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Discussion of diving methods and equipment available prior to the development of BCDs beyond the horse collar. This forum is dedicated to the pre-1970 diving.
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timbo
Lung Diver
Posts: 53
Joined: Fri Apr 02, 2010 1:56 pm
First Name: tim
Location: belgium

Royal mistral

Fri Sep 01, 2017 9:18 am

Hello,

I own a bunch of La Spirotechnique Mistral and Royal Mistral regulators.
I have been diving with one for some years now. I recently started to service some others that where not in working order
to start giving some pool introductions in my diving club. I have 6 now in woking order and noticed something strange.
I tuned them al with the same gauge and they all have the new silicone membrane from this site. There is a difirence in breathing effort
between them. Some go verry well and others are less. What could cause this difference?

regards

tim

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simonbeans
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Joined: Sat Jun 25, 2005 2:00 pm
First Name: Allan
Location: Rochester NY

Re: Royal mistral

Fri Sep 01, 2017 10:06 am

First guess: Lever height.
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Bryan
Plank Owner
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First Name: Bryan
Location: Wesley Chapel Florida
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Re: Royal mistral

Fri Sep 01, 2017 10:32 am

Lever height.....Tension on the diaphragm.
Doing it right should include some common sense, not just blindly following specs and instructions. .Gary D, AWAP on SB

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timbo
Lung Diver
Posts: 53
Joined: Fri Apr 02, 2010 1:56 pm
First Name: tim
Location: belgium

Re: Royal mistral

Fri Sep 01, 2017 12:36 pm

That was my guess to but I used a level gauge so the height should be the same on all of them.

Tim

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ScubaLawyer
Master Diver
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First Name: Mark
Location: Laguna Beach, CA

Re: Royal mistral

Fri Sep 01, 2017 2:01 pm

timbo wrote:That was my guess to but I used a level gauge so the height should be the same on all of them.

Tim
Proper lever height on Mistrals is an art, not a science. I have two mistrals, neither of which work properly at the "gauge measured" height. Took a lot of futzing around to find the sweet spot, and both sweet spots are different on each Mistral. Go figure. Mark
"The diver who collects specimens of underwater life has fun and becomes a keen underwater observer. .. seek slow-moving or attached organisms such as corals, starfish, or shelled creatures." (Golden Guide to Scuba Diving, 1968) :D

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georgeaustin
Master Diver
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First Name: george
Location: Los Angeles CA

Re: Royal mistral

Fri Sep 01, 2017 3:45 pm

Since we're back on the Royal Mistral topic - Are they worth the effort and headache for the collector who wants to dive and maintain them regularly or is there some design or material flaw that makes this a regulator that oughta be passed on as consideration for purchase? It's not really a good sign that production was discontinued after a short time.

I have an acquaintance that was with US Divers in the 60's and 70's here in LA but he can't remember anything good or bad about them.

I've heard stories and read threads. . .

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Bryan
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Location: Wesley Chapel Florida
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Re: Royal mistral

Fri Sep 01, 2017 4:07 pm

LaSpirotechniqe Mistrals/ Royal Mistrals are fantastic regulators.
US Divers Royal Mistrals are better looked at than dived.

Two totally different creatures all together though.

Sent from my SM-J700T using Tapatalk
Doing it right should include some common sense, not just blindly following specs and instructions. .Gary D, AWAP on SB

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antique diver
Master Diver
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First Name: Bill
Location: North-Central Texas

Re: Royal mistral

Fri Sep 01, 2017 7:59 pm

The springs may vary in tension from one reg to another.
The older I get the better I was.

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timbo
Lung Diver
Posts: 53
Joined: Fri Apr 02, 2010 1:56 pm
First Name: tim
Location: belgium

Re: Royal mistral

Sat Sep 02, 2017 2:00 pm

I have been thinking the same things.
I wil try some fine tuning and wil see where it goes.
Here in Belgium the oldtimers al dove La spirotechnique mistrals or Royal Mistrals so I think they must been ok.

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