Quick update

We've been progressing this week with the Polaron IV upgrade. The booster parachute deployment mechanisms are now finished on all three boosters.

I made an extra reinforced bottle for the main stage, but after gluing and heat shrinking I noticed that the coupling was sitting at a bit of an angle. This would have resulted in bent rocket, so I tried to straighten it, but instead of improving it, I managed to break the coupling. :( So I threw that bottle away and had to make up another one. The whole process takes about an hour to reinforce the bottle. We are waiting for the glue to cure before we do a full pressure test.

We've reserved Friday for a full pressure test of the new main stage and new boosters as well. If the weather is favourable we'd like to fly it on Saturday.

We also did some experiments this week in creating foam in a bucket by blowing air through a sintered metal filter into the bubble bath solution. The tiny holes help make foam more readily. We want to try generating foam on the pad to see how it compares with it generated in the air. The main observation was that if the air flowed too fast then the bubbles would re-combine into larger ones, but a slower rate created more smaller bubbles.

There have been some really good discussions on the Yahoo Water Rocket forum this week regarding internal temperatures. It may help to explain why we have had some unexpected failures of the bigger boosters under test. I'll cover this in more detail in the next web update.
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Progress Updates

We have updated our main site with a few more details of what we've been up to in the workshop. The update also includes some great pictures from the last launch day taken by Andrew from NSWRA.

The update is here: http://www.AirCommandRockets.com/day58.htm



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Tornado Couplings

This weekend we finally managed to produce a number of good Tornado couplings. Tornado couplings connect bottles neck to neck. These one's are easy to make out of gardening supplies from the local hardware store.


Some features:

• They have a 15mm hole
• Weigh 13 grams
• Require no glue
• Have been tested to 130psi, but can most likely hold more.
• Require no special tools
• All plastic construction - no metal.

We have been wanting to make these cost effectively for a while now since we plan on using lots of them to join the spliced pairs of bottles. We will give full construction details in future updates on the main site. We want to put them to use first on the Polaron IV boosters to extend their capacity by another bottle each.

We are also currently working on another staging mechanism design that will be hopefully a lot lighter than the one we have been using on our two stage rocket. Since we are still in the early stages of development, we will describe the design later, once it is more finalised. We have lots of testing and prototyping to do still.
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2 Stage flights

We had a great weekend launching our rockets at the NSWRA launch event. We flew our newly rebuilt 2 stage Acceleron IV rocket up to 525' (160m). We also flew the Polaron IV rocket with drop away boosters to 510'.

The full update with photos and highlights video is available here:

http://www.AirCommandRockets.com/day57.htm

Here is an panorama from around 500' as the rocket pitched over at apogee.
(click on the image to enlarge)

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Acceleron IV progress

We spent this weekend working on the Acceleron IV booster getting it back into a working state for next week. We did a pressure test to make sure that everything is still fine, but we found out that the rocket was not holding pressure at all. We pretty quickly discovered that three of the Robinson couplings were missing their seals. Ooops. When we put those back in and everything checked out okay. We must have missed them during preliminary assembly.

We only pressure tested the rocket to ~100psi since the neighbours were out in their back yard, and having had this rocket fail a pressure test in the past, we didn't want to push it. We did have the video camera recording though just in case. The rocket will most likely get launched at 120psi on the day. The rocket theoretically should hold up to around 140psi operational pressure, with a burst pressure of around 180psi.

We hooked up all the electronics and and made sure the staging still worked when the pressure in the rocket dropped. We replaced the sustainer in the test with a small bottle full of water which fired as expected.

We replaced the rubber bands in the staging mechanism as keeping them stretched all this time in storage caused them to deteriorate quite badly. The same went for the wide rubber bands that held the fins on.

The booster segments are now attached with velcro straps which makes it a lot easier to service the segments.

The launcher has also had an upgrade with new longer fill tubes that allow us to use the spliced pairs of bottles on the bottom of each segment.

Some work has also been done on the sustainer. The altimeter has been moved into the space between the bottles which should help protect it. The altimeter is attached to the inter-bottle ring and having its own power supply allows us to swap it between rockets. We still have to re-attach the fins to the sustainer and also mount the new FlyCamOne2 camera to the payload section.

If we get time this week we also want to finish building a reinforced rocket that should be capable of around 180-200psi. It is only a two 1.25L Robinson coupled rocket but we are including the baffle we made a few months back to prevent the blow through effect with this rocket. The higher pressure would only make it worse.

We also made a couple of rocket carriers that help us transport and protect the rockets. They also help prevent the rockets from sagging in warm conditions.
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Flight Computer V1.5

Last night I finished soldering up the new board for the latest flight computer. Everything worked as expected which is good, and we will fly it soon.


The large bright LED display allows you to stand back from the rocket while it is pressurised and ensure the correct settings are set. It also has a small buzzer that allows you to hear whether it is armed or not while standing back.

A little more software needs to be written for the flight computer to support the new functionality. The intention is that the code base will be universal enough to be used for regular water rockets, but also for multi-stage, or dual-parachute.
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Launcher Details in 3D

We spent this weekend documenting our Polaron IV launcher and rocket. We've produced an explanation video of how the launcher works as it is much easier to explain the configuration.

The details are available here:

http://www.AirCommandRockets.com/day56.htm

The update also includes a number of anaglyphs of various parts that you can view in 3D using regular red-blue 3D glasses.

Click on the image to enlarge.
You will need red-blue 3D glasses to see this image properly

Also a quick update on flight computer V1.5 - We received our first PCB this week so we are keen to solder it up and see how it performs. If no changes are required we will get another 9 PCBs made so that we will have total of 10 flight computers ready to go for the up coming experiments.

The new flight software is also progressing and should be finished within the next couple of weeks. Once the flight computer has had a successful couple of test flights, we will publish the full design again, including the PCB layout.

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Parachutes

After a short break last week to catch up on non-rocket related projects we are back in full swing again.

We ordered some great lightweight ripstop nylon parachute material from the UK this week. It was comparatively cheap at only AUD$32 delivered for 10m x 1m of the stuff. It is a nice orange that should make it easily visible. From the time of order to delivery it only took about 6 days to get here which is pretty fast considering it had to go half way round the world.

We want to make a new lighter parachute to replace the one on the Polaron rocket. The parachute will weigh less than half the weight of the existing one, and also use up about half the space. For the shroud lines we are going to use TigerTail - a very strong light-weight line typically used for making necklaces. It is stranded stainless steel cable coated with nylon. It is very light, doesn't kink, is only 0.3mm thick and has very high tensile strength. This will allow us to make a strong parachute and should pack into a much smaller space.

If this parachute goes well, we will most likely make up more parachutes for the other rockets, including Acceleron.

We have also been doing some more work on flight computer V1.5 and hopefully the prototype should be ready soon. We are getting a number of PCB boards made up so it will take up minimal space and weight. Once finished it will be used on all of our rockets as it is capable of driving two separate servos and has a few more nice features compared to the previous version.

I turned off comments here on blogger (temporarily) due to excessive amount of SPAM last week, so if you would like to ask questions, just visit the main site and go to the contact page.
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Polaron IV Boosted flights

We had a great weekend of flying the Polaron IV rocket with the drop away boosters. The boosters behaved exactly as expected and gave the rocket a nice kick on launch.


The on-board video also turned out great.

The full details of the launch day with lots of pictures and video of the highlights is available here:

http://www.AirCommandRockets.com/day55.htm




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Successful Booster Test Flights

In preparation for launching Polaron IV we wanted to make sure that the whole launcher will work with the boosters and the main stage all together. We weren't sure if it would come off the launcher cleanly, or if the boosters would fall off, or how the new guide rail would go.


We built a dummy main stage out of old bottles and an old nose cone that used the nosecone-off-at-apogee technique for deploying a parachute. The main stage only had the bottom 2 L bottle pressurised. And had 1.5L of water in it so virtually no air. We added a little ballast into the nose in the form of a zip-lock bag with water in it.

We had two successful vertical take-offs with the boosters all falling off almost simultaneously on both occasions. The boosters were filled with 1L of water and everything was launched at 100psi.

The dummy main stage weighing in at close to 800 grams was still able to reach ~80-90 meters
The parachute opened on the first flight right at apogee, and failed to open on the second flight.
The dummy main stage was destroyed, but luckily all the bits we needed for the Polaron IV rocket survived. The boosters also survived their tumble recoveries.


We proved to ourselves that this particular launcher and booster concept works, and so we are hoping to get at least one flight out of the Polaron IV rocket on Saturday. There are always things that can go wrong on the day, but we will worry about those when they happen.

We have also finished repairing the Hyperon and J4 rockets, so we will have those as backups on Saturday as well.

Full details of the days events with videos of this booster test will be again published on our main site after the launch day.
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Launcher Completed

We spent most of the day in the workshop again today. We are really pushing hard to get Polaron IV and its launcher ready for the next NSWRA launch day. It is only 6 days away.

We did finish the launcher today, which I am really happy about. It now sports a single 2m launch rail. The rocket will use launch lugs to hold onto the rail. We had to switch to this system since there really isn't room for the 3 guide rails we have been using. We ended up using 2 of the feet and guide rails from our medium launcher to support the new launch rail which really reduced the amount of stuff we had to make. The legs are still usable on the other launcher so the nice part is we have less hardware to carry with us when we take both launchers.

We are now finishing off the rocket and the booster retaining mechanisms on the rocket, and then it should be ready to fly. If there is a nice launch opportunity between now and Saturday we may try the boosters with the dummy main stage at our local park.
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Splicing Bottles and Pressure Tests

The weather hasn't been too co-operative this weekend so we spent quite a bit of time in the workshop. We have updated our main site with the latest developments here:

http://www.AirCommandRockets.com/day54.htm



The update includes a video tutorial into how we splice our bottles. It also includes an update on the progress of our Polaron IV rocket, and the Acceleron IIIb booster.
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Glueing and PCB layout

Splicing and Couplings

This week it's been a bit of a mixed bag. Now that we have the PL Premium glue, we are gluing together pairs of 1.25L bottles. These glued sections have a thread at either end allowing us to join them to other sections. We have 6 made up, and two more will get made today. They will be used in constructing boosters and rockets bodies as well.

To join these together we have also been experimenting with making simple "Tornado" couplings. We are still waiting for the glue to dry before we do a full pressure test. We've made up four of these so far and if they work well, we have the materials to make a lot more. They weigh around 7 grams. The other nice thing about these couplings is that they have a 19mm hole which is about 6 times bigger in cross sectional area than the Robinson couplings we have been making. This leads to better internal efficiencies and also means we can put a long 19mm launch tube through them.

The simulator predicts well improved altitudes for rockets made out of the spliced pairs and the tornado couplings.

Repairs

We have also been doing repairs to the two crashed rockets from last week. This will require a little more work since the nosecones and deployment systems need to be rebuilt.

PCB Layout for Flight Computer V1.5
As a part of making life easier when doing repairs we have been finalising the PCB layouts for the next iteration of the flight computer. We are going to do a small run of these PCBs and make up a number of the computers so that we can quickly replace them should they become damaged. The board will be about 43mm x 55mm in size or about 30% smaller than what we have been making on the prototype board. It will have dual servo motor outputs making it suitable for single and dual stage rockets. It also has a buzzer for audio feedback of mode changes as well as helping to locate it in tall grass.

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Launcher Pressure Test

In the last few days we've pressure tested the Polaron IV launcher to make sure there are no leaks. There are a lot of connections and we were not sure how well the seals would seal around the plastic compression seals around some of the copper manifold pipes.

All was good and we took the pressure up to 215 psi ( ~15 bar ) for both the main stage line and the booster manifold.

When pressurising, we really have to think about what valves get open or closed and in what order.

For the first launch the pressures will be in the order 110 - 130psi.

We made dummy plugs for the booster nozzle seats for the test. This allowed us to test that side of things without having to put the boosters on the launcher. We fitted a strapping tape reinforced small 300ml coke bottle to the main stage release head and used the 7mm aluminium nozzle that the main stage will use. All held up well, and we tested the bleed valves
for both the main stage and the boosters with success.

We are now working on the booster retention mechanisms and getting those attached to the boosters and main stage.

The update from last Saturday's launch event is also now available on the main site:

http://www.AirCommandRockets.com/day53.htm

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NSWRA and Polaron IV Main Stage

Yesterday was a fantastic day for rockets. We are now members of the newly re-grouped NSW Rocketry Association (NSWRA) and went to one of their launch events at Doonside. There were many rockets flown on the day and we got a chance to fly three of ours.


We ended up finishing the Polaron IV main stage rocket at about midnight the night before and so we got a chance to test it. We flew it twice with the full payload (new camera, altimeter and flight computer). Both flights were very good and the new parachute also worked well.

The Polaron IV rocket is now pretty much ready to be fitted with the boosters and ready to go. We will probably run some tests first on the boosters being launched from the new launcher with a dummy main stage.


Full details of the flight day will be published shortly with pictures and videos.

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Black Tape and Sun

As I was inspecting a couple of our rockets last night and getting them ready for tomorrow's launch day, I noticed that the bottles were warped in a couple of places. It appears that the warping was most severe where the wide black tape was. This also occurred on the unpressurised sections of the rocket.

This was likely to have been caused during the last launch day when we left the rockets sitting out in the sun for a couple of hours. The heat absorbed by the tape was enough to shrink the bottles a little under the tape.

This is likely to occur to other rockets that are painted in dark colours. I think we will be storing our rockets in the shade from now on, and perhaps switch to lighter coloured tape when the black stuff runs out.

I spent most of the last couple of nights trying to get the Polaron IV main stage ready for flight on Saturday. The payload section now has the new FlyCamOne camera built in, the Z-log altimeter, servo motor, batteries and a newly built version of our flight computer (V1.3.2). I just have to attach the door and latch mechanism to the payload bay and then attach the whole thing to the rocket body.

We want to test fly it by itself to make sure all the systems and recovery works before we attach the boosters to it.

If we do get to fly it this weekend, I will post pictures soon after that.
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Booster Tests and Launcher Details

We've updated the main site with the latest details of the Polaron IV launcher and the new Gluon boosters.
The name Gluon was chosen because it continues with the sub-atomic particle naming convention we have been using for our rockets and also because it is our first operational spliced rocket using PL Premium glue.

The update can be found here:

http://AirCommandRockets.com/day52.htm

The update also includes a video of the booster tests. It's not overly exciting but included for those who are interested.

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Launcher and Booster Tests

We've had a very productive weekend this week. We completed the majority of the new Polaron IV launcher, spending about 8 hours in the workshop on Saturday.

The image below shows the state of the launcher currently. I will do a full update this week and post it on our main website that shows all the details and discuss some of the design issues.

On Sunday it was too windy to launch regular rockets and so we opted to do a number of booster test launches. We fitted a booster with a regular nozzle and launched it from our medium launcher. The main aim of the test was to see how the booster behaved in flight and how its recovery system would work. Full details of the booster will also be posted with the next web update.

The larger parachute is now finished for the Polaron IV rocket and the payload section is also well under way. With the altimeter, flight computer, and video camera, the payload section alone is worth around $300. Hmmm... I think I will add a padded nosecone extension for protection in the trial flights. This padded nosecone will be removed for the higher performance flights once the design is proven.
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Holidays over

Having been OS for the last 3 weeks the holidays are over, and we are back in full time production of the Polaron IV launcher and rocket. We are concentrating our efforts on this in order to get it done as soon as possible. During the holidays dad machined up a lot of the necessary components for the launcher, and now we are pretty much ready to start assembling it all together. Dad also did a bit of work around the workshop putting up some new shelves and fixing a few things making it easier to do development.

The Polaron IV rocket will also be fitted with one of the new FlyCamOne cameras as well as the altimeter. I am weighing up whether to build the next version of the flight computer for this rocket or just use one of the existing ones. I may use V1.3.1 in the first few trials and then upgrade when the next version is finished.

This weekend looks like weather is not going to play ball so workshop time is in order. Hopefully we can get most of the launcher done.

This launcher is intended to take us up to the next level in rocket pressure and size. We eventually intend to be launching reinforced rockets from this launcher and hence it is being designed to handle 35bar (500psi) operational pressure. It will support both single nozzle rockets as well as rockets with 3 boosters. The booster nozzles can slide in and out allowing us to used different sized boosters and main stage.

I'll take some pictures over the weekend of the launcher and post them here or on the main site.

PL Premium Glue

We still have a number of tubes of 10oz (300ml) PL Premium glue available so if anyone in Australia is interested please let us know. Just email me: katz.george at gmail.com.
The tubes are AUD$8 each + shipping from Sydney. Standard postage rates apply. You can check the Australian Post office website for shipping charges.


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Katz Stager and new cameras

Katz Stager

While developing our regular rockets we have been working on a new staging mechanism in the background - the Katz stager. We normally don't release details of concepts until we test fly them, but since it's been a while that we've done an update I thought I'd include it. We have built a prototype and test fired it a number of times by hand, but it is still to fly and at full pressure.


The full details of the stager and photos of the prototype can be found here:

http://www.AirCommandRockets.com/day51.htm

New video cameras

We have also bought a pair of FlyCamOne V2 video cameras this week. So far we are very happy with the functionality and performance of these cameras, and are looking forward to mounting them inside rockets and flying them. They can record video at 640 x 480 resolution @ 25fps with sound, which is not bad for a 37 gram package. Recording onto an SD card allows you to get up to 30 minutes of video. Compare that to our existing cameras that record 320 x 240 @ 15fps and can only capture 30 seconds of video.

The other nice feature is the optional external power supply, the swiveling lens+sensor for minimal drag in the air stream and external shutter contacts to allow a flight computer to trigger recording or take 1280 x 1024 pictures.
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