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At my urging, my dad purchased and built an Aerotech N2220 Dark Matter motor for his L3 cert flight at MMWP last spring. But coming up to the launch we learned that the club is unable to set up the away cell at MMWP, so he had to fly his cert flight on an M motor instead. This left him with an assembled N motor begging to be flown. So in the planning for MWP we decided to fly the N2220 in his upscale Mean Machine. The sims predicted the flight to reach just over 12k ft and 1200 ft/s - this was going to be fun.
This Really Really Mean Machine is a 5.5" upscale with a length of 21ft. It was first flown at LDRS33 and shown in ROCKETS magazine vol.8 issue 6, and in that year's Rockets of High Power calendar. The rocket was built to be extremely rigid and not wobble like most Mean Machines. It was constructed with a 5.5" outer tube and a 4" inner tube with expanding foam in between to make a rigid beam. That said, it was not designed with mach in mind, but you never know where the limits are until you push them.
For this flight we removed the 3" motor adapter and tried fitting the N motor, only to find there was a bulk head and some coupler 34" into the tube leaving the motor hanging 6 inches out the back. We built a hole saw setup and with some effort and a ton of torque and drive extensions we were able to bore out and size the inside of the tube. With the addition of a Aeropack retainter the motor was fitted.
We also decided it was absolutely necessary to capture the flight on video. We mounted a Mobius camera on the rocket a bit above the fins and another high speed camera was mounted off an extension pole on the antenna tower. The tower camera was 26ft up, less than a foot from the center line of the rocket looking down at the blast plate.
When the button was pushed, the rocket left the pad in a hurry with a bit of a wobble. Then less than a half of a second before burn out the rocket shredded. Best we can tell, one of the out of frame fins let go first resulting in a violent clockwise roll. This removed the rest of the fins and the rocket came down in several pieces. In the video two pieces can be seen coming down under the completely shredded chutes and if you look very closely on the left of the frame the tail can be seen free falling. Upon recovery the rocket was found in 7 pieces: the nose section, still shear pinned to the top of the mid section, was intact, but everthing else was broken up. The motor hardware, electronics, and camera were recovered without damage. At least we got some awesome video.
This Really Really Mean Machine is a 5.5" upscale with a length of 21ft. It was first flown at LDRS33 and shown in ROCKETS magazine vol.8 issue 6, and in that year's Rockets of High Power calendar. The rocket was built to be extremely rigid and not wobble like most Mean Machines. It was constructed with a 5.5" outer tube and a 4" inner tube with expanding foam in between to make a rigid beam. That said, it was not designed with mach in mind, but you never know where the limits are until you push them.
For this flight we removed the 3" motor adapter and tried fitting the N motor, only to find there was a bulk head and some coupler 34" into the tube leaving the motor hanging 6 inches out the back. We built a hole saw setup and with some effort and a ton of torque and drive extensions we were able to bore out and size the inside of the tube. With the addition of a Aeropack retainter the motor was fitted.
We also decided it was absolutely necessary to capture the flight on video. We mounted a Mobius camera on the rocket a bit above the fins and another high speed camera was mounted off an extension pole on the antenna tower. The tower camera was 26ft up, less than a foot from the center line of the rocket looking down at the blast plate.
When the button was pushed, the rocket left the pad in a hurry with a bit of a wobble. Then less than a half of a second before burn out the rocket shredded. Best we can tell, one of the out of frame fins let go first resulting in a violent clockwise roll. This removed the rest of the fins and the rocket came down in several pieces. In the video two pieces can be seen coming down under the completely shredded chutes and if you look very closely on the left of the frame the tail can be seen free falling. Upon recovery the rocket was found in 7 pieces: the nose section, still shear pinned to the top of the mid section, was intact, but everthing else was broken up. The motor hardware, electronics, and camera were recovered without damage. At least we got some awesome video.