Today was the season opener for Tripoli Colorado at their launch site on the buffalo ranch near Hartsel, Colorado. After huge snowfalls along the front range of the mountains in the last few days, we were a little tentative about going, but it turned out to be nearly perfect flying conditions! There was apparently much less snow this week on the high plains west of the front range, and by this morning the snow had almost entirely disappeared, the skies were clear and blue, and the winds were calm except for a few gusty bursts in the afternoon. This launch site is really something special, at 8800 feet above mean sea level, in the middle of a huge area of wide-open short grass prairie. We love flying there, and today the drive to and from the launch site through the snow-covered Colorado Rockies was just beautiful!

Son Robert and I flew three rockets today, including his LOC/Precision Lil Nuke with added payload section on an Aerotech G54W-M reload, and our Polecat Aerospace 5.5 inch Goblin kit on one of the relatively new Aerotech I245G-M "Mojave Green" green-flame reloads. But by far the highlight of the day was flying my Giant Leap Vertical Assault on a Cesaroni J335 red-flame reload... with serial number 1 of TeleMetrum on board collecting our first-ever flight data!

From the ground, it looked like a textbook perfect dual-deploy flight, with a small drogue chute out at apogee around 4000 feet above ground, and the main chute deploying at 700 feet above ground for a beautiful, soft landing only a couple minutes walk from the launch rail.

The ejection events were controlled by a PerfectFlite MiniAlt/WD. The data recovered from it shows a big negative spike in the altitude right at apogee, coincident with firing of the apogee deployment charge. I have to assume this means the aft bulkhead on the avionics bay in the reconstructed coupler section isn't sealing well, and some pressure from the apogee deployment charge leaked in to the avionics bay "fooling" the altimeter into thinking the altitude was lower for a sample or two. Clearly, that needs to get fixed before that airframe flies again.

Further evidence that we had a mighty kick from the apogee ejection charge was discovered when we went to clean the motor casing. The Cesaroni reloads are packaged in a plastic liner tube that slides into the reusable aluminum case. When we pulled the spent reload out of the case, it was significantly shorter than when it was loaded, suggesting that the ejection charge forced the forward closure on the reload backwards compressing the heat-softened plastic. This could be evidence that the reconstructed coupler was slow to separate from the booster airframe due to excessive friction?

The flight data recovered from the TeleMetrum board looks great until apogee, when the data collection stopped. Since I flew firmware that was compiled and flashed on the flight line from Keith's latest git commit as of this morning, it's entirely possible that there was a software bug that caused data collection to terminate at apogee. We'll investigate that. But I personally think what actually happened is that we experienced a temporary short in the power supply at the time the apogee ejection charge fired. On extraction of the electronics sled from the avionics bay this evening, I noticed that one of the mounting screws has gone missing. If it wasn't snug enough, and vibrated loose during flight, it could have been torn loose at the time of the ejection event and shorted something as it rattled around in the avionics bay. The screw is now just missing, but may have fallen out when we were extracting data on the flight line just after the flight without being noticed at the time. So I'm not inclined to worry much about this, at least until we can get some more flight data!

Keith post-processed the raw flight data and presented me with a plot showing two traces, acceleration and barometric altitude. The data from the accelerometer closely matches the published data for the motor we flew, which is a really cool result, and my 10-year-old son enjoyed figuring out why the rocket showed negative acceleration after the motor burn out but was still climbing. (See, there really is some science education hidden in the fun!)

All in all, we had a great time, and it's totally cool to have data from a first flight of TeleMetrum! Can't wait to fly it again!