Transcript Rubberband Powered Plane - UTK EFD News/Announcements

Rubber band Powered Plane
Kourtney Henderson, Rachel
Lenhart, John Scott, Seth Pierson,
and Chris Cihlar
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
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.
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
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
Construction Process
I.
II.
III.
IV.
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.
V.
Attached wings and tail
to body, as well as cross
braces for wings.
VI. Constructed and attached
propeller mount and
metal hook for rubber
band.
VII. Modified original mount
to reduce friction and
balance propeller by
adding spare pieces of
wood and push pins.
Problems
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.
Our Plane
First Results
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.
Results after Corrections
Correction: added
weight to the nose
Correction: removed
the lower wing
Result: stopped
stalling, increased
hang time by
approximately .3
seconds
Results: decrease in
drag, smoother
gliding, increased
hang time by
approximately 1
second
Conclusions
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.
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/wha
mmy_series/whammy.htm
http://www.answers.com/topic/biplane
http://www.casde.iitb.ac.in/IMSL/video_FP/de
sign.htm