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First, here's the earliest
rocket picture I have. This was my first attempt at real stability,
after I'd just learned what that
means. The "engine" is a single 1 liter bottle, the other bottles
are just taped on to help lengthen the rocket (this was before any of
us knew how to join bottles).
The nose cone is thin cardboard wrapped into a cone shape and
laminates with Tyvek, the fins are shaped balsa covered with Tyvek. I
honestly don't remember how well it performed, it was rapidly
superseded by better designs.
Here's the HOV-1, since deceased
(HOV stands for Hoary Old Veteran). This is one of the rockets that
came with my Bigfoot Launcher,
so isn't truly mine, though I heavily modified it over time. After a
landing or two, the original rocket got all busted up around the nose
and started breaking fins off, so I added this duct tape nose, filled
with scraps of foam rubber, and kept taping the fins back on whenever
they popped off. Crude but effective. This one was my first "bounce
recovery" rocket -- it sometimes bounced over 20 feet in the air! --
and it survived many, many launches. Alas, all things must pass, and
this rocket finally died. The fins were carved from blue foam
insulation panels, the engine was a single 2 liter bottle. (The
second rocket that came with my launcher is still in pristine
condition, occupying a place of honor in my Water Rocket Museum, and
will never be launched. It's too pretty to destroy.)
This is
a collection of rockets from an early outing with Bill Robinson,
after whom the Robinson Coupling is
named. Lying down in the front is my Lawn Dart, it's made from 3
robinson-coupled 1 liter bottles, balsa/Tyvek fins, and a commercial
plastic nose cone (very heavy!) sold for large model rockets. This
rocket flew beautifully. However, it always landed hard, having no
recovery system, and the sharp and heavy nose cone would bury itself
several inches into the ground every time. Truly dangerous. At the
right is the previously seen HOV-1, still hangin' in there.
In the center is a helicopter recovery rocket that Bill made. The helicopter unit is from an Estes kit, the body tube is thin butyrate tubing he found at TAP Plastics, with a bottle neck epoxied in the end. Painted balsa fins (green). This tubing held 100 psi if it wasn't cracked, but it was brittle. In fact, this is the only rocket I've ever seen blow up: the tube at the bottle neck was a little thicker than my Bigfoot Launcher was designed for, so we had to really squeeze the trigger mechanism to make it close. Getting ready for the second launch, the tube cracked, but we didn't notice. We pumped it up, everything seemed fine, there was a crowd of interested bystanders watching, and when Bill pulled the string, the rocket simply blew apart into a hundred little shards of lighweight plastic (thank goodness it was lightweight! It just fluttered harmlessly to the ground.). Apparently the trigger mechanism was holding it together on the pad. The onlookers weren't impressed.
Finally, on the left is another of Bill's rockets, this one
modeled after the now-legendary Super Soaker rocket. The same
butyrate tube was used for the extension, and the parachute was just
draped over the top of the rocket before launch. Worked fine, though
the parachute flapping in the breeze caused a LOT of drag. Gary
Ensmenger later developed his
"Vortex" rockets
with a similar tail extension made from PVC, which is lots safer.
This is a great design, stability-wise, as it gets the fins way back
behind most of the mass. My Long-Tail
rockets are another example of a tail extension, but in that case
the the tube doesn't get pressurized.
My first (and so far only)
2-stage rocket is shown here. It was really just a quick experiment
to test the
"Crushing
Sleeve" staging mechanism that Bruce Berggren came up with. The
booster (first stage) is made from 2 1-liter bottles, the sustainer
(second stage) is a single 20 oz. bottle, with nose extensions for
stability. The fins are my usual shaped balsa with covering, glued on
with Shoe Goo. It didn't go very high, but the staging mechanism
worked flawlessly. The remains of "The
Skewer" are currently being transformed into a 5 foot tube
sustainer for a real try at high altitude.
This rocket is made from several 20
oz. bottles, joined with a
circumferential splice. The
rocket has flown many times, and is a great performer, but the nose
cone shown here is special: I got a little badge at a trade show that
had a blinking red LED on it. I took it apart and extracted the LED
and circuit board, and mounted it so the LED shines up inside a ping
pong ball. The result is a very bright, blinking red orb for a nose.
For obvious reasons, I called it the "Rudolph" nose, and though I
still haven't launched it, I'm ready for a night launch any time. The
chute release is an airspeed flap. And I
finally got smart on this rocket and started putting the fins on a
removable sleeve, taped to the rocket. This is now my standard
procedure, since fins are one of the most time-consuming parts of
building a rocket.
Finally, here's Old Reliable, still my favorite (and
longest lasting) rocket. It's made from 2 robinson-coupled 1-liter
bottles, hemispherical nose, airspeed flap chute release, the usual
balsa fins. This rocket just keeps going, and going, and going...
It's been launched probably 50 times by now, and the parachute
release has never failed once. I have no idea what I did to make it
so reliable, other airspeed flap release have been more finicky. This
rocket consistently gets 120 meter altitudes at 100 psi. I've also
used the bottom bottle as a "test bed" for many other tests, a real
advantage of the Robinson Coupling (I can just twist off the upper
section and replace it with another, in about 10 seconds.) Come to
think of it, the bottom bottle is the same one shown above on the
Lawn Dart, so it's been around forever.
There's another photo of Old Reliable at the bottom of the
Robinson Coupling page. Get your own
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