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C P R ES S E D IR ...LIFT- FF!
B low yourfrlends aw ay as you send thls
25-cent rocket hund reds offeetIn the alr.
You can buIId thls easy Iauncherand
rocketw lth co m m o n hardw are store
Item s In an afternoo n
A IIthe parts forthis sim ple but im pressive air rocketand
Iauncherare cheap and easy to find.B uilding itis a breeze
and the m odifications are endless.It's Iegalin a big city,
reusable,clean,and can be Iaunched even in high w inds
on a sl'rlaIIfieId .
Believe m e,fo lks are quite taken by the 20 0 -to 3 00 -foot
flights fueled by 18 o rso bicycle pum ps ofco m presseclair.
W hetheryou're Iaunching o n yourow n orw ith a w ho le
group ofrocketeers,w atch the crow ds gather ...3 ,2 ,1,
and aw ay.1
! C:.'xt1Tl:7pk:E7.#.pkt7b.ëQ'lJS r'PrJ.ifC1T
Ainorm aliem perz ures.szandard Schedule40 PVC has
aworkingpressureofaroundl50psi.buihe2 .sunlMhi.
sokenis.scraicheL andiim e m ake ihe m aieriallose
sirength'andevenatihe75qsiusedforihisqrojed.iiwill
iehvaeinicuaanl1Jefaihilr.oWwhnewnihfagilrse.aifwoirlclebrbeyaikhientcolmrapgremsesenidsair.
Foraddedsdeiy.wearsafdygojjlesandwrapPVC
eIem enisin severallayersofducttape (noishow n)io
minimizeanypossibleshraqnel.Forabomb.proofmodel.
you could alsobuild ihe eno're sysiem ouiofgalvanirad
sieelpipe 2 agreaierexpense.
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D O IN G D O N U T S
A sm o ke ring ,orvortex,is a beguiling
thing to w atch:a co herent,m oving
structure m ade outofthin air.Llere
are 3 cannons thatcan throw these
''
chunks ofair''across a roo m
I'd been aw are ofvo rtex cannons forquite som e tim e,
m ostly as an interesting toy,anclafter Ikept stum bling on
the conceptw hile touring the w eb,Idecided Ihad to build
m y ow n.T here's som ething fascinating abo uttaking a
substance as ubiquitous and am o rphous as airand trans-
form ing it into a coherentand persistent structure,alm ost
Iike a crystal.Ialso hoped to find som e use fo rrrly cannon ,
perhaps to propelscents org ive the touch ofa gho st in
a haunted house.
A n extrem e exam ple ofthe vortex's ''reach outand touch
som eone''pow eris the m ilitary vortex gun,w hich uses
explosives to clrive airrings thatcan knock peo ple over,or
at Ieastgenerate enough sound pressure to renderan area
uninhabitable.A nd the Shockw ave C annon created by S ur-
vivalResearch Labs delivers an invisible bootto the head .
Thisprojectdoesn'tgo thatfar,butitw illshow you how to
m ake 3 differentcannons:a s-m inute version ,a com puter-
controlled version driven by a subw oofer,and a pow erful
11 onebasedonrrlyBoom Stickproject(MAIL'E,Volum e13,
1 age224)
tP .
p.
r.Setup:p.117 M ake it:p.118 Use it:p.121
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FLA M E O N
W itù no m oving parts,this Sim ple
energy-recycling generato rscavenges
w aste heatfrom a cand le and turns
itinto usable electricity.
Peltiercells are flat devices that clraw heatfrom one side
to the otherthrough a therm oelectric principle called the
Peltiereffect.The cells are com m only used to pum p heat
aw ay from C PLJS orgraphics cards,and are also found
in cam ping coolers and heaters.T he A m azing Seebeck
G eneratoruses one ofthese devices in reverse,to turn a
heatdifferentialinto electricity,ratherthan using electricity
to produce a heatdifferential.
Ioriginallym ade the projectbecause Iwanted som ething
Iike a steam -pow ered generator,butw ithoutthe noise and
m aintenance issues associated w ith steam .Iw as pleasantly
surprised w hen Ifound thatrrly $5,37-wattPeltiercellfrom
eBay could capture the heatfro m a single tea candle or
alcoholburnerand use itto generate about5 volts at1 am p,
w hich m ade itperfectforpow ering radio s,m obile phones,
and LED Iights.You can m ake the A m azing Seebeck G en-
eratorin Iess than an ho urusing m ostly scrap or recycled
parts,and it has a distinctly steam punk feelto it.
1 M ake it: useit:
'1 setup:
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