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 click the browser's BACK button to return back to the page.

Date: 30th June 2012, 8:30am - 12:30pm
Location: Doonside, NSW, Australia
Conditions:  Calm 0 - 5km/h wind, mild ~15C, blue skies
Team Members at Event:  Paul K, PK and GK

After a few months break we started repairing the Shadow about 3 weeks ago. Most of it was straight forward as we really weren't redesigning anything new on the rocket. We knew that the deployment mechanism worked well on the first flight so we wanted to see if we could get it to work again on these flights. We decided to simplify the whole setup and just use the single Servo Timer II (no uMAD) and with a break wire to trigger it. To save on weight, we used two 100mAh LiPo batteries to power the ST II, servo and the zLog altimeter instead of the normal 9V battery.

We also replaced the normal slide power switch with a screw switch to ensure good contact at the high accelerations.

In final testing the night before launch, I did a number of deploys and the nosecone became wedged on two test runs. This was bad. After carefully removing the nosecone I noticed that the parachute was jammed diagonally pushing only on one side of the nosecone. The parachute was packed the same way (long and thin) on the flight that crashed. This is most likely the cause of the crash. So I repacked the parachute short and stubby so it fit fairly snugly into the body tube. I also sanded the nosecone coupler down to make it even looser. Next I added about 1cm of dense foam into the nosecone coupler so the piston would need less travel to eject the parachute. Less travel means it can eject it with greater force. I also greased up the piston guide and the spring mechanism to let it slide as easily as possible. With these changes, the next 5 tests were successful. I didn't want to make the nosecone too loose as there is always a danger of drag separation especially since the deceleration was going to be around -1.7G.

I also decided to check the #16 camera after fully charging it for a couple of hours the night before....nothing... the camera just didn't want to turn on as if the battery was completely dead. I plugged it into the computer, but it was fine, it just wasn't holding a charge for very long. So I removed it and replaced it with the older #11 camera. This one worked fine. The lesson is to always double check everything the night before, and leave yourself enough time to fix anything you may find.

Launch Day Events

We woke to a beautiful morning with blue skies and a little bit of wind. We normally have some wind on the coast, but because Doonside is about 50km away inland we were hoping the wind would be calmer. When we arrived at the launch site it was almost completely calm. Yes! Perfect launch conditions.

It took about 40 minutes to set up the launcher and rocket and we were ready to launch. We decided to change the launch procedure a little bit, because the rocket is almost a foot taller. It is harder to get to the electronics to turn everything on. Because the access holes are all around the rocket it would have meant relocating the ladder several times. Since the quick launcher allows the rocket to be removed from the base, we simply lifted it off, laid it horizontally and turned on the power, camera, and altimeter, and then put the rocket back on the pad and inserted the locking pin.

We also used the extra hose extension for this rocket to put us back about 20m in case it decided to scatter itself into little pieces.

Launch #1

The rocket was slowly pressurised to 400psi. When the count down came and it was time to pull the cord, the rocket didn't want to release. Poor Paul was trying as hard as he could until with one final pull the rocket released. It seems that with the high pressures the release ring just does not want to slide down as easily. With the amount of pull Paul was putting on the release mechanism I was sure glad that the whole thing was pinned to the ground.

The rocket took of very fast with a loud bang. It went up perfectly straight as an arrow. As we increase the launch pressures we look very carefully to see if the rocket is bending. The rocket was quite difficult to see at that altitude, but the orange helped. The parachute ejected just as the rocket was passing through apogee and nicely opened. We set the delay to 8 seconds even though the sims predicted about 8.6 seconds to apogee. We'd rather start the whole parachute ejection just a little sooner in case the sim is a little optimistic. As it turned out the 8 seconds was spot on.

The rocket came down fairly gently about 180m from the launch pad. Even though the parachute we use is a little under sized for what it should be the rocket itself generates quite a bit of drag and so the combination is quite reasonable.

We hooked up the altimeter to the laptop and downloaded the data. The maximum altitude was 1173 feet (357m)! This was a great result and was our new personal best altitude. The sim had predicted 1246 feet for this launch pressure, but from past experience we knew this was optimistic and so were expecting something closer to 1100 feet.

Here is the altimeter plot for the flight:

The on-board video was also pretty good, although the camera mount must have moved because a part of the window was visible in the frame. The other nice thing was that the rocket only did one approximately 360 degree turn from launch to apogee. This made for much more stable video. Here is a selection of on-board frame captures from flight #1:

Launch #2

The wind had picked up a little bit by now but within acceptable limits. I was kind of umm-ing and ahh-ing whether to launch again, but dad managed to convince me to have another go. So we agreed to a 420psi launch pressure to see if we could push things a little more since we still had very nice weather, and we knew the rocket was able to handle the previous launch without problems. The rocket had never been tested beyond 400psi and so it was a bit of a gamble.

The set up was very much similar to the first except when we slid the rocket onto the launcher we managed to push the nozzle and bulkhead about 5cm into the rocket. A little air pressure through the launcher made the bulkhead pop right back and we were able to load up the rocket as normal. We also discussed a number of options for extending the lever arm to make the next launch easier. In the end we just jammed a big screwdriver into the top of the arm and tied the string to that. We'll extend the arm properly for the next launch.

The release this time didn't give us any trouble and the take off was again very much like the first - very fast and loud. Thanks very much to Chris for helping to launch the rocket this time.

The rocket again opened it's parachute right near apogee and landed only about 30 meters from where it landed last time. This time the parachute had got caught on the branch of a tree but only about 2m above ground. The rocket survived without any damage.

Downloading the data from the altimeter gave us a new personal best at 1239 feet ( 377m )! The altimeter data also shows that the parachute probably opened just a little early as you can't see the nice apogee curve before the descent curved. This quite possibly took several feet from the peak altitude, but from the onboard camera you could see that the rocket was very close to it. 

Here is the altimeter plot from flight 2.

And here are the two plots combined for comparison.

Here are some stills from the onboard video. On the second flight the rocket only turned about 300 degrees from launch to apogee and in the same direction. We're pretty happy with the fin alignment. :)

Here is a highlights video from the two launches:

After the second launch we set up Paul's Pod 2 rocket for a 2 stage flight on a C6-0 staging to a C6-5. The rocket went great and the second stage ignited right on time. The rocket landed well and we set it up again, but this time only as a single stage on a C6-5. The rocket flew well although the parachute opened a little late.

So a great day all round, and we look forward to more launches with this rocket.

Flight Details