[roc-chat] Re: Contest idea, Scratch building on the cheap
- From: Rick Maschek <rickmaschek@xxxxxxxxxxx>
- To: ROC-Chat <roc-chat@xxxxxxxxxxxxx>
- Date: Wed, 22 Aug 2012 21:01:47 -0700
ENHolmberg wrote: "Ok I'll bite, how do you build a scratch built a dual deploy
"I" powered rocket with reload for $20? "
Two three inch od U-Line mailing tubes at dollar
store.................................................$2.00
One of those is cut in pieces, a one foot long piece for recovery section
A one inch long piece for the band around the avionics bay
Two eight inch long pieces for the avionics bay slit and glued into each
other
Scrap left other for second av bay
Four fins/centering rings cut from discarded 4' x 8' Luan door skin from Home
Depot......Free
Enough for a hundred more fins
One foot by sixty inch piece of fiber glass
clothe..........................................................$1.50
Epoxy for glassing the
fins.......................................................................................<$1.00
38mm x 48" motor mount tube free from Walmart (they throw them
away).....................Free
4" x 4" x 1 foot piece of redwood for nose cone from
Lowe's.........................................$2.00
Sugar for rocket fuel, 100
grams.................................................................................$0.30
...
Potassium nitrate for rocket oxidizer, 200
grams...........................................................$0.50
Four sheets 8" x 11" computer printer paper for casting
tubes........................................$0.04
Four ounce bottle of Elmers glue (on
sale)....................................................................$0.49
One yard 44" rip stop nylon fabric from Walmart for making two
chutes...........................$1.50
One hank of nylon chord for chute
lines.........................................................................$0.99
Twenty feet of nylon chord for
tethers..........................................................................$1.99
Two scrounged bullet casings for deployment
charges....................................................Free
Two U bolts for av
bay................................................................................................$1.68
Two Screw links for U
bolts.........................................................................................$1.98
Assorted nuts and all
thread........................................................................................$1.95
Creativity and
time..................................................................................................Priceless
I built my Tripoli Level-II rocket fins using counter top samples from Home
Depot that were free, the granite looks cool. We could have saved the cost of
the fiber glassing of the fins by using them but I wanted the students to get
practice fiber glassing.
We did a second back up rocket using a 'Skull and Crossbone' printed cotton
fabric applied to another set of U-Line mailing tubes. Even the cost of the
U-line tubes could have been saved if we chose to use 4" tubes from the
carpet/linoleum department at Lowe's (when they finish selling the material on
the cardboard tubes they throw them away). I have many as I wanted to sell a
"Scratch Build a Rocket" kit for a ROC competition years ago. They are 12' long
so I usually bring a hand saw and cut them into two, three, or four pieces in
the parking lot to get them home in my car.
For the flight, they used heavier 7/16" nylon web for the tethers since they
bought it for a larger rocket and wanted to use it.
For the ends of the av bay besides using the door skin, we also used some scrap
polycarbonate from Lowe's that was free. We used some for the altimeter
platform also.
It would really be cheap if done as a minimum diameter rocket simply using the
38mm tube from Walmart, a 2" x 2" x 6" piece of wood NC, and counter top fins.
The last entry is the key. If you have lots of time, a scratch built high power
rocket can be made for next to nothing, I'm designing a less than $99 10,000
Nsec rocket that includes EVERYTHING except the launch pad (airframe, recovery,
motor, propellant, etc) but it requires TIME and for many, TIME is MONEY. When
I first did rockets at school the principal thought it was the coolest thing
ever. When I brought him the $600 bill for all the student rockets and motors
he refused to reimburse me, lesson learned so I did scratch building with
students. If you spend your time working and just funding a rocket for yourself
it makes sense that you buy ready made kits and or components that help support
our vendors who supply us with many other things.
http://www.youtube.com/watch?v=I62PZzxmeuE
Rick
From: ENHolmberg@xxxxxxx
Date: Wed, 22 Aug 2012 00:42:37 -0400
Subject: [roc-chat] Re: Contest idea
To: roc-chat@xxxxxxxxxxxxx
Ok I'll bite, how do you build a scratch built a dual deploy "I" powered rocket
with reload for $20?
In a message dated 8/19/2012 7:33:34 P.M. Pacific Daylight Time,
rickmaschek@xxxxxxxxxxx writes:
Yesterday the students I'm helping launched their scratch built dual deploy "I"
powered rocket. Total cost excluding Perfect Flight but including propellant
reload, airframe, fins, motor mount, nose cone, chutes less than $20 and could
have been less if that was the goal. Motor eject could have been used.
Rick
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