[603] in Humor
HUMOR: Match Rocketry
daemon@ATHENA.MIT.EDU (abennett@MIT.EDU)
Mon Dec 12 09:44:42 1994
From: abennett@MIT.EDU
To: humor@MIT.EDU
Date: Mon, 12 Dec 1994 09:41:05 EST
I used to do this as a kid! (OK, I used to hold lit firecrackers in my hand,
too, but let's not dwell on the past, OK?)
-Drew
Date: Thu, 08 Dec 1994 20:37:15 +0000 (GMT)
From: Espacionaute Spiff domine! <MATOSSIAN@aries.colorado.edu>
From: ron.schaefer@cabin.com (Ron Schaefer)
How I could have gone 36 years and never heard of doing this is
wonder. I found this in the pyrotechinques FAQ on the net. I
immediately had to try it out and it is fun, on my 5th attempt it
went ~10 feet.
I propose contests be held in Stockholm for the longest/highest
flights.
Ron Schaefer
ron.schaefer@cabin.com
How To Build A Match Rocket
Version 1.1
9/29/93 [Slightly edited for FAQ 09AUG94]
Brett K. Carver
brett@sr.hp.com
Disclaimer: Please notice that the title is not "How To Build THE
Match Rocket". This describes how I built match rockets and
represents only one method of construction. Others will have
different/better ideas. This should be enough to get one started.
Warning: Improper construction of match rockets can cause
them to explode KILLING YOU INSTANTLY; Improper firing of
match rockets can cause them to penetrate your body KILLING
YOU INSTANTLY. (well, probably not, but be careful anyway).
Definition: Basically, a match rocket is a paper match with
something wrapped over the match-head to form a combustion
chamber and focus the flow of escaping gas. The match is then
heated until it ignites and the escaping gases cause it to take off.
Parts: You'll need the following:
a book of paper matches
aluminum foil
cellophane tape (i.e. Scotch tape)
two sewing needles
scissors
Constructions: This roughly how I built them...
1. Remove a match. Trim off the end to remove the frayed
edges.
2. Use about 1 square inch of foil and 'wrap' it around the
head of the match extending between 1/4 and 1/2 inch past the
head. I left 'wrap' vague since there a many ways to do it. The
goals are to: a) keep weight down, b) get several layers of foil
around the match head, and c) keep things neat and clean.
3. [optional] I had a lot of trouble with blow-out (the
force of combustion tearing a hole in the foil), so I started
wrapping the foil with a few layers of cellophane tape. It seemed
to solve my blow-out problems without adding as much weight as
additional foil did.
4. Add two exhaust ports, one down each side of the
match. This can be done two ways: a) after step #3, push a
sewing needle along the match-stick, under the foil, up to the
match-head, or b) do steps #2 and #3 with the needles already in
place. In either case the important thing is to get a small well-
formed port. I used the smallest sewing needles I could find (the
head of a regular pin caused it not to lay flat creating poor ports).
In addition, I'd run my finger-nail along the side of the needle to
force the foil down so that I'd have a nice clean tube rather than
just a crude gap between the match-stick and the foil. I use two
needles because with only one I'd always end up damaging one
port while creating the other. Obviously, remove the needles
when done.
Firing: Put the completed rocket in a launcher. It is often
suggested that one use a bent paper-clip as a launcher. Don't
waste your time. I used a short piece of 1/4 inch copper tube
mounted to a hinge. The launch angle was adjustable by turning
a screw. The tube was short enought that the match-head just
extended enough to apply heat. The back of the tube was
blocked off. Besides the obvious ease of launch-angle
adjustment, the smooth tube reduced friction or hang-ups when
firing, and the blocked off tube produced some back-pressure
that I think helped produce higher launch velocities. Anyway,
once in the launcher, aim it, and heat the match-head until it
ignites. A lighter works better than a match for this as it takes a
while for ignition and sometime the match would burn out first.
Distances: I saved my record-breaking matches writing the
distances on them. Launches inside the house became limited
by the ceiling and the far wall. The longest inside launch I got
(hitting the far wall) was:
29' 6"
Outside shots were not so limited. The longest outside
launch was:
44' 8"
So, there are some target numbers to shoot for... :-)
Fine-tuning: The point of building match-rockets is not to simply
'learn how to do it', but to get started and fine-tune the rockets to
improve distance. Construction materials, construction
techniques, launcher design, launch angle, and many other
things all come into play at getting a long-distance flight.
Experiment.
Things that didn't work: The following are things I tried that didn't
improve my flight distance.
1. Wooden matches - they were too heavy.
2. Using two or more matches - too heavy and I couldn't get
a good seal on the combustion chamber.
3. Adding extra match-heads - adding extra 'fuel' presented
two problems: a) I had trouble getting a nice tight wrap of the foil
with the extra material in there, b) if I did get a good one built, it
would 'blow-out' at launch (adding more foil just seemed to make
it too heavy). I had my best results with simple one-head rockets
so I stopped trying for more fuel.
Enjoy RS
