Had a meeting with my university rocketry team that I mentor, to meet the new team members. Their electronics recently passed CDR.
Tested my telemetry link fully, end-to-end, to verify I am getting location packets now. All good. Managed to kill a LiPo in the process
. Replaced LiPo. This link will eventually feed data to the Automatic Antenna Tracker.
Decided I have no way of knowing what my transmit power is on my telemetry links, so I ordered a small RF Power Meter. That will take some of the guesswork out of things.
https://www.getfpv.com/immersionrc-rf-power-meter-v2.html
Thought I had better purchase a spare flight computer board for my Vertical Trajectory System. I found they are getting very difficult to buy due to the world-wide electronic parts shortages affecting automotive and other manufacturing. Lots of the microcontroller, and other, chips are in short supply due to covid. Managed to get one (Matek F765-WING) locally anyway.
Over the past few days I have been looking at reducing temperatures in the VTS and have ordered a 15x15x4mm fan to keep the flight computer cool. I also modeled up some parts and 3D printed them to be able to mount the fan when it arrives. I was going to mount the fan external to the FC, but figured I could lift the top PCA by an extra 10mm and mount the fan within the FC volume. I will use some PLA parts to check fit before getting them printed in glass-filled resin.
I think in the next incarnation of the VTS I will have provision for cooling air to flow though the stack. That way I can provide cooling air via an umbilical whilst on the pad to help with thermal management. Also planning on electrical feeds similarly so pad time will be unlimited. I get nervous running the batteries down waiting for the flight.
I have also been cleaning up the wiring on the VTS, since there were a couple of points where there were connectors in-line but are now just a single cable run. Some of the wires were also upgraded to silicone insulated wire (more flexible than PVC) to provide less stress on the connectors to the FC.
After upgrading the firmware in the FC I have been diving into the additional capabilities unit now. It has some more parameters for me to set (
) but there are some nice new capabilities. One, for instance, is the temperature calibration of the IMU. A calibration run can be done from low temperature to high and the trims for the gyros and accelerometers are all recorded and applied in the future as needed to keep IMU drift to a minimum. Neato. There is some expansion of the scripting facilities and also provision for automatically adjusting PID gains down if the craft oscillates. Ardupilot really is a great bit of software.
https://ardupilot.org/
. Scott Binder of SBR rockets flew his BIG Fuson rocket on a "N" skidmark, and it was impressive. If I can upload the flight video from my phone ,I will post it.
