The COPIS (Ko-pes) Megalodon

Hi Ron, my understanding is that once you get the hang of a needle, you almost never have to push the button, just adjust the knob once or twice to match consumption. I believe that is part of the object-not to have to push the button. So, no you shouldn't be having to decide all the time whether to push the button or not.

And while the needle is infinitely variable, you don't need to know what your exact flow rate is, only whether you have too much or too little because...it's adjustable. So actually you are constantly checking the flow rate everytime you look at your PO2. We all understand the importance of checking PO2 often, so what's the difference btw checking your displays to see if the flow is good or whether you need to push a button?

IMHO, this strikes me as a difference in what people define as "task loading". A person who dives fixed orafice MCCR is conditioned to the physical activity of pushing the button and looking at the display. A person who manages to master the needle valve is checking their display just as often and thinking about his flow rate everytime he begins to work more or less or changes depth and performing the physical task of adjusting the knob less often than the button pusher in a dive with a variety of workloads. Which is more complacent or task loaded? Is a diver with a fixed orafice, who has an easy dive that matches his predetermined flow and only has to push the button once or twice on a nice slow ascent more complacent than a diver using a needle valve that has to be adjusted twice during a dive, even while finning hard into a current while trying hard not get blown off into blue water or seperated from their buddies?

Personally, I prefer more mental task loading than physical. Why? because I can think about many more things simultaneously than I can physically do things-I'm a better thinker than I am a juggler. I'd guess that Jet pilots are better thinkers than jugglers too.

Oops, I think I hear Sutton running down the tarmac, better get in the bunker...

You make good points too, heres my last bit of input on that, I know that my fixed orifice will always revert to my "at rest" flow rate anytime I am not manually adding, I like this part. Maybe the needle valve with a set screw so one could always turn fully down and be at the "at rest" rate might be a good alternative, and a similar point for the max flow rate, with maybe one turn in between for adjustment, this could keep one out of trouble by not allowing flow rates beyond the "safe" range.