Rubber band Powered Plane

1. Rubber band Powered Plane Kourtney Henderson, Rachel Lenhart, John Scott, Seth Pierson, and Chris Cihlar

2. Problem Statement • To analyze the flight of a typical rubber band powered model airplane • To construct an improved and larger scale model of the plane from scratch • To increase the hang time of the toy despite the increase in size

3. Background • Planes are simple and small, allowing for a short hang time. • Most of the toys fly for only 12 to 15 seconds, covering 250 to 300 feet. • Difficult to play with or measure hang time because it flies away • There is only one set of wings, so the amount of lift is limited. • Although designed for family projects, construction time lasts less than 5 minutes.

4. Design • Biplane design to increase surface area of wings, therefore increasing lift and hang time • Flies in circles to the left to measure flight time more efficiently • Constructed from Balsa Wood to maintain low weight • Plastic covered wings to increase lift, decrease air resistance, and to avoid the weight of solid balsa wood wings

5. Materials Used • Yard long rods of balsa wood • Lite-weight wooden propeller • Rubber bands • Food City grocery bag • Wood glue • Push pins • Wax paper • Metal rod • Duct and masking tape

6. Used modified, scaled plans as a template for wings, tail and body. Used wooden blocks to hold wings to get proper angle on wings. Covered wings and tail with plastic bags. Made necessary modifications to body to accommodate biplane design. Attached wings and tail to body, as well as cross braces for wings. Constructed and attached propeller mount and metal hook for rubber band. Modified original mount to reduce friction and balance propeller by adding spare pieces of wood and push pins. Construction Process

7. Couldn’t find long enough rubber band, linked many smaller ones together instead. Metal rod too thick to make proper angle, used hammer to get best possible shape. Original tail design too weak, modified by increasing glue surface area. Too much friction, wobbliness in propeller, used multiple push pins to elevate and wood block to stabilize. Problems

8. Our Plane

9. Hang time comparison: prefabricated plane: 6.2 sec constructed plane: 3.1 sec Our plane flew forward for only a short time before stalling and beginning to glide backward and forward until hitting the ground. First Results

10. Correction: added weight to the nose Result: stopped stalling, increased hang time by approximately .3 seconds Correction: removed the lower wing Results: decrease in drag, smoother gliding, increased hang time by approximately 1 second Results after Corrections

11. The construction of the propeller was a problem. The metal rod began to deform the wood and the duct tape began to give out causing some of the failure. The connection between the rod and the propeller was not secure enough to hold at high rates of spinning. The propeller wasn’t large enough to create enough air flow. The spin speed of the propeller reduced rapidly and was not sufficient enough to create air flow. The additional wing would have provided more lift, but without appropriate propeller power and air flow there was too much drag. Conclusions

12. References • http://travel.howstuffworks.com/framed.htm?parent=airplane.htm&url=http://www.eskimo.com/~billb/wing/airfoil.html • http://travel.howstuffworks.com/airplane.htm • http://freeflight.org/jlf/beginners_corner/whammy_series/whammy.htm • http://www.answers.com/topic/biplane • http://www.casde.iitb.ac.in/IMSL/video_FP/design.htm