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New dry pneumatic!

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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gitano

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Feb 20, 2003
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I have looked high and low for info here in the States about new dry pneumatic but have had no luck. When I was leaving Italy the rumor mill was generating a buzz about a pneumatic gun with a dry internal barrel. This supposedly facilitates lower internal precharge pressures and more accuracy. The fact of the matter I have not heard of any american(or non euro for that matter) made pneumatics and was curious about the view on pneumatics here and around the world.

I have a love hate relationship with my Cyrano that I could ramble on about but I will refrain. I am very interested to here what people have to say.

Is there anyone out there who is modifying pneumatics if so I would like to know how to improve the cyrano and skorpion both.
Thanks guys:cool:
 

fuzz

Hawaiian transplant...
Sep 9, 2002
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Iya's friend has a super-pneumatic :D i'm sure he'll come in soon & write an essay on his experiences :)

Other than that, please ramble on about your Cyrano musings - we can learn something from everybody's insight. :hmm


Also, do you have any info on these new guns? I thought the whole principle of pneumatics was they were all "dry" in the chamber? After all, they're charged by compressing the air with the piston right? Did you mean the area around the shaft after loaded? :confused: Please elaborate.
 
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gitano

New Member
Feb 20, 2003
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some like dry, some like it wet

Pneumatics are a very different beast. The most advanced pneumatics in Italy are called oleopneumatici, this is a much more precise name for the popular production guns, as it refers to their use of both oil and pneumatic for energy production.

Yes if you want the gun to fire at full power add to the precharged air pressure to the resevoir. If you would like less power it is possible to drain the air pressure. I know that this is all very elementary but it leads me other finer points such as flooding the resevoir to reduce the volume. The end effect is the capability of maintaining high pressures(good initial thust) with a lower volume(less trajectory) this makes a gun good for fish that have hidden amongst rock ie. the spear makes a very powerfull short jab.

The internal of the second barrel which contains the piston and spear shaft is traditionally wet from ambient water. The new guns use a seal that keeps that chamber dry too. The lack of ambient water equals less resitance from mass v force friction. The major hindrance is the need to maintain a very specific spear diameter dedicated by the internal diameter of the seals.

The claim is that the dry oil and pneumatic guns can achieve with 22-27 atm what other oil and pneumatics attain with 30-40 atm.

Sorry about the huge post.
 

Iyadiver

Mr. Long Post
Apr 22, 2002
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Here comes Iya..................zoooommmmm

Gitano please get more info on that dry pneu, what brand is it and does it need a special loading pump , not the air pump to fill the air pressure but a pump that loads the shaft in, if any.

I did not do underwater test with my friends pneu because the special loading pump was leaking that day. Now the gun is back with him. This gun is also a dry firing type, so I can fire on land. I did twice, once with its shaft and one with water ( filled up the chamber where the shaft supposed to be ). Look at my old post, u can see how powerful it is, going thru inches of teak wood, plywood and penetrate my concrete wall a few inches.

If what comes out of Italy resembles what my friend made in function, operation and loading........just too much a coincidence.:naughty

Dry firing pneu will be definitely be powerful. Typical pneu uses 11-13mm piston. The shaft is 7 or 8mm. There is at least 3mm area of water multiplied by the barrel length........that's a lot. Pushing water at high speed out of the barrel thru the muzzle side holes require lots of energy, that's why being dry is a good thing but the muzzle and piston dampers will need to be super strong. A wet (regular ) pneu doing dry shot ( I never try ) will probably last under 10 shots.

My friend's pneu uses 23mm piston and can take up to 11 or 12mm shaft. The shaft have o rings to make the chamber dry.
The key to the power is the chamber must be dry. He tested flooding the chamber and power dropped like hell because his piston area allowed way too much water. The 23mm piston is needed to deliver the mass and drive big shaft. The logic is simple, PSI of air means Pound Per Square inch. An 11-13mm piston does not qualify 1 inch surface area, thus when pumped at 22ATM/330 PSI, it doesn't fully utilize the pressure because there is not enough piston surface area to carry the load. That's what he explained to me....something like that.

His pneu testing have proved that he can launch a 8mm shaft out of the gun underwater with 180 lbs cable of 10 meters and still the shaft got lost because the left over energy snapped the cable. With the test I did (dry) and that hole in the wall of mine, I believe it. It operates on 25 BAR only.

I have told him to make me a 11 or 12mm shaft. At 110cm, this pneu might shoot further than the +-170cm Riffe Blue Water. It is shame I had that pump leak when I was testing and I already got him to make me a 9.5mm shaft, instead of the 8mm he was initially using.

It is funny, of all the places in the world, he found me in this forum. My own city boy !!! I once posted for recoiless super magnum speargun and his pneu is what he brought me.

If Italy makes mass production like what my friend has and perfected it: Riffe, Alexander, Kitto, Wong and whatever 4-6 bands weapon out there will look quite sissy if not overly too big and bulky.

By then I will feel sad for my friend because he initially wanted to sell his patents/design abroad......:waterwork .

Let's hope Italy comes up with something beautiful and powerful. Good stuff should not be kept a secret too long.

Gee...my post is not long enough :D :D
 

fuzz

Hawaiian transplant...
Sep 9, 2002
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IYA - Super Poster to the rescue!

This phrase of yours intrigues me: "The shaft have o rings to make the chamber dry."

How would you accomplish this?
Where does the o-ring sit?
I'm assuming at the muzzle to block out the water?

If so, when shooting, wouldn't there be a conflict between water trying to enter the chamber and air trying to escape it?
When the gun shoots, I'd assume there'd be an explosion of the air surrounding the shaft?

How would you reload when scubadiving if the chamber has to be dry?

Inquiring mind wants to know :D
 

Jay Styron

New Member
Aug 31, 2001
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Just a thought on this, I don't shoot pneumo's now personally but have in the past and I do own a few. If there were a gland or o-ring of some type in the internal bore that fit snuggly around the shaft when it was being loaded(attempting to keep the water out) that would create a pretty big vacum in the bore. I don't think the o-ring could hold back the water pressure trying to get in. If the o-ring was tight enough to accomplish this it would be a bear to load. Make any sense:confused:
Jay
 

gitano

New Member
Feb 20, 2003
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production, somewhat

Wow, and where is your friend that is making this super dry pneumatic? The biggest problem for your friend is that the theory that the guys have at MaoriSub is patented. Yes MaoriSub is the maker of the Mamba. Their website is underconstruction so there is no use in posting it. They make two guns a 90cm and a 110cm. The guns only fire a 6.5mm shaft, it would seem that they are still only interested in small fish. The 110 retails for 230 euro and takes 20 days to make after ordered. I know that this sounds like some little old Italian artisan in a small dusty shop is producing these guns and that very well may be the case.

I have been working like mad to translate an Italian review of the gun and get permission to distribute it. To capture peoples interest is the most difficult thing in making a paradigm shift. I have had the opportunity to fire a prototype 2 years ago(of a different maker) and found the gun as easy and quick to load as a single band euro gun of similar length but with the power of a twin. I am aware that I am compairing apples and oranges, but anything else would take too long to write and more measuring insturments to give true performance data. The gun was also scary accurate.

The problem is that these guns are still just a little too euro read 6.5mm shaft. When the people at Maori get more info to me I will post it.

Regards,
El Gitano

P.S. The guns affore mentioned needed only spear insertion like a standard pneumatic, yet remained dry. I will make no claims that this technology will make all band guns obsolete, rather it will give them some competition in the near future.
 

gitano

New Member
Feb 20, 2003
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what if???

I see your point Jay the O-ring is on the shaft and the moment that it passes(the first few cm of ejection) seal is momentarily lost until the piston seats in its full extention. The out rush of air(a few minuscule bubles) causes no air to enter the spear chamber.

To reload you must surface and position the butt of the gun on the instep of your foot and reload just like any other pneumatic. The gun I tried required one to keep the muzzle out of the water but I believe that this has somehow been resolved.
 

w3ac

I should be working
Nov 8, 2002
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hmmm.....

All this discussion has got me curious. The very fisrt speargun I used was a Mares Californian Pneumatic. The thing sucked! No range, and very loud. After using a rubber gun, I swore I'd never use a pneumatic again. That is until seeing this post. Can a pneumatic actually shoot 10 meters acurately? This would rival my 66 inch blue water gun. If this could be fit with an Alexander slip tip and rigged to a breakaway system then they have just put most blue water gun makers out of business. I would love to be able to take long shots on Ono and other blue water game fish with a 110 cm euro style gun instead of my bulky 66 inch. How is the recoil on this super pneumatic and would Iya's friend be interested in selling one?

Brad :hmm
 

gitano

New Member
Feb 20, 2003
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don't get your hopes up

like I said the 110 gun I tried had a perfomance similar to a two band 110. I don't know about you but I tend to like a bigger gun for the big fish.

Hey W3ac I will be coming your way with a 110 Maorisub Mamba that will be my reef gun(from what you have read do you think it will work?). You can try it when I get there if you like. Have you read your private messages? I wanted your opinion on an other euro gun for the big stuff, a 130 SeaTec Gabbiano. Send me a pm with your thoughts.
 

fuzz

Hawaiian transplant...
Sep 9, 2002
995
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I think w3ac was referring to IYA's post - 110cm long & 10m range.




:hmm
 

Iyadiver

Mr. Long Post
Apr 22, 2002
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Here are some answers to the questions :

The concept of this super-pneu from my friend is basically the same as what I have always wanted in a gun. Short, no longer than 110cm, powerful like a Blue Water gun that can shoot at least 8 meters deadly. Recoiless or at least low recoil. Mid handle design for easy swing. Trigger quality like Riffe or Alexander or at least close to it. Lightweight, in proportion to its power output. Accurate. Unfortunately pneumatic can not be made quiet like band guns with open muzzle and no slide ring.

01. FIRING CHAMBER/BARREL MUST BE DRY
In a normal pneu, you cock the piston to lock in the trigger by pushing in the shaft. The shaft sits on the piston, push the piston
down all the way in till it get engaged on the trigger sear. Water will enter the barrel/chamber into whatever gap there is between barrel diameter and shaft diameter. An o-ring at the shaft front will be useless at this stage because water is already in. Unless you want to remove the shaft (hopefully not getting killed in the process ), fill air in the barrel/chamber by lifting the gun out of the water or by using a small straw or hose while keeping the gun inverted. When air has filled up the entire barrel/chamber, load the shaft back in and that o-ring will keep the air in. One problem. This kind of pneu will not allow the use of slide ring for the shooting line because if an air tight seal is to be provided at the front part of the shaft, it means the diameter of that particular air tight area of the shaft will be bigger than the diameter of the butt of the shaft which normaly has the cone adaptor that allows the shaft to sit tight on the piston.

So, the shooting line attachment can not use the normal slide ring or be positioned at the back of the shaft. It must be attached at the forward part of the shaft. Accuracy effected ? Must experiment in depth.

Let's say we fill up the barrel with air at surface level which is 1 ATM, we dive down to 90 feet, the o-ring on the shaft must be good enough to withstand at least up to 150 feet or 5 ATM of pressure, not a difficult task. If a scubadiver owns this gun and fill the barrel at 90 feet and he later go shallow at 30 feet, the air in that barrel will expand and might push the shaft out of the gun. Thus the design of the o-ring on the shaft must also withstand that air expansion. This is why my friend wanted me to test for him because he is not a scubadiver. I wanted to bring down the gun to 140 feet and see how the o-ring seal work. I will also need to fill up the barrel with air at 140 feet and later surface, to see if the shaft gets pop out of its piston seat due to air expansion. I never could find the time to do this tests.
It seems the design will be better for a freediver who does all loading/cocking on the surface at 1 ATM.


02. SUPER POWER
Any pneu that can be loaded the way a normal pneu is loaded, by pushing the shaft in and cock the piston, can never be super powerful. The limit of the power is then limited to the single cocking capability of the hunter. What make band gun so powerful is that the total accumulation of so many powerbands can be cocked one by one. If say a Blue Water Gun using 4 x 5/8 bands is to be designed with a single band of 64mm, no one could ever load the gun. This is the dead end for pneu designer. Want more power......?....easy to make on the engineering side but how would one load the gun ?? Cobra of Brazil use a special dummy shaft to load their powerful model, something like that. But how much force can be applied to load that shaft without having to bring say a car jack ? The limitation will also be on the shaft that load the gun. There is a limit on how much force can be applied to a pneu using its own shaft before actually bending the shaft itself during the cocking stage. With the available free play between shaft diameter and piston diameter, the shaft have room to flex.

Now assuming I have a super pneu with a piston diameter that qualifies to be 1 inch square. I pump/charged the gun to 25ATM or 375PSI. I will need to overcome a force of 375 pounds to drive the piston down with the shaft, plus friction and add the increased pressure as the barrel area become smaller and air get compressed even higher. How the hell do I push a shaft in with such tremendous power ?? Bring my neighbours ?? Here is where every pneumatic gun designer start to scratch their heads, engineering design is possible but loading is impossible. My pneu friend got stuck at this for a year. Untill one day he told himself, damn what a dummy I am. The solution has been around us all this while. Since water is where the gun will be used, the medium to load the gun will be readily available to the hunter. Water is incompressible, that's the answer !!!!! He built a small hand held hydraulic pump using sea water as the pumping fluid. He used the water pressure to cock the piston in place....MAN,,,a genius !!! Hydraulic pump can pump tons of of pressure easy. The pump is only 40cm long and 1/4" diameter. With only under 30 strokes of the pump, the super pneu get cocked without ever using it's own shaft and it is so easy to do it because the power applied is bit by bit with the stroke of the pump. Same principal as hydraulic car jack but with no oil reservoir, the entire sea water is the fluid we ever need !!!

I weigh 72kg/158 pound. I tried loading his pneu with my entire body weight, the piston won't even move a bit.

This is the REAL key to his super power pneu, I might as well broadcast it here. As far as I know, no pneu in the world operate with 23mm piston because no one can ever load the gun but that kind of piston diameter is required to produce power output beyond belief. Yes, the firing barrel must be dry too, this is the second key to the power.

So this gun is a real dry firing pneu, can be use on land or in the water. Much work was done on the muzzle side because the shock damper that get banged by the piston must survived hell load of a job. The normal trigger found on say a Mares, can not be used on this kind of pneu. At certain pressure level, the trigger pull become offensive. The designer was having this trigger problem because I told him a blue water gun have to have a superb smooth release trigger. The last shot I did on land was using his newly designed trigger and it was nice. Designing a superb trigger on a pneu is not easy because everything must work in that air tight area of the 25ATM. Just imagine making a multi-stage trigger like an Alexander or Riffe unit and it must be air tight !!!!



If my friend lives in Italy, I am sure he will get hired by some speargun company.

I have tested the procedure of loading this gun. Pump it with the special pump, blow air into the barrel and place the shaft in. It does not take any longer than loading my gun with 4 x 5/8 bands. However, u need a place to store the pump and the small air hose. For freedivers you can always put it in ur float, for scubahunter a bit of extra hassle.

If ever such mass production of the super pneu is feasible, a lot of exotic metal will be required to keep it light and strong at the muzzle. Owing to the short 110cm to keep it agile and swing pretty, an 11-12mm shaft of 115-120cm will be required to transfer the massive energy.

If anyone interested in the design plan for mass production or whatever, I'll hook them to my friend. In my opinion nothing can be patended on the operation side of the gun like pumping with water to cock and o-ring on the shaft. Only the internal engineering ( already patent pending ) can be patended.

My friend does not own a machine shop, he is a computer guy. He has been in this pneu project for more than 3 years, out of love of spearfishing. I think his bank account been drained dry with all his experiment.

I want one of his gun but this is a slow refining process because he redesigned his unit when I give him ideas and a set of criterias and now he does not live in my city. Pneu gun is very complicated and can't be easily made by just anyone. Every part of this gun is stainless steel for the time being. So much work to be done just to alter a bit here and there. When everything satisfy me, I will then make one using a lighter weight material for my own use. Exotic metal or composite is not easy to get in my city.

Maybe another year boys ................:eek: :eek:
 

w3ac

I should be working
Nov 8, 2002
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Insantiy man, insanity. If that gun is ever made for retail, is affordable, and is relatively problem free oohhh buddy! You and your friend would be heros in the spearfishing world. I would jump on that bandwagon. Please keep us updated on how this super pneu is coming.

Brad :martial
 
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