In this section of the website there will be a quick paragraph now and then, on our most recent updates and projects, (the most recent updates are nearer the top):
Please note that some of the Launch Reports have not yet been uploaded! But the most recent reports are ok.
JSB Rocketry 2018/2019 Update
Dear reader of this very outdated blog, whoever you are, wherever you are reading from, you may be interested to know why this website hasn't been updated in such a long time (so it may seem). My last entry to the blog talks about applying to university. Well, I am happy to report I achieved the required exam results to study Electronic Engineering with Space Sciences and Technology and the University of Bath. If I may be so bold, I bloody deserved to get there and be here now! The sacrifices I made, to do well in some exams I sat in a smelly sports hall, I will never forget.
I was drawn to Bath for several reasons which I won't bore you with, but long story short, it is top ten for Electronic Engineering in the UK and has a very illustrious reputation which, after completing one and a half years of my degree here, I can vouch for.
However, an engineering degree isn't simply given away. If something is too good to be true in life, it probably is. After living in a house without family for the first time, paying bills, as well as intensive study for undoubtedly the most challenging academic examinations I will ever encounter, regretfully Water Rocketry progress has ceased. The rockets and launcher are safe, at home in the shed, with all the equipment and resources easily at hand. While at university in the spare time I have, I've enjoyed flying model aircraft with firm friends. I will try and do some launches of rockets in the holidays, in good weather, but those two events rarely coexist at the same time. For what it's been worth, this stint of designing, making, launching and learning has led to some of the best memories of my life. If someone asks me what the most important thing in life is, obviously I will say family. But not far behind family comes hobbies. Hobbies that spark intellectual wonder and demonstrate uniqueness in an individual. They are what really show our true colours, not what we are doing to tick a box, impress a crowd or climb a ladder, but a hobby is what we do for pure pleasure. It reveals who we are as a human. But remember, how we share that hobby with others, is just as important as actually having the hobby. Chapter 1 of my Water Rocket hobby finished a while ago. The plot for chapter 2 is only just beginning to be envisaged.
Jamie Bignell, 18.01.18
August 2015- I'M BACK!!
All, for an extended period of time I have been very busy and preoccupied with
my A-Level exams. I have also been to Japan on the World Scout Jamboree. Now
all that has passed and I have a period of respite before travelling to the
Peak District at the end of the Summer. Very little rocket launching has
occurred but a new project has been started and development has been going on
in the background.
I have started development of a new Rocket Recovery Timer- the Rocket Recovery System (RRS). This is a small PCB that deploys a parachute via activating a servo motor but it is no longer a timer. It uses a new sensor to deploy a parachute. It uses a Magnetic Field Sensor to detect when the Rocket has tipped over more that 100 degrees to then activate the parachute. This concept has been visited before and was used in Air Commands MAD (Magnetic Apogee Detector) in conjunction with there Servo Timer 2. However my board is different, in the fact that is doesn’t interface with any of my older timers and uses a brand new type of microprocessor programmed in C!
Recently, I have been visiting Universities and I visited the University of York on an Electronics day on the 3rd of July and saw many awesome gadgets such as Cluster Robots and a 3D naughts and crosses game using LEDs. York were kind enough to present us all with Arduino Uno's as gifts. I had heard of the Arduino, as it was similar to the microcontroller I used presently- the PICAXE. The Arduino is a open source electronics development platform, which uses a version of C to program it. It comes with its own easy to use IDE and is a good step up from the PICAXE and its interpreted BASIC.
The Arduino System is based around an Atmel ATmega IC called the ATmega 328p. This is a raw microcontroller with a Arduino Bootloader. Microcontrollers are usually programmed through a programmer unless you have a piece of firmware in your microcontroller that allows installing new firmware using an external programmer. This is called a bootloader. I had a play at York using a shield that plugs into the top and found that it was FANTASTIC. I have therefore decided to use an Arduino in my next Rocket Recovery Timer. The Uno is rather large, and the bare IC can be used, but this is very large in a DIL package so I have decided to use a Arduino Nano. A different package of the Uno, which is smaller and includes the Voltage Regulator which means I can use the two cell lipos for power! The Nano was purchased of eBay for £1.73 along with the Magnetic Field Sensor which was £0.99.
So, how does it work? Well the Magnetic Field Sensor is called the HMC5883L. This is comes in a small package/PCB that can be plugged into a breadboard or using some female headers, a PCB. This communicates with the Arduino Nano using I2C. I2C uses 2 wires that are pulled up to +ve volts with some 4k7 resistors, that allow Serial Communication between the AVR and the HMC5883L. The HMC5883L sends data back to the Arduino in multiples of Gauss (magnetic field strength). A vector quantity as it has a direction and magnitude. When facing the north pole, it is strongly positive, when facing the South pole, it is strongly negative. Depending on the orientation of the sensor. The strength of the earths magnetic field is different. The readings can be positive or negative and are sent back to the microcontroller in the form of 2's compliment (slightly confusing if you don't do electronics). The data is send in Binary and the MSB is either a 1 or a 0 saying if the data is +ve or –ve.
Anyway, using some fancy trigonometry you can work out the angle that the rocket is at using both x, y and z readings. Using the vector from the x and y gives the angle of the rocket tipping left and right and the vector from the z and y give the angle for tipping forwards and backwards. It is awfully tricky to explain without using an animation but I am not very good at that. The code is relatively straightforward though not completely finalised. I have been doing plenty of experimentation using the breadboard and the PCB design is very simple as there are not many connections. This project is software heavy! With the Arduino Nano, I have access to all trigonometric functions, datatypes and programming structures, unlike with the PICAXE which struggles to process non-integer numbers!
Well that gives a brief overview. I will release a more detailed overview some point soon on the website, but for now that gives a good overview of what I am doing.
Please leave some constructive criticism or some comments about the project. I would love to hear your feedback and any tips you may have.
This month hasn't seen any launches, but
there had been development in other areas worthy of commenting!
If you ask any water rocketeer for advice on splicing bottles, they will say that PL Premium is the glue for splicing and nothing else can rival it. Well at JSB rocketry we have had issues in getting the glue here in the UK. Because of this, we have had to settle for runny Polyurethane glue which works well, but is expensive and doesn't cure very well. It runs and makes a mess! For several months now we have been desperate to get our hands on some PL. The glue we have works, but we have had some failures. I asked my Uncle if he could buy some as his job involves visiting the USA quite regularly. He very kindly bought us some from Home Depot and JSB Rocketry now has PL Premium!!!! It is much cheaper than the present glue we use and the exchange rate is excellent. I would personally like to say thank you to my uncle Lincoln! Although I haven't been able to do much construction recently due to school, when I have some free time, I will make a couple of splices to test!
As far as progress goes, little is to be said for our fibreglassing attempts. The failures have been costly and haven’t gained much more altitude- at least less than we were expecting. Therefore I am disappointed to say that we are shelving this project until the summer and will aim on perfecting our low pressure systems we have presently. This will involved trying new camera mounts and repairing older release mechanisms and generally having a sort out. Though for Christmas I did receive an MD80 camera as they are now really cheap compared to the kite camera and the wide angle lens on the keychain camera means that panoramas are distorted. None the less, because the fibreglassing project has been shelved we will try to reduce the weight of the rockets and try to reduce spin, all in the quest for altitude. The Blue Diamond 2 flights to 120 meters last month were a huge leap last year and although the same configuration Blue Diamond 3 didn't work out great, we later traced this to a faring that wasn't supportive enough for the splice in front and this allowed it to bend with the g forces. Therefore the fairings will be remade properly using Air Commands tutorial. We also recently released a new video on the Blue Diamond 3a fights last month showing the most successful of the fiberglass flights which can be seen on the Present Rocketry Technology page, this set the Altitude record for JSB Rocketry at 434 feet.
Plus this month will soon see the release of the RRT2 user video. This video shows the process of making your own timer, laying out the specifications and then moving through the design stages and manufacturing and testing the timer. The video does drag on a bit, but it thoroughly shows how it all works and what it involves. This is also the first video which involves my commentary over the top. I apologies in advance if my voice is annoying!
Although this mouth has not seen much physical launching or making, I have done some more on the computer as well as making the other two videos. I finalized spreadsheet for the RRT2 manufacture and for Christmas I received the components and board needed to make 5. These will be made to finalize the design as there were some features on then prototype that needed fixing such as the fact that the Piezo buzzer is not connected to a pwm pin and in order to interrupt the buzzer at launch I need to use a pwm pin! Luckily the LED pin for the launch LED uses a pwm pin so I swapped those around. This means the code a lot easier to write and understand and makes the Piezo beep a lot louder and clearer instead of manually trying to create the pwm using the pulsout command. The RRT2 will be made on a white PCB as this provides better tracking layout as the time to expose is exactly 1 min as these are the same boards we use at school. The prototyping board is higher quality but we didn't know how long to expose the board precisely and thus lead to tracks being left out. I am also going to try and use some smaller resistors on this new batch. These are CR12 rather than the larger CR25 resistors that can take more current. But most of the current being drawn is from the servo which is isolated by the transistor. This rest of the components draw very little current- around 20mA.
This Christmas we were also lucky enough to receive a Blade 350 QX2 Quadcopter and Spektrum transmitter. This was a family present and included the battery and some spare propellers in case of crashes. The Blade 350 includes all the latest technologies of the latest Quadcopters including a barometric pressure sensor to detect altitude, GPS for position lock, along with the return to home feature which is good when you lose control. The quadcopter also includes several modes for flying. A safe mode which allows the user to have complete control no matter how the quadcopter is orientated. This mode allows the copter to be altitude locked locked using the throttle stick. This will make filming the rocket of launches simply lock the quadcopter in altitude and launch. The copter can carry the Gopro and superb video can be obtained. This means that you don't need to worry about controlling the copter using the RC remote. Once the rockets is descending under a parachute you can regain control of the UAS and follow the rocket in close up when it is falling which will hopefully lead to some great footage! The copter has a flight time of around 15 min which is plenty of time for the UAS to record several flights. The altitude lock function is a handy feature that will make the filming easier. It is also a fun toy!
I got a bit of free time this month so I launched the Blue Diamond 2 at a solid 120 psi. Just to see if this makes a difference between the nominal 110-110. I was trying to correct some of the spin that was occurring. The rocket flew straight as an arrow and reached a personal record for a non-reinforced rocket at 121 metres! This was incredible as at 100 psi this rocket usally hits ~90 metres. Perhaps the new nose cone helped reduce drag or the slightly higher pressure has a significant effect on altitude?
On that same day a catastrophe occurred. I decided to pressure test a Fiberglassed Splice. The Splice hit 200 psi- the target! But then disaster! The Nozzle made from a Soap dispenser lid failed, and the resulting shock wave destroyed the bottle :( A large tear protruded the beautiful fibreglass skin. The test was done with water, but it was my fault as I should have known that the nozzle was never going to survive that pressure and hence, should have used the ABS nozzle I got with the Maplins kit. Lesson learned, fiberglassing is now on the back burner as a very exciting prospect will be announced in the next update!!
In the launch report you can see that there were only 2 sets of launches this month. After the success of the Blue Diamond 2 flights earlier on in the month, I decided to launch the Blue Diamond 3 at the same pressure these flights were eventful but only minorly damaging! During pressurization off the first flight, the rocket became separated from the Guide rail and fear of it launching over in a parabola, I tried to prop it back up. Nope! The rocket self-launched, though a bit more vertical than it was, the altitude was disappointing at 84 metres. The second flight pressurizing went well, until the rocket bent at take-off. The increased drag meant that the rocket reached a lower altitude and the parachute timer meant that the primary didn't go off in time. However I dived for the RC unit that controls the reserve and although the rocket crashed, it was at a lower speed as the reserve opened just in time so little damage was done- only the nosecone and the two fairings were buckled.
This month has been quite in the development of rocketry due to my school work, but I got some background work done!
The RRT2 development has been going well. Although I have started 6th Form, I have managed to update the firmware using y=mx+c function. Before I was having issues because the PICAXE cannot use float numbers. So to correct this I have used word variables. These can use values over 255 unlike the b0 variables. It just means that I cannot use b0 or b1 if I use the w0 variable. Because of this I have used variables such as w15 to stay out of the way of the smaller variables.
The further developments of rocketry are that I was thinking of selling individual RRT2 timers to raise money for my World Jamboree Scouting funds. I have made a spreadsheet in order to calculate the profits and costs of the electronic components (expenses). I have decided to create a batch with the components I will (hopefully) for Christmas and I will post how that all goes nearer the time!
This month has been a flurry of activity with mixed results! I started 6th Form College this month which has been a good experience so far. Water Rocketry still continues to progress, test flights of the RRT2 have been underway, along with test flights of the new Fiberglassed bottles. All this will be posted in a video soon(ish) depending on the amount of work I get.
I also put together the Jet Foaming Spacer I have been meaning to make for a while. With all the parts lying around it took less than an hour. Its construction is relatively simply. More can be seen in the Present Rocket Technology. Many other rocketeers have had great success with Jet Foaming, not only looking cool, but significantly increasing the altitude of the rocket as well. Although this didn't go to plan- a quick modification to the design now allows the Spacer to work accordingly. We also made the new Fin can to replace the fins that ripped off previously, see the present rocketry development for more details.
On the Launch day, we flew the Blue Diamond 2a Fibreglass 5 times. The 3 of the flights were successful. The first flight was with the 15mm nozzle and 1m launch tube, the rocket reached 101 metres at 130 psi which was reassuring as this rocket reaches around 80m at 100 psi so we had an improvement. On the Second flight we pressurised the rocket to 150 psi. The rocket took off at a noticeably higher speed, and at peak velocity the nose cone folded at 90 degrees. The drag increased and the rocket reached a erratic 79 metres. The parachutes still opened which was a relief. This problem was caused due to the fact that the rocket nose cone was only attached with 2 screws at 180 degrees to each other allowing the nosecone to pivot at maximum velocity. Plus the camera fairing was mounted on top of the fibreglass bottles meaning it could easily fold as it did. To fix this we are going to fly a bigger rocket that allows the camera to be mounted between the bottles and the release mechanism on top with the nose cone attach with 4 screws. This makes sure that there is as little PET plastic between the release mechanism and the rocket to prevent areas of weakness.
We decided to swap the release heads over to the 9mm nozzle for the remaining 3 flights as the force on the rocket would only get higher at high pressures so we figured that this would be a good idea to test the new Jet Foaming Spacer. Smaller nozzle size would equal a lower force on the rocket. The first two flights with the Spacer worked well giving a really awesome sound to the rocket and a sustained burn. These flights reached around 80 metres at 120 psi which was expected. We decided to keep the pressure down for the remained of the day because of the bend nose cone.
The fifth flight was a little deflating! The rocket was pressurized to 120 psi with the Spacer and foam. Immediately after take off things didn't seem right. A non-laminar flow made a on-off thrust pattern. The Spacer had be forced from the neck of the bottle and was blocking the nozzle. The rocket reached 30 metres, before hurtling back to the ground. The parachute opened just in time to save the release mechanism, but the bottom of the rocket spun round to destroy the bottom bottle.
The neck was still in the tornado Coupling and although disappointing, was the only fatality. Lesson: create a bigger lip for the spacer to sit on the top of the bottleneck to that it cannot be forced into the bottle. this took around 5 minutes using a hotplate and now it has been fixed. I am also contemplating whether to replace the secondary flight computer with a RC system, so that if (in quite a few of our cases) the rocket reaches a lower than expected altitude, the parachute can be deployed earlier than expected to save the rocket. Though this will need to include a controller on the ground, which is another thing to think about, but I am sure will be well worth it.
Two more fiberglass bottles are underway, and next weekend I intend to launch Blue Diamond 3a at 160psi with all these improvements with an intention in setting a new personal record in Altitude.
We tried launching the Blue Diamond 3a today at around 145psi to test the launcher and rocket systems. Despite the pressure, many other aspects of the rocket will be put under stress. Both the nose cone and the fins will be put under stress. This was seen on the earlier flights even at lower pressures. The Blue Diamond 3 had one of its fins rip of at 120 psi and caused a crash. Because of this, I decided to design and make a new set of fins that is unique. Me and my Dad designed a fin clamp, we started this in September. The 3 fins are fibreglassed to a piece of PET plastic. The fins are fibreglassed to the PET plastic and then two opposite pieces of PET plastic are fibreglassed together and a 3 screws are put through them. This is then tightened to the rocket and some rubber tabs are placed underneath to prevent slipping. These performed well under tests and they can be removed and moved between rockets. This arrangement also means that the fins are evenly spaced as I can actually measure the space in radians.
Anyway, we woke to a crisp, cold, yet sunny day that was quite windy. Nevertheless, we made our way up to the field for what would be a historic day for JSB Rocketry! We set up the rocket and checked all the new systems. The new fins and Flight Computer were quite crucial components that we didn't want going wrong! The rocket was pressurised to 140 before the compressor link between the rocket and launcher sprang a leak. Thinking of the small hole in the dam scenario we quickly launched the rocket!! It accelerated rapidly upto 142 metres!! A personal best so far, but disappointing since all the work with the fibreglassing only gained 30 metres :( The leak was due to some PTFE tape coming undone and I couldn't fix it at the launch site. We decided to try and launch the rocket again, but the launcher leaked at the same pressure and we launched again at around 145 psi. The rocket shot up, though at a slight angle due to the cross wind, but still up to 143 metres (434 feet). This doesn't break the 500 feet mark, but at that pressure we were satisfied with the results. A video will be published before Christmas.
There were a couple of casual flights as well this month. However on the bad side, one of these flights got stuck in another tree! Though it was quickly got out again with the notorious long pole method. Alas, we lost the small LiPo for the altimeter and looking at the plot it appears to have fallen out at Apogee. After hours of searching- no luck! Oh well. You can buy small LiPo's of Hobbyking for £1 so I will get some for Christmas! I have always fancied making my own LiPo packs any who.
mouth has been a mixture of success and failure in water rocketry, with lots of
other non rocketry related on goings happening as well. We went on this year’s
summer camp with Scouts to Gloucestershire as well as visiting Scotland for a
couple of weeks, remembering to take the RC Boat!
In terms of Water Rocketry more progress has been made with fibreglassing. Our first splice was partially melted by the hot bulbs that must have been blown against the bottle by the wind. Although disappointing, when pressure tested, it still went up to 160 psi and was still holding. This was a good sign, and the second splice was perfect as we had added two more flaps at the end of the bottle for the overlapping of the fiberglass cloth and increased the length of the flaps as well which meant less folding. This splice cured with a glossy look, this was because of excess epoxy being used and although this will not affect the strength of the splice, it will add a few unwanted grams that are not necessary. Thanks to Air Command for the tip. More splices with be made and the first fiberglass rocket will be 2 splices up to ~160psi- giving a volume of 6.6 litres and a predicted height of around 140 metres- that is of course, if the splices hold up to those pressures during the tests.
The RRT2 is nearly finished as well; final debugging is underway as although the timer works as wanted, there are a few bugs that need to be fixed. One of these bugs that was fixed is that the timer was drawing 70ma via the breakwire, compared to the expected 20. This was to be a firmware error despite the thorough hardware checks we did. It was simply a matter of setting the inputs and outputs of the PIC as opposites. Plus during the etching of the RRT2 because the board is double sided, it was very difficult to manufacture at home and because of that some tracks were lost. Some wire overlays are a temporary solution, but a conductive pen will be used in future. Another bug includes the timer jumping from the servo setting state to the Launch setting when the variable resistor is moved to fast, some neatening up of the code in the car on the way to Scotland made short work of this nasty!
A video on the fibreglassing and the RRT2 will be coming out some time these next few months. We have also done some casual flights of Blue diamond 1 that will be posted on YouTube as well as how the rocket is prepared for launch. As for the negatives: we tried to launch Blue Diamond 4 this month trying out the new emergency release system and RRT1 firmware update. The rocket alas flew a disappointing 97 metres considering the fact that this rocket should fly to 140 metres. The takeoff was very slow as too much water was used and the low pressure of 100 psi didn't help either. Because of this the parachute opened late causing the rocket to bend, buckling the new camera fairing. This flight was also the first with the new nosecone which looked cool!!
Because of the slow takeoff, we ditched a splice and decided to launch Blue Diamond 3, a well performing rocket with the new nosecone. At maximum velocity, one if the fins ripped off causing the rocket to spiral round into a relieving back glide until about 10 metres off the ground- then of course it decided to perform a perfect lawn dart destroying the nosecone, the release system, and all the fairings. Because of this, all further launches will be suspended until a fiberglass fin can has been made that will survive the acceleration of the newer high pressure rockets. This, I suppose, will give me time to make some of the YouTube videos I have been intending to make for some time.
On other flight computer notes, on the laptop on the way to Scotland, I did a firmware update for the RRT1. It enables you to change the time delay using the breakwire, rather than having to download a new program each time. If the time is powered on and the wires are touching then the timer goes into the launch state and waits for the wire to break after the timer is triggered. If the time is powered on and the wires are not touching then the timer goes into setting time delay mode. You then hold the wires together for your many seconds you want the delay to be before pulling them apart and that value is then written to the EEPROM ready to be used at launch.
This month has been very busy and I have
done quite a lot due to the end of my exams. We went for a launch of Blue Diamond
1 with a new nozzle that I have made out of an Gardena connector a lid from a soap
dispenser at the field. The advantage of making a new nozzle rather than using
the prefabricated 9mm nozzles we have been using at the moment is that the homemade nozzle gives a far more laminar flow for the water and thus increases
Also, after much thought we decided to run the RRT2 off 5v rather than 3.7v. This is because we need a steady constant voltage for the ADC to work, above 4.8v for the servo to work, and the voltage needs to be below a safety margin of the battery. For example, at the moment we used a ~4v lipo. If we used a 4 volt regulator then after a short amount of time the battery voltage would drop below this and therefore the input voltage would vary, therefore all the analogue values would change that have been pre-programmed in the PIC. Because of this we decided to run the timer off a 2 cell lipo to give a good safety margin. We purchased two cell LiPo batteries with a capacity of 150mAh. These can power the STII and the RRT2 nicely. The RRT1 can be run off 3.7 volts because it doesn’t need a fixed voltage as it has no analogue components. Plus the LiPo provides 4.2v when fully charged and this is enough to power the servo but it is risky.
Throughout this month I have been doing some launches of some smaller rockets in the playing field. The tests just try to see if certain tasks can be improved, such as deploying the drogue first rather than the main or vice versa along with testing release timings. I have also been using the new nozzle for a laminar flow. This works well and I also tried launching a few with foam. Most worked well, the only failures I have had are through power issues and no serious damage was done.
We have also been doing some more testing with splices and the recovery system. More info on that can be seen in the 'Present Rocket Technology' Page.
Below shows the Altimeter Flight Log recorded on the last flight of the day on the 17.07.14. The rocket reached 78 metres. Various other relevant photographs are also shown.
Again, in the middle of my exams so little development. However my grandma has made me a new parachute! This is 1.2 meters in diameter which is bigger than the 0.8 for the normal chutes. This is because this parachute is designed for the fibreglass rocket that we are presently in the design phase of. However when folded, it is a tight squeeze for the parachute to fit in the payload bay and hence I think I will make a new release system as this one is getting a bit tatty! We tried a new way of attaching the shroud lines. A hole was punched and then reinforced with tape very similar to USWaterRockets technique. A umbrella cut to size for this chute that a friend gave to me a school!
I am also thinking of submitting the Blue Diamond Fiberglass rocket in as my EPQ (Extended project Qualification). It is early days, but this a project that I will do at Sixth Form while doing my A-Levels which will allow me to use one of my hobbies (Rocketry!!) as a project to gain UCAS points to hopefully enter university. I will keep a detailed log of photos I will easily be able to analysis if it comes to it!
Also, we at JSB Rocketry have ordered the parts need for the RRT2!! We ordered them from Tech Supplies UK and they arrive in 2 days!! I would highly recommend them as they work close with the PICAXE company. PICAXE is a company that sells PIC's with a bootstrap code that allows easy coding in a flowchart or BASIC and I would highly recommend them for any water rocketry enthusiast as a basis for making a flight computer!
I have had little time for rockets as I have had my GCSE exams- however just before they started I decided to launch a smaller rocket with a 9mm nozzle in the playing field with the GoPro to see how things looked- no video this time as I didn't film every launch.
In the video and with the eye it was noticeable that this rocket accelerated much quicker and gained a better altitude than the older rockets we used to launch with a 9mm nozzle. that would probably be because the nozzle was on 7mm and pressures weren't that high. This time I manage to put the Altimeter on the rocket on one or two of the flights and we were reaching 70/80 meters which is around what the simulator predicted and visually you can see that they rocket went higher than the older ones.
We used the RRT1 on these flights with a 4 second delay, though 3.5 seconds would have been more appropriate as the chute did open a bit late. 4 flights were made in total, all being recovered safely!
In other news, I have been tinkering with the new RRT2 design and finalised the PCB layout. This difference from before as I have learnt of the large amount of electrical noise generated by the Servo. Because of this I have added in some hefty 220nF noise reduction capacitors to prevent the servo from 'jittering'. The voltage regulator also required 4 extra capacitors. Two of them decoupling and the others were electrolytics to help smooth the output voltage to a steady 3.3 voltage for the analogue input of the potential divider containing the potentiometer. I havn't finished the code yet- but that will come later!
Again, little development. Although I have now started to write the source code for the RRT2! This is an improved version of the RRT1. It will allow the user to change the time delay, Servo starting and ending positions and will have two trigger options. The new RRT uses a PICAXE 14M2 as the brain of the Flight Computer (FC). The PCB has also be designed using DesignSpark PCB. The PCB is double sided, yet still uses through-hole components. The 3d drawing done below was done in DesignSpark from the original design.
I am also making a new Camera Fairing for the #16 v3 keychain cam. This has a wide angle lens to capture the sights at apogee, and the Fairing I have at the moment is good, but limiting in the footage and I have decided to point the camera down the rocket. Thanks to Air Command for the photo's they sent me of their fairings. I also need to think about mounting the altimeter in this faring. Presently I am using the back of the camera mount to attach the Altimeter too, with velcro. This set up works surprisingly well, and is quick, simple and easy to manage. I will attach the Altimeter to the back of this new camera mount with Velcro as previously done.
Here shows a 3D view of the board. The board will have an optional G Switch launch detection or a break wire detect. The user will choose which they want via the program button. There is a large variable resistor which will be used to change the time delay and servo position. There are four LEDs which will show the user which setting they are changing, or whether the system is armed and ready for launch!
It is just early days, the PIC is a PICAXE microcontroller, the code is written in BASIC and converted to assembly code. There is a programming socket to download the program directly to the board.
There has been little rocket development over this time due to my GCSE's coming up. Although we did go for a Launch. This time we launched the Blue Diamond 3 at a conservative 100 psi, with the due parachute deployment, with a primary set delay of 6 seconds and the secondary with a delay of 8 seconds. All three flights went well even though the first two bent the rocket as the chute opened. This was caused by the delay being to long and thus the chute opening to late. No matter though. It was all good fun. I also got a GoPro Hero 3+ Black for my Birthday so we made good use of the 240 fps function on the launch day and got some great footage.
I have started to make a new parachute that has a larger diameter of 1.2 metres. This will make sure the rocket comes down even slower at a modest 3m/s to prevent any damage.
We have replace the RC deployment in the reserve deploy module and replace it with a Servo Timer 2, that Aircommand kindly provided the .brd and .hex files for which we are very grateful for. Once we sent them off to EuroCircuit for manufacture and they work great. We have 2 and we use the G-Switch for the input trigger. We tested this on the Blue Diamond 3 rocket with 3 launches, a Youtube video can be seen below:
All flights worked well with the Main deploying first on all flights followed by a new 500mm diameter for the reserve so that it doesn't protrude the airflow when the rocket is accelerating, as the 800mm parachute didn't seem to fit in the payload bay that well. However on the first flight the rocket bent due to the higher speed deployment. The parachute cord also slipped down the rocket on the second deployment meaning that the rocket came down nose first, but no obvious damage was evident. The third flight, was the highest at 118m and no problems after deployment. All flights were above the 100m mark and all were personal bests one after the other!! It is great to break past the 100 mark, this is a bigger rocket than BD2 as BD3 has a extra splice, but the flights were all done at 110PSI as we didn't want to push the bottles as these were relatively new. We also used the RRT1 with the breakwire at a delay of 6 seconds. The HD camera was used to capture the footage from a different perspective, it was mounted vertically so we could get better panoramas. The HK altimeter was simply mounted using velcro, on the back of the mounting.
After one bottle exploded on the pad in january, we also decided to make 2 new splices using the Asymmetric Splicing technique, as seen on Air Commands Website. The both held up to 130 psi which was good as well. One of these was used in the flights below:
We have finished the RRT1 and have done some new test flights using the Blue Diamond 1. First flights didn't go very well because a unenforced bottle blew on the pad, which caused the rocket to launch early and the parachute was deployed after impact, meaning that the deployment system was totally. So we fixed it for the next day but used a bigger rocket BD2 thinking that all troubles were behind use. And who would know it- a perfect launch, but the chute caught on a fin and the rocket crashed from 80m. All the bottles were fine but the fairings were destroyed along with the deployment system. The battery, servo and RRT1 survived! Enough was enough. We decided to add in the reserve chute we built a while ago using the old RC deployment for this and a longer shock cord. We also removed one of the fins, to leave 3 and these were made more slanted so that if the chute got stuck then it would slide off.
These flights also used the new compressor which does not disappoint!! It lived up to the flow rates we calculated and the results can be seen in the Present Rocket Technology page. The new manifold connects up to the copper pipe with the same thread as the old schrader valve connection which is convenient . the manifold used a quick connector to attach the air hose and has a build in non return valve along with the pressure release value, which is used to abort a launch.
A week later launch was ready and we went up to the field on a perfect day with no clouds and little wind. We managed to fly the Blue Diamond 2 four times and all were successes. The chute (typically) opened every time without the need for the backup but it is more fun flying with the backup as even though it adds 150 grams to the rocket and decreases altitude by a few meters, there is less tension as it takes off! Deciding that the RRT1 worked fine, we wanted to make out rocket completely self recovering, more on that in the later updates:
Here is a Youtube Video, of the flights:
We have have been developing a new flight computer, called the RRT. More details of the timers can be seen in the flight computer section.
Plus we have been buying the materials needed for our new Fibreglassing project that we have started designing. The fibreglassing will be using a double wrap of 200 gsm fibreglass and West Systems Epoxy. More info on the process will be uploaded to the 'Present to the Future' page. We have also been designing the rotisserie and pressure testing stand. All the various fins and fairings can be reused with the new fibreglass rocket. We have got some new Tornado Tubes which are more expensive- but stronger and have been tested to 270 PSI and not failed- more in the 'Present to the Future' page.
The Spliced pairs that are going to be fiberglassed have also been shrunk, sanded and sealed, ready for reinforcement. We used Air Commands regular asymmetrical splicing technique for this as it is worth the weight penalty for the safety of the larger overlap. We will also put a few filaments in the groves of the bottles to help with more reinforcement- these bottles will eventually have a burst pressure of ~300 PSI.
We have also been researching new parts and air hoses for a more powerful compressor, to pressurize the larger rockets. We have done some calculations for the rockets in our fleet and concluded that it will take around 2 min for our regular Blue Diamond 2 rocket at 130 PSI with a volume of 8.3 litres, for the fibreglass rocket we will be expecting around 7 min to pressures the 13.3 litre rocket to 200 PSI- not bad considering our standard compressor will take 9 min to get to 90 PSI with 8.3 litres!! We also have incorporated a non return valve into the design, so we can reliable launch rockets without a launch tube and a pressure release value into the manifold at the bottom of the launcher so we can abort the launch if necessary. I will receive this on Christmas day!!
No launches this month, due to bad compressor connection- we will get some launches under way after Christmas, incorporating all of the above.
Please feel free to leave any comments, suggestions or constructive criticism in the comments section below:
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