My little Chinese BALLS 2012 Project

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Will this project meet its stated goals? [See slide 2]

Yes
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Not a snowballs chance in hell
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Maybe
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Total votes: 0

Sumo310
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Re: My little Chinese BALLS 2012 Project

Postby Sumo310 » Mon Sep 02, 2013 9:14 pm

Time for a canopy Mike!
L3

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Re: My little Chinese BALLS 2012 Project

Postby Passaretti » Mon Sep 09, 2013 11:34 am

I fell behind this past week but made up some ground this weekend. Nic is helping out tremendously with the avionics bay, wherever he can really. THANKS NIC!!!!

Barnes900 ground station packaged up into a enclosure to keep the playa out. This should help keep the unit safe from the expected rough handling these things see in the field.
IMAG0517.jpg


Single channel wireless launch controller just about done. Waiting on a small SMA jumper cable to route the RX antenna to the top of the panel in the enclosure. A new 15' extension cord was hacked up to serve as igniter leads.
IMAG0524.jpg

IMAG0525.jpg


I'm going to use larger main chute this year, an 84" TAC-1 instead of the 72" version last year. This should help for a slighly softer landing as well as longer time aloft to help with tracking. All of the shock cord and canopy bridle lines are packed into the d-bag elastic bands. This shoud slide in/out of the airframe with very little effort.
IMAG0528.jpg
IMAG0528.jpg (226.22 KiB) Viewed 1522 times


This is the forward bulk-plate which makes up the top of the new avionics bay. The components were moved inward slightly, but otherwise the set-up is identical to last year.
IMAG0543.jpg
IMAG0543.jpg (60.63 KiB) Viewed 1522 times

IMAG0547.jpg
IMAG0547.jpg (53.45 KiB) Viewed 1522 times

All that remains is bonding into the avionics bay outer tube, and installation of threaded inserts to fasten everything to the airframe.
IMAG0545.jpg
Mike Passaretti, TRA 5369

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Re: My little Chinese BALLS 2012 Project

Postby Passaretti » Mon Sep 09, 2013 11:53 am

I've been dreading this part for some time now ... Finally this morning I kicked myself in the ass and got going on the aluminum outer shroud for the nosecone. I started by cutting a test piece/template from some poster board of comparable thickness to the Aluminum I was planning on using (0.015" thickness 3xxx series Al).

image003.png


IMAG0551.jpg


The fit was close but not perfect. I made some adjustments and jumped right into cutting of the Al sheet.
IMAG0554.jpg
IMAG0554.jpg (51.6 KiB) Viewed 1520 times


Shears for the curved sections.
IMAG0561.jpg


The straight sections were scored and snapped with clamps and a straight edge
IMAG0558.jpg


A strip of oak was cut and drilled every 1-inch to accept a small SS wood #2 screw.
IMAG0566.jpg
IMAG0566.jpg (55.01 KiB) Viewed 1520 times


IMAG0567.jpg


Some clamps held the strip in place as I pre-drilled and inserted all of the screws.
IMAG0568.jpg
IMAG0568.jpg (47.07 KiB) Viewed 1520 times


The purpose of the oak strip is to clamp down and secure the aluminum shroud as I roll and form it to the outside of the NC.
IMAG0571.jpg
IMAG0571.jpg (41.96 KiB) Viewed 1520 times


This took some care and patience, but I finally started to see the light at the end of the tunnel...
IMAG0572.jpg
IMAG0572.jpg (56.96 KiB) Viewed 1520 times


When I had rolled/formed the Al as much as I could, I removed the oak strip an carefully worked the rest by hand, using Kaptop tape (great tensile strength) to carefully close the gap,working my way up/down the seam several times. I drilled right through the tape to create the remaining holes for fasteners.
IMAG0574.jpg


Hard part over, now it's time to bond the shroud to the surface. But first ...
IMAG0575.jpg
IMAG0575.jpg (52.41 KiB) Viewed 1520 times


I milled a shallow trough to accept the thermocouple such that it will remain in contact with the aluminum NC tip but not the shroud. This should enable temperature measurements of the tip in flight.
IMAG0579.jpg


It's difficult to see here but the thermocouple is touching the (embedded) shoulder of the aluminum NC tip. I'll pack some heat sink compound around it to drive out any air and form a better thermal path. The rest will get packed with epoxy before the shroud is bonded in place covering the whole thing up for good.
IMAG0576.jpg
Mike Passaretti, TRA 5369

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Re: My little Chinese BALLS 2012 Project

Postby Passaretti » Mon Sep 09, 2013 12:02 pm

Some shots of the new avionics bay, as designed and built by Nic! This came out far better than I could have accomplished in what little time I have left ... To do with without a laser cutter, would take days I bet ...

All that should remain is fitting of the electronics, batteries and harnessing. It looks like Nic will be hand carrying this part from Oz and FedEx'ing it when he arrives in Reno this Wednesday.

Capture.JPG
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PICT5651.jpg


PICT5652.jpg


PICT5653.jpg


PICT5654.jpg
Mike Passaretti, TRA 5369

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Re: My little Chinese BALLS 2012 Project

Postby ROCKet STAR » Mon Sep 09, 2013 1:58 pm

Looking good, Mike! I imagine that forming the aluminium cone accurately was no easy task.

One thing (and I'm sure you have probably already considered this), is that given the GPS system is to be mounted in the AV bay inverted, it may be prudent to add a bit of double sided foam tape to the back of the header connector to the GPS reciever. That way there will be no risk of the connector being pulled off by the G forces experienced during boost.
Chris Barnes

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Re: My little Chinese BALLS 2012 Project

Postby Passaretti » Tue Sep 10, 2013 6:52 am

ROCKet STAR wrote:Looking good, Mike! I imagine that forming the aluminium cone accurately was no easy task.


As usual, I built it up in my head to be a monumental pain in the ass but the truth is it wasn't that bad. Tedious work but the results were pretty good (I think) first shot. The true test is whether she will hold up to M3+.

ROCKet STAR wrote:One thing (and I'm sure you have probably already considered this), is that given the GPS system is to be mounted in the AV bay inverted, it may be prudent to add a bit of double sided foam tape to the back of the header connector to the GPS reciever. That way there will be no risk of the connector being pulled off by the G forces experienced during boost.


Yes, once everything is installed and tested I plan on putting hot melt glue over all connectors. I'll also strain relieve the antennas or other bits that might want to wobble around. Foam, double stick tape, hot melt, zip ties, etc...

Thanks for the feedback!
Mike Passaretti, TRA 5369

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Re: My little Chinese BALLS 2012 Project

Postby Passaretti » Thu Sep 12, 2013 1:40 pm

Brief update. All major items are complete, however the list of little things to-do is growing by the minute! Nic was able to drop the av-sled off at UPS in LA today. It should be waiting for me when I get back to my shop with Dave tomm. afternoon.

Need to wake up early to grab Dave from JFK tomm!



After the thermocouple was bonded in place (Monday night) and tested, the shroud was bonded to the NC surface with Hysol E120-HP epoxy (Tuesday night). Not the most temperature tolerant adhesive, but a rock solid compound I've used for some time now. So long as the fasteners along the seam hold, my thinking is that the adhesive will not see very much load at all. This epoxy also has a nice long pot life which comes in handy for first attempts like this one.
IMAG0607_.jpg


The seam pulled together nicely with the help of several, several feet of Kapton tape.
IMAG0606_.jpg


Some clamps were added and the whole thing was left to cure for 24-hours.
IMAG0610_.jpg


If it weren't for the fastener heads, and a few spots at the NC tip interface, the seam is practically hidden after sanding.
IMAG0623_.jpg


Not too bad for my first attempt?
IMAG0618_.jpg


And finally the coupler is here!
IMAG0629_.jpg


IMAG0628_.jpg


IMAG0625_.jpg
Mike Passaretti, TRA 5369

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Re: My little Chinese BALLS 2012 Project

Postby OverTheTop » Thu Sep 12, 2013 3:53 pm

I hope the flight goes well for you Mike. Looking forward to seeing the results! :D
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Re: My little Chinese BALLS 2012 Project

Postby rocket_troy » Thu Sep 12, 2013 5:40 pm

Love that NC! :)

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Re: My little Chinese BALLS 2012 Project

Postby Passaretti » Mon Sep 30, 2013 12:17 pm

As mentioned previously, I did not fly at BALLS 22. Sunday morning was my chosen opportunity to fly. While at the pad it was determined that there was a problem with the GPS module. The 900MHz link was working, GPS string headers were being received but it contained no usable information. The strings appeared to be blank...

Rewind 4-days - When I reversed the input power polarity to the Barnes900 board and blew a tantalum cap in spectacular fashion. After replacing the cap I stupidly did not shake out the functionality of the entire system, really only checked the voltages and performance of the 900MHz radio. Upon having issues at the pad, I suspected that they might be attributed somehow to the polarity issue I created.

Nic promptly offered to drive back to Brunos to get a spare GPS but I declined his generous offer. The weather & recovery conditions later in the day were a bit iffy from my standpoint and I did not feel comfortable rushing into anything. I made the difficult decision to pull the rocket, break down the pad and wait for next year.

At the moment I have not gotten to the bottom of the issue. Mainly because I have not tried. In addition to the GPS module being damaged, I am also entertaining the thought that there might be RF interference caused by the 100mW 433MHz beacon operating in near proximity. Anyhow, I will get to the bottom of all of this soon enough.

The good news is that the next flight I plan for this motor will be for a new and wait for it ...... OPTIMIZED (key word there) version of this rocket.

And of course, the week would not be complete without safe disposal of the ejection charges:

http://youtu.be/W4i9KA4cjCM

Thanks for following! Stay tuned for a new thread, chock full of unconventional machining methods, ejection canons and the like - "Optimize This!"
Mike Passaretti, TRA 5369

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Re: My little Chinese BALLS 2012 Project

Postby Passaretti » Thu Dec 25, 2014 9:51 am

It's been a tough year for me and rockets. New job and new place have me located about 100km's from home base where my shop is. The weekends just aren't as productive as they used to be. Anyhow, with the few days I have for Christmas, I decided to undo something I did two years ago. Remove DDT's Al fincan that was bonded in place with polyurethane construction adhesive "Liquid Nails" or something similar. I don't remember the exact brand, but I do remember thinking about how hard it would be to remove the fin can someday. Nic and I bonded this in place on the playa the night before DDT launched in 2012. That day came .... today. Holy ______ this was not an easy task.

I've been meaning to pull the fin can off for some time now. And then, this past summer I dropped the case and severely damaged the side wall of the case at the very end near the forward threads. To salvage the case I arranged to have it cut down and machined to a 4G or 6G configuration . But I need to get the fin can off first... Here is how that went:

I started by plugging the end of the case and filling it with boiling water. The purpose of the hot water was two fold: 1) preheat the case to start to loosen up the glue (hopefully), 2) prevent the case from being overheated by the blow torch & heat gun. The finc an was propped up on blocks such that the case could slide down a few inches before hitting the floor. 100lbs of dead weight was added for encouragement.
IMG_8254.JPG


After a lot of heating with the heat gun and blow torch, the case did not budge from the can. So I took the next logical step and took out a 10lb sledge hammer. Smacking through a block of wood on top of the weights eventually got things going. This was just the beginning as the glue still inside the ID of the can would fight the whole F*%#ing way ...
IMG_8255.JPG


Once the case reached the floor, I carefully removed the weights and dumped the water. I then proceeded to smack the case into a block of wood on the concrete floor pushing down on the fin can each time. It was hard work but eventually the fin can made it to the other end of the case.
IMG_8264.JPG


The forward threads rolled over from the pounding, but this part of the case is going to be cut off anyway.
IMG_8262.JPG


The remnants of the polyurethane glue cleaned up quickly with a wire brush and plenty of alcohol.
IMG_8265.JPG


Next step is to cut off the end of the case / fin can and send out the salvaged part of the case for machining. I should be able to salvage the fin can from the cut off piece of the tube without to much trouble. Liquid Nails ... never again!
Mike Passaretti, TRA 5369

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Re: My little Chinese BALLS 2012 Project

Postby cryoscum » Fri Dec 26, 2014 3:33 pm

Glad you got that fincan loose! I didn't actually expect it to budge at all! :)
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