SMR
Entropy Demonstrator
- Joined
- May 15, 2009
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Hi All, I had an idea for a rocketry challenge. The goal would be to launch a rocket to 100,000 feet with the limit of using LOC Precision-style parts such as cardboard tubes and plywood fins. No fiberglass/carbon and minimal metal parts allowed. Bolts for the electronics bay and motor retention would be okay. Another rule would be Tripoli certified motors.
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Cheers, Alex
This segues nicely to introduce a project I have been quietly working on in the background for the last decade or so. It started with Jackson L. questioning if we could reach the stratosphere. (We can). Never came up with a good name, since any acronyms using the project limitations somehow always included a distasteful Jack London reference. As we all know, I work really slowly, since deadlines force errors and I am basically lazy.FWIW, the original concept is a point worth exploring. What IS the limit for the majority of us, with average building skills and off-the-shelf components.
Ramblings...
The idea of staging an N5800 to an O3400 was intriguing, but unfortunately it (slightly) bumps over the 40,960 Ns limit for Class 2 rockets. But the project started with that concept - a two stage rocket with commercial motors. Half the atmosphere is below 18,000', 3/4 of it is below 35,000'. So, generally, if we could get above most of the air molecules, drag is less of a factor. The third stage grew from that.
Min diameter for staging doesn't work for me. I know, people have had good success with it, but my average building skills prefer through-the-wall fins to have a viable tang (1). And which leaves internal space to route ignition circuitry (2). (No head-end ignition for me, either.) And coupling the stages is easier when the aft closure isn't the widest part of the rocket (3).
I tend to build heavy, (the average building skills part), which is probably the biggest limiting factor. I am sure with off the shelf components, 35,000' can be easily reached, with the possibility (and goal) of 10 miles high (52,800').
Progress to date (photos to follow) ...
This is a long-term project, expected launch at least 2 years down the road, so there won't be daily updates until we get closer to launch. Currently (no plan survives contact) we sit with a 6"/98mm booster (75% complete), a 5.5"/98mm second (waiting on rings from Tim), and a 3"/54mm third (95%). My 1st Gen Kate fits in the 3" nose. The 6"-to-5.5" ISC (50%) and the 5.5"-to-3" ISC (80%) are currently on the workbench. Some kit bashing but mostly assembled from commercial components. My fins from 3/16" G-10 stock. Slow road.
The stages will be flown individually, then in combo's of two, and finally in the full stack with smaller motors, working the way up the motor chain as launch opportunities evolve.
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