Tony Lazzaro had a very nice flight today with a prototype Raven4. A K2045 slammed it with up to 96 Gs of thrust, which got it up to 1856 feet/second (Mach 1.65) in under 1 second. The deployments were all nominal, and there were a few interesting bits of data. Here is a zoomed in view of the motor burn:
There were 4 drops in the thrust, maybe from stuff getting ejected from the motor?
The baro sensor recorded a pressure increase during the initial part of the thrust. This can be a response to a high-G event. The column of air inside the av-bay during a 100G burn gets pushed to the back of the rocket, which can measurably affect the measured pressure.
Here's the rest of the ascent:
The effect of a Mach transition is evident in the blue line. The default check for velocity being less than 400 feet/second prevents this transient from causing a premature apogee deployment.
The accel-based apogee detection did pretty well, coming in about 1 second early on a 24.5 second time to apogee. Next is a zoom in on the apogee event:
The baro-based apogee detection allows the apogee pressure readings to take place, and the triggers the apogee deployment. You can see a big positive acceleration from the av-bay in the upper section accelerating forward, and then a negative acceleration when the slack goes out of the deployment harness. Shortly after that, there is a large lateral acceleration without much axial accel, which is likely a re-contact between the two portions of airframe. When I asked Tony about that, he said that in fact there was a mark on both sections that support that theory.
On the descent, you can see the main deployment happening right on time. The continuity voltages for the apogee and 3rd channels start to rise again during the descent. This is pretty common after a charge fires, something about the black powder residue becomes more conductive again after it cools off.
The 3rd and apogee continuity channels are moving closely together because Tony connected both channels to the same charge. The 3rd channel was set to fire at an altitude > 13,500 feet so that if the rocket were accidentally approaching the site FAA waiver, it would fire in time to prevent it from getting there. By connecting them together, then there isn't an un-fired charge hanging around Very nice idea, Tony!