In my last post I talked about building a rocket. This past weekend I actually flew it! I went out to the middle of nowhere in Eastern Oregon for Oregon Rocketry's “Summer Skies” launch. My plan was to launch with an H motor and then a J to get my level 1 and level 2 TRA certifications. I was also there to help Portland State Aerospace Society launch their much larger rocket. Both rockets were a success, though each with their own caveat. Regardless I had a blast!
The night before I prepared my rocket, getting the chute folded and all the parts put into place. I also calculated the stability using OpenRocket and decided to add some weight to the nose to offset all the weight of all the epoxy in the tail.
Then it was off to Brothers Oregon, or at least some empty piece of desert nearby. I discovered upon arriving that the different altitude/temperature/humidity/something had changed the nosecone fit. I ended up spending an hour sanding it down so it fit better. But after that all I had to do was load the first engine and fly!
The first flight was nearly perfect! My delay charge was a little too long and so the chute opened a little after apogee. But otherwise it was did exactly what it should have done: go up about 1000 feet and land a little ways away unharmed. Level 1 achieved!
Level 2 requires taking a test and flying a rocket on a larger motor. The test was no problem, but a larger motor means bigger forces, more speed and more things that can go wrong. After checking over my rocket I decided that it was still in prime condition so I loaded up the larger J335 motor (75 lbs of thrust for 2 seconds) and flew it again. This time the rocket would go to an altitude of about 3000 feet.
The takeoff was beautiful! If you're wondering, the launch rail was tilted to compensate for wind. 10 seconds later I was expecting to see a chute, but for the second time it was late! In fact a bunch of people that day had the same problem. We are beginning to suspect that some our motor delays were mislabeled. At any rate the chute did open and I could see it come down in binoculars.
But when I got to it (this time it came down over half a mile away) I found out that the top had “zippered”. What happened is that the since the chute didn't open at apogee the rocket started to fall and had picket up so much speed that when the chute opened the chord yanked the cardboard body tube around and cut into it.
Oh well, it turns out that it's still flyable, all I have to do is trim the tube a little. And because it's still flyable I still got my level 2 certification!
By this point I was pretty tired so I called it a night. Unfortunately there was a full moon that night so there wasn't much to see star-wise. Someone brought a telescope and we looked at Saturn which was beautiful. The next morning everyone got up and worked on the main even: Portland State Aerospace Society's LV2c rocket. Equipped with cameras, flight computers, an electronic roll control system and a massive N2000 motor this 70 pound behemoth blasted 15,700 feet into the air. A lot more info can be found on their launch data page. Here is a video of the launch from about a mile away on a nearby hill:
I plan to continue working with PSAS and hopefully launch another big rocket in September in Black Rock Desert, Nevada. Until then I work on understanding the complex interaction between roll control canards and rear fins, which turned out to be more problematic than anticipated (on PSAS's rocket). I don't know if I'll fix up and fly mine again. Maybe someday.