Thunda2 flight was a bit of a disaster – that is how it felt. On reflection, there were small sparks of success.
What Happened
The launch of BumbleBee didn’t quite go to plan. Communications failed and I was unable to locate the rocket. I walked probably about 20km through fields and forest in vain. It went approximately 8000 feet and to be completely honest, it was too high up to see a deployment, though I’m reasonably confident the first ejection charge (deployment) did occur because it has worked in all previous occasions. Also, if it didn’t work, it would have come down quite quickly and it would have landed closer and chances of finding it probably would have been greater (I think).
We did get an excellent video of it launching from the GO-PRO that was situated right next to it. Below is a link to it.
The launch tower was my own that I brought all the way down from Cairns and despite the problems setting it up it functioned extremely well. The difficulties setting it up were probably related to my tiredness and lack of light (I set it up at dusk after the range was closed). I had no assistance whatsoever.
I have since put a post on AusRocketry Forum, asking for anyone who does find it (and I am sure it will be found eventually), to return it…I’ll pay for return and I’ll provide a small reward. It has video camera in it and I’m sure it successfully recorded some awesome footage of Thunda2.
Accomplishments
First Scratch-Build using High Powered Motor
Second use of launch tower
First use of Minimum Diameter Aeropak launch hardware
First High Power Motor since my L2
Lessons Learnt
Redundancy is SO important, especially with tracking electronics. From now on, I will be having TWO tracking systems. I just can’t comprise on that. A lot of expensive components were lost in that. It is true that it was a very very compact build and so there was absolutely no room for anything else, but this is just not going to do in the future. If I can’t get my rocket back to fly again, I’m missing the point.
I wrote a single page e-mail to family on the days proceedings. I decided I would share this here on the blog.
The days proceedings
Jeremy, Grandma Patsy and I got up at some crazy time 04:30 for Grandma Patsy and 05:00 for Jeremy and myself.
We had a quick bit of breakfeast - weetbix…teas and other foods.
Then I loaded all the boxes (which I had left near the front door) into the roomy Toyota Kluger… and then we set off.
We all spotted some Hot air balloons as we started our ~60min journey to Cedar Grove Road. Most of the trip was in lovely rural surroundings.
About 1/2 way into the trip we all stopped off at a small cafe in Canungra called the “Outpost Cafe”.
There Grandma Patsy got a coffee – flat white – hot in a take-away cup, and I got two slices of toast with Vegemite…sharing the facilities
with middle-aged(and older) “friendly” bikies.
Then after the usual pit stop activities, we resumed our drive.
Eventually we got to Jimboomba…I was a little anxious because the road seemed to go on forever and was wondering if I’d missed some vital turn-off.
I had nothing to worry about. About 10 min later, we spied the launch site. The first thing I could see were blue portaloos. I was delighted to see them.
2 mins later we were driving into a paddock. Grandma Patsy did the honors opening the gate and then we were back together. Thanks Grandma Patsy 🙂
We met up with about 4 other chaps who kindly suggested we not park so close to the toilets. We took their advice and parked further away.
There was no equipment at this stage…and it became apparent that the arrival of the equipment was lagging. Eventually a huge truck made its way and before we knew it, Jeremy and myself were helping set up all the equipment. We stuck mostly to erecting several Gazebos. Jeremy was terrific getting the pegs and hammering them in.
We got our equipment on to a table…one nice chap said…possession is nine / tenths of the law….
Then someone stole the two tables from under us!!
Fortunately, someone loaned a table and the Tarp I brought all the way from Cairns, suddenly became valuable property!
8:30 came and the launches started. Dave, Lake, Reef and Vanessa’s father arrived…and eagerly watched. At various occasions I helped them set-up their rockets. Jeremy gave up waiting for me to get him a motor….I suggested he approach Blake with some money and ask him for some advice on what motor he required. Blake helped Jeremy with the motor purchase and I helped Jeremy assemble the motor. Jeremy’s flight went really well.
For about 4 hours I set-up the rocket. Everyone was looking in…Jeremy was taking photos. Grandma Patsy helped as much as possible, making sure no one got too close. I was a little nervous having this awesomely powerful motor on the table and people casually walking past it. But we were following procedures to a tee.
I had my instruction manual with check-boxes and pictures…and only after inspecting all components, did I actually start assembling components. So many things were checked and re-checked.
Then at about 12:30….the launch pad that I wanted to use was vacated…their rocket went up…and then splashed down into the Logan river….(only about 4 hrs later did some university students practice their swimming skills to pull that rocket…a 4 metre beast…from the river. Lucky they don’t have crocodiles down this way!!).
I didn’t take any photos myself… I wanted to see it through my own eyes and be in the moment…so to speak.
Recovery
After the flight, Jeremy, Lake and myself bounded up the paddock, through long grass to recover it. 30 min later, we were talking back….Lake was holding the Nose cone, Jeremy was holding the large Parachute and I holding the rest of the “bits” as best as I could….across the muddy river bed in my best Black shoes (well almost the best…the ones I wear to Darwin for work).
Hot, tired, sweaty and alive. 2 litres of fluids later…felt a bit more alive…Sweet feeling of success.
On the 13th of September, we did a Model Rocket Launch session at Trinity Beach State School (Jeremy and Isaac’s primary school). Eleven students launched their model rockets.
Cairns Post came along and photographed the event. It went quite well.
Joe Readying the rocket. Jeremy checking the rocket launch deskRocket Launch Controller and list of rocketeers and the rod they are on.Close up of Joe setting up the rockets – inserting igniters
We finally launched the Model Rocket “JAJI Aerospace” again. It nearly didn’t happen!
We hope you find this interesting and inspiring.
Launch Issues
The Electronics performed perfectly, but the igniters and the pyrogen on the tips refused to ignite the motors. So eventually I needed to use a Copperhead Igniter from my spare G76-10 Motor Kit to get the rocket launched.
Data
The Air Pressure/temperature measurements didn’t work. No idea why this didn’t work. Tests in the office and running up the hill worked. Very strange.
Gyro data was produced and is downloadable (unprocessed) from:-
I then process this file data.csv with a Java 3D app to generate an accurate real-time depiction of the Rockets rotation during flight. The data only goes for 8 seconds…right to the point of Apogee.
Feel free to download and use this data.
On-board Camera
We had an on-board camera taking footage. I’ve created two YouTube videos. One is the original footage (un-edited). The second is one slowed down by a factor of 8. At approx 3min and 10 second mark, you will see white spots on the ground. These are people (us) watching the launch. If you look carefully you will also notice the rocket dangling down and the rocket exhaust trail.
Ground based Camera
We had a Canon G12 camera rolling away on a Tripod about 20 metres away. I’ve uploaded a Youtube video showing this launch.
Future Improvements
There is a lot we can do to improve the launch. These points we will be focusing on are:-
Work out a more suitably sized parachute (While the recovery all went well, I think with the extra payload weight, a slightly bigger parachute would have been better).
I need to practice the installation of Copperheads a bit… I think.
And I need to figure out why the air pressure/temperature sensor didn’t work.
Work out a better camera system…and one that takes movies looking down…with a wide angle lense.
Figure out what type of igniter I can use (with reasonable chances of success) with the remaining G76-10 Motor.
Experiment and determine why the air pressure sensor did not measure any values.
Final preparations are being made for Launch 4 which we hope will take place tomorrow, weather permitting.
The Weather
The wind speed is going to be approximately 10 to 15 knots. We don’t really want to fly if more then 15 knots. Rain is 50% chance which sounds bad, but this is over a large area, so it probably a lot less chance then 50%. We will check the radar before we leave to see what is about. We’ll also check the motion of the trees on the mountain next to where we live as they will provide us a good indication of wind speed.
The motor
I have assembled the G76-10 motor. This included reducing the delay from 10 seconds to 6 seconds using the AeroTech tool. One thing I have not done is install the igniter. I want to do that on the day just before launch. The igniter is delicate and I think it is bad practice to install igniters until one is ready to launch.
Here are some pictures of the assembly.
All the parts of G76-10 laid outAft Cap with delay charge with 4 seconds removed.Two grains assembled togetherGrains inside AeroTech Case with insulator at topNozzle of motor before brass cap screwed on.
Batteries
All batteries have been charged, even if I thought they were okay. I found that the igniter battery was completely flat! Very glad I checked this. This could be because the voltage measuring resistors have flattened the battery. I will leave this disconnected from now on, unless I’m going to sue it.
Test Ignition
I put a high value resistance resistor as the igniter and I was able to perform ARM, CONTINUITY TEST and a trial ignition. I measured a voltage of 12.5 volts across it. Great!
All the Parts
I’ve gone over the checklist and packed everything away. Ready to go. Also packed the rocket in its delivery box with lots of padding. I decided to roll up newspaper and put in aft and rear of motor to stop rubbish getting in. Before doing this I folded up the parachute and inserted it in as carefully possible. We will need to tie the cord to the bottom of the electronics bay payload before launch.
Everything packed away and ready for launch day.
Last minute Check
I confirmed the steps for the payload turn on. I’ve also got some Masking Take (from my very generous and helpful friend – Alex). This will be used to ensure no shorting of jumpers
This post is a little late, but still worth getting out.
On the 10th of January 2016, myself, Anna, Jeremy, Isaac and “Grandpa Val” travelled to the Goldcoast to attend a Queensland Rocketry Society Launch day. We all got to fly a rocket! Even Anna did!
Isaac’s Rocket
Isaac flew a Small 15 Gram model rocket with a B-Engine. He was initially very scared of the noise and wanted to sit further back with the cars. Eventually he got the courage to participate in the rocket launching. Very pound of you Isaac!
Here are some pictures of Isaacs rocket and the boy himself!
Isaac hecking the continuity of his rocket launch line
Isaac’s rocket is one with blue nose coneIsaac with his GrandpaThree rocketeers!
Jeremy’s Rocket
Jeremy’s rocket is an exceptional rocket for a first timer. This rocket had a D-engine expertly installed by Blake (Owner of Ausrocketry). It deployed its parachute perfectly! Lovely work Jeremy!
Jeremy with his rocket on launch padJeremy recovers his rocket – all intact!Jeremy filling out his launch card
Anna’s (Mummy) Rocket (UFO)
Anna couldn’t miss out on the action and launched a UFO rocket. This had a C-Engine in it. It flew really well!
Anna carefully setting up her ‘Rocket’ for launch.
Joe’s L1 Attempt
Well I decided to go for my L1. This was very exciting. It took a lot of time to set-up the engine, even though it was just a CTI engine! I was taking things very carefully. Didn’t want to make any mistakes.
Inspecting the business end.Jeremy standing next to my rocket where it landedFound my rocket. All perfectly intact and only about 100 metres from launch pad.Setting up the IgnitorReady for launch photo shoot.Successful parachute deployment
A lot of work has been done constructing the payload and programming the micro-controller. Preparations are now underway for the next model rocket launch.
Below is a picture with everything assembled.
Payload assembled into Rocket
The payload airframe section (the grey section in the above picture) will be painted white. Read on to find out more about the payload and what it can do.
Payload
The launch will have an experimental payload included on it which will:-
Capture Video of flight at 720 x 480 with sound using a 808 keychain camera
Surveillance Camera
Capture and record gyroscope data (rotational speed) using a L3G4200D breakout board
Gyroscope sensor
Capture and record air pressure and temperature measurements using a MPL3115A2 sensor
i2c based MEMS Air Pressure sensor
The final payload (before sliding into air-frame) looks like:-
Front view of payload tray
The sensors are sandwiched between the PCBs and the battery board. Space really is a premium.
Back view of payload
Notice the coin cell batter and the rotary switch on the LHS and the camera on the RHS. The rotary switch is accessible from the outside.
Payload Data
It is certainly an ambitious project, but hopefully will produce some results that will allow us to characterize the motion of the rocket as well as test our payload design and operation. The Air Pressure results will allow us to approximate the altitude of the model rocket over the flight which we will then be able to compare to our simulations. The gyroscope readings will be very interesting when we compare with video recorded motion of the rocket. Temperature will be interesting, but is of less importance.
I’ve created a video that allows us to compare the ‘real world motion’ of the payload when compared with the motion depicted using the gyroscope data. See below.
The Rocket Motor
We will be utilising a G76-10G Aerotech engine. This translates to an average thrust of 76 Newtons over the total burn time of approximately Below is a plot from OpenRocket.
Simulation of launch
As you can see, this rocket will achieve an altitude just shy of 300 metres. (less then 1000 feet). This is well short of the 4000 feet ceiling we have at our launch site. We still expect the launch to be spectacular.
Remaining Preparations
Remaining preparations include:-
Generating Launch simulation to ascertain key information like ejection delay, speed of rocket off the launch rail
Confirming CG and CP points (checking stability of the rocket)
Confirming launch location suitability and timing
Checking and testing launch Electronics systems
Charging batteries
Performing inventory check and packing boxes with required items
Writing and testing procedures
Double checking motor risks (issues that other people have recognised with the motor). The AusRocketry forums were helpful in this respect.
A launch of the JAJI rocket was done on the 1stof November 2015 at the mud-flats situated approximately mid-way between Palm Cove and Port Douglas.
Launch location
It was an extremely hot day to launch the rocket. I had to walk about 8km in total to get all the equipment out to the launch area. I got a lot of blisters. I will definitely be trying to work out a better way to get the launch site setup next time.
Eventually we got everything setup, but then had some issues with the GroundStation Electronics. The groundstation.pl process kept finding non-ascii characters and crashing. As a result we almost didn’t get to launch the rocket. We managed to get through all the stages of the launch sequence by restarting the Groundstation between each step.
We have since discovered the cause of the Groundstation issue. It was due to overflow of the Serial Buffers. We’d lose some data and we’d get ‘pieces’ of data. This totally confused the groundstation perl script and crashed it. One improvement that we are looking at implementing is a re-start on crash script. Other improvements include ensuring Serial Buffers cannot be overflowed.
The engine we used was a HP110-G250VM-14A and the rocket we used was ‘JAJI AEROSPACE’, a Callisto rocket. We used OpenRocket to predict the speed and altitude. These are below.
Graph of altitude, velocity and acceleration
Summary information
A video of the launch is below.
Below is a picture of the landing.
Rocket Landing site – Notice the imprint of the motor in mud
The piston was slightly damaged by the shock cord. See a picture of this damage below.
Damaged Piston Tube
This damage is minor. It was repaired using some areldite and masking tape. Then it was sanded down so it could easily slide up and down inside the airframe.
