Aluminum nosecone and transition - among the best options for high performance hobby rockets. Perhaps only second to steel or exotic metals like titanium for overall performance and strength at mach 3+.
Similarly, aluminum fin cans find an ideal balance between heat resistance, strength, and weight.
To ignite the upper stage, timers were crammed into the nozzle. Clearly it worked, but head-end ignition (considered for this project) is now the more viable option. It also allows for electronics to stay with the rocket for recovery, and record flight performance.
The mighty O 10,000 comes to life. Note that this is the same thrust as an N 10,000 with double the burn time, or just over 2 seconds.
This remains among my favorite rocket projects. First there is the insane paring of a very fast O to a very fast M. Then there is the fact that these two rockets are extremely thin (4 inches and 2.5 inches!) and entirely made of metal. These two factors, combined with a bit of Kosdon flare for the extreme, give us some really fun numbers: 90,000 feet and mach 4. Because data were not recovered from this flight, it is worth being conservative. Still, it is safe to say at least 50,000 feet and mach 3 were achieved. I posted about this project many years ago, but was only able to include a few images. Now there is a video available online:
If you want to know more about this project, and the development of the O 10,000, Visit AHPRA.ORG.