Hi Joe, yes I'm aware that comparisons are difficult, given the 2 differing test protocols, that's why I qualified what I said by referencing the USN tests specifically. I'm not trying to give any impression other than the facts as they are documented in the NEDU test data, as I said. So please stop giving the impression that I'm trying to give some impression other than what I posted.
But since you brought up the subject of cross test comparisons, please remember that Alex Deas bothered to include the Prism in a WOB chart on an RBW thread, after making adjustments for internal diver WOB and the deeper NEDU test depth in the calculations and the unit still came out with lower WOB than all except Boris. I don't take it as fact, but those were Alex's calculations not mine and he is a stickler for detail of the highest order. The NEDU Prism tests also include a hydrostatic load measurement for both prone(.47kpa average) and upright(-.09kpa average), both of which exceed their 1.0kpa test criteria. And if I understand the figures correctly, the hydrostatic load is actually higher in the prone position, the opposite of Boris and which might be another reason why the NEDU WOB tests are done in the prone position, other than divers typically working hardest while swimming... -Andy
The hydrostatic imbalance peak depends on the design.. some are optimized for vertical some for horizntal.. This is different from resistive breathing.. The latest chart that alex put out doesn't have the prism on it.. Correcting for the diver's wob is easy.. you just have to add a bit to the prism (or subtract from all the others), the difficulty comes in is that there is no direct way to compare verticle vs prone position.. All sorts of otehr things come into play. especially the way lungs or hoses can collapse.. at low ventillation rates these do not make a huge difference but at high rates they do...
The standard testing these days for wob in the ce tests is at 40m.. this point is listed in the nedu tests, in the past 50m was frequently used..
I am not saying I agree with the CE liimits and protocol just thats why people have been using to do the tests..
Take a rig like the rEvo in the vertical position the breathing is significantly higher than the prone position, this is especially true on the exhale.. Paul used a few tricks to optimize the breathing when in the prone position.. 2 key tricks he used is that the inhale and exhale lungs are different sizes, and that the inhale lung is at a lower point than the exhale lung.., This uses the fact that our lungs are more efficient blowing than sucking, so the inhale is very easy on the rEvo, and we don;t notice the exhale.. Paul once gave me the numbers for a single test in this position on a rig without all the upgrades, and the numbers were lower than any other test number I heard.. He wount publish these results as first they are a single test and second it was done without all the recent upgrades..
on ots rigs the changes will be less drastic but will still be influenced on how well the gas path stays open or is collapsed..
The trick of 2 different sized lungs also has another benefit.. when 2 counterlungs are used a smaller exhale helps increase scrubber efficiency as the gas is not allowed to cool as much.. a design using a signle lung, that immediately passes the gas through the scrubber before capturing it should in theory have the best efficiency (as long as flow is not too fast).
as to me implying what you imply.. I understand you being passionate, but for those that really are new to this thing, the way the messages come across implies they can just look at the numbers to see relative ease of breathing, but this is not the case..