Each flight log entry usually
represents a launch or test day, and describes the
events that took place.
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Day 62 - 15mm Nozzles with long launch tube and CATOs
Prepping Tachyon IV for first flight.
At ~170psi the coupling fails and the top
section is ejected.
An old workhorse - J4 getting ready to fly.
Perfect weather conditions to launch in.
You need to keep your eyes peeled at all
times.
Some of the Pyro rockets flown on the day by
other members of NSWRA.
Axion launched with 15mm nozzle and a long
launch tube.
Axion reached 480 feet. (146m)
Axion's second flight.
Too close to the rocket eating trees.
J4 Flight 1
(Photo:Andrew
Eltobaji)
Water only flights are visibly faster than
foam flights at the same pressure.
(Photo:Andrew Eltobaji)
A deployed parachute is always good to see.
(Photo:Andrew Eltobaji)
Katz stager Mk2.
Stager undergoing ground tests at various
pressures.
Mk2 stager connected to the booster on the
bottom with a dummy second stage on the top.
Date:28th June
2008
Location:Doonside, NSW
Conditions:Cool, light westerly breeze, mostly sunny. Temp: 10-18 degrees C
Team Members at Event:
GK, AK, PaulK and JK
With dad in Europe this launch day, we didn't launch any of the bigger rockets
as we
need to bring both cars to fit all the
equipment in. But there were a few new
experiments we wanted to try with the
smaller rockets. Photos of pyro rockets from
the launch day are available:
here.
Launch Day Events
First up we wanted to fly
Tachyon IV a reinforced
pair of bottles made at least 6
months earlier. This Robinson coupled
pair of bottles has been hydrostatically
tested to 200psi when it was made, and
again to 180psi a few days before the
launch. However, the coupling gave way on
the pad at around 160-170psi. The bottom of
the bottle failed and the upper bottle with
payload flew off. The bottom bottle was
forced downward over the release head
and I had to cut the nozzle out of
the deformed bottle.
We were testing 4 new things
on this flight:
a) Flight testing V1.5 of the
flight computer.
b) Launch detect contacts connected
to the flight computer. A plastic
strip attached to the launcher
gets pulled out during launch
triggering the flight computer. This
is an alternative to using a
G-switch.
c) High pressure launch using
Robinson coupled re-enforced
bottles.
d) A baffle connected to the
Robinson coupling to prevent the
blow-through effect on a high
pressure launch.
We learned a couple of things from
the failed launch. You should always
expect the rocket to blow even though it
has been tested. The flight computer survived the
violent acceleration of the explosion. The
baffle was ripped out of the bottom
bottle, but because all the air was
redirected in 4 directions sideways it
prevented the top bottle from flying too
high. The entire payload section
survived without damage.
To get at least one good launch under our
belt we launched the trusty J4 with water
only. It was a good uneventful flight. We
flew it again for the next launch but with
foam this time. Again it was a good flight
with a good landing.
Next we replaced the standard 9mm release
head on the medium launcher with a 15mm release head. This release head has an 1120mm
long integrated launch tube. The Axion
rocket with its
full bore Tornado couplings was chosen as
the rocket for the test. This was our first
long launch-tube launch. We filled the
rocket with 1800mL of water.
The launch
was a lot faster than what we are normally
used to and the launch tube and release
mechanism worked well. We applied some
silicone grease to the launch tube prior to
launch to minimize the friction effects of
the launch tube against the nozzle. The
rocket was flown with a video camera and an
altimeter. The camera got a nice steady shot
on the way up. Altitude was 345 feet (105 m).
This release head will be used for our
first FTC trials.
As we were filling the rocket for
the second attempt and approached 130psi, one of the
middle Tornado couplings let go of the
bottle thread and the top part of the rocket
flew off. Surprisingly there was no damage
done to any part of the rocket. The top
section flew up quite a ways but being
unstable simply tumbled back down and landed
on the grass. The on board video camera
filmed the entire episode. As I was the
person pressurising the rocket I couldn't be
filming the rocket at the same time and so
we don't have any ground footage of the
incident.
I unscrewed the coupling and tried
it on another bottle. If tightened too
much it jumped a thread. Perhaps the
coupling was just over-tightened. The
rocket had been sitting in the sun for a
while as well and the coupling being
black may have heated up and softened further.
Not really sure what happened here.
I replaced the coupling just to make sure,
and screwed in the Tachyon IV payload
section as I wanted to test the V1.5 flight
computer in flight. We filled it and launched it again
without incident. This time the rocket flew
to 480 feet (146 m) . Since the payload section
wasn't setup to fly with a video camera no
onboard footage was obtained.
(If the video does not play, try the latest
Flash player from Macromedia)
We are happy with how the 15mm launch tube and release head
worked and we'll be using more
of it in the future.
Katz Stager Mk2.
A number of ground tests were performed in
the last couple of weeks of the Mk2 staging
mechanism. The video below shows the ground
tests. The first couple of tests are of an
earlier prototype with the final two tests
being with the actual flight hardware. The
second stage in these videos is completely
filled with water to prevent it from flying
anywhere.
(If the video does not play, try the latest
Flash player from Macromedia)
We are now building a small second stage
rocket and booster to test it in flight.
