Proton 2.0!

[AdrianParticipant]

As for the lighting the outboard motors from the ground, that has its own potential problems, as has been demonstrated on a number of other failed or close-call big projects. When we go to smaller outboards to reduce the potential for offset thrust, if they were ground-started we would need to make sure that they wouldn’t move the rocket in their own. The I115 that was mentioned has just enough peak thrust on their own to nudge the rocket off the rail while the central motors come up to pressure. If we do ground-start all together, we would need to choose motors that are really pretty wimpy, and they would spend a lot of their burn time with the rocket sitting on the rail.

The 3 Ms we used were barely enough to produce the 3 Gs necessary to trigger liftoff detection. With the 4th one to produce 33% more initial thrust, and lower overall weight with the smaller outboards, we would have better acceleration off the pad and quicker liftoff detection than we had this time. And now that we’re aware of the wiring damage risk, we can protect the outboard wiring much better if we decide to continue with the concept of air-started outboards.

[BEAR]

I have been working on a design to start events on rockets that is not a pull pin, (per the technical details) that could work on this project. It is bascially a spring loaded plunger switch. (Like a pressure switch) This switch has a rod, a spring, and some caps that act as limiters on it. I am thinking of brass tubing and a brass rod, but it could even be a maple dowel and an aluminum tube or even a large diameter plastic straw. The pin is in the bottom of the rocket or even in a separation of stages. By the pin being pushed up, where a spring on the other end is trying to push it down, it keeps contacts separated until the rocket moves a predetermined distance. When the rocket moves, the plunger starts closing the gap on contacts, being forced closed by the spring, until the contacts touch, forcefully, and the circuit is closed, thereby causing a new event to take place such as ignition of motors. This whole switch assembly has another switch, such as one of the Featherweight screw switches installed in line in the circuit, so that the plunger switched is never armed until the rocket is ready ot fly. I would be happy to build up a couple to show everyone to see if it would be acceptable. It could be made that the rocket has to move three feet before the circuit is closed. I have been reading the arguments in the TRA Forum and the plunger switch, IMHO, does not fall within the criteria for being a pull pin or any other device that has been eliminated from use in the discussion/rules. Any opinions or other comments?

[Kevin OslerParticipant]

WHOOHOO! Check out the ad in the last ROCKETRY Mag for Photo’s by Nadine, she is advertising the 2013 calendar, looks like we are on the cover!

I tried to go out to her website but it seems to be down or no longer exist.

Kevin Osler

[Author]

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