Wow, that went quick. How many lbs of thrust are you getting out of it?
Ahh! I was thinking the cap was a screw on type so it could be reused.
I’ll stick with my little model right engines and rockets for now as I don’t have the time yet to get into the big stuff. They have a rocket club that does launches from the Johnson Space Center here in Houston every weekend or so. They have the area setup near the Saturn V. They apparently launch the big and little ones there so I’m going to get into that club someday soon I hope.
Good luck and Godspeed!
@ Chris: I don’t have a setup to measure the thrust as yet, but I am in the process of designing a test stand with a hydraulic ram (automotive brake master cylinder) connected to a electronic hydraulic pressure sensor, and some software on my laptop to calculate the thrust based on the hydraulic pressure.
@ logitechs: I was in the United States in April for a conference, I would have loved to have got to Johnson to check the place out. It would be awesome to launch a scale Saturn V in the shadow of the real thing. I did spend a LOT of money (over $1200) for flights from Los Angeles to Orlando and back so I could spend about 8-10hrs there to watch Discovery launch on STS-131. It was the most awesome thing I have ever seen, and I was wanting to see it since I was a kid, it was very fortunate I got to see one before the program was scrapped.
I’ve seen 4 shuttle launches at the Cape about 5 to 10 miles away from the pad on a military causeway we had to get passes for back in the 80s. It was an awesome experience each time to see and feel those machines lift off. I saw the last successfull launch of Challenger and the Hubble scope on one of them.
I’m really interesting in creating a launch control, data collection, and recovery tracking system for model rockets. I will continue tinkering as time permits. FEZ Domino has been added to my controllers to work with as it seems to have everything and then some to do the tasks needed. I’m thinking a thermocoupler sensory input ability would be a nice add-on to the FEZ accessory product line. A couple op amps and multiplexed A/D converter would seem to do the job.
So my parts have arrived from Sparkfun. I have already got the GPS working and aquiring a lock. I need to modify the GPS class to support altitude and speed values.
I am working on the driver now for the BMP085 Barometric Pressure Sensor. Once I get the driver working I will provide another source dump for the community.
I have also done some more engine tests, and had two perfect burns back-to-back and am in the process of building the engine which will launch my Stage 1 rocket (ballistic return) tomorrow. I have posted videos of the static tests on my YouTube channel (http://www.youtube.com/user/MistahHeffo)
I have finally launched my first generation rocket. It was a much better launch than I anticipated, There was a nice crack sound as it broke the sound barrier on the way up. It was a nice gentle recovery even without any recovery system on board, it came down sideways with the large side profile acting as an air-brake.
I have put a video of it on my YouTube channel. http://www.youtube.com/user/MistahHeffo
Next I am going to the second generation with a parachute recovery system and a simple 555 based system for the chute deployment. When that is working, my FEZ controller will go up as a payload logging data but no control, then it will go up as a primary control with the 555 as backup, then for generation three, the FEZ will be by itself (on a custom PCB by this time) without a net so to speak.
[quote]the FEZ will be by itself (on a custom PCB by this time) without a net so to speak.
[/quote]
.NET with no net, he he 
Bump - note to Heffo (only - sorry, have no other way). (removed email address), I have ordered the SD daughtercard for you…
Where did you manage to find the KNO3 to make your rocket candy? I can’t find it anywhere in aus.
Have you tried adding 5% micronised aluminium powder for more power?
What are you making the nozzle out of, is it just packed bentonite? Would love to know if you’re making them on a lathe for the thread and how you’re inserting the metal plate. Wouldn’t mind getting some off you to experiment with. Estes black powder rockets got boring long ago for me.
Love what you’re doing with the rocket, that’s seriously cool stuff.
Brett: sweet, contact me at robheffo ‘at’ live ‘dot’ com 'dot au with the details on my share of the cost, account details, etc about the order
MarkH: I get my KNO3 from eBay. There are a couple of vendors in the country who supply it. I don’t use aluminium powder but I do use a tiny amount of FE2O3. I used to make my nozzles from bentonite but ramming nozzles for 40mm diameter motors was cracking the PVC causing failures. I moved to Cement but it was too brittle and sandy, so I managed to find a supplier of Rockite in Sydney.
Rockite would have to be the most awesome stuff ever. It expands when it dries making an extremely tight fit, It’s smooth textured and pours like water almost and sets harder than concrete in about 20-30mins. I do use a steel section cast inside the Rockite nozzle as the throat since Rockite still does erode slightly at the burning temperature of the R-Candy.
To form the nozzle I have had a 3-Part tool made. A main section that fits snug in the PVC body with a 45 degree taper to form the internal convergent cone. A core rod that slots into the main section, the steel throat insert slides over that. Then I pour the Rockite. After 10mins and the rockite has started firming up, I remove the core rod and replace it with another rod that has two tapered protrusions to scrape out the Rockite to form the exit cone. Since I started using this nozzle design I haven’t had an issue with them at all.
Next time I build a motor I will video and post on youtube my process. Send me an email at my above address and I will send you some more specific details.
I’ve seen KNO3 on ebay before but wasnt sure of ordering it online/shipping it over to WA. I’d be very interested to hear more about your process. I couldn’t find an email address in this thread, you could drop me an email? markh@ rris.com.au