Aqualung Mistral

[Ltstanfo]

If your Royal Aqua Master is not breathing at least as good as the new Mistral, may I recommend sending it for an overhaul to Bryan at VintageDoubleHose.com or Dan at VintageScubaSupply.com. These regulators are rugged, but after 35 years or more they need servicing and some of the tuning techniques we are using help exceed the original performance. You well intentioned long time LDS regulator mechanic may not be keeping up with some of the improvements we are doing in the vintage community.

Thanks for the advice Luis. My LDS services the Royal once a year, using original parts still in inventory. The shop owner (now mostly retired) was a USD retailer from day one and has at least one example of every double hose USD ever put out. That is where I obtained my Royal from.

You have my attention on one item...what improvements are you doing to "tweak" the performance of the Royal over original specs (which is what my reg is tuned for)?

Regards,
Ltstanfo

PS: I am quite interested to see your upgrade go into production. I could see myself purchasing one.

 

[fishb0y]

I've been following Luis' work on the Pheonix for a couple of months now... I have a DAAM waiting for the conversion.

Even without the Pheniox conversion, I will dive my double hose regs as much as possible. Nothing beats the reaction of people when I am getting out of the water wearing a double hose reg and no BC. Questions such as how deep did you go and did you see any shark are asked differently.

 

[fishb0y]

Thanks for the advice Luis. My LDS services the Royal once a year, using original parts still in inventory. The shop owner (now mostly retired) was a USD retailer from day one and has at least one example of every double hose USD ever put out. That is where I obtained my Royal from.

You have my attention on one item...what improvements are you doing to "tweak" the performance of the Royal over original specs (which is what my reg is tuned for)?

Regards,
Ltstanfo

PS: I am quite interested to see your upgrade go into production. I could see myself purchasing one.

Your best bet is to go to www.vintagedoublehose.com. Lots of great info there...

 

[Ltstanfo]

I agree that double hose regs are fun to dive! I also love watching the expressions on people's faces when I enter / exit the water with my double hose (and sometimes a horse collar BC). The younger divers will ask if I am using a rebreather and the older divers will usually say something like "I remember those..." or "I started out with one of those".

Regards,
Ltstanfo

 

[Luis H]

Your best bet is to go to www.vintagedoublehose.com. Lots of great info there...

Agreed


The simplest improvement (that most of us are using) is the use of higher IP than originally recommended. The idea is to balance as close as possible (without a free flow) the second stage spring force. This works best with a RAM, but it also works with a DA. This is actually an old trick, but most shops don’t use it.

Some of us also back of the second stage retainer to reduce the spring pressure on the seat. This has to be done on 1/3 of a turn at a time to line up a venturi hole with the intake horn. Again, this is to balance the IP force with the spring force. I am not recommending you do this.

Bryan has new more flexible silicon diaphragms on the works.

There are other refinements (some under development) discussed in the vintage message boards. I have a few other ideas and several other NAVED members are working on different ideas.


I do all my own regulator maintenance (and in general I am extremely pleased with the performance of my Royals Aqua Master, etc.), but my understanding is that the performance of Bryan’s rebuilds is outstanding.

 

[Nemrod]

"You have my attention on one item...what improvements are you doing to "tweak" the performance of the Royal over original specs (which is what my reg is tuned for)?"

Well, some sources are supplying Titan/Conshelf HP seats and there are also nylon squash seals, silicone cage valves (they come and go). The high(er) IP is something I have played with but because I use a conventional second stage octapus I am not thrilled about jacking the IP way up. I run 145 to 150 but I do play around with the second stage spring pressure. Polishing the surfaces of the horsehoe and the tabls, also the HP diaphram buttons and light silicone grease on them to prevent sticktion. Some horsehoes drag or bind on the twisted posts, be careful that these do not bind the rocking motion of the lever, untwist them if need be. I don't think they need to be twisted anyways. Careful centering of the tabs onto the horsehoe is important also. These are a lot of little thing but they add up.

I also do all of my own work and as of late the biggest improvement is the Phoenix nozzle assembly. The next big improvlemt will be the silicone main diaphams. These two things will make for some happy divers I predict.

Hey, this is out in left field but I throw it in every now and then, please do not stick your mouth over or on the output and breath in. The venturi will produce a powerful flow and will possibly embolize you and it likely would be fatal. Uncontrolled HP or LP air injected into your mouth is not good. If you are playing around trying to adjust these things always reinstall the hose and mouthpiece such that the exhaust cage valve provides a pressure escape. Approximately 4 psi can rupture the esophagus and LP air is 140 plus and HP is 3,000---don't do it. N