Howdy all!! I have been waiting for an opportunity to launch for the past few weeks and haven't had one due to Tropical Storm Debbie. Plus I had to find a larger field to fly in. Anyway, Saturday, June 30th, I finally had the opportunity and went and launched my rocket. It was a 8 litre capacity. I put in about 3/4 litre. Using a new bike pump (the last one exploded!!!) I (I should say my dad) got it up to about 80 psi and then we realised there were some minor leaking issues from the quick connect. I chose to launch it and it launched perfectly!!! I am guessing it got to about 100 feet, maybe a little more than that. Anyway, then the new parachute release system deployed just after apogee, about 2.5 seconds in, and the chute deployed beautifully. The chute unfolding in about 15 - 20 feet, and then the shock cord broke!!! It was probably 60 feet up and fell straight down to earth!! That exact thing happened the only other time that I got a successful deploy! Well, after I recovered the rocket, Dad mentions that the line probably broke because it was around 10 yrs old. Anyway, to make a long story short I promptly headed to Wal-Mart and got some new string. I am using fishing line and decided to get 60 lb test. This should hold better.
So, since my release mechanism is completely destroyed, I decided to rebuild it from the ground up. This time I am going with a side eject tube style. I am using a pepsi bottle for the tube and got a spring out of a nerf gun to push the parachute out. I am planning on holding the parachute in with a rubber band system, which would be attached to a servo. I was using a tomy timer system of my own design previously, but this time, I was loking around in Radio Shack and found this: http://www.vellemanusa.com/products/vie ... &id=350494
. I got it for $20 and thought that was a good price. I have yet to put it together and add it to the rocket. I do have a few questions:
1. Does it look like this start/stop timer will work very well?
2. What would be the best (and cheapest) way to have it start after lift off?
3. Is fishing line a good choice for shock cord?
4. Should I clobber my Dad for not telling me that the last fishing line I used was 10 yrs old?