Canon EOS 5D Mark IV
Ζ/20
286 mm
1/800
800
The mystery of my supersonic-shred overhead, solved today (in comments below).
From my photos, the upper half of the rocket disintegrated 2.1 seconds after launch.
The Cesaroni Aerospace K454 motor (from Canada) provided 139 lbs. of peak thrust to a 3-lb airframe, built from a lightweight composite mortar shell tube. I ran a pre-flight RockSim flight simulation that shows it pulling 20 g’s as it leaps from 0 to 946 MPH. It has a fiberglass and aluminum nose cone (plenty strong for this flight) and a HD 808 key fob camera in custom 3D-printed holder, which lost the camera on the supersonic climb (I know how to secure it next time). So…. last photo has the diagnosis.
Launch video.
…a tribute to this Black Rock Desert launch location where we first met (and then I led their first two investment rounds, back when they were in a garage and before they had incorporated). Here is a fun 
So I found the moment of failure in my DSLR photos… When the motor burns out sideways, it’s like having a rocket engine firing orthogonal to the line of flight, and in this case, at the far edge of the rocket. That induced an immediate pinwheel spiral of death overhead and the upper body couldn’t take it. The kevlar shock cord ripped the aluminum anchor bolt assembly out of the airframe, and all of the parachute shroud lines ripped apart.
I was able to bang out the motor today… and it was not a manufacturer fault. It was my assembly mistake (a new one for me!). I did not have the rear screw fully tightened. I was talking and showing a new rocketeer how we assemble these motors, and I was not paying good attention to my work, clearly. Motor on left, burn hole on airframe on right. There is a tiny gap that I left in sealing it up.
But good news⦠the base can fly again only the motor is lost
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