For this project I had to design an airplane that would be powered with rubber bands. The plane had to be able to fly in a circular path. Throughout this project I made eight planes but only two survived.
This plane was my first attempt. The mainly plane was made out of velum and balsa wood. I also 3D printed a propeller.
This plane had a lot of problems. The wings didn't have any curve to them so they couldn't generate life, the wing span was not large enough for the weight of the plane and length of the plane, and the rudder was too small which caused the plane not to be able to turn. I do not have any pictures of this plane because it broke
This plane was created in between my first and 6th version. This version had a much larger rudder, tail, and wing span than the first one. This plane didn't have curved wings yet.
This was my 6th attempt. This plane worked much better than the first one but still had multiple problems. What I changed between my first and 6th design was that this plane now had a much larger wingspan, bigger rudder, and had a high wing.
This plane still had its problems. Problems included stalling because the propeller couldn't generate enough speed, how often it would break, and the propeller was too heavy/big for the plane design.
This was my 10th and final attempt. What changed between my 6th and 10th attempt was the wingspan got larger, the tail became elongated, the wingspan was larger, the fuselage was longer, and it had a newly designed propeller. The new propeller required a lot less torque to turn it which enable it to spin faster. This caused more air to be pushed under the wings which generated more lift.
This plane still had some problems. It could only do a maximum of 3/4th of a circle.
Final Plane: Top View
Final Plane: Bottom View
Final Plane: Bottom View
Final Plane: Isometric View
Final Plane: Side View
Looking at the side of the wings they should have a curved shape to them. The top view should be rectangular. This is so the wings will be able to efficiently generate lift. The wingspan should be 35%-25% larger than the fuselage. Also the wings should be angled up slightly. This is called dihedral wings. These wings help to make the aircraft more stable. Also the wings should be above the propeller.
Air needs to flow faster across the top of the wings so it creates a low pressure area. The low pressure area is crucial in helping to generate lift. This is because the high pressure area underneath the wing is pushing up and you need a lower pressure area on top of the wing to not counteract what the high pressure area is doing. The low pressure area on top of the wing pushes down slightly, unlike the high pressure area which pushes up with a great force. This creates lift. If there was a higher amount of pressure on top of the wing than on the bottom the plane would not take off because it would be getting pushed down. What force is stronger is the direction in which the plane will go. High pressure=stronger, low pressure=weaker.
Fast moving air creates a low pressure area because according to Bernoulli’s principle “the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy” (Wikipedia, 2016). The faster a fluid is moving the lower the pressure will be and vice versa. In the example with airplane wings the air is moving faster over the top of the wing. This air contains a higher amount of kinetic energy which creates a low pressure area because Bernoulli’s principle states that the faster a fluid is moving the pressure simultaneously decreases.
Slow moving air creates a high pressure area because of Bernoulli’s principle “the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy” (Wikipedia, 2016). The slower a fluid is moving the higher the pressure will be and vice versa. In the example with airplane wings the air is moving slower over the bottom of the wing. This air contains a lower amount of kinetic energy which creates a high pressure area because Bernoulli’s principle states that the slower a fluid moves the pressure simultaneously increases.
How I was able to control the air pressure was by having the top of the wing on my plane more curved than the bottom. This cause the air on top of the wing to move faster which created a lower pressure area. The less curved bottom caused air to move slower which created a high pressure area. Elevators can also impact on air pressure. When elevators are in the down position this causes air on the top of the horizontal stabilizer to decrease speed which creates a higher pressure on top than on the bottom. This causes the plane to descend and vice versa.