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All About Guns What's your weapon of choice, and why? Discuss the beloved speargun here!

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Old 03-20-2017, 05:47 PM   #16
popgun pete
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Re: A Different Evolution

I have pieced together the evolution of the "RPS-3" by looking through the pages of "Athlete-Submariner" where new equipment was discussed for the benefit of divers and spearfishermen in Soviet-era Russia. The Russians were well aware of what went on outside their borders and turned their minds to making improvements or modifications that suited their own requirements.
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Old 03-21-2017, 05:05 AM   #17
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Re: A Different Evolution

Now armed with more information I went looking for the original Russian patent and I have just found it. You can see that the original design grew in complexity once the factory engineers got to it as the simple looking rear section was eventually made as complicated as possible, although in my view that is the most intriguing part of the "RPS-3" gun. It is also the part that rusts!
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Old 03-21-2017, 05:06 PM   #18
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Re: A Different Evolution

What was eventually produced.
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Old 03-22-2017, 04:53 PM   #19
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Re: A Different Evolution

Sergiy Kravchenko, manufacturer of the "Aquatech" hydropneumatic speargun which in a sense is also a descendant of the Italian Alcedo "Hydra", tried some modifications on a couple of "RPS-3" spearguns. One gun had its inner barrel replaced and a sliding annular piston performed the function of a moving bulkhead instead of a flexible rubber pipe. Basically it was like an "Aquatech" gun, but retained the mechanical sear catch system of the "RPS-3" speargun that holds onto the spear tail. The modified gun has a tank of a different color to the usual green. A second gun had all its ports drilled out to 1.4 mm diameter from the original 1.0 mm, but everything else remained the same. The following table shows the shooting results which demonstrate a significant improvement in efficiency.

Enlarging the inner barrel ports decreases the life of the rubber pipe and was only evaluated to assess the effect of port size rather than done as a "fix".
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Old 03-22-2017, 07:48 PM   #20
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Re: A Different Evolution

This is an "Aquatech 500A" (500 mm powered spear travel as against 400 mm for the "RPS-3"; "A" denotes rear handle) which uses a variation on the "Hydra" gun's hydraulic locking trigger mechanism. Its efficiency is much greater and this gun can use multiple spear insertion strokes to charge the gun to whatever your strength can give as essentially it has a variable compression ratio. Like the "RPS-3" it sinks like a stone when you drop it, but at least it saves you from sending a search team downriver to recover your lost gun.

The stylistic homage to the "RPS-3" is apparent if you look at it carefully. The rear handle section of the "RPS-3" takes up a lot of gun length, but adds nothing to propulsion, whereas in the "Aquatech" the inner barrel runs through most of the gun's length (refer layout diagram).
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