Taimen - Russian pneumovacuum speargun

[popgun pete]

Pete, maybe you haven't seen this video before.

ОбÑлуживание подводного Ñ€ÑƒÐ¶ÑŒÑ Ð¢Ð°Ð¹Ð¼ÐµÐ½ÑŒ - YouTube

I finally got around to watching this video. The gun is the earlier version judging by the foam in the grip handle. The newer guns have wider slots to act as keying positions so that a special tool can be used to undo and tighten the various parts, plus you do not have to use the spear as a guide as shown in this video. I think that is the founder performing the demonstration. It is good video and shows everything about the gun without the power regulator.

 

[popgun pete]

It is very light. Some all in plastic pistons has 3 g. In such cases shock absorber is not a critical part. What is normal working pressure of Taimen? It is 10 mm barrel, right?

Working pressure is 20 to 25 kg/cm2. You are not allowed to exceed 30 kg/cm2. The gun with 8 mm diameter spear has an 11 mm ID inner barrel, otherwise it is 10 mm ID.

The "Zelinka" design is used in a number of guns, it is a releasing valve gun where the inner barrel slides back and forth in the gun body to provide the opening action of the releasing valve, hence the trigger controls the reciprocating inner barrel's movements instead of operating the rear mounted valve body which is fixed in the gun. Very ingenious, but the design makes for a heavy gun as the gun cannot use the inner barrel as the structural element that holds the gun together. That job is performed by the outer tank which has to be thick enough in section to carry screw threads.

 

[popgun pete]

Here is the "Speargun Pump Table" from the English language version of the "Taimen" handbook. Note less hand pump strokes are needed for the gun using the 8 mm diameter spear as the larger ID of the 11 mm inner barrel increases the barrel's swept volume which therefore slightly raises that gun's compression ratio compared to the compression ratio of the "Taimen" guns with the 10 mm ID inner barrel. The smaller inner barrel is used in the guns which are dedicated to shoot either 6.5 mm or 7 mm shafts. So "Taimen" guns are made to shoot one shaft size only using a different muzzle bore size for each of the available spear diameters and in the case of the 8 mm version a different inner barrel. It may be that the OD of the larger ID inner barrel tube is increased to compensate for its larger bore, so that will remove some of the volumetric capacity of the air pressure reservoir. The barrels are turned down for the majority of their length to reduce their weight.

 

[tromic]

For my Cyrano 850 I need about 400 pumping strokes to get it to 25 bar.
Is the slider made in aluminum or titanium? Has the back boring in slider cone shape? How heavy it is?

 

[popgun pete]

For my Cyrano 850 I need about 400 pumping strokes to get it to 25 bar.
Is the slider made in aluminum or titanium? Has the back boring in slider cone shape? How heavy it is?

I cannot tell you about the slider (line slide) details as all the spears (4), the hand pump and some other spare parts are in a second package which is still on its way here. Two separate packages, with a considerable time gap (for obvious reasons!) between sending them was the simplest solution to the shipment not being rejected for a second time. I asked for the second package to be delayed until the first package arrived, so I may be in for another long wait. It all depends on whether it comes by sea, which is a real possibility regardless of the significant amount paid for shipping.

 

[tromic]

I see.. I hope you'll get it.

 

[popgun pete]

I see.. I hope you'll get it.

Well it has been a very long wait, but now I have everything as the second parcel arrived today. The "Taimen" gun is very nice, everything looks well made, it has exceeded my every expectation in terms of how it looks and the standard of construction. Now I have to put it back together!

 

[tromic]

Well it has been a very long wait, but now I have everything as the second parcel arrived today. The "Taimen" gun is very nice, everything looks well made, it has exceeded my every expectation in terms of how it looks and the standard of construction. Now I have to put it back together!

I am glad to hear that!

 

[foxfish]

At last! that is good news indeed.

 

[popgun pete]

For my Cyrano 850 I need about 400 pumping strokes to get it to 25 bar.
Is the slider made in aluminum or titanium? Has the back boring in slider cone shape? How heavy it is?

The line slide or slider appears to be made from aluminium. I don't have those scales to weigh it on that I had access to before, but the line slide seems very light. The line slide body has a 7 mm bore, but from the rear end it is bored out to a depth of 1 cm with a larger bore of 7.6 mm. That is also the length of the polyurethane bush on the shaft tail, i.e. 1 cm. The polyurethane bush tapers gradually going from the front to the rear where its mamixium OD is 8 mm, while at the front it is virtually the same as the shaft diameter of 7 mm. During the shot the polyurethane bush gets squeezed into the larger rear bore of the line slide where it has to push any water out that will be inside it, so I suppose there is a bit of hydraulic damping going on to avoid the line slide jamming. Like everything that polyurethane bush will probably wear out eventually, that is why I purchased 3 extra spears and 3 extra speartips to go with them.

 

[tromic]

The line slide or slider appears to be made from aluminium. I don't have those scales to weigh it on that I had access to before, but the line slide seems very light. The line slide body has a 7 mm bore, but from the rear end it is bored out to a depth of 1 cm with a larger bore of 7.6 mm. That is also the length of the polyurethane bush on the shaft tail, i.e. 1 cm. The polyurethane bush tapers gradually going from the front to the rear where its mamixium OD is 8 mm, while at the front it is virtually the same as the shaft diameter of 7 mm. During the shot the polyurethane bush gets squeezed into the larger rear bore of the line slide where it has to push any water out that will be inside it, so I suppose there is a bit of hydraulic damping going on to avoid the line slide jamming. Like everything that polyurethane bush will probably wear out eventually, that is why I purchased 3 extra spears and 3 extra speartips to go with them.

Interesting! I thought the rear end of the slider was taper shape too.

 

[popgun pete]

Interesting! I thought the rear end of the slider was taper shape too.

It seems to be a cylindrical bore, I can see a tiny step at the "base" of the larger hole where the 7.6 mm bore returns to 7 mm.

 

[popgun pete]

I put some air back in the gun after letting it all out and then tried loading the shaft. It was not very hard to push in, but I only had a minimum of air in it. When I pulled the trigger I was surprised at the kick it gave, I had the shaft without speartip pushed down onto a block of rubber and I was leaning on the gun from above to resist it moving, but it still came up quicker than I was expecting. I greased the shaft first and had wet the gun down to provide lubrication to all the seals, so it will be reasonably powerful with more air in it as it would only have about 10 or 15 pump strokes in it now. I only put the air in as the oil leaks out the inlet valve with zero pressure in the gun, probably because the inlet valve stem has no return spring. I will not take it up to operating pressure until I look like using it, but our spearfishing season is virtually over as my dive gear usually gets packed away in mid-April each year. I had hoped the gun would have arrived at the latest in mid-February, but as you know it only arrived here yesterday once the second parcel arrived. I knew it was coming as the tracking picked it up once it was transferred to "Australia Post".

 

[popgun pete]

Here is a photo comparison with a Sporasub "Stealth" for size. "Taimen" has a 28 mm OD tank, the Mares gun (it was a re-badge effort) has a 40 mm OD tank.

 

[tromic]

Nice spear gun! I expect it would be pretty quiet in water (polyurethane shaft end, light piston).

 

[popgun pete]

One thing that I found out by cocking the "Taimen" on land, something that I would not normally recommend as it is risky even with low pressure inside the gun, was that if you pull the spear shaft out a centimetre or so then it is sucked back in virtually immediately by the vacuum. Once I cocked the gun I quickly inverted it towards the floor and then had to wiggle my Mares plastic "universal" loader off the shaft's bare screw threads as it had jammed slightly on them. In doing so the shaft moved slightly forwards, it is not held tightly in the piston at all, it is actually a loose fit. So if your muzzle vacuum seal is not sealing then the shaft comes out as an indicator. We discussed this possibility some time ago and sure enough that is how the "Taimen" works. You never shoot the gun without the shaft, it relies on having to push the shaft to slow the piston down or it will slam into the muzzle with possibly disastrous effects, even underwater.

It is very impressive that a pneumatic gun with the physical dimensions of a band gun (with a metal tubing barrel) not only appears to be powerful, but with the inner works of a pneumatic gun it also floats. I know that for sure as I placed it in a tub of water to check it out, the rear handle's buoyancy offsets the weight in the muzzle. The metal muzzle, which is also the nose cone, is drilled and machined out in every direction to get rid of unnecessary material. That is why the gun would be expensive to make, a lot of material is machined away to create these light metal parts.

Hence the "Taimen" is dimensionally the equivalent of a rubber powered Arbalete, but without the drag of stretched rubber bands as it is pneumatically powered, so it should be highly manoeuvrable underwater. The angled handgrip's centre of grip pressure is right up behind the barrel as you can see from my photo above, that is why the inlet valve cover is shaped the way that it is, being a plastic molded plug.

 

[tromic]

One thing that I found out by cocking the "Taimen" on land, something that I would not normally recommend as it is risky even with low pressure inside the gun, was that if you pull the spear shaft out a centimtre or so then it is sucked back in virtually immediately by the vacuum. Once I cocked the gun I quickly inverted it towards the floor and then had to wiggle my Mares plastic "universal" loader off the shaft's bare screw threads as it had jammed slightly on them. In doing so the shaft moved slightly forwards, it is not held tightly in the piston at all, it is actually a loose fit. So if your muzzle vacuum seal is not sealing then the shaft comes out as an indicator. We discussed this possibility some time ago and sure enough that is how the "Taimen" works. You never shoot the gun without the shaft, it relies on having to push the shaft to slow the piston down or it will slam into the muzzle with possibly disastrous effects, even underwater.

It is very impressive that a pneumatic gun with the physical dimensions of a band gun (with a metal tubing barrel) not only appears to be powerful, but with the inner works of a pneumatic gun it also floats. I know that for sure as I placed it in a tub of water to check it out, the rear handle's buoyancy offsets the weight in the muzzle. The metal muzzle, which is also the nose cone, is drilled and machined out in every direction to get rid of unnecessary material. That is why the gun would be expensive to make, a lot of material is machined away to create these light metal parts.

Hence the "Taimen" is dimensionally the equivalent of an air powered Arbalete, but without the drag of stretched rubber bands, so should be highly manoeuvrable underwater. The angled handgrip's centre of grip pressure is right up behind the barrel as you can see from my photo above, that is why the inlet valve cover is shaped the way that it is, being a plastic molded plug.

That is what I like too, the position of centre of grip pressure. Some time ago, when Airbalete appeared, I was thinking to modify my Cyarano handle in that way. Sucked back spear shaft also means friction is very low.

 

[popgun pete]

In this photo you can see the ring of holes that lighten the "Taimen" muzzle. Four of them are alternate positions for the line carabineer, the smaller ones in-between are to remove weight from the muzzle.

 

[tromic]

Pete, what is the possible angle of tilt of the slider (alone, without shaft) in muzzle? Or to ask it other way. What is the ID of boring in muzzle for the slider, and what is the OD of the slider, and its lenght? How deep it get into the muzzle?

 

[popgun pete]

Here is a schematic for the "Taimen" muzzle's vacuum seal, which is a rubber molding. The schematic is not a scale drawing, but is close enough to show the various features. The rounded lip sealing ring is recessed from the leading edge by a short distance (the entrance into the seal is cupped) and has low friction on the spear shaft. The seal can stretch circumferentially at its front end in order to swallow the slightly larger diameter polyurethane bush on the spear tail without damaging either the sealing edge or the surface of the polyurethane bush. The tapered shape of this rear bush is an important part of the pneumo-vacuum design to cater for the shaft travelling in either direction through the seal. Shaft exits are made at much higher velocity than shaft loading, so the polyurethane bush gradually tapers outwards towards its rear end where it has a rounded profile that matches the entry face on the rubber seal. Any hydraulic lock condition once the sealing edges first take up on spear tail insertion will probably expand the seal's front sleeve section radially outwards thus releasing the water until the piston is actually pushed back by the spear tail. Note the "hinge point" located at the annular groove recess in the forward outer face of the rubber seal that will allow this temporary expansion (this is just a guess on my part, but usually any features are incorporated for a purpose and are not there for decoration).

The muzzle vacuum seal is produced in three sizes for the 6.5, 7.0 and 8.0 mm diameter spear shaft models of these spearguns. A tiny amount of grease is occasionally applied to the seal lip to assist with its lubrication.