My new G250Vs and ramblings

[lexvil]

You guys are barking up the wrong tree. Both Dr. Rob and I have suggested the issue is with the lever as that is what separates the hard and soft seats. If you want to experiment, change one thing at a time in the same regulator under the same conditions.

For the record: I still believe the manuals that state for maximum flow the vane crescent should face the aspirator is incorrect. Look at the wording: "facing forward toward the back of the diaphragm" & "facing forward toward the mouthpiece." What sort of double-speak is that? Someone just made a typo or editing error and (just like in the aircraft manuals I've read over the years) the mistake was copied by the script writer.

Speaking of aircraft, if I were to ask you to design an airfoil with a crescent; would you put the crescent on the leading edge or trailing edge?

Would the airfoils purpose to smooth flow or disrupt flow?

 

[Open Ocean Diver]

You guys are barking up the wrong tree. Both Dr. Rob and I have suggested the issue is with the lever as that is what separates the hard and soft seats. If you want to experiment, change one thing at a time in the same regulator under the same conditions.

For the record: I still believe the manuals that state for maximum flow the vane crescent should face the aspirator is incorrect. Look at the wording: "facing forward toward the back of the diaphragm" & "facing forward toward the mouthpiece." What sort of double-speak is that? Someone just made a typo or editing error and (just like in the aircraft manuals I've read over the years) the mistake was copied by the script writer.

Speaking of aircraft, if I were to ask you to design an airfoil with a crescent; would you put the crescent on the leading edge or trailing edge?

Leading edge...

 

[Open Ocean Diver]

You guys are barking up the wrong tree. Both Dr. Rob and I have suggested the issue is with the lever as that is what separates the hard and soft seats. If you want to experiment, change one thing at a time in the same regulator under the same conditions.

For the record: I still believe the manuals that state for maximum flow the vane crescent should face the aspirator is incorrect. Look at the wording: "facing forward toward the back of the diaphragm" & "facing forward toward the mouthpiece." What sort of double-speak is that? Someone just made a typo or editing error and (just like in the aircraft manuals I've read over the years) the mistake was copied by the script writer.

Speaking of aircraft, if I were to ask you to design an airfoil with a crescent; would you put the crescent on the leading edge or trailing edge?

I will check my lever height next.

 

[Open Ocean Diver]

Changed the vane around in the free flowing unit and it still free flows. Ugh

 

[Geo7]

For the record: I still believe the manuals that state for maximum flow the vane crescent should face the aspirator is incorrect. Look at the wording: "facing forward toward the back of the diaphragm" & "facing forward toward the mouthpiece." What sort of double-speak is that? Someone just made a typo or editing error and (just like in the aircraft manuals I've read over the years) the mistake was copied by the script writer.

Speaking of aircraft, if I were to ask you to design an airfoil with a crescent; would you put the crescent on the leading edge or trailing edge?

Maybe someone can record a dynamic performance curve on a flow analyzer? I don't have one, but figure this should show in which position venturi is stronger?

I think a plain straght vain should achieve stronger venturi then the cutout in either position. And yes, point taken from couv and rsingler that the tolerances and fit of the lever might be the main source of variance.

 

[Open Ocean Diver]

Lever height seems fine but the spread at the feet seems loose. Don’t know if that’s to much play?

 

[Couv]

Would the airfoils purpose to smooth flow or disrupt flow?

I know you know this ;-) but you put the question out there. The purpose of the vane is to create a venturi effect (Venturi Initiated Vacuum Assist.) If I wanted an airfoil to do such a thing with maximum effect, I would put the crescent on the trailing edge. Most swallow tails I've seen were in accordance with Mr. Venturi & Mr. Bernoulli.

 

[rsingler]

Maybe someone can record a dynamic performance curve on a flow analyzer? I don't have one, but figure this should show in which position venturi is stronger?

@Open Ocean Diver posted his results above.
Flow test
The greater improvement in dynamic inhalation resistance was with the crescent facing forward (apologies to @couv , with whom I will continue to disagree until we resolve whether this is an airfoil or some other design issue at work). I'll grant you, this was two different regs, but until someone does a side by side comparison changing only the vane, I think this supports the page from the manual also posted earlier about having crescent facing the diaphragm.

 

[lexvil]

I know you know this ;-) but you put the question out there. The purpose of the vane is to create a venturi effect (Venturi Initiated Vacuum Assist.) If I wanted an airfoil to do such a thing with maximum effect, I would put the crescent on the trailing edge. Most swallow tails I've seen were in accordance with Mr. Venturi & Mr. Bernoulli.

But, I wonder what the thought process was when it was added to the design, I’ve never felt it served much good as designed, to show what a Venturi assist should look like peek into an old HOG or Zeagle ZX they used a curved insert (now no longer installed in HOG’s) I think case design is a better way to achieve the Venturi and the rotating flow disrupters like HOG/APEKS/Deep 6, even the SP C 370 are much better at this function. Although I like the SP design better overall this is a funky troublesome solution.

 

[Geo7]

@Open Ocean Diver posted his results above.
Flow test
The greater improvement in dynamic inhalation resistance was with the crescent facing forward (apologies to @couv , with whom I will continue to disagree until we resolve whether this is an airfoil or some other design issue at work). I'll grant you, this was two different regs, but until someone does a side by side comparison changing only the vane, I think this supports the page from the manual also posted earlier about having crescent facing the diaphragm.

Ah thanks, missed that... Even though it was not a test of the same individual reg with one part replaced, I think that comparison is conclusive. The airfoil principle is well established, but perhaps here it is a matter of how much surface area is being put into the path of the airflow (similar, but not identical, to what Atomic does). I wish it was a straight vane like on the g260 and S620ti...