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All Springer/NP/PCP Air Gun Discussion General > Machine Shop Talk & AG Parts Machining

Spring Piston Designs - Delayed Pressure Release??

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Duane38:
Just musing....

Has there ever been a design in a springer powerplant to delay the exhaust pressure? 

I posit that, in conventional design, the pellet begins to move well before the piston ends it's travel. 

Is it possible, or even beneficial, to design a system where the swept heated charge of air is compressed into a sub-valve that is subsequently knocked open upon piston bottoming out?  This would produce a higher pressure charge to be exhausted all at once over the conventional design. 

Understandably, in the conventional design, the pellet begins to move when the equilibrium in force is no more.  A pressure of X is developed at point of release while the piston is still moving and pressure is somewhat maintained until piston stops moving. 

There will need to be some careful design parameters for a knock-open valve at the end of stroke. 

mackeral5:

--- Quote from: Duane38 on August 20, 2023, 03:57:34 PM ---Just musing....

Has there ever been a design in a springer powerplant to delay the exhaust pressure? 

I posit that, in conventional design, the pellet begins to move well before the piston ends it's travel. 

Is it possible, or even beneficial, to design a system where the swept heated charge of air is compressed into a sub-valve that is subsequently knocked open upon piston bottoming out?  This would produce a higher pressure charge to be exhausted all at once over the conventional design. 

Understandably, in the conventional design, the pellet begins to move when the equilibrium in force is no more.  A pressure of X is developed at point of release while the piston is still moving and pressure is somewhat maintained until piston stops moving. 

There will need to be some careful design parameters for a knock-open valve at the end of stroke.

--- End quote ---

Makes sense to me--Seating a pellet deeper into the rifling will yield slower velocities in many piston guns, as the pellet begins to move at a much lower pressure.... At what point in the pressure spike and at what time in the piston stroke is ideal, I bet the piston gun gurus have this figured out and do their best to control it with breech/rifling entry design and pellet selection.

Ronno6:
I am way out of my depth here, but......
I wonder if the ram would continue to the end of stroke with the same force in the face of mounting back pressure.

Kinda sounds like you are describing a hybrid break barrel/SSP air rifle.......

sb327:
I don’t think it would make the whole stroke in conventional form. It would stop wherever the pressure and spring/piston diameter causes the forces to equalize. Maybe a touch more due to momentum of piston.

If it had maybe something that tripped the valve open along the piston’s travel, it might be used to optimize the operation. Maybe with a small holding plenum with x amount of volume. Have the sear actuated by pressure maybe.

Interesting to think about.

Dave

KWK:
The volume of the air in that system would reduce efficiency

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