last updated: 16th March 2017 - Day 178 & day 181 Acoustic Apogee Detector

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#181 - Acoustic Apogee 2

#180 - Light Shadow

#179 - Stratologger

#178 - Acoustic Apogee 1

#177 - Reefing Chutes

#176 - 10 Years

#175 - NSWRA Events

#174 - Mullaley Launch

#173 - Oobleck Rocket

#172 - Coming Soon

#171 - Measuring Altitude

#170 - How Much Water?

#169 - Windy

#168 - Casual Flights 2

#167 - Casual Flights

#166 - Dark Shadow II

#165 - Liquid Density 2

#164 - Liquid Density 1

#163 - Channel 7 News

#162 - Axion and Polaron

#161 - Fog and Boom

#160 - Chasing Rockets

#159 - Measurement

#158 - Dark Shadow

#157 - Polaron G2

#156 - Foam Flights

#155 - Down The Barrel

#154 - Revisits

#153 - ClearCam

#152 - Mullaley, Axion G2

#151 - Competition Day

#150 - Rocket Salvos

#149 - Glide Fins

#148 - Too Windy

#147 - Descent Rates

#146 - G2 Launcher

#145 - Harness

#144 - Water vs Foam

#143 - Whalan Reserve

#142 - Doonside

#141 - Windy

#1 to #140 (Updates)


Dark Shadow - Build Log

Continued from Part 1...

The log is in chronological order so to see the most recent post you need to Jump To The Bottom. You may need to refresh this page to see any latest updates.

CAUTION: If you are going to attempt to build rockets such as these, please exercise extreme care when testing and flying them. This rocket uses very high pressures that can potentially cause severe injury to yourself and those around you. Always double check your equipment and review safety procedures before every test and flight. See more information on Safety Guidelines.

Build Log

1 January 2015 - Machined up launch tube inserts to plug holes in the launch tube. this is because it was the only 15mm launch tube we could find. We glued these in place. Machined up wooden end plug for machining down PVC pipe to make coupler mandrel. Made coupler mandrel. Mandrel OD is 59.15mm

Made a 5 wrap coupler out of 200gsm glass (glass was 100cm long) this will be used for nosecones.

Made 4 wrap 84gsm coupler. One layer of baking paper. (1 pump and brush) This coupler will be used to join the long tubes.

Laminated one side of balsa sandwich 200gsm lower layer bias cut, with 1 layer of 84gsm normal cut. Used left over glue from 4 wrap coupler.

Made 6x 8.2mm wide PVC rings to be used in deployment mechanisms to tap holes into.

Machining end plugs for mandrel

Launch tube hole covers

Making coupler and
balsa sandwich

Machining mandrel

That's one way to grow hair

PVC rings

Rolling new nosecone coupler

Mandrel and wooden end plugs

End plugs in mandrel


Cured coupler on mandrel

2 January 2015 - Made a 5 wrap coupler out of 84gsm cloth. 160 x 980mm - Used 1 pump for this and with the left over epoxy we made the second half of the balsa sandwich. We trimmed and sanded the coupler made yesterday.

3 January 2015 - Trimmed long tubes and 5 wrap coupler. Coupler fits well into long tubes. Made a second coupler with 5 wraps and also made the electronics mounting tube. We spent a considerable amount of time thinking how to attach everything inside the payload section against the G loads. We are going to try going with a central fiberglass tube to attach everything to rather than bulkheads made with the balsa sandwiches. We found a paper roll that was the right diameter and so we made a 5 wrap 200gsm cloth wrap.

Rolling coupler and electronics tube

Curing on the rotiserrie

Payload and nosecone bulkheads



Tube test assembly


4 January 2015 - We trimmed the second coupler and also the electronics tube. We mounted the servo motor inside this and looks solid enough to hold against the g forces. We are going to try to mount the electronics a little differently this time. We are going to use velcro on the inner tube and on the back of all the devices to hold them in place. This also allows us to remove them and use them on other projects or replace failed ones easily. The devices will also sit against the bottom bulkhead to withstand the +ve g forces. Having all the electronics mounted around the tube facing outward, gives us easy access to all the buttons and displays.

We will most likely use a screw switch as we did on the Shadow to make sure the power can't get interrupted during high acceleration.

We also glued the PVC ring to one of the bulkheads and made the thrust ring for the nosecone coupler. The nosecone coupler was cut to the right size as well.

Electronics tube with servo motor

Nosecone coupler and
top payload bulkhead

5 January 2015 - Worked mostly on the launcher release head to fit the lever arm. Lots of filing to do, this would have been so much easier if we had a milling machine. With the pivot in this location, the lever arm has about a 40:1 ratio. This means there is going to be around 2kg pushing down at the end.

Launcher fitted with lever arm

6 January 2015 - Bought more of the 84gsm plain weave cloth. This looks like the original version we had so I am keen to see if it will behave better when we make up the tail-cone and top bulkhead. We also continued work on the launcher. The servo motor has been attached to the end frame and the small lever was also made. The mechanism feels nice and solid but we'll need to do a full pressure test to see if it holds.

End frame with servo motor attached

Other side

Lever arm in the released position

7 January 2015 - Made the tailcone and forward closure today. We used the new cloth for these and it worked much better. The glass did not lift off at all. Again we used 10 gores and a single wrap around the base. We also worked on the launcher adding the spring, attaching the pins and small lever. I also had difficulties driving the servo motor via the cluster launcher. The new servo didn't want to move properly. When I tried with a different servo timer and a 9V battery then it worked fine. It may simply be a battery issue and may need re-charging.

Prepping tail cone plug

Tailcone curing

Forward closure curing
30' roll of CF sleeve

Spring fitted to smaller lever

Reverse view

8 January 2015 - We pulled the tailcone and forward closure off the plugs and sanded them. We then tried shrinking the forward bottle over the forward closure on the lathe with the heat gun, but when it came to pulling it off there were two cracks that developed in the forward closure. There must have been a gap between the fiberglass and the plug and the fiberglass simply got crushed. We will make a new one rather than repair it.

We also made the nozzle insert and after several goes we finally made one that looks good. We had to increase the internal diameter of the PVC to 18.1mm from around 17.8mm so that the thread could be cut and the nozzle wasn't too tight.

We then shrunk the tail cone bottle over the insert and tailcone on the lathe. We had to do this twice as the first bottle neck was slightly too narrow for the nozzle to fit in.

We glued the insert into the tailcone bottle with 24Hr epoxy and removed the flange with a sanding wheel in a Dremmel tool.

We also received the parachutes from Aerocon. While the parachutes themselves look good the shroud lines made from thin flat braided nylon and look like they have been through a blender. They have a few cuts, are frayed in a number of places and are held at the end with a small metal clip. We are going to need to replace some of the shroud lines if not all. We'll see.

Nozzle insert in bottle

top view


Cracks in forward closure

36" Aerocon Chute

Shroud line condition

Deployment bags from 1973!

9 January 2015 - We made up second pair of forward closure and with the spare glue made the tail cone. This time we used 11 gores for each to make them a little stronger as the last forward closure had a weak spot along which it cracked when heat shrinking the bottle over the top.

Making new tailcone and forward closure

10 January 2015 - Glued the coupler into one of the long tubes. We also glued the bottles to the tail cone and forward closure. Using the left over glue, we glued in the nosecone bulkheads.

Coupler glued into tube

Weights holding down bottles

Bulkheads glued in for nosecone couplers.

11 January 2015 - Glued the forward closure and tailcone to their respective tubes. This makes it easier to work on both ends and we'll glue the whole thing together once the ends are finished.

Launch tube used for alignment.
Bottom of launch tube is in a centering ring

Forward closure glued into place.

12 January 2015 - Bought 38mm hinges at Bunnings, as well as 33 x 300 Al round bar from Edcon steel to make up a spare nozzle. The hinges were cut down to size with the Dremmel and cut off wheel. We also bought polyester ribbon to replace the nylon shroud lines. We weren't able to easily source the nylon cord, but the polyester looks like it may work.

13 January 2015 - Applied filler made up of epoxy and microballoons to the rough interfaces between the glued sections on the tailcone and forward closure. My wife picked out the threads from the shroud lines so they can be re-sewn. She managed to do it at least 3 times faster than what I would have been able to do.

Glued and sanded

Filled with microballoons/epoxy

same for the forward closure

14 January 2015 - Sanded the tailcone and forward closure interfaces smooth. Worked on the grapple arms for the deployment mechanism. These are now attached along with the hinges.

New grapple arms closed

Grapple arms open

Another view

Filled and Sanded

15 January 2015 - We glued the two pressure chambers together today. We used 3 aluminium L brackets held on with rubber bands to keep the joint aligned. We also made up another forward closure using 10 somewhat wider gores and a single wrap at the bottom. We also made up a new full length tube using 4 wraps of the new 85gsm cloth. The previous 11 gore forward closure was too tight a fit in the tube and required a lot of sanding. We also glued another PVC ring to the balsa sandwich bulkhead and glued the centering ring to the electronics tube.

Two halves sanded and
ready for gluing

Gluing the two halves together
using Al brackets for alignment

New forward closure

New full length tube

16 January 2015 - This morning we discovered that the tail cone section was glued in slightly crooked. Although we had the launch tube going through a centering ring at one end of the tube and the other end going through the nozzle, the whole section had tilted slightly. Weighing up the options we decided to cut off the tail section and glue in a new one. At the kinds of speeds and forces we are dealing with here we could be in a lot of trouble if we are out a degree. We'll lose a few cm of length, but we'll also lose a bit of weight. We'll make up an alignment jig with the angled brackets to align the nozzle and tail section better.

We pulled yesterday's tube off the mandrel. A pair of new nozzle inserts and tail cone bottles were also made up.  These were then glued together with the 24Hr epoxy.

Gluing inserts into bottles

Here you can see the misaligned tail cone

17 January 2015 - We rolled another full length 4 wrap tube. We also made up the replacement tail cone. We glued the nozzle insert onto the previously made tailcone. Dad also machined up a new second nozzle. We also had the two scuba tanks refilled today. We will use them for testing over the next few weeks and get them re-filled again for the trip.

Machining nozzle

More nozzle work

Gluing bottle to tailcone

making up a replacement tailcone

18 January 2015 - Made the nozzle alignment jig today. This is basically a cylinder of the rocket diameter with a short length of launch tube right down the middle. This gets inserted into the nozzle and the aluminium brackets hold the cylinder aligned with the rest of the rocket. We cut the misaligned tailcone off the rocket and used the new jig to align the new tailcone.

We also trimmed the full length tubes and glued the coupler into one of them. The top closure also had the bottle glued to it as did the second tailcone. The second nosecone had it's little ball glued into the nose. Lastly we cut off a second length of the electronics tube and glued a centering ring to it.

Nozzle alignment jig in place while gluing
in the tailcone.

Gluing the bottle to the forward closure

 19 January 2015 - When we were about to glue the #2 tailcone into the long tube we discovered that the nozzle and bottle weren't quite aligned at the top of the fiberglass tailcone. The bottle must had been shrunk at a bit of an angle. While there is some give in the tailcone to tube join it wasn't enough to correct the deviation with the nozzle alignment jig. So we opted to build a whole new tail cone ... again! This was going to push the schedule back a little but there is still time. I was able to peel off the bottle and nozzle insert from the original tailcone that was cut off so that will save a few hours work and at least a day in waiting for glue to dry.

We glued the forward closure to the long tube. With the spare glue we glued a few more small components on the deployment mechanism. We also cut out 11 gores for the new tailcone and made up the tail cone on the plug.

 20 January 2015 - After sanding, we glued the nozzle insert and bottle onto the tailcone. We also continued with making of the deployment mechanism. The holes for the nosecone as well as the payload bay were tapped. We did the first tests with the deployment mechanism and one set of rubber bands. We may need to add a second rubber band or replace existing ones with stronger ones.


 21 January 2015 - We glued the tailcone into the long tube. We also tested the deployment mechanism with stronger rubber bands. They seem to be working well and I think we'll probably go with those.

Nozzle alignment jig

22 January 2015 - We continued work on the second deployment mechanism grapple arms. We also fitted a servo motor into the second electronics tube.

23 January 2015 - Today we glued the #2 two long tubes together and again let it rest vertically. We also made up the grapple base and cut the hinges to size and attached everything to the nosecone bulk head.

24 January 2015 - We bought some Epiglue today to see if it is good at making fillets as they say. We want to use it for the fin fillets or as general filler.

We also did a leak test of the #1 and #2 pressure chambers to around 20psi to make sure there are no tiny holes like we saw with the test pressure chamber. Both chambers came up well and passed the leak test.

We also made up the control box for the launcher and mounted it under the servo motor. We are using 6 x AA batteries rather than a 9V battery in case we need a little more current when operating the larger servo. The control box just has the battery pack, a servo timer II set to 0 time, a switch with a water proof hood and an RCA connector to connect the remote trigger switch.

Getting ready to do leak test

Using the launcher to connect to rocket

Pressurised to 20psi

Both #1 and #2 check out OK

Launcher control box components

Launcher assembled

Control box mounted under launcher

Gluing in thermocouple

25 January 2015 - We sanded the rockets down getting rid of any bumps. One of the places where we glued the coupler in the middle of the rocket dried with a decent sized bubble. So we drilled (by hand) through the first layer with a 1mm drill and used a syringe to squeeze the epoxy into the void. This worked quite well and reduced the bubble greatly. The epoxy when cured came out of the syringe very easily.

We also glued the PVC ring into the nosecone as well as the second bulkhead on the #2 payload bay.

Rocket being sanded prior to having sleeve applied

26 January 2015 - We finished sanding the rocket ready for gluing the sleeve on. We spent a bit of time prepping everything to be ready to glue the sleeve on. Once you start gluing you have to finish the whole job. Nic Lottering gave us some good tips about how to carry out the process. We ended up using mohair rollers rather than the foam rollers we normally use. We put the sleeve on dry and then used the rollers to roll out the epoxy. We had just enough time to finish the whole job before the glue started to gel. My wife helped mix epoxy as we went while dad and I did the pouring rolling. My sister helped take photos and video of the whole process. We hadn't fully stretched the sleeve initially to allow for gaps between the weave and hopefully allow the glue to penetrate. About half way through the process we finally stretched the sleeve as far as it would go and continued to roll on the glue. Once it was nicely soaked we tied the ends down with wire to hold the sleeve in place. Then we quickly applied two wraps of peel ply and rollered that on with a couple of the foam rollers. This worked well to soak up the extra glue. When it was all finished we stood the whole rocket up on its end to prevent it from curing like a banana.

Mum also finished sewing the new shroud lines to the parachute and it looks like they are going to work well.

Putting on sleeve

Rolling on epoxy

Tying wires on the ends

Applying peel ply

27 January 2015 - We peeled off the peel ply and trimmed the ends of the CF sleeve. It was evident that more glue was needed in some areas, so we will go back and fill those in with another coat of epoxy. The sleeve otherwise looks good and the whole pressure chamber weighs 983 grams. Shadow by comparison is almost the same length and with nozzle and fins weighs 1096 grams without the deployment mechanism.

We also finished up working on the #2 nosecone and grapple arms as well as mounting the #2 payload bay.

#1, Shadow and #2
meet for the first time

Raw weight of pressure chamber before
being filled in

New grapple arms attached to #2

28 January 2015 - Worked on #2 deployment mechanism finalizing nosecone and grapple arms as well as mounting the payload bay.

29 January 2015 - We filled some of the holes in the pressure chamber with more West Systems epoxy and placed the whole rocket on the rotisserie. We used 2 pumps and the foam roller to get the epoxy on. We then also used a scraper to try to spread some of the glue out more evenly.  We wanted to use the thin stuff to penetrate any fibers that weren't properly wetted out during the original layup. Next we'll use the west systems with microbaloons to fill in the remainder of the divots. We also wrapped the ends of the pressure chamber with glass fibers to replace the original wire used to hold the sleeve down.

We also reprogrammed the Servo Timer II's to add 5 seconds to all delay timing settings. The 12 second limit of the normal Servo Timer was not enough.

Applying extra epoxy on top to fill holes

Sanding tailcone

30 January 2015 - We applied filler to gaps in the #1 pressure chamber. The filler was just a mix of West Systems epoxy and microballoons in a toothpaste consistency. This was applied using a scraper made out of a piece of plastic,

Dad picked up some more peel ply from Nuplex as well as we have now run out.

1 February 2015 - We covered the #2 pressure chamber with the carbon fiber sleeve today. The process was a lot smoother as we knew what we were expecting, and having put on more epoxy meant that the gaps were filled out better. We also had patches of peel ply ready for the curved end sections and those were then wrapped with electrical tape to press them down against the tube.

We also did a thermal pressure test on the test chamber to see how much temperature increases inside the pressure chamber. The temperature needs to stay below about 60 degrees C to make sure we don't significantly weaken the epoxy. During the test we started at 19 degrees C and increased the pressure at normal speed and the rocket reached a temperature of 38 C when we reached 200psi. Leaving the pressure chamber at that pressure made the rocket drop at least 10 degrees within about 1 minute. The rate of cooling was significant and we'll probably do a fill and hold scenario to give the rocket time to cool. Letting the air out through the pressure release valve made the temperature drop to 0C.

Repeating the experiment to 200psi but this time significantly faster raised the temperature to 45 C. Again the temperature decreased fairly quickly after pressure stabilized.

Lastly we cut out three fins from the 1.5mm CF sheets from hobby king. The sheet cuts well but it blunted the saw blade fairly quickly.

Getting ready to put the sleeve on

Ambient temp

Pressurised to 200psi quickly

Pressure released

2 February 2015 - We pulled the peel ply off the #2 pressure chamber. This is always a lot more work than expected, but in the end it came off fairly cleanly and the finish is a lot better than #1. We won't need to do a second coat of epoxy, we'll just go straight to the filler, although we may make it a little more runny and then put the whole thing on the rotisserie.

We also sanded down the #1 pressure chamber with 120 grit paper to remove all the lumps and bumps. Other than filling the top with epoxy the pressure chamber is ready for hydro testing. We'll wait a few days for #2 to fully cure before pressure testing both at the same time.

Peel ply has been peeled off.

3 February 2015 - We filled in the #2 pressure chamber with epoxy/microballoon mix and again scraped it down with a piece of plastic. This time we used a slightly thinner mix to help it penetrate a little better. This took just one pump. We also wrapped the ends in fiberglass tow to replace the wire we removed.

4 February 2015 - We filled the top cavity of the forward closure with epoxy. This provides support for the forward seal. It will be drilled out a little later so that we can put a pin in and attach the shock cord.

We also made the fin alignment jig. This is just made out of a number of aluminium brackets screwed together. It just sits on top of the rocket to keep the fin aligned. The fins will be tacked on with 24Hr epoxy and then fillets will be made with Epiglue.

Filling tops with epoxy

Fin alignment jig

Gap is set to width of fin


5 February 2015 - Big milestone today. We successfully pressure tested both pressure chambers to 515psi. This now allows us to attach the fins and forward mounting ring. We also measured the total capacity of both chambers. #1 is 6.77L and #2 is 7.06L We also weighed the two and they came in a little heavier than what we were hoping for, but I suspect next time if we use vacuum bagging  to squeeze out more epoxy, that weight should come down a little more.

We also cut out the 3 remaining fins for #2. These are now ready to glue on.

Pressure test setup

Launcher is supported to prevent it from
tipping over

First set of fins

Second set of fins

Scuba hose adaptor

#1 tested to 515psi

Filling #2 with water for hydro test

#2 tested to 515psi

6 February 2015 - We attached the first fin today to #1.


7 February 2015 - We attached the second and third fins to #1 and took a while to sand down #2. We then made a pair of PVC rings from the same material the mandrel is made off. One internal edge was bevelled as that will sit up against the pressure chamber. After these are glued in place we will tap 8 holes around the circumference.

We also did a little more work on the #2 deployment mechanism making the servo access holes. The camera was also mounted in the nosecone of the rocket on a block of foam. Access holes for the lens and switches was also cut in the nosecone.

Lastly we drilled a small hole in the top closure bottle neck of #2 and then drilled a second larger hole from the end that will hold the shock cord loop. A pin gets pushed into the small hole and holds the shock cord in place. The pin is then held down with tape to prevent it sliding out. When it is inside the electronics tube the pin cannot slide sideways.

We now have 2 pins + 1 spare.

We used the shadow fin alignment jig to
ensure we had 120 degree separation between fins

Test assembly on launcher

8 February 2015 - We attached the first and second fins on #2.

9 February 2015 - We attached the third fin to #2 and added a pin to the top of #1 to attach the shock cord. We then masked off the fins and added two Epiglue fillets to each of the rockets. We used 8ml of Resin and 4ml of hardener which was just enough but we should mix up 9-10mL next time.

Taking photos for GYBTT article.


Adding masking tape for fillets

Both rockets were done at the same time



Epiglue fillets


10 February 2015 - We masked off the fins with electrical tape and then used Epiglue to make the fillets. We use a short piece of PVC pipe to smooth them out and give them the correct shape. When we are done we remove the masking tape from around the joints which allows the masked edges to cleanly separate and the edges become somewhat more rounded then when the tape is removed after the glue has cured. We managed to do a set of 8 fillets during the day, 2 at a time on each rocket.

We also discovered that the nosecone on #2 didn't sit quite right and was tilted at a slight angle. We pulled out an old record player and put the entire payload and nosecone on it to see how much it wobbled as it spun. We sanded the lower edge of the nosecone to level it out, but some of the holes for the attachment will now need to be re-done.

11 February 2015 - We tacked on the PVC ring to the top of the pressure chamber that will hold the payload bay in place. Luckily Epiglue doesn't drip and so we were able to glue it in place on it's side, We used 3 angle brackets to keep the ring aligned with the rest of the rocket.
We also cut new shroud lines to length for #2. These will be again sewn on to the parachute.

Tacking on PVC ring

Using payload section body for alignment

3 aluminium bracks used to keep
everything aligned.

12 February 2015 - We tacked on the top PVC ring for #2, and then filled in the spaces with the extra glue under the #1 ring. We then sanded the tail section and smoothed out the leading and trailing edges of the fillets on the fins.

PVC ring for mounting payload section

13 February 2015 - We attached the top PVC ring to #2 with Epiglue.

14 February 2015 - We tapped M3 holes in the PVC ring #1 and #2 to support the payload bays.

Because we wanted to test the launcher at full pressure we machined up a plugged nozzle out of aluminium. In order to catch the nozzle we mounted a PVC pipe filled with rags, newspapers and tissues just above the launcher. We did 2 release tests at 600psi and 650psi. Both went well but there were dents on the nozzle where the launcher had released it.
We also machined up an adaptor for the launch tube and a launch tube insert so that we could screw the two together when needed and unscrew them for easier transport. These were glued in place with the super strength epoxy.

We weren't sure that the way the payload section was mounted would hold up to the G forces on launch so we shortened the payload section tube so that that the electronics unit would sit on top of the PVC ring. The electronics unit has 6 screws holding it in place, and the payload section has 8 screws holding it in place. At 60G the entire payload mechanism would exert about 18Kgf on those screws, and although the bottom of the tube was resting against the top of the pressure chamber, it was resting against the tapered side of the chamber. There was the danger that the tube would be forced onto the tapered section and split, so we glued a fiberglass ring to the top of the pressure chamber for the payload section to sit on. This way it could not slide any further.

We also ended up buying red, yellow and black spray paint along with a couple of cans of spray putty from Supercheap Auto.

PVC pipe used to catch nozzle slug


Launcher in place for test

Nozzle slug

Test 1 @600psi

Test 2 @ 650psi

Nozzle seat with screw thread extension

Fiberglass payload bay support rings

15 February 2015 - We made a couple of screw switches today out of old PCB. We are using these to get a secure power connection during the high G launch. They are also nice and compact.

We filled gaps with epoxy around base of the payload bays. We also pulled off the shroud lines from the second parachute ready to have the new ones sewn on.

Adding extra support for PVC rings

16 February 2015 Today we masked off the fins and nozzle and sanded the rockets back with 240grit paper to get them ready for painting.

Masking fins and nozzles

17 February 2015 - We spray painted both #1 and #2 with Spray putty and then let it cure after about 4 coats. Later that night we sanded it back to almost the CF again giving a fairly reasonable smooth finish. We also replaced the top fiberglass hinges of the launcher legs with brass ones as the old ones started to crack.

Suspended ready for painting

Fins and nozzle are masked

Spray putty used for filling gaps


Sanding back putty

18 February 2015 - We painted #1 and #2 with yellow spray paint. We did 3 coats but will need to do another 1 or 2 because a little bit of the underlying CF is still showing through a little. Overall the finish is quite good and better than what was expected.

Yellow was chosen so they are easy to see and
won't heat up too much in the sun.

19 February 2015 We sprayed another couple of coats of paint on #1 and #2.

20 February 2015 - We continued to work on deployment mechanisms.

21 February 2015 - The electronics in the payload bay are mounted around the outside of the inner fiberglass tube. When trying to come up with a best way to mount the flat PCBs onto the tube, we tried velcro, but it didn't give enough security for the electronics in a high G environment, and then my wife suggested what about pockets? And so we went with that. We made a set of pockets from PET plastic that allows us to see any displays with holes cut out for buttons access. The electronics PCBs rest up against the bottom bulkhead to withstand the acceleration forces. The pockets allow us to remove the electronics and place them on other rockets as needed. There is a pocket each for: zLog altimeter, Servo Timer II, Battery pack and, Altimeter One. The whole set of pockets is screwed together with a couple of screws to hold it securely around the central tube. The screw switch is mounted permanently to the fiberglass tube opposite the servo motor. We finished mounting everything for the first rocket.

PET pockets for electroncis

Top view

The electronics fits snugly inside

Battery pack

22 February 2015 - Today we made a second set of pockets for the second rocket and mounted all the electronics in it.

Two payload sections almost ready to go

23 February 2015 - We are using an AltimeterOne as a second altimeter so we can correlate the data from the zLog. Because in it's case the AltimeterOne is just a little too thick, we just removed it from its case and placed the battery next to the PCB. We mounted this with double sided tape to a piece of PET backing plate.

We also drilled all the access holes for the electronics in both payload bays. We also mounted the cameras in the nosecones sitting at an angle on dense foam.

24 February 2015 - We attached the wire loop to one of the grapple arms that hooks over the servo motor horn. We did this for both the deployment mechanisms. For the shock cord we are using 3mm braided nylon cord, it's the same stuff we use on all of our rockets. Connection is very simple we just make a loop at one end which then pins to the top of the pressure chamber, The other end is threaded through the deployment mechanism, and then threads through the nosecone. Friction keeps the nosecone in place on the shock cord and then finally it goes to the parachute where we make another loop.

Lastly we used the Open Rocket simulator to model the rocket so we could figure out the positions of the CP in relation to CG. We marked the CP point on the rocket as the LCO may want to check the rocket stability.

25 February 2015 - We washed the nosecones and payload bays with warm soapy water to try to remove any greasy finger prints that may have made their way onto them. After drying we then sanded them back with 240grit paper and spray painted them with spray putty. We'll let them dry overnight and we can do the first paint coat tomorrow.

Sprayed with putty and sanding back

26 February 2015 - We sanded the putty back to the fiberglass and sprayed the first coat of paint.

Spray painting payload section

Lever arm length comparison

More painting

And can't forget the nosecone

27 February 2015 - We sprayed 3 more coats of paint onto both nosecones today. I'm not liking this paint that much as it doesn't give very good coverage and needs multiple coats. We also ran some simulations to see how the rocket would likely perform.

28 February 2015 - We sprayed the black bands on nosecones today which finishes the painting for these rockets.

Painting all done
Business end

Pointy end

Almost ready to go... are they

13 & 15 March 2015 - Good launch days at Westmar QLD. See Day 158 for full flight report.

12 September 2015 - Great launch day at Mullaley, NSW. See Day 166 for full flight report.


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