Compressed Air Rocket - Rick Schertle.pdf

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PROJECTS:
air rocket
makezine.com/15/airrocket
coMpressed
air rocket
By rick schertle
102
™
Make:
Volume 15
PAPER, TAPE,
COMPRESSED AIR … LIFT-OFF!
Blow your friends away as you send this
25-cent rocket hundreds of feet in the air.
You can build this easy launcher and
rocket with common hardware store
items in an afternoon.
All the parts for this simple but impressive air rocket and
launcher are cheap and easy to find. Building it is a breeze
and the modifications are endless. It’s legal in a big city,
reusable, clean, and can be launched even in high winds
on a small field.
Believe me, folks are quite taken by the 200- to 300-foot
flights fueled by 18 or so bicycle pumps of compressed air.
Whether you’re launching on your own or with a whole
group of rocketeers, watch the crowds gather … 3, 2, 1,
and away!
CAUTION: DANGEROUS PROJECT
At normal temperatures, standard Schedule 40 PVC has
a working pressure of around 150psi, but heat, sunlight,
solvents, scratches, and time make the material lose
strength, and even at the 75psi used for this project, it will
eventually fail. When it fails, it will break into fragments
that can be thrown with great force by the compressed air.
For added safety, wear safety goggles and wrap PVC
elements in several layers of duct tape (not shown) to
minimize any possible shrapnel. For a bomb-proof model,
you could also build the entire system out of galvanized
steel pipe at a greater expense.
Photograph by Gabriela Hasbun
!
Set up:
p.105
Make it:
p.106
Use it:
p.113
Rick Schertle
(schertle@yahoo.com) is a master at the craft of teaching middle school in San Jose and a novice maker
at home. His diverse interests include backyard chickens, adventure travel, veggie oil-fueled cars, and geocaching — all
made more fun with the enthusiastic support of his wife and the crazy antics of his young son and daughter.
Make:
103
PROJECTS:
aiR ROCkET
makezine.com/15/airrocket
PuMP iT uP, uP, and away!
aiR ROCkET anaTOMy
1
2
Bicycle pump
Tire valve
Allows PVC chamber to
be pressurized.
¾" inline electric sprinkler valve
Releases the pressure in an instant
burst.
Paired wires
Connect the battery
button and sprinkler valve.
Button
Triggers the sprinkler valve
for the launch.
R/C toy or power tool battery
Provides the juice necessary to
trigger the valve under pressure.
3
4
5
6
My 5-year-old son demonstrated the
physics of an air rocket recently at a
hamburger joint when he shot the wrapper
off his soda straw. That’s basically how
this air rocket works.
The launcher is made from PVC pipe,
and has a chamber that’s pressurized using
a bicycle pump. The pressure is released in
a split second through an electric sprinkler
valve, sending the paper-and-tape rocket
into the sky.
What’s unique about this design (as
opposed to a solid-fuel model rocket or
soda-bottle water rocket) is that the force
of the air propelling the rocket upward is
applied all at once. It still blows my mind
that just this initial blast of air can send
the rocket so high.
If you want more info on the basic
physics of the air rocket, this NASA link
gives a nice simple description:
makezine.
com/go/airnasa.
NASA’s description of how
air-powered rockets work also includes a
nice Flash animation.
3
3
2
4
4
~18x
2
5
4.8V
600mah
6
1
104
™
Make:
Volume 15
Illustration by Nik Schulz
SET UP.
A
B
C
E
I
X
W
J
V
Q
R
U
O
N
T
M
S
[M]
Tire air valve
[N]
Teflon tape
[O]
Electrical tape
[P]
Wood screws, size
#6×1�½" or similar (8)
[Q]
10' length of
7"
(outside diameter) ×
6"
(inside diameter) flexible
vinyl tubing
[R]
¼" hex bolts, 2"
long (2), wing nuts (2),
and washers (4)
[S]
PVC cement and primer
[T]
24"×24" piece of
�½" plywood
as a base for
the launch tower
[U]
¾" inline 24V electric
sprinkler valve
Cheap is
fine, just make sure you
get an inline one.
[V]
Hose clamps: size #4,
8"–0"
(2) and size #72,
3�½"–5" (2)
[W]
�½" male threaded ×
1"
female threaded brass
reducer bushing
[X]
6"
hose barb ×
1"
male threaded brass fitting
Power tool or R/C toy
battery
to trigger the sprin-
kler valve. Under pressure,
the valve requires higher
amperage: a power tool or
R/C toy battery will work,
minimum 4.8V, 600mAh.
Bicycle pump and pressure
gauge
Use a pump with a
built-in gauge, or just use
an ordinary pen-type tire
pressure gauge.
ROCKET BUILDING
MATERIALS
[AA]
Paper napkin
[BB]
Glue stick
[CC]
2"-wide masking tape
[DD]
¾"-wide masking
tape
[EE]
Printed rocket
template
Download it
from
makezine.com/15/
airrocket
and print on
8�½"×14" paper.
[FF]
13" length of �½" PVC
pipe
for rocket-building
stand
[GG]
5�½" length of
scrap 2×6 lumber
Please note:
Only
Schedule 40 PVC
should be used.
L
[NOT SHOWN]
Battery connector
Connectors can be the
standard R/C toy type
used for rechargeable
batteries, or a generic
bullet type.
P
GG
K
FF
EE
H
D
F
AA
G
BB
CC
DD
TOOLS
[NOT SHOWN]
Hacksaw or PVC cutter
A cheap PVC cutter is a
super handy tool for cut-
ting hose, PVC pipe, etc.
Fine sandpaper
Rubber mallet
Utility knife
Screwdrivers
Drill and bits:
r",
¼",
�½",
q"
Saw for cutting lumber
to various sizes
Soldering iron and solder
(optional)
Socket set (optional)
Scissors
Wire cutters
Adjustable wrench
Channel-lock pliers
Large C-clamp
MATERIALS
[A]
¾" PVC slip end caps
(2)
see below
[B]
¾" PVC adapters,
¾" male threaded ×
¾" female slip (2)
[C]
¾" PVC reducers:
¾" male slip × �½" female
threaded and �½" female
slip × ¾" male slip
[D]
2" PVC slip tee
[E]
2" PVC slip end cap
[F]
2" PVC reducer bush-
ings, male slip × ¾" female
slip (2)
[G]
2" PVC pipe, 10" length
[H]
¾" PVC pipe, 3" and
4" lengths
[I]
�½" PVC pipe, 16" length
for launch tube
Photography by Rick Schertle
[J]
48" length of 1×3 pine
board
to be cut to various
sizes for the launch tower
[K]
10' length of paired
wire
I used speaker wire.
[L]
Button momentary
switch
RadioShack part
#275-609
Make:
105
PROJECTS:
AIR ROCKET
makezine.com/15/airrocket
MAKE IT.
BUILD YOUR AIR
ROCKET LAUNCHER
AND ROCKETS
START
>>
Time:
An Afternoon
Complexity:
Easy
1.
ASSEMBLE THE PRESSURE CHAMBER
1a.
Use PVC primer, then cement,
to glue the 2" male slip × ¾" female
slip PVC reducer bushing into the
2" slip tee. Next, prime and glue the
¾" male slip × �½" female threaded
PVC reducer into the 2" male slip × ¾"
female slip PVC reducer bushing.
1b.
Apply teflon tape to the threads of
both brass fittings. Screw the brass
barbed fitting to the brass �½"×1"
reducer bushing. Screw the �½"×1"
brass reducer bushing into the ¾"
male slip × �½" female threaded PVC
reducer. Tighten all connections with
an adjustable wrench.
1c.
To complete the pressure chamber
assembly, prime and glue the 2" end
cap onto the 10" length of 2" PVC
pipe. Next, glue the 10" piece of 2"
pipe into the other end of the 2" tee
as shown.
106
Make:
Volume 15

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