Are those switches sealed against all the chlorine containing combustion products they are going to see?
In any case, going to a mechanical system seems like a step backwards.
Yes, great point. I brought home and cleaned the rail today. It's only been used two times, and you would be surprised how dirty/worn it has was after just two rockets. And, the white lightning and redline are not "dirty" motors.
I was an equipment manager for about one year for a club and I've cleaned a lot of rods and rails, but I didn't realize the abuse of just one or two motors on a rail. And, the sensor was showing it too.
For the new sensor arrangement, I have some FR4-G10 shields for the LED and Sensor. On the 1515 rail, I'll be using K's and L's and I bet it's going to be tough on these electronics. Anything mechanical will be effected quickly. It might even mess it up on the first rocket.
With experience, I'm seeing that a more remote sensing arrangement or the video analysis method might be the most practical. Although, from the drop testing, using the GoPro at 240 frames/sec will not be as accurate as the break beam.
Or, maybe even rocket accelerometer data, although I don't have the expertise to obtain good results for that method.
I'm considering a better high speed video camera. I would greatly appreciate some guidance on that.
There's another thing I'm thinking about when I cleaned the rail; the wear (pitting) and the deposits from motors might be a big factor in slowing rail velocity. So, it's going to be interesting when I start using used rails.
Sorry I'm going on a bit. But, I think it would be interesting to take a 2' long block of wood, install a couple of new rail buttons on it and run it through the track of new and used rails. When you are loading a rocket, the mass of the rocket moving on the rail may mask the amount of resistance the rail is putting on the launch guide. And, like I mentioned previously, there could be significant binding because of lateral movement of the rocket during the launch, like from wind or from lateral movement of the pad from supersonic exhaust hitting a blast deflector.
Dirty/worn rail, rail buttons that have lots of play, and lateral movement causing binding may significantly affect the rail exit velocity.