GTA
All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Topic started by: JPSAXNC on June 13, 2025, 12:53:23 PM
-
I use to make valves with an airfoil on the inside like a ram jet engine. My thinking was that when the valve opened the high speed high pressure air would create a boost in power. yay or Nay.
-
Not exactly sure what you mean by the position of the airfoil. Is it part of the sealing surface or built into the valve?
From the limited knowledge I have misunderstood. You can’t boost anything. Just reduce losses. Cylinder head tuning in four stroke engines found bigger ports reduce volume because the fluid speed is reduced. But that is for a car engine not an airgun.
-
The airfoil, If you sawed the valve in half down the middle, instead of the sides being straight, it would be an air foil shape.
-
The complex interactions here make airflow predictions best left to the computer simulation process. I've read many assumptions about airgun airflow that are more myth than reality.
Air has mass so it has inertia and once moving has momentum. It can't move instantaneously and once moving can't stop instantaneously either.
A ramjet inlet shape causes a pressure increase at the cost of a loss in velocity. This just prior to fuel injection and ignition. IMO this does little to enhance airgun performance.
Sufficient sizing and smoothing of the air path to the pellet is GOOD.
CAUTION... too much porting volume can change the IMPULSE (pressure-time function) which may affect pellet velocity negatively.
-
I’ve wondered if a springer transfer port were configured as a more refined aerodynamic Venturi would it effect performance?
-
If thinking along the line of an SR71's cone intakes that produce a low pressure at & beyond there root diameter increasing air flow from side intake vents .... This is a constant flow event happening :o
Contained pressure released to an ambient pressure space happening in milliseconds and see no way for this boost proposed to mature that quickly and make a difference ... IMO
As a long time 2 stroke engine technician, to gain boost or move air in short duration cycles there has to be changes in atmospheric differential pressures that attract one another so flow happens in direction wanted being greatly assisted by these forces.
Way beyond me to give the math .... but do & have worked on mechanical devises be them engines or airguns to understand loosely many of the dynamics of accelerated air flow.
Just thoughts shared ???