This week, I finished up a series of lectures on Aeronautical engineering. This particular series was on the structures and actual design of a plane. At the end of the series, the professor challenged all students to make a paper airplane that would follow the things we had learned in the series, particularly about stability. He encouraged us to use multiple pieces of paper, and stray away from the traditional designs you see all the time. With this, I got to work. Since I would be using paper, I decided to stray away from doing complicated math on lift and drag, as each time I would throw the plane, it would change its shape and therefore change those elements. Instead, I decided to focus mostly on stability. In the lecture, we learned about the effects of an elevator on airflow and how that impacts plane design. The main concept that I learned was that the center of lift, which is where the lift is on average within the plane, must be behind the center of gravity of the plane. This is why many paper airplanes use complicated folds in the front, as they require more paper and shift the center of gravity forward. So, for my design, I decided to use about a third of a sheet of paper to make a wing. This created quite a large airfoil, which in turn generated a lot of lift, and so after some early tests, I used paper clips to reduce the overall size of the foil. Next, I put together a small elevator that would help trim the aircraft’s nose to face down. Finally, I added a rudder to keep the plane stable in the y axis, as I was worried it might fly off at an angle. As expected, in early flights the plane was longitudinally unstable (meaning the center of lift was ahead of the center of gravity). I saw this as each time I threw the plane out, its nose would shoot into the air, it would lose all lift and fall. I decided to first move the wing back along the fuselage (forcing the center of lift backward) and then I decided to place a very heavy paper clip in the front of the plane, to help move the center of gravity forward. This immediately fixed the issue, and the ‘Rosenblum flyer MK 1’ took to the skies. I’m certain my design could be more improved, however, because if you can avoid using paper clips, the plane could potentially generate more lift than weight, allowing it to float up before it begins its glide slope down. 

 

After finishing my design I was curious to see if other paper airplanes considered these factors as well. I decided to do a little research and figure out exactly what plane to make. I landed on a paper airplane called the DC3 Swallow, which is supposed to have a very good hang time compared to most paper airplanes. I constructed the plane and immediately noticed several complicated folds directly at the center of the plane. This forced the center of gravity forward, while the wing itself had a delta shape, ensuring the majority of the lift was located near the back. I knew I had picked a good airplane to test, and it seemed entirely stable.

 

After exhaustive flight testing, I can say with confidence that while my flyer might not fly as far as the DC3, it was able to hold a candle to it. The DC3 flew about 20ft (including a quite dramatic loop) during its furthest flight, while the Rosenblum Flyer MK 1 probably only made it about 15 ish feet. I am certain that if I learned how to throw the airplanes more efficiently, and had an indoor space (the wind was quite high today) that both planes would have made it further. 

 

Reflecting on my design I think I would have made a much smaller airfoil, which in turn would have allowed me to make the entire plane smaller which would have significantly reduced the drag. I also would have attempted to change the way I mounted the wings, to ensure that they wouldn’t lean. This leaning element caused the lift to be off-balance causing the entire plane to bank. This caused multiple crashes. I could have also made the wings slightly V-shaped to help ensure that if there was a disturbance in flight, that it would return to normal. I would also add a slight sweep to the wings to eliminate the need for a rudder because I believe that my rudder may have also contributed to the rolling issues that I encountered, and at the very least made them worse as they forced the plane down as it spun.