Each flight log entry usually
represents a launch or test day, and describes the
events that took place.
Click on an image to view a larger image, and
browser's BACK button to return back to the
Day 44 -
Foam Flights, FC V1.3.2 tests flights.
Two new V1.3.2 flight computers and
deployment systems. The one on the left shows
the camera location, the other showing the
Parachute door and camera doors open.
6:30am, we are still trying to wake up.
Ready to test the new flight computer on
...now John .... it's 3,2,1 ... then "GO"
Being a bit too close to the rocket ensures
an early shower, with shampoo and everything.
Apogee image taken from the video sequence.
River next to the park. This was a fairly
high altitude flight.
You have to walk a fine line between
pressure and wind conditions.
This coupling ripped out of the lower bottle
of J4 II.
The G-forces during the explosion bent
connectors, components and separated the servo
in two. Note this damage is not the result of
impact. The entire nosecone is undamaged.
20076:30am - 8:00 am
Location:Denzil Joyce Oval
Clear skies, mild temperatures, increasing
(click the name for rocket details)
An old rocket that has had a fin
and deployment system upgrade.
Team Members at
GK, PK, John K, Paul K.
The purpose of today's flights was to
V1.3.2 of the flight computer. It
started out as a beautiful day but as soon
as the sum came out, the wind started
picking up. It was fun morning of launches
although we did get a wakeup call about
Flight Day Events
The first flight of the day was
Hyperon III with a camera mounted on the
inside of the nosecone. We only used
water (no foam) for this flight since we
didn't know how well the computer would
work and we wanted to keep the flight as
stable as possible. It was a great
flight and the parachute deployed when
it was supposed to. The rocket drifted
almost 200 meters down range in the
strong breeze. The in-flight video of
this is shown in the highlights video
below. If you listen carefully you can
hear the servo motor at apogee and then
a couple seconds later as it returns to
Next up was the newly upgraded J4 III.
J4 III had new fins fitted and was equipped
with an identical deployment mechanism
as Hyperon III. As we started filling
it, I was doing the customary arming of
the flight computer. As I was just
finishing up the top section of J4 exploded
from the rest of the rocket. My face was
about 1 foot from the failure
point. It was a pretty loud bang as you
expect, and I would not recommend others
repeating the experience.
I think I was extremely lucky in that I
only suffered a drenching and the video
camera around my neck too was saturated.
Again no video of the incident is
available as it was totally unexpected.
Although now we should expect it every
The second bottle from the top burst at
the base and neatly ripped out a piece
of PET with the coupling. The coupling
remained attached to the top bottle. The
bottle had burst at around 100psi. We
were surprised to find that it was still
one of our early brass couplings. This
coupling and bottles must have been in
place for perhaps 6 months. Looking
back, J4 II had its fair share of
launches and crashes, and the bottle base
must have been weakened by all the
The flight computer on top of the blown
off section suffered damage due to the
very high G-forces of the explosion.
Components and connectors were bent, and
more notably the RC servo motor split in
two revealing the gears. The servo top
and bottom shells are not screwed
together, but rather held by friction by
4 little plastic pins slotting into
corresponding tight holes. I didn't know
the servos were constructed like this, I
thought they were just glued together.
We know this wasn't caused by impact
with the ground because none of the
nosecone or bulkheads were damaged in
Perhaps a positive note that came
out of it is that it could have provided
an explanation as to why the Tachyon sustainer
failed to open its parachute during the
boosted flight with Damo's 6-splice
that day I noticed that the servo had
also come apart, but thought it was the
result of the impact. The servos were
attached in a similar manner on both
rockets. With the large booster using a
full bore nozzle and no water in the sustainer, it was a very fast takeoff.
This might have caused the servo to come
apart and stop functioning. The launch
detect switch and flight computer had
still worked after that impact and even
turned the motor in the broken servo
gearbox. The previous bent release pin
hypothesis is now running second.
I will now glue these motors together to
make sure that doesn't again become an issue. I guess cheap servos weren't
meant for this kind of punishment.
Fixes to J4 II are minor and we will
be replacing all the couplings and
bottles with new ones.
The third flight we flew Hyperon III
again but this time the camera was pointing down.
Due to the increasing wind, we decided
on only 110psi to keep the peak altitude
down, and reduce down range drift.
Because there are only 30 seconds of
video on the camera, I decided to start
counting down while I was finishing
activating it, figuring that 4 year old
John on the end of the release cord
would wait for the "GO" call.
Being as assertive as he is and since he
was the director of launch control at
the time he decided to pull it just
after I said "1". .... although it was
my second drenching for the day, we did
get a great flight in. We also got good onboard
video of the foam trail as the rocket
ascended. The parachute deployed just
before apogee so it all ended up well.
We didn't get a whole lot of good ground
video this time for a number of
"drenching" and "sun-in-the-eyes"
Due to the increasing winds we moved
the launcher up wind another 20 meters
and lowered the launch pressure. On the
in-flight videos it is quite evident to see
the buffeting caused by the gusty wind
The last flight was again with foam
and we made a good ground video of that.
The foam flights were pretty straight on
this day, but the rockets used the 9mm nozzle.
On the last flight the rocket landed on
the hard paved car park. Even though it
landed under parachute the nose cone
still hit pretty hard and the
battery came loose and hit the servo
motor .. and you can guess what happened
to the servo motor. ... they definitely
need to be glued.
All things considered, it was still
a good day, and proved FC V1.3.2 works
well. We will put the flight computers to work now
on some of the experiments we have
(If the video does not play, try the latest
Flash player from Macromedia)
It was evident the damage high
G-forces can make to the electronics.
Everything has to be secured really well.
We were lucky no one was hurt when the
rocket exploded. Safety glasses will be
mandatory at every launch from now. This stuff is
Small kids pulling the release cord should be
encouraged to practice counting backwards and
following instructions exactly.
Camera flight. Good
vertical flight. Parachute opened near
apogee, drifted long way down range. "7"
setting on computer. Good landing.
Catastrophic failure on
launch pad. bottle base exploded. Minor
Very nice straight
flight. Taped downwards looking camera
to side. Good deploy and good landing.
Used "7" setting on computer.
Good flight, slowly
pitching over into the breeze, but
achieved 28.4 second flight duration.
Landed hard on paved road. Minor damage
to flight computer. Used "7" setting on
We've also started looking into FTC.
Damo kindly gave us some during our last
visit. I hadn't seen FTC first hand
before and was quite impressed with the
strength so I ordered some from
JR Turk. A few days later my package
of four 5 foot lengths arrived. I was
pretty disappointed when I found out the
tubes had much thinner walls (0.5mm)
compared to the tube (0.9mm) that I got
from Damo. I didn't realise they came in
different thicknesses. This means its
not going to be able to hold as much
pressure, but its not a total loss as
these can be used for payload sections and other components. We
will still pressure test them both
un-reinforced and reinforced to see how
It appears that long term stresses
on bottle couplings may be an issue. Polaron,
J4 II, Acceleron appear to have all failed
at the base after many flights and some
hard landings. It may be prudent to
replace bottles after a certain number
The battery contacts have been
directly soldered to the wires to ensure
After a number of hard landings with the
on board cameras, the internal battery contacts
have become deformed and stopped making
reliable contacts. This was fixed by
soldering a blob of solder to both ends of
the battery, increasing the battery's
length and making a better contact.
The total weight of the integrated
nosecone and recovery section including
batteries, flight computer, parachute
and camera now weighs 182 grams.