Switch Testing

[JohnCoker]

Good stuff, John. I would be curious if the results of the vibration test would be different if you repeated the testing with different orientations of the switches. The test setup in the video looks like the vibration table is vibrating up and down, which would be the most stressing case for the featherweight switch since the vibration is occurring exactly perpendicular to the switch contact area. I don’t think this is necessarily true for the other switches.

That's a good idea. Do we have any clue what vibration would be present in flight?

 

[Crayok]

Do we have any clue what vibration would be present in flight?

The motor vibration spec derived from the raw motor test data would be a good thing. I have this chart from years ago when the rocket electronics industry was not taking into consideration motor "vibration", particularly on hybrids vs the low sample rates the electronics provided at the time. Solids seem to be a magnitude lower. I look for not shock or g specs on switches but more importantly the vibration spec if a switch has one.

Nicely done on the testing of the switches John, unfortunately it removes the magic of these devices
dB

 

[rharshberger]

The motor vibration spec derived from the raw motor test data would be a good thing. I have this chart from years ago when the rocket electronics industry was not taking into consideration motor "vibration", particularly on hybrids vs the low sample rates the electronics provided at the time. Solids seem to be a magnitude lower. I look for not shock or g specs on switches but more importantly the vibration spec if a switch has one.

Nicely done on the testing of the switches John, unfortunately it removes the magic of these devices
dB

Lets not forget about rocket rotation in addition to vibration.

 

[JohnCoker]

The motor vibration spec derived from the raw motor test data would be a good thing. I have this chart from years ago when the rocket electronics industry was not taking into consideration motor "vibration", particularly on hybrids vs the low sample rates the electronics provided at the time. Solids seem to be a magnitude lower. I look for not shock or g specs on switches but more importantly the vibration spec if a switch has one.

I didn't see any effects below 500Hz (I tested at 10, 100, 250 and 500Hz) so I would say those low-amplitude vibrations at 100Hz and lower would not affect any switches.

 

[jd2cylman]

The Missileworks screw switches can be purchased with a nylon over block (guide) that keeps the screw from falling out. It also allows you to unscrew it until it pushes up against the block, thus keeping tension on the screw in the open position also. All my screw switches have these guides and I’ve never had one vibrate on since installing them. However… if you put too much pressure on the screw, you can push off the nut. So a good touch is needed.