My new G250Vs and ramblings

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Yeah, that was unfair of me to throw Poseidon under the bus. With the Venturi collar in the right position, it's a fantastic reg.
 
Thanks for the insightful post @rsingler! Since this thread is about venturi design, I am now wondering what the dynamic flow curve looks like for the D420 in comparison?
 
I am now wondering what the dynamic flow curve looks like for the D420 in comparison?
Frigging awesome, to be honest.
Screen capture from a video:
20210111_150404.jpg

20210111_150529.jpg


And remember, this plot is on the surface. Standard reg position in the water adds another 0.75" of pressure on the valve. Looking at those plots above, that explains why the thing is dang near effortless. From 0-4CFM (common breathing flow), inhalation resistance underwater actually becomes 0.5" to 0.05"!!!
 
Well let's not derail Simon's thread much further, but if EN250 conditions at high RMV and great depth are in any way related to, say, 25+ CFM flow rates at the surface (see "Reynolds number"), then it looks like the D420 crosses gently into freeflow a bit past where I measured it. But not flagrantly.
Screenshot_20210111-151425_Gallery.jpg

But if this bears further discussion, how 'bout we head over to the D420 thread?
 
https://www.shearwater.com/products/perdix-ai/

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