Inalex Alpha C1 Pneumatic Speargun

trromic said:

Useful translation Pete! Interesting desing, althougt I prefer more simple solutions. Hydropneumatic spearguns are also too complicated for me. What is the main advantage of hydro-pneumatic gun over pneumatic or pneumo-vacuum spearguns? Alpha C1 solves the problem of possible damage to piston and shock absorber using very light piston. I think that efficient shock absorber solves the main disadvantage of regular water barrel and vacuum barrel guns on high pressure.

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Actually a complete rewrite rather than a simple translation, plus I had to fix some part numbering errors on the third diagram, some of the numbers were switched around.

The advantage of a hydropneumatic gun is if you push the spear in then it stops just where you left it, regardless of how far you reached in inserting the spear into the gun, but only on the valve operated hydropneumatic models. Mechanical sear tooth hydropneumatic guns have no such advantage and their only "plus" is a quiet shot. If we neglect the oddball expanding and collapsing rubber hose guns like the "RPS-3" and "Kobra" then they usually have an annular piston sliding on the exterior of the inner barrel tube. This annular piston moves at a slower velocity than a regular pneumatic gun piston, but it pushes along a fatter column of water which speeds up when it drives through into the smaller diameter inner barrel due to the constriction in water column diameter while maintaining the same water mass flow rate, so the spear is propelled at a higher velocity than that of the annular piston. That is what makes for a quiet shot. Biggest problems for hydropneumatic guns is you need to clean them out after saltwater use (not entirely arduous or complicated, but perhaps beyond some people in terms of their motivation to do it) and they don't float after the shot, or at least the ones that I have encountered so far.

One of the enemies of pneumatic/hydropneumatic guns of any type is water penetrating the inner spaces where you cannot see it, where with all the oxygen available in the compressed air chamber it can slowly nibble away at the metal parts gradually turning them all to scrap. This is why I think very fast moving parts slamming into a wall of water inside the confines of a gun's inner barrel are avoided as much as possible, just in case the water overwhelms the piston seals and enters the gun's pressure chamber without any external sign of it happening. I think this is why vacuum barrel guns are a problematic area for mainstream manufacturers as are hydro-braked muzzles, they don't want to risk water being caught inside a closed space where it cannot be ejected before back pressure builds up too much in the trapped water. The only reason this does not happen in the annular piston hydropneumatic guns is the large diameter piston is moving much slower, although it is possible water also gets past their seals, something that I would rather not think about!

trromic said:

Pete I agree about all.
Oddball expanding... What is that? Have you some drawing of principle?

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Oddball just means unusual or strange, the rubber hose is shown on the "RPS-3" thread (hydro/pneumatic speargun).

popgun pete said:

"Air pump" mode is achieving by unscrewing the muzzle one third of a turn so that the piston during barrel pumping with the spear can breathe air from the atmosphere via the then exposed slotted channels in the front end of the inner barrel bore. Once barrel pumping concludes the muzzle is retightened and the gun is ready for shooting, the seal on the piston no longer being able to move past the slotted channels that allowed air into the gun.

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I think that should read a third of the number of turns to unscrew the muzzle on the gun, having adjusted the sketch to simulate it. The piston is actually longer than the sketch shows, being too short in the original.

I just received a communication from Alex Orfanidis and he confirmed the operation of his very interesting Inalex Alpha C1 pneumatic speargun. More to follow as he sent me some photos. For now here is the gun in its latest form and a summary diagram that I just rearranged.

These fish have had some experience of the "Alpha C1". Unfortunately for them they have been at the other end of it! So we know the gun shoots OK, but it is not yet a floater if I interpret correctly what Alex says in his messages. Some parts may require weight reduction via use of more moulded components, but that is something that seems to be planned for the future provided the gun can attract a large enough market to justify the additional cost of the tooling.



One method of increasing a gun's water displacement and without removing or reducing parts, although there will be some additional material required, is to use a hydroformed tank. Personally I don't like hydroformed tanks as it places more stress on the tank wall as air pressure tries to return it to a cylindrical shape, but there are a number of pneumatic guns using them now and the tanks have not given any trouble to date. We have seen the "Pelengas" gun with both a simple cylindrical and a bulged wall, hydroformed tank, so for a gun to carry extra weight such as a reel and still float after the shot then the tank needs to "fatten up". Offsetting that is the gun becomes more of a paddle as its tank profile broadens in one plane or another, usually the horizontal plane.

The dimensions of the Inalex "Alpha C1" gun are as follows:

Inner Barrel ID: 14 mm; hence so is the piston which is tail-less and is held by the vacuum behind it situated between its rear end and the front face of the releasing valve when the gun is cocked to shoot (that is how all the releasing valve guns work, even the hydropneumatic versions).

The "Alpha C1" models available are, in terms of gun overall length (barrel length): 77 cm (60 cm), 97 cm (80 cm), 117 cm (100 cm) and 137 cm (120 cm). I assume the "barrel length" is the working course of the piston, so to obtain the working course of the piston you subtract 17 from the overall length of the gun in centimetres.

The grip handle can be placed at whatever position you want on the gun when you order it. The main change is the length of the pull rod connecting the remote trigger located in the grip handle to the rear releasing valve mechanism situated in the butt end of the gun.

Maximum Operating Pressure: 30 Bar
Usual Operating Pressure: 18 - 20 Bar
Loading Effort: 22 - 25 kgf for the above air pressures

The "Alpha C1" gun uses the inner barrel as the hand pump with the muzzle set to "air pump" mode. The compression ratio of the hand pump is deliberately limited by the pump stroke to produce only 30 Bar so users cannot go beyond that pressure regardless of how many times they pump the gun as a safety measure. The gun's shooting safety is activated by screwing the rear butt power controller right up to imprison the releasing valve, so there is no chance of a shot in this situation, again an emphasis on safety which Alex says was an important factor in his design. Hence no safety lever to flip back and forth and forget just where it is at as on so many other spearguns, but the gun can be rendered safe while you conduct your shooting line wraps, which is what you want a speargun safety for. Then you set your desired power level and commence the hunt.

The "Alpha C1" gun can be muzzle loaded with repeated spear insertion strokes until you are able to insert the spear all the way into the gun.

Once you have pushed all the compressed air behind the piston through the releasing valve's front end valve the piston stays back except for a very short rebound action which occurs on all releasing valve guns (I know this from using the GSD trigger valve-operated guns, it is just residual air expanding from a tiny, highly pressurized volume back to ambient pressure).

Note that with a 14 mm inner barrel you gain more propulsive force for any given chamber pressure, which of course you have to load against unless you opt for a lower pressure to compensate. A similar releasing valve gun was the GSD "Katiuscia", it also had a 14 mm ID inner barrel and was a floater, unlike its "Dynamic" predecessor. As far as I know the GSD pneumatic gun was the only releasing valve, rear handle gun available in the West and with its departure there was nothing to replace it. The next GSD gun produced was the "Punto", but it was a mechanical catch, ball sear gun despite its strong family resemblance to its GSD predecessors.

From what I have seen of it the "Alpha C1" looks to be well designed and finished with very good attention to detail, just check out this latest image of the muzzle. The white grip gun handle photos are ones I saved earlier when the gun first appeared in print.


An action shot:

tromic said:

The only drawback for me is the high force required to cock the gun or to pump it. This is the same force as the force required to load the shaft for shooting.

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That is only because the pump bore is the same size as the inner barrel, being the same tube for both uses. On a Mares gun the hand pump bore is smaller than the inner barrel bore for say a "Sten", so the effort is less, but you have to pump more strokes. On my Scubapro "Magnum" the hand pump bore is larger than that for the Mares pump, it is closer to the inner barrel diameter (13 mm), so I need less pump strokes to pressurize that gun. Makes no difference to loading and shooting, you only pump the gun up once, maybe twice, a season.

The idea of using the same bore diameter for the hand pump as is used for the inner barrel of the gun is that if you can press the pump handle down for the last centimetre or so of pump travel as the air transfers from the pump into the gun then you can also latch the gun at that same pressure. Another example of a "big bore" hand pump being used for gun pressurization is the "Seabear" or "Pirometer RP" mid-handle pneumatic speargun.

This long video shows how the "Alpha C1" gun is pumped up and the use of the power regulator "collar" that is the revolving rear butt on the gun: https://www.youtube.com/watch?v=USfpFDuFRgo

NB. You will need to get rid of the highlighted section here which the site adds for some reason.
http://forums.deeperblue.com/wlmailhtml:%7BB2C17DA8-1348-4132-8B1F-A3D46D708B45%7Dmid://00000036/!x-usc:https://www.youtube.com/watch?v=USfpFDuFRgo

Alex has just told me that the "Alpha C1" models from 97 cm to 137 cm do float after the shot, so that makes the "Alpha C1" speargun an attractive proposition for free-diving spearfishermen. I don't make a habit of recommending guns or participating in this versus that debates, but it seems to me that any impediment to buying this gun is now removed. I have spearfished with "sinkers" (such as my "Black Sea" BST850A hydropneumatic gun), but it is way easier with a gun that floats in my opinion and for the locations that I dive in (with plenty of rocks on the bottom waiting for my gun to fall!). Hence basically the most used sizes are floaters, so the gun requires no changes at all, it is OK as is.

The detail photo of the muzzle shown above has it in "air pump" mode, you can see the air breather holes in the side of the barrel tube.

There are more "You Tube" videos about this "Alpha C1" pneumatic speargun, they can all be found here. http://www.youtube.com/user/construktorALPHAgun/videos

Alex is on Facebook if you want to contact him directly, however he only communicates in Russian and consequently I have been using the on-line translators (e.g. Bing) to do so. If you translate into Russian first and then translate it back into English to check what you have just said then you cannot go too far wrong. It is an iterative process, but the translator works as fast as you can type when doing minor adjustments to get things right, i.e. making sense rather than nonsense. Avoid using colloquial expressions as the translators often interpret them very literally with sometimes strange results.

https://www.facebook.com/alex.orfanidis.7

If the link does not work then type it exactly as above into your URL box (same problem as above with unwanted extra text inserted at first by the site).

There is now a new web-site: http://inalex.biz/

It looks like it is still under development, but the basic layout and text are there, as are the contact details if you are interested in purchasing an Inalex "Alpha C1" speargun.

Very interesting to hear from someone who has actually used one. The "Alpha C1" gun has changed slightly over the last few years, so I assume your gun has the white handle grip and the slightly different barrel length to what is now being offered.

How do you find the moving butt mechanism reset action, is it easy to do? Also is the gun a quiet shooter? The line release appears to be controlled by the releasing valve movement, so a successful reset probably holds the release arm in the line wrapping position, but maybe you can tell us how it works.

The 14 mm ID inner barrel should make the gun more powerful than a "Cyrano", everything else being equal, however it may have a better internal air flow as well. Did the float improve the balance of the gun in terms of it being nose heavy? Mares used to add a similar float to their longest gun, but it was not a cuttle-bone/cuttlefish shape, being a bulbous form instead.

Actually now I have just looked at it I guess you could say that it was cuttlefish shape, see attachment from the "Sten Competition Line" Schematic (Sten 87).

I recently revisited the web-site and see that there is now a "Bazooka" version of the gun. Here is a portion of a photo from the site, click on the "models" button at the top of the home page to see the rest of it. The front end of the gun now has an elliptical shape, but I don't know anything more about it, although there also appears to be another length available which is 127 cm.