Split Compression Piston - Crosman Patent

[subscriber]

Just to show that I don't love the above idea because it is mine; here is why it is flawed:

There will be too much friction on the forward stroke.  The "bristles" or friction rings will need an additional aspect that retracts them when the piston is moving forward, and deploys them on piston deceleration or reversal.  Perhaps it will take some directional wedges behind the rings to do that; or a combination with some other idea that someone else is inspired to dream up...

It may be possible that just making the bristles longer might unload them enough when the piston moves forwards.  However, rubber has more friction and less stiffness than actual wire bristles.  One won't know if an idea has value, unless you try it out.

[MartyMcFly]

Just to show that I don't love the above idea because it is mine; here is why it is flawed:

There will be too much friction on the forward stroke.  The "bristles" or friction rings will need an additional aspect that retracts them when the piston is moving forward, and deploys them on piston deceleration or reversal.  Perhaps it will take some directional wedges behind the rings to do that; or a combination with some other idea that someone else is inspired to dream up...

It may be possible that just making the bristles longer might unload them enough when the piston moves forwards.  However, rubber has more friction and less stiffness than actual wire bristles.  One won't know if an idea has value, unless you try it out.

I had a similar idea when posting about the grommets, but in the version I had in mind I was going to make cuts into the circumference of the piston behind the forward lip of the parachute. The cuts/channels would require some material removal and would be cut at an angle  (maybe 30 degrees), letting the material to role over itself to catch the outer comp wall. I abandoned it because I thought it would catch the walls too easily during the cocking stroke...

Anyways, I think it would be a doable experiment with a spare piston seal and some careful cutting.

-Marty

[MartyMcFly]

I take your friction brake and raise you a transfer port reed valve . 

The latter does not care if the piston bounces because the high pressure air is trapped in the TP.  The valve would need to be on the inside of the compression chamber...

subscriber, I raise your port reed valve with a Tesla value. Over engineered? Yes, but no moving parts. Hehe.

-Marty

[subscriber]

subscriber, I raise your port reed valve with a Tesla value. Over engineered? Yes, but no moving parts. Hehe.

-Marty

Clever, but making the TP long enough to be a forked tube that loops back on itself will increase its volume and the overall friction losses at high flow.  Making the TP short and of limited volume are the single best things you can do to improve springer power and efficiency.

Now; Tesla valves have other airgun applications; such as to slow down air escaping from a bulge at the muzzle end - if you know what I mean

[MartyMcFly]

subscriber, I raise your port reed valve with a Tesla value. Over engineered? Yes, but no moving parts. Hehe.

-Marty

Clever, but making the TP long enough to be a forked tube that loops back on itself will increase its volume and the overall friction losses at high flow.  Making the TP short and of limited volume are the single best things you can do to improve springer power and efficiency.

Now; Tesla valves have other airgun applications; such as to slow down air escaping from a bulge at the muzzle end - if you know what I mean

The muzzle end adaptations was the first thought I had. That said, I’ve seen a very short Tesla valve diagram somewhere, just need to find it again... don’t know if it was less effective.

-Marty