|
Post by SeaRat on Oct 29, 2022 18:59:42 GMT -8
Luis,
I hear you, and am glad I made you laugh. But, if you look at the Snark III mushroom, and compare it to the Mentor, you’ll see a big difference in size. By the way, the Snark III does bubble a bit when it is vertical in the water. So I’m not sure that’s a real problem.
I still now think Aqualung used a lot of existing parts for both the Mentor and the New Mistral.
John
|
|
|
Post by luis on Oct 29, 2022 19:33:41 GMT -8
I have had the Mentor in my hands and I opened it up. Most of it is very unique. The first stage internals are standard Aqua Lung (same as my Argonaut) with the use of the RAM or Conshelf parts, but most everything else is very unique. And when you are holding it, you can tell that cost was not one of the priorities. Many engineers dream of having that kind of a budget... I am just saying... The Snark III does have a huge valve, but I am not impressed (or not favorably impressed) with the flow area under the valve. I am not sure if they are all the same, but the ones I own have some relatively small round holes under the huge valve. It is not a very good design. Talking about cost savings... I don't really know why they did that. But, at least my impression is that the Mentor exhaust valve system is far better than the Snark III. Oh, and the valve (in the Snark III) itself is not that flexible either. It is a very old design. The modern valves relies on a geometry that creates the sealing stiffness required, but they buckle out of the way when they start to flex. Valve design has change a lot.
The valve support can also be much more of a restriction than an actual modern mushroom valve.
It is not only size that matters... I have heard that before somewhere. As I mentioned, I very specifically and very carefully, made that design trade-off analysis when designing the Argonaut. I had others suggesting to look at the design of the Snark III... I did and I am not impressed or not favorably impressed. I have played a lot with the tuning of my Argonauts and even with the size of my existing valve, I can easily tune the cracking effort to less than 0.6 inWC and can cause a decent free-flow in the vertical position. The new Mistral has a completely off-the-shelf Titan first stage, with only two parts that are different: the ring that holds the second stage and the logo. That is it. That Titan is not in production anymore, but neither is the new Mistral. The second stage probably uses a number of off-the-shelf parts, not the housing and I don't even think that it shares the diaphragm with any single hose (which is kind of bad), but some of the demand valve components look familiar. Keep in mind the new Mistral and the Mentor are two completely different design approach and budget. Aqua Lung paid to design and produce the new Mistral, the Navy paid for the design and production of the Mentor. That makes a huge difference.
|
|
|
Post by SeaRat on Oct 29, 2022 19:46:08 GMT -8
Luis,
I hope you don’t take my discussion as anything other than that. Through my observations/discussions I have been successful in getting some interesting details of how regulator design comes about from you, and I really, really appreciate that. I would love to dive the Mentor sometime.
John
|
|
|
Post by vance on Oct 30, 2022 8:30:52 GMT -8
Not having one to look at, it's difficult to know, but what about a whole new second stage body design, with the orifice(s) on or near the top so the air jet is directed down the intake horn? Maybe with a bleed jet or two as well? I assume you are referring to the new Mistral and not the Mentor. The real problem with the new Mistral is the case (the housing). The housing is relatively small and the horn is directly opposite to the opening for the second stage body. Designing a new second stage is always a possibility, but it would be tricky in the existing housing. Yes, I am referring to, and trying to gently direct us back to the topic of the thread, the new Mistral. As I said, I don't have one to look at, and I certainly believe your judgement that it would be tricky. I suppose that it's also too tight for some kind of added air director? I don't mean a tube, but something fitted into the housing. I'm thinking of some single hose seconds that had a sheet metal piece fitted in the housing. But instead of metal, a 3D printed part? Or how about a 3D printed housing with an integrated second stage body?
|
|
|
Post by antique diver on Oct 30, 2022 8:55:20 GMT -8
I think that if I had one of the "new" Mistrals I would be modifying some holes and drilling an new one somewhere in the second stage body. Well, I know I would if I could get my hands on an extra body just in case I screwed it up worse.
|
|
|
Post by vance on Oct 30, 2022 9:23:14 GMT -8
I'm with you! But, I'm not paying the kind of money people are asking for these things. Maybe Mark S will get to work on his!
|
|
|
Post by spirou on Oct 30, 2022 9:46:28 GMT -8
I am not home for two days, when home I send you a video of the venturi effect on this reg it blows hard. I try ones, but I don't make a video it can be I interesting 🤔
|
|
|
Post by scubalawyer on Oct 30, 2022 18:19:21 GMT -8
I'm with you! But, I'm not paying the kind of money people are asking for these things. Maybe Mark S will get to work on his! All I need is desire, interest and time. 😎 I do like the concept of trying to improve it but too many other projects screaming at me at present. One of these days. I don't think the bar is very high to do better than the original USD design engineers, unless of course they bungled the design so bad that it is FUBAR. 😇
|
|
|
Post by spirou on Nov 3, 2022 8:30:33 GMT -8
|
|
|
Post by spirou on Nov 3, 2022 8:45:59 GMT -8
|
|
dso
Regular Diver
Posts: 31
|
Post by dso on Sept 28, 2023 14:41:02 GMT -8
First...I am late to the party and this thread....I bought an almost new '06 Mistral several years ago and only recently 'tried' to dive with it....fine until you go face down horizontal [normal swimming position] and then you are breathing through a straw, at best....I have decades of diving two hose regs, literally growing up with them and this reg is the worst I have ever tried. MP gauged at 9.4bars, in specs and at high end....no other adjustments possible that I could find. Hate to even sell it, since other than a museum piece I could not recommend trying to dive with it.. Any "new" schemes to make it work, please share them. Thanks for the thoughtful discussion. DSO
|
|
|
Post by SeaRat on Sept 28, 2023 16:02:50 GMT -8
First...I am late to the party and this thread....I bought an almost new '06 Mistral several years ago and only recently 'tried' to dive with it....fine until you go face down horizontal [normal swimming position] and then you are breathing through a straw, at best....I have decades of diving two hose regs, literally growing up with them and this reg is the worst I have ever tried. MP gauged at 9.4bars, in specs and at high end....no other adjustments possible that I could find. Hate to even sell it, since other than a museum piece I could not recommend trying to dive with it.. Any "new" schemes to make it work, please share them. Thanks for the thoughtful discussion. DSO I’ve seen some European divers who did disconnect the first and second stages, used a longer LP line, and did chest-mount the second stage successfully. After re-reading some of our threads on this regulator, that seems to be the best answer. The Venturi is negated on this regulator by being aimed against the case, thus decreasing its effectiveness. According to Louis, there simply isn’t room inside the case to do anything differently. I decided early not to purchase this regulator (the “New Mistral” by Aqualung) because with the short hose, it was impossible to mount onto my doubles. ‘Looks like I made a good choice, and I now use one of the few Mossback Mark 3 adaptations on my DA Aquamaster. John
|
|
|
Post by spirou on Oct 4, 2023 11:05:35 GMT -8
First...I am late to the party and this thread....I bought an almost new '06 Mistral several years ago and only recently 'tried' to dive with it....fine until you go face down horizontal [normal swimming position] and then you are breathing through a straw, at best....I have decades of diving two hose regs, literally growing up with them and this reg is the worst I have ever tried. MP gauged at 9.4bars, in specs and at high end....no other adjustments possible that I could find. Hate to even sell it, since other than a museum piece I could not recommend trying to dive with it.. Any "new" schemes to make it work, please share them. Thanks for the thoughtful discussion. DSO I owned also 2005 mistral, first time I dive with it I feel that he is hard to breath, but I just buy it. So I make my self a complete maintenance. MP is important, must be between 9 and 9.5 ( aqualung titan manual) but the second stage is really important. The ventury is very strong, without the hose, much more than old USD mistral, the second stage must be perfectly adjust , another things is the non return valve. These valves can have a great influence if they are too strong. There not much technicians who well known this regulator. Don't forget that at this time it is the only double hose regulator who passed the EN250 , (EUROPEAN NORM FOR REGULATOR) , The mentor failed when aqualung try to get EN250 certification, first they would purpose a commercial version of the military mentor version. That is why aqualung decided to created something different. Respectfully Fred
|
|
|
Post by spirou on Oct 4, 2023 11:34:43 GMT -8
First...I am late to the party and this thread....I bought an almost new '06 Mistral several years ago and only recently 'tried' to dive with it....fine until you go face down horizontal [normal swimming position] and then you are breathing through a straw, at best....I have decades of diving two hose regs, literally growing up with them and this reg is the worst I have ever tried. MP gauged at 9.4bars, in specs and at high end....no other adjustments possible that I could find. Hate to even sell it, since other than a museum piece I could not recommend trying to dive with it.. Any "new" schemes to make it work, please share them. Thanks for the thoughtful discussion. DSO I’ve seen some European divers who did disconnect the first and second stages, used a longer LP line, and did chest-mount the second stage successfully. After re-reading some of our threads on this regulator, that seems to be the best answer. The Venturi is negated on this regulator by being aimed against the case, thus decreasing its effectiveness. According to Louis, there simply isn’t room inside the case to do anything differently. I decided early not to purchase this regulator (the “New Mistral” by Aqualung) because with the short hose, it was impossible to mount onto my doubles. ‘Looks like I made a good choice, and I now use one of the few Mossback Mark 3 adaptations on my DA Aquamaster. John Screenshot_2023-10-04-21-14-52-073~2 by Patrick Michel, sur Flickr Another mistral who was adapted by another European 🙄
|
|
|
Post by SeaRat on Oct 4, 2023 11:48:31 GMT -8
First...I am late to the party and this thread....I bought an almost new '06 Mistral several years ago and only recently 'tried' to dive with it....fine until you go face down horizontal [normal swimming position] and then you are breathing through a straw, at best....I have decades of diving two hose regs, literally growing up with them and this reg is the worst I have ever tried. MP gauged at 9.4bars, in specs and at high end....no other adjustments possible that I could find. Hate to even sell it, since other than a museum piece I could not recommend trying to dive with it.. Any "new" schemes to make it work, please share them. Thanks for the thoughtful discussion. DSO I owned also 2005 mistral, first time I dive with it I feel that he is hard to breath, but I just buy it. So I make my self a complete maintenance. MP is important, must be between 9 and 9.5 ( aqualung titan manual) but the second stage is really important. The ventury is very strong, without the hose, much more than old USD mistral, the second stage must be perfectly adjust , another things is the non return valve. These valves can have a great influence if they are too strong. There not much technicians who well known this regulator.Don't forget that at this time it is the only double hose regulator who passed the EN250 , (EUROPEAN NORM FOR REGULATOR) , The mentor failed when aqualung try to get EN250 certification, first they would purpose a commercial version of the military mentor version. That is why aqualung decided to created something different, two young ingeneers were dedicated to design that. Respectfully Fred Okay, looking at my calculations for changing from BAR to PSI, that's a interstage pressure of between 132 and 140 psig. You say the Venturi is very strong, but Luis says it is very weak due to colliding with the main case. I'm not sure what to think unless I can get o New Mistral and try it out. I'd agree that very few technicians would know about the New Mistral and its particularities. John
|
|