I made it to my first high-power launch in about two years, traveling to Indiana Rocketry’s field in Pence, IN for NAR’s NSL-East event. Some things went right, and some things went wrong, but for the most part, the important things went right. I’ll start off with a list of those things, and then get into a brief report on my flights.
- Right: just to start the list with a good thing, I went to a launch. I had just returned from visiting my sister in Las Vegas and was on the fence about turning right around and going out of town again, but I’m very glad I did. It was kind of a last-minute decision, so…I forgot some things. See below.
- Wrong: the night before I left town, as I was finishing up prep on Kerbal, I found that the altimeter lost power if the 9V battery was pulled just a few degrees away from its holder. I had planned to zip-tie the battery in place, but having a glitchy connection for something so critical made me not trust the whole thing. I had already been thinking about rebuilding Kerbal’s sled (even though it still hasn’t flown!) to use one of the new LiPo batteries I used in Black Widow’s redesign. Anyway, Kerbal got benched and Berthimus Prime stepped in.
- Wrong: I forgot the parachute for my main flight. I wanted to use one of my 48″ Fruity Chutes for Black Widow, and due to carelessness, I left the parachute behind in my workshop. I woke up at 3:30am on the day of the launch and realized I had not brought the parachute, and it bugged me so much I couldn’t go back to sleep. I ended up using the Top Flight 70″ X Chute that I brought for Berthimus Prime, which is a bit small for Black Widow, but it was fine.
- Wrong: I forgot the motor for my main flight. I planned to fly Black Widow on one of the Aerotech L1000 motors that I originally bought for Kestrel (but as it turned out, they did not fit Kestrel, so they’ve been sitting in a box). I could have sworn I put the motor in the car when I loaded, but when I unloaded on launch day, I found I’d left that behind, too. I might have chosen a different motor (I had a built J760 with me), but a friend was already on his way that morning from St. Louis to watch the launch…so I went to Wildman and bought another L1000. So I still have two of them…
- Right: My friend Aaditya, our club’s Junior L1 / Tripoli TMP member, came to the launch to help with and video-record the Black Widow launch. Thanks, Aaditya!
- Wrong: I forgot to turn on Black Widow’s onboard camera before putting the rocket on the rail, and then after catching that error, I still left the lens cap on the camera. This is not the first time I have made this mistake. I have a note in my checklist, in all caps, to remove the cap, but at that point in the process I am always starting to skim and skip details, because I always feel like I’m holding up the launch and wasting the pad manager’s time by being slow at the launch pad. So two things: I need to change my checklists to say to not even put the lens cap back on the camera during prep, and I need to stop getting in a hurry at the launch pad.
- Wrong: I put the pad camera too close to the pad for Black Widow’s flight. Once the motor lit, the entire frame was entirely engulfed by smoke and dust, obscuring the rocket. I need to add to my checklist that the pad camera should be further back (and higher off the ground) for big, fast motors like the L1000.
- Right: Black Widow’s flight and recovery were successful. Despite all of the other issues, the actual prep of the rocket was quite easy with the new av-bay setup, and the flight went perfectly. The landing point of the rocket may have been closer to the car than the launch point – I will have to look at the GPS data to see.
- Right: no issues with building the J420, which worked perfectly for Berthimus Prime. I can finally give Mike his casing back!
- Wrong: My Chute Release bands had all dry-rotted, and I hadn’t thought to restock before the launch. I went to Chris’ Rocket Supplies to get more, but he was out of them, so I tried to improvise with a short piece of Estes rubber shock cord. The main came out very early in Berthimus Prime’s flight; Mike suggested that the bundle probably just came loose rather than the Chute Release triggering early, and I think he’s right. So I had a more distant recovery, but most of that distance was along the road (so I could drive north to get close to the landing point) and the walk wasn’t that bad. NOTE: Chris mentioned that people were discovering that elastic hair ties actually work better than the rubber bands, so I will likely try that next time. Unfortunately, I did not have any with me on the trip.
- Wrong: My faithful old AltimeterTwo, now almost eleven years old, seems to be dead – it didn’t light up when I plugged it in to charge the night before Berthimus Prime’s flight. I may crack it open and try to replace the battery (Wildman sells them), or just buy a new one.
On to the flights:
Black Widow flew to 10,829 feet AGL on the L1000, with a maximum velocity of 1140.74 feet per second, just over Mach 1 (as indicated by the BlueRaven). I have not downloaded the device data yet, but the BlueRaven’s phone app breaks out a lot of interesting statistics: 2.6 sec burn time, 24.7 sec to apogee, roll rate at burnout 716.2 deg/sec, max boost acceleration 23.4 G, max drag deceleration 2.6 G, drogue descent rate 115.7 ft/sec, main descent rate 27.2 ft/sec. (The app reports drogue rate as a negative number and main rate as a positive number, so I don’t know whether one of those is a bogus measurement or it’s just a bug in the app.)
Berthimus Prime flew on the Aerotech J420R that I bought from Mike a few years ago. As noted above, my AltimeterTwo was dead, so I have no data on the flight. But it looked good!
All in all, it was a very good outing. Good to be back in the field. Hopefully we will have a launch in Elsberry next month – I need to figure out what I want to fly. I might go back to the drawing board a bit on Gravity’s Just a Habit (that’ll be a separate post), so if I’m not flying that I might put another L1000 in Black Widow, with the right parachute and the lens cap off…