was a fail, each group member learned some extremely valuable skills that would help in future projects. For our project to have worked, we think that we needed to add beads to the brass part connecting the blades. This would have resulted in the blades to release and fly.

The four forces that act on a helicopter are drag, lift, thrust, and weight. The weight of a helicopter affects its flight because this pulls the helicopter down; too much weight, then there is not enough power get it into the air. Drag is a force acting opposite to the relative motion of any object moving. If there is too much drag, then this will result in the helicopter being pulled down. Furthermore, thrust is the force that acts against gravity. To make our helicopter fly, we need more thrust than weight and drag. Finally, lift is also a force dependent on how much power the blades have. If the blades don't spin fast enough, then there will be no lift. To make our helicopter fly, we can't have too much weight and we need to minimize the drag. Our helicopter needs to have maximum thrust and speed to get the best air time.