Wednesday, September 12, 2012

Launch Report 2012-14

Location: My 'hood
Weather: mid-70's, wind 0+ mph, clear
Total flights: Today - (10); YTD - 80
Total motors: Today - -; YTD - 95
Motors by class YTD: (Air -22); MicroHybrid -1; MMX -6; A -6; B -5; C -32; D -7; E -23; F -6; G -9

I picked up a short piece of 1/2" PVC and a couple of adapter parts. When I got home, I found I needed a male screw in elbow v. the female I bought. D'oh! Luckily, I had a suitable straight coupler. Because I got the wrong part, I merely press fit the parts and headed out.  As I passed our common area, I decided I'd try to fly the new, small rockets near the house rather than venturing a couple of miles to the park. If I lost a couple to the trees, that would be OK. All the flights were made at an angle of about 60-70 degrees to ensure they landed in the grass away from the road.  This also helped me see the flights when standing right at the launcher. I limited the pressure just because pressure builds so slowly after 30psi. During the 6th flight, my pump began shutting itself off despite me letting it sit after every 2 flights. May need a new one soon.


Here are the flights using the nomenclature from yesterday's post.
  1. 4FNC, fins on the bottom where they belong @30psi - I started at this pressure to see how they performed. It went high and came down. The nose was slightly bent but not too badly. The nose section pushed down as designed and was easily moved back into the launch position..
  2. 4FNC, fins on the bottom where they belong @40psi - Higher pressure = higher altitude. 'Nuff said.
  3. 3FNC,  fins on the bottom where they belong @40psi - Couldn't tell if this out performed the 4 fin version. It careened off a tree branch but wasn't even dinged.  The nose section did push down, though.
  4. 3FNC, fins just below the middle @40psi - This corkscrewed a little and didn't go as high as the previous flights.
  5. 3FNC, fins near the top @30psi - I used a lower pressure because I expected this to be unstable...and it was. It landed about 20' from the pad.
  6. 3 tube fins (on the bottom) @30psi - I stuck with the lower pressure because the pump began cutting out. This one flew well.
  7. No fins @30psi - This one was more stable and went over twice as far as flight #5.  The unstable rockets will be retrofitted with more fins.
  8. 3 canted fins @30psi - This performed well and was fast enough that I couldn't even tell if it spun.  
  9. 3 sets of three fins (various patterns are provided) @30psi -  This swooped a bit. Thought it was lost to a tree but somehow it made it back to the ground. performance was certainly lower than the ones with straight fins at the base. As would be expected.
  10. 4FNC, fins on the bottom where they belong @50psi - On the last flight, I thought I'd go for broke. I coaxed the pump to keep going but it jsut wouldn't get over 50psi. Don't know if this was due to the pump dying of if the launcher vessel sprng a leak. The 50psi flight was noticeably higher. I'd like to see one go up at 100+ psi but that isn't happening with my set-up. The final interesting thing to note is that the PVC tube/1"-1/2" coupler also launched. It went further than the earlier unstable rockets! Time to get the right angle and glue the parts together.
It was interesting to see how these performed.  This rocket pack would be great for school or scout groups. The flight profiles were pretty much as expected and nicely demonstrate rocket performance and stability.