Sunday 26 June 2011

Start of holidays, and a what i have been up to (or lack of)

I finished my last exam on friday, and am quite happy to be holidays and working on rocket stuff again. I completely stopped building anything over the exam period as I have difficulty balancing building stuff and study. I am getting better balancing my time, and i can work fairly well on both during the semester but I have difficulty

I have decided to postpone any peroxide work at the moment so I can concentrate on building the nitrous demonstration engine. My chemist postgrad friend has gone overseas also so he isn't able to help for a while also. I still really want to develop some peroxide stuff, but i get the feeling that its just a distraction and at the moment i really just need to get something going. On the peroxide note I do have a possible source for silver mesh : Art stores. I was in one the other day and they sold copper mesh. I asked the manager if they had any silver mesh and she said she thought they used to but dident sell it anymore. She got my details and said she would look into it for me (probably wont hear from her) especially after i told her what i was using it for but I might try calling some other stores if i have time. Also it might not be real silver, but just something that looks like it.


I spend most of today cleaning up the workshop and the office as everything had gotten a bit messy over exam period. I also got the chance to try out a new toy i ordered before exams but hadn't gotten a chance to try. I have always wanted a plasma cutter but could never really justify the cost. Well lately I have been making lots of parts made from plate steel and aluminium and cutting them from the metal band saw is very slow and a bit dangerous. For thick plates you need to apply allot of force towards the blade, and slipping means your fingers go into the blade with a lot of force (that hasn't happened to me). So i figured i would treat myself. Its a chinese knock off of an italian model (from ebay) but seems to to work quite well. Its 50A and apparently it can cut up to 16mm of steel, although at about 45A it trips the circuit breaker in my house so i haven't been able to test it.

I have also decided to ditch the usb-lan cable in favour of a wireless xbee (serial wireless module) I have ordered a 60mW pair which are quite easy to program with ardwino. I am slightly concerned about the safety aspects of using a wireless module to control the test stand, but with a wired cable to control arming/emergency stop  it should be fine. The module says it can go 1600m. There is also a 1W variant for only $180 each which would work very nicely for telemetry on a flight vehicle. I remember reading that Paul from unreasonable rocket used a 100mw xbee at 900mhz (instead of the 433mhz i have) for telemetry on his helicopter.

I would like to be ready for a test in two weeks (10th). There is quite a bit of work to be done, but I am looking forward to the challenge.

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