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Rotating Kite
Submitted By: Actua (modified by
Pamela Lee-Shanok)
Overview
Age
Cost
Time
Complexity
Objective
8-13
$0.40
Preparation time:
0
Preparation: 1
To learn about
flight in terms
of drag and
rotation
Topic Area(s)
Fluid Dynamics
Execution: 3
Execution time:
30min+
Hook
Kids love kites! Especially rotating ones!
Necessary Background Information
Rotor kites are wide field of study. There are
many different forms, but they all use drag
and rotational lift to stay aloft.
Traditional “fixed wing” kites use drag as the
only force to stay aloft, similar to the way that
the wind propels a sailboat. This can be
demonstrated by the tension felt in the tether
line that you hold and by the fact that if the
tension is lost the kite will crash.
Rotor kites use a combination of drag and
rotational lift (also known as the “Magnus
Effect”) to stay aloft. The spinning of the kite
body creates a slower airflow at the bottom
of the kite (where the rotation is opposite to
the wind flow direction) and a faster airflow at
the top (where the rotation is with the wind
flow direction). This difference in pressure
creates lift, in the direction of the lower pressure gradient, and keeps the kite flying (and spinning).
This is similar to the “Bernoulli Effect” (the phenomenon that allows planes to fly) but it is created by
a different mechanism (rotational momentum vs. differential airflow profiles).
Because of their low lift generation and low drag profiles, rotor kites require higher winds to stay
aloft than regular fixed wing kites. This particular design requires approximately 15 km/h of wind to
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stay aloft. Rotor kites work best in strong, steady wind conditions. If used in gusting winds care
must be taken to avoid a crash. Due to the fragile nature of Styrofoam crashing this design can be
catastrophic!
Materials
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1 Styrofoam meat tray (about 8’’ x 6’’)
2 foam dinner plates (about 8’’)
1 wooden skewer 14’’ long
6 grey film canister lids
50’’ fishing line
Hot glue or super glue
Safety Considerations
Careful with hot glue!
Procedure
1. Take the skewer and poke a hole in the centre of 4 of the film canister lids. Poke and extra
big hole in the other two film canister lids, such that the lid can easily spin around the
skewer without much
friction. Set the lids
aside.
2. Trim the ends of the
foam tray (along lines
A and B) and then split
in half, longitudinally
(along line C) [see
figure 1]
3. Flip Section 1 of the foam tray upside down, so that the remaining lips form an elongated “S”
shape and glue the two
halves of the foam tray
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to the wooden skewer [see figure 2]
4. Poke the skewer
through the centers of
the two foam plates,
with the concave
surface facing away
from center of the kite.
There should be a
plate on each side of
the foam tray. Glue in
place
[see figure 3]
5. Place three film
canister lids on
each end of the
skewer as it
protrudes from the
plates. Ensure
that the middle of
the three lids (the
‘free’ one) is the
one with the
biggest hole. Fix
the inside and
outside lids, leave the center lid to rotate freely.
[see figure 4]
The entire kite should rotate freely around the central lids on each side.
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6. Tie a decent amount of
fishing line to each central
lid and tie the free ends of
the fishing line together. If
it’s rubbing against the
plates, simply cut the
plates to size. Attach more
fishing line to the final knot
in the centre [see figure 5]
7. Now add other materials to
the kite to help it fly better!
The kids can engineer their
own kite with materials
from the ‘store’ !!!