Do Pistons rotate?

[Buliwyf]

The moon rotates on it's axis. 27 days to complete one rotation. That's the same time it takes to orbit the earth, so it appears, to us here, to not rotate.

But if it didn't rotate, we'd see the smooth side, and China would see the cratered side. The moon actually has a "high tide" on the Earth side. Which makes that side heavier to Earths gravity, so the moon is even less likely to now rotate at any speed that doesn't match it's orbit. It's pretty much locked in.

As for your scuba piston........Sharpie Marker, and report back.

 

[Couv]

Diaphragm, piston.....I think I'll develop Wankel/rotary type first stage. What name should I give it? Loony Tunes?

 

[Alastor]

Loosey Turnes

 

[sealark]

Ok, so what if they do rotate. I say hell no prove me wrong lets see a picture.

 

[Nemrod]

Actually the moon rotates on it's axis once per orbit but from the earth we do not see it as so, but from another vantage point on the sun, where it is awfully warm, you would certainly see the moon rotate.

Whatever.

The piston on a regulator can/does rotate, when the coil is compressed, being a coil spring, each end turns opposite the other, if one end is fixed, the the rotation is doubled on the free end. Since the piston is not captured in a positive manner on any first stage I have had to disassemble, the piston may or may not rotate as dependent upon which is greater, friction applied to the bottom of the piston by the spring coil or friction from the O-ring. I suspect, that in time the piston does rotate and I know this from some of my Mark V clones where I have notated a particular position upon assembly and they are not in that same position when taken apart later.

N