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Day 99 - G2 Nosecone Test Flights
G2 nosecone ready to be fitted to the test
To stop the nosecone from separating from
the rest of the rocket it is attached with epoxy
and a nylon line.
John was a great help on the day with rocket
prep, launching and retrieval.
Setting up for first launch.
The rocket used a 9mm nozzle and 1L of
Launched at 100psi, as the rocket weather
cocks into the wind.
A sequence showing the parachute deployment.
Recovery crew is on the scene within seconds
Setting up for the second flight.
Rocket starts pitching over soon after take
off in the strong wind.
Up up and away. A good action shot.
Coming in for a gently landing with a big
An all round successful day.
The fin can is made removable just in case
we need to replace the spliced quad that it is
As is, it weighs 155 grams.
The removable fin can attached to the
The Polaron G2 rocket is 3m long (~10 feet)
Breadboarding the ServoTimer II.
Date:22nd January 2011
Location:Denzil Joyce Oval, NSW, Australia
Conditions:26 Degrees C, wind
25km/h gusting to 30km/h mostly clear.
Team Members at Event:PK, John K and
It has been a while since the last
update. My family and I had been visiting
the US for the last three weeks for
Christmas and new year. We closely
investigated white solid rocket fuel lying
all over the mountain slopes in Colorado. It
was nice to have a break from building and
launching rockets, but we are looking
forward to more development and rocket
launches this year. I now have a better
appreciation for those who launch water rockets in freezing conditions.
We brought back a few tubes of PL premium
from the US as we only had a couple left
which are close to their expiry date. With
the fiberglass reinforcements we find that
we don't use it much for splicing anymore,
and use it mainly for attaching things to
the PET bottles like fins.
Polaron G2 - Progress
Since the last update we have decided to
extend the Polaron G2 rocket by another
spliced-quad to give us a total of just over
21L capacity. The nosecone has also been
completed and tested.
The nosecone has to be attached
differently to how we normally do it due to
the tape not bonding well to fiberglass.
We had to glue a section of a PET bottle to
the top spliced quad and then tap a number
of holes so that screws could hold down the
nosecone mechanism. We use big blobs of PL
premium on the inside of the PET section and
drill smaller holes into those. The machine
screws then tap their own thread when you
screw them in.
The fins for this rocket were constructed
from Coreflute and attached with PL premium to
a removable brace. All up they weigh 155
grams. This let's us swap the fins easily if
they are damaged, or the spliced quad that
they are attached to is damaged. Normally we
tape the fin can on to the rocket, but
because tape won't hold to the fiberglass,
we are using a few small PL premium blobs to
hold it in place.
We are also adding
Craig's flight computer to the rocket's
payload bay to gather data on the first
flights. It will also serve as a back-up
altimeter. I am interested in seeing what
kind of G loading the rocket undergoes
during launch. This will help us design
components for future versions of the
The rocket is mostly ready for flight
now, but we still need to pressure test it
whole to around 150psi to check for
leaks in the tornado couplings.
The entire G2 deployment mechanism
including the G2 parachute weighs in at 361
grams. This is somewhat on the heavier side,
but compared to the rest of the G2, it isn't
too bad. There are weight savings possible,
but we won't bother with this version.
I borrowed the idea of attaching the
nosecone to the main parachute line from my
LOC/Precision weasel pyro rocket and how it
attaches the shock cord to the inside the
body tube using epoxy and nylon line. I
didn't want to put another hole in the
G2 Nosecone Test Flight Report
We went down to the local park today to
test fly the G2 nosecone. The wind was
blowing pretty hard at around 25km/h so we
nearly cancelled the launch. We decided to
move up wind at the oval away from our usual
launch area. Because the wind was going away from the
road and down the length of the oval we
decided to launch. When we launch the G2 we
are going to have to do it in steady
conditions to stop it drifting too far.
The first flight flew @100psi and
slightly into the wind which meant it
wouldn't drift nearly as far, especially
with the bigger parachute. The nosecone
separated soon after apogee, but it took the
parachute a little longer to fully deploy as
it had a few wraps of the main line on it.
The rocket landed well without damage.
We flew the rocket again with an
identical setup, but this time it flew down
range during the boost phase, but luckily it
didn't drift far and again landed without
damage. We stopped after two flights as we
didn't want to take the risk of damaging or
loosing it in a tree.
The tests showed that the mechanism works
well and can survive landings. The mechanism
will experience bigger loads during the G2
launch, but the actual launch will be as good a test as any. We will now attach the nosecone to the G2
rocket for it's first flight. Although the
deploy delay was set for 3.1 seconds after
launch, the parachute didn't fully inflate
until 5.8 and 6.1 seconds.
Here is a highlights video showing
the operational detail and the two test
Day 99 - Highlights
Servo Timer II
I've also been spending quite a bit of
time over the last few weeks working on the
next iteration of the flight computer we use
on our rockets. The new version is smaller
and easier to use. It has all new firmware
which was mostly written on the bus while
commuting to and from work. Sometimes you
just wish the bus took a little longer when
you're in the middle of debugging. I'll be
posting more progress details on this in the
coming months. I have the prototype working
on a breadboard currently, and have started
ordering the components. I'll get a few test
boards made up first and fly them before
making a bigger run. I also still need to
write the user manual for it.