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represents a launch or test day, and describes the
events that took place.
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Day 33 -
Simultaneous Launches and Foam Flights
Setting up our first simultaneous triple
launch.
Left to right:
OO, J4 II and Acceleron II
Pressurised and ready to go. This is the
view from launch control.
1st Attempt -
Using food colouring makes launches more
colourful.
They never collided but came close.
2nd Attempt -
Its a vertical drag race.
Although J4 II was quicker off the mark,
Acceleron II soon overtook it.
J4 II being launched with blue foam.
The foam as it comes out is a lot paler
blue, but still clearly visible.
J4 II descending. You can still see the
remnants of the foam spray.
Standard J4 II foam take off.
A great looking foam trail. The rocket flew
relatively straight but the cross breeze blew
the trail around.
Another launch of J4 II soon after takeoff.
New launch location where we will start
launching multi stage rockets. Abandoned air
field.
Date:21st
April
2007 6:45am -
9:20
am
Location:
Denzil Joyce Oval. (launch site #4)
Conditions:
Clear skies and cooler temperatures. Light breeze
becoming moderate.
Rockets:
(click the name for rocket details)
This rocket remained in the same
configuration since it last flew.
Team Members at
Launch Event:
PK, GK, John K and Paul K. Number
of launches:9
It had been three weeks since we flew
rockets, having spent the last two weekends
doing static tests with foam. Since we have
3 launchers we decided to have a go at
launching 3 rockets simultaneously. This was
partly for fun, but also a practice run for
launching multistage rockets, where a lot
has to be done on the launch pad to get it
all ready.
We also launched three jet foaming
flights, again just for fun for the kids....
you know .... the big kids.
Flight Day Events
We arrived early again, because we
knew that setting up three launchers was
going to take a while. During the week we
made a distribution manifold for the air
supply so that three rockets could be
pressurised simultaneously. The manifold
has three hoses connected to it with quick
release fittings.
The setup time from arrival to launch was
close to 50 minutes!
We wanted to use an in-flight camera,
but it turns out the AAA battery had just
died and we only had spare AAs. Need to
bring spare AAAs for next time.
We knew that Acceleron II would be
much slower than J4 II and OO on takeoff,
so we put 7mm nozzles on the faster
rockets to slow them
down a little.
On our first simultaneous triple
launch we forgot to put in the ballast
water on the Acceleron II rocket. The OO rocket
also did not fire at the same time,
but just a little later. There is a lot
that happens on the launch pad to remember
everything, including operating two still
cameras and two video cameras at the same
time.
The flights were good, but the parachute on J4
failed to open and it landed heavily. OO's
parachute opened about 3 meters above
ground so it landed well. It's good to
see one of our oldest rockets still
flying.
On the second attempt things went a
lot better. Although OO was again a little
late off the pad, but it was still pretty
good. The parachutes opened on all three
rockets. Since Acceleron had the ballast water
in the payload section it was a lot more stable. It flew very
straight and to its highest altitude to
date. In excess of 100 meters.
The only downside was that the single guy
on the field putting up soccer nets had a
close shave as Acceleron landed 2 meters
from him. Murphy in action I think. He
wasn't too happy, so we apologised but
didn't have any further trouble. The only
other people on the field were on our
team.
We then flew J4 II by itself a number
of times with foam because it is fun to
see the column of foam and the noise it
makes. In the first two launches with a
7mm straight through nozzle, the rocket
had a very slow start and became quite
unstable during flight starting to pitch
over during the burn. This may have been
due to the strengthening cross breeze, and
also most likely the weight of the
water/foam at the bottom of the rocket.
On one of the flights the parachute opened
while the rocket was still in the thrust
phase but probably at an altitude of 60
meters. (see video)
On J4's last launch we used the 9mm CD
nozzle that we tested last week. We wanted to
characterise its performance in flight.
The rocket
flew and more or less confirmed our
results from the CD nozzle static tests.
The flight was pretty spectacular because
the rocket looked like it had the guidance
of a moth near a light. The nosecone
deployed, but the parachute never opened
and so it ended up landing rather heavily.
With minor repairs, it will fly again.
We have been looking for a new launch
site for the past couple of weeks because
the oval where we are is too small for
multistage rockets and the close shave
with the guy only confirmed it today.
In the afternoon we went to check out a
potential launch site after scouring for
sites on Google Earth around Sydney. On
Google Earth we found an abandoned air
field, about 40 minutes away from home,
and it is very easy to get to. The one
great thing with satellite photos is that
you can see trees, and their absence.
The site is a great location where we have
a couple of hundred meters radius of flat
terrain without any trees. I think we have
found the spot for our higher altitude
projects. (see photos at left)
(If the video does not play, try the latest
Flash player from Macromedia)
Flight Record
Launch
Rocket
Pressure (PSI)
Notes
1a
J4 II
120
7mm nozzle, good flight, but
parachute failed to open. Some
nosecone damage, but flyable. Used
1.25L of water.
1b
Acceleron II
120
Forgot to put ballast water in it,
but it remained stable and had a
good deploy and landing. Used 1.5L
of water per segment.
1c
OO
120
7mm nozzle, rocket flew well, with
the parachute opening about 3 meters
above ground. Used 700ml of water.
2a
J4 II
120
Very good flight with a 7mm nozzle,
good deploy although a little early.
Used 1.25L of water.
2b
Acceleron II
120
Excellent flight. This was Acceleron
II's best flight to date. It went
straight up and very high. +100m.
Parachute opened a little after
apogee. Good landing.
2c
OO
120
Very good flight with 7mm nozzle and
700ml of water. Good deploy and
landed well.
3
J4 II
130
Used a 7mm straight through nozzle
with Jet foaming. Beautiful slow
take off with long foam trail.
Parachute deployed too early. Rocket
landed well. Used 1.25L of water.
4
J4 II
130
Used a 7mm straight through nozzle
with Jet foaming. Beautiful slow
take off again with long foam trail.
Parachute deployed a little too
early as well. Rocket landed well.
Used 1.25L of water.
5
J4 II
130
Used a 9mm CD nozzle and jet
foaming, with a very good slow take
off. The rocket lost flight
stability during the thrust phase.
Nosecone fell off, but parachute
failed to open. Rocket spiralled
down, with a little TLC it will be
up and lfying again.