Post by angusfoggie on Mar 7, 2019 9:39:17 GMT -8
Hi, first time posting. I wrote a history of Scubapro for its 50th anniversary. The book was never published. But in the course of many interviews with former Scubapro employees I had the pleasure of interviewing Tony Christianson.
He has recently shared the sotry of the Pilot regulator on this board: vintagescuba.proboards.com/post/43079/thread
And he invited me to chip in. I’m posting here the chapter covering the Pilot regulator I wrote for the unpublished book.
I’m assuming Scubapro will be cool with this, after all once of the conditions of Tony talking to me was that I tell his story as I heard it from the people and source material I had access to when I wrote the book:
LET ME SAIL AWAY FROM HERE
The 1970s began with SCUBAPRO in a strong position. Its catalogues had some of the best products on the market and it was expanding across the world. Some new products made a splash: the MK 6 first stage was on the market from 1969-75. The only difference that it had from the MK 5 is that the yoke was pneumatically attached to the tank valve instead of with a yoke screw. The MK 7 came on the market in 1971 and had a unique appearance. It is the only SCUBAPRO regulator that has a fixed non-swivel yoke. It is very large and heavy and had an audible alarm when the tank pressure dropped to approximately 40 bars. When your air got to this point, the regulator would vibrate to cause a honking sound, which earned this regulator the nick name “The Honker”. The piston and seat of this first stage were exactly the same as the MK 5. Audible alarms were nothing new, they had been available since Healthways but this was the first built into a first stage. But if anyone thought the 1970s was going to be a decade without significant regulator innovation they were far from the truth. The designer of the MK 7 was a young man called Tony Christianson and in 1977 he and SCUBAPRO rewrote the book with the Pilot second stage.
Testing the new piece in Mustique, Gustav Dalla Valle had this to say: “Practically zero inhalation effort and very little effort also in exhalation. (…) After you breathe with the new regulator (the Pilot) and you switch back to your old second stage, the difference is so strong that you feel that with the regular second stage you have a hard time inhaling.”
The Pilot had not been developed by a SCUBAPRO engineer but by an independent inventor of diving and climbing gear called Tony Christianson. Dick Anderson remembered a meeting at Healthways in the 1950s “One of the people doing the sub-assemblies (of the Scubair) was a polite kid named Tony Christianson. He was 13 or 14. Tony did good work and he felt compelled to call me ‘Mr Anderson.’ He told me his ambition was to one day develop his own regulator and do what I was doing. ‘No reason why you can’t,’ I said. ‘Fat chance’ I thought.”
Tony received a PhD in Human Factors Engineering from the University of California in Los Angeles. His specialty was underwater life-support. Then he went on to consult with SCUBAPRO designing a mouthpiece that was marketed and a regulator that was prototyped but never put into production. Dick paid Tony’s work the highest compliment “One of his first developments was a mouthpiece for SCUBABPRO. I was so impressed with his sensible design I let myself be inspired by it when I was called upon to develop a mouthpiece for another company. I don’t know whether Tony was flattered or angered by the similarity of our designs. Pure invention is very, very rare. Tony tamed the pilot valve with pure invention.”
Tony said, “The Pilot was offered to USDivers, Techna and SCUBAPRO. I eventually granted SCUBAPRO an exclusive worldwide license to manufacture and market the invention. I retained full ownership of the Pilot patents and received royalties from SCUBAPRO based on sales.”
Test after test came in and everyone declared the Pilot regulator a thing of wonder. It breathed more easily than any other regulator even when the tank was at low pressure, One of the testers, Jim Hall at PADI International said “For the first time in many, many years I was surprised to see how low my air supply was during my dive – I had breathed past that point of increased resistance that usually warns me to surface.”
What Dick Anderson called “the magic” was a pilot valve system that provided an extremely high airflow and was very easy to breath, especially at the deeper depths. The diaphragm was attached to the case on its lower portion, the upper portion was free to open and close thus acting as a huge exhaust valve. Inhalation opened a pilot valve, which in turn pressurized the control chamber and opened the air supply valve. The pilot valve needed to open by only a tiny amount 0.005 inches (0.127mm) to allow air to flow into the control chamber. The air supply valve has a piston behind it, which is driven by the air in the control chamber balancing the second stage. So the intermediate pressure between the first and second stage is irrelevant to pressure of the air supplied by the second stage. It was the first balanced second stage produced in the US.
The Pilot was so easy to breathe that free flow was an issue. If a normal regulator of the 1970s was out of the divers mouth under ten inches (25cm) of water the water pressure alone could make it flow. With the Pilot it took only half an inch (12mm) of water to activate free flow. To counteract this difficulty the regulator was fitted with a dive/pre-dive switch so that it could be turned off when it wasn’t in use.
AHEAD OF ITS TIME
The Pilot was the best second stage on the market. But it was a complicated piece of engineering. The difficulties of manufacturing such a precise piece of engineering were beyond the technological capabilities of the time. Tony said of his own invention: “My hand-built prototypes worked beautifully, but some of the parts required precise machining. In a way, the Pilot was ahead of its time, what can be easily machined precisely with CNC (computer numerical control) technology today was not available in the 1970's. The result was a temperamental regulator that lasted only several years on the market.” With regular maintenance at SCUBAPRO approved dealers the product could be kept in ideal condition but the complexity of it drove SCUBAPRO to seek an alternative with similar breathing characteristics that was easier to maintain. Tony worked hard to optimize his design so that it could be manufactured reliably under the industrial tolerances of the time. But at SCUBAPRO the inhouse engineers were inspired by the Pilot and were working to produce their own design, the eventual replacement for the Pilot the AIR I.
The Pilot regulator’s amazing performance allowed it to perform at extreme depths. In 1979 the US Navy Experimental Diving Unit (NEDU) wanted to do some testing on mental abilities during very deep dives under a variety of circumstances. The Navy asked for volunteers and set about pressurizing a complex of chambers to simulate conditions under 1,800 feet (427 meters) of water. Then they made the volunteers stay in the tanks for 37 days. Some of the time the men were in a water-filled tank in conditions that effectively made the exercise the world’s deepest dive. They chose the Pilot regulator, which performed handsomely and they awarded Tony Christianson a plaque in honour of his remarkable piece of engineering.
He has recently shared the sotry of the Pilot regulator on this board: vintagescuba.proboards.com/post/43079/thread
And he invited me to chip in. I’m posting here the chapter covering the Pilot regulator I wrote for the unpublished book.
I’m assuming Scubapro will be cool with this, after all once of the conditions of Tony talking to me was that I tell his story as I heard it from the people and source material I had access to when I wrote the book:
LET ME SAIL AWAY FROM HERE
The 1970s began with SCUBAPRO in a strong position. Its catalogues had some of the best products on the market and it was expanding across the world. Some new products made a splash: the MK 6 first stage was on the market from 1969-75. The only difference that it had from the MK 5 is that the yoke was pneumatically attached to the tank valve instead of with a yoke screw. The MK 7 came on the market in 1971 and had a unique appearance. It is the only SCUBAPRO regulator that has a fixed non-swivel yoke. It is very large and heavy and had an audible alarm when the tank pressure dropped to approximately 40 bars. When your air got to this point, the regulator would vibrate to cause a honking sound, which earned this regulator the nick name “The Honker”. The piston and seat of this first stage were exactly the same as the MK 5. Audible alarms were nothing new, they had been available since Healthways but this was the first built into a first stage. But if anyone thought the 1970s was going to be a decade without significant regulator innovation they were far from the truth. The designer of the MK 7 was a young man called Tony Christianson and in 1977 he and SCUBAPRO rewrote the book with the Pilot second stage.
Testing the new piece in Mustique, Gustav Dalla Valle had this to say: “Practically zero inhalation effort and very little effort also in exhalation. (…) After you breathe with the new regulator (the Pilot) and you switch back to your old second stage, the difference is so strong that you feel that with the regular second stage you have a hard time inhaling.”
The Pilot had not been developed by a SCUBAPRO engineer but by an independent inventor of diving and climbing gear called Tony Christianson. Dick Anderson remembered a meeting at Healthways in the 1950s “One of the people doing the sub-assemblies (of the Scubair) was a polite kid named Tony Christianson. He was 13 or 14. Tony did good work and he felt compelled to call me ‘Mr Anderson.’ He told me his ambition was to one day develop his own regulator and do what I was doing. ‘No reason why you can’t,’ I said. ‘Fat chance’ I thought.”
Tony received a PhD in Human Factors Engineering from the University of California in Los Angeles. His specialty was underwater life-support. Then he went on to consult with SCUBAPRO designing a mouthpiece that was marketed and a regulator that was prototyped but never put into production. Dick paid Tony’s work the highest compliment “One of his first developments was a mouthpiece for SCUBABPRO. I was so impressed with his sensible design I let myself be inspired by it when I was called upon to develop a mouthpiece for another company. I don’t know whether Tony was flattered or angered by the similarity of our designs. Pure invention is very, very rare. Tony tamed the pilot valve with pure invention.”
Tony said, “The Pilot was offered to USDivers, Techna and SCUBAPRO. I eventually granted SCUBAPRO an exclusive worldwide license to manufacture and market the invention. I retained full ownership of the Pilot patents and received royalties from SCUBAPRO based on sales.”
Test after test came in and everyone declared the Pilot regulator a thing of wonder. It breathed more easily than any other regulator even when the tank was at low pressure, One of the testers, Jim Hall at PADI International said “For the first time in many, many years I was surprised to see how low my air supply was during my dive – I had breathed past that point of increased resistance that usually warns me to surface.”
What Dick Anderson called “the magic” was a pilot valve system that provided an extremely high airflow and was very easy to breath, especially at the deeper depths. The diaphragm was attached to the case on its lower portion, the upper portion was free to open and close thus acting as a huge exhaust valve. Inhalation opened a pilot valve, which in turn pressurized the control chamber and opened the air supply valve. The pilot valve needed to open by only a tiny amount 0.005 inches (0.127mm) to allow air to flow into the control chamber. The air supply valve has a piston behind it, which is driven by the air in the control chamber balancing the second stage. So the intermediate pressure between the first and second stage is irrelevant to pressure of the air supplied by the second stage. It was the first balanced second stage produced in the US.
The Pilot was so easy to breathe that free flow was an issue. If a normal regulator of the 1970s was out of the divers mouth under ten inches (25cm) of water the water pressure alone could make it flow. With the Pilot it took only half an inch (12mm) of water to activate free flow. To counteract this difficulty the regulator was fitted with a dive/pre-dive switch so that it could be turned off when it wasn’t in use.
AHEAD OF ITS TIME
The Pilot was the best second stage on the market. But it was a complicated piece of engineering. The difficulties of manufacturing such a precise piece of engineering were beyond the technological capabilities of the time. Tony said of his own invention: “My hand-built prototypes worked beautifully, but some of the parts required precise machining. In a way, the Pilot was ahead of its time, what can be easily machined precisely with CNC (computer numerical control) technology today was not available in the 1970's. The result was a temperamental regulator that lasted only several years on the market.” With regular maintenance at SCUBAPRO approved dealers the product could be kept in ideal condition but the complexity of it drove SCUBAPRO to seek an alternative with similar breathing characteristics that was easier to maintain. Tony worked hard to optimize his design so that it could be manufactured reliably under the industrial tolerances of the time. But at SCUBAPRO the inhouse engineers were inspired by the Pilot and were working to produce their own design, the eventual replacement for the Pilot the AIR I.
The Pilot regulator’s amazing performance allowed it to perform at extreme depths. In 1979 the US Navy Experimental Diving Unit (NEDU) wanted to do some testing on mental abilities during very deep dives under a variety of circumstances. The Navy asked for volunteers and set about pressurizing a complex of chambers to simulate conditions under 1,800 feet (427 meters) of water. Then they made the volunteers stay in the tanks for 37 days. Some of the time the men were in a water-filled tank in conditions that effectively made the exercise the world’s deepest dive. They chose the Pilot regulator, which performed handsomely and they awarded Tony Christianson a plaque in honour of his remarkable piece of engineering.
I'm a big fan of Healthways gear, and also a student of history, so whenever I can hear about the old days of diving, I appreciate it.
