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Bluewater Pneumatics - Pros and Limitations
- Thread starterGazz
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I’m not so sure of that but I think that’s because of comp spearos being a conservative bunch. E.g. if you look at the World champs I don’t think (m)any of them shoot oleos, yet they all tend to be Med guys.
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I agree, just to clarify for all I was referring to strictly speargun competitions where they do target shooting/power testing/accuracy competitions etc..
As for a standard test, I like the setup Majd has where he always pairs penetration with accuracy. His penetration tests are on either 10 or 15cm XPS foam and if you match his density I guess the tests should match his well. I actually did this a few years back and shot a 125cm x 7.5mm shaft halfway (or fully, can’t recall) through 10cm of foam at 6m. I emailed Majd the news and he hardly couldn’t believe such a light shaft could do it. Don’t have it on video but I know it happened;-). Speaks to your point about how even the most educated/experienced spearos still have no clue how much power we can get out of these guns.
As for a much more “scientific” test we have to measure shaft speed and we have a thread for that (no need to start a new one;-)). And if I really had the time (I don’t) I would make an impact test with force gauges. With Arduinos all this tech has become super cheap. I would think a triangular plate with a force gauge in each corner and some averaging of the values could work out. Think of shooting a bathroom scale hanging vertically and you get the idea. It could be paired with speed sensors and you would have a very cool setup that could be replicated by many people all over the world.
As for stored energy, at say 20 bar, we don’t really have more than a 2-banded gun, right? I think we have less and way less than some pulley guns. But we have better efficiency. A few years ago, before the advent of small ID bands and souped up inverters I was certain of the advantage of a 30-35bar oleo but then I thought perhaps the opposition was catching up. So, it’s good to hear you don’t think they are - at least that’s what I think you think;-)
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As for a much more “scientific” test we have to measure shaft speed and we have a thread for that (no need to start a new one;-)). And if I really had the time (I don’t) I would make an impact test with force gauges. With Arduinos all this tech has become super cheap. I would think a triangular plate with a force gauge in each corner and some averaging of the values could work out. Think of shooting a bathroom scale hanging vertically and you get the idea. It could be paired with speed sensors and you would have a very cool setup that could be replicated by many people all over the world.
As for stored energy, at say 20 bar, we don’t really have more than a 2-banded gun, right? I think we have less and way less than some pulley guns. But we have better efficiency. A few years ago, before the advent of small ID bands and souped up inverters I was certain of the advantage of a 30-35bar oleo but then I thought perhaps the opposition was catching up. So, it’s good to hear you don’t think they are - at least that’s what I think you think;-)
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Gotcha. When testing speed and energy, yep - the tests I have seen show them come out ahead.
For target shooting competitions - which is a real thing - I think the trick to high accuracy is that the guns are often depowered quite a lot. Hence why when a manufacturer shows their guns to shoot bulls eye it doesn’t really matter match - you can make many guns shoot super precise once you take recoil out of the equation;-)
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Here’s the link to the speed testing ideas - it’s a good read
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Measuring speed of the shaft
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:Measuring speed of the shaft
Measuring speed of the shaft
I made a design of this small equipment for measuring the speed of the spear gun shaft underwater. It is supposed to measure speed on any distance from the gun, along path of about 10 cm for which time should be calculated from the voltage shown on DVM before and after shoot. 220 uF...
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Shafts only column buckle during the acceleration phase out of the gun, once the drive on the spear tail stops the oscillations of the shaft soon damp out due to the travel through the dense medium of water. The trick with band guns is to drive the shaft at just below the buckling acceleration or use a thicker and stiffer shaft. On top slotted enclosed track guns the shaft can be driven harder as the track holds the shaft straight, but the shaft bends against the track and rubs on it, so to gain more power on the shot you have to throw some energy away due to shaft rubbing. The same applies for the totally enclosed pneumatic speargun track, but if you use rusty spears you risk tearing up the alloy barrel surface if the bowed shaft skids along the inner barrel. Traditionally pneumatic guns used relatively short shafts of thicker diameters to take the stresses of muzzle loading, something a band gun shaft never is exposed to. The close fitting inner barrel hydropneumatic guns have stainless steel barrels and stainless steel shafts whereby the shaft can be driven at very high velocities to shoot 30 meters with the very long guns, but these guns are heavy and not the best guns to dive with being made of stainless steel and titanium. Plastic handles are a shell sitting on a stainless steel sub-frame, so that is why the guns are heavy. Those guns need to be heavy as the recoil would be otherwise excessive.
I have a photo of poor quality. These are guns of the master from Crimea krim4ak
Andrzhievsky Oleg. I held these guns in my hands. And this is a very high class of manufacture. This is not hydro pneumatics. These are pneumatic guns in which the piston is pushed into the gun with water. Made of titanium.
For such a system, Pete's conclusions are correct that they can be dangerous during charging. I myself have witnessed an accidental shot and a finger injury.
Andrzhievsky Oleg. I held these guns in my hands. And this is a very high class of manufacture. This is not hydro pneumatics. These are pneumatic guns in which the piston is pushed into the gun with water. Made of titanium.
For such a system, Pete's conclusions are correct that they can be dangerous during charging. I myself have witnessed an accidental shot and a finger injury.
Attachments
@quakeos, sorry if I missed it somewhere but I don't think I did, so allow me to ask again
After your "hydro pump loading" of the piston, do you lift the gun out of the water, muzzle down, to empty out the water from the barrel when you insert the shaft? If yes, on a long gun, how much of a hassle do you feel this is?
The reason I am asking is that for my own future design/build, one of the goals is that it has to be able to be loaded fully submerged. The Tomba system without mods, needs to be lifted out of the water when inserting the shaft and for many spearos that's totally OK. I'd just rather not have to do it on a long 135 gun in bluewater.
Also, what kind of slider are you using? After you bored out and tapped the front of the Vuoto muzzle for your hydro pump, does the slider still sit snugly centered in the muzzle? Not that it did in the first place on a stock Vuoto, come to think about it... But if you can make it so that the slider/slide ring is completely centered it helps guide the tang through the shock absorber without hitting it.
Finally, I think you accidentally deleted your very first post here? Now, I only see the two posts with the pics as your very first posts.
After your "hydro pump loading" of the piston, do you lift the gun out of the water, muzzle down, to empty out the water from the barrel when you insert the shaft? If yes, on a long gun, how much of a hassle do you feel this is?
The reason I am asking is that for my own future design/build, one of the goals is that it has to be able to be loaded fully submerged. The Tomba system without mods, needs to be lifted out of the water when inserting the shaft and for many spearos that's totally OK. I'd just rather not have to do it on a long 135 gun in bluewater.
Also, what kind of slider are you using? After you bored out and tapped the front of the Vuoto muzzle for your hydro pump, does the slider still sit snugly centered in the muzzle? Not that it did in the first place on a stock Vuoto, come to think about it... But if you can make it so that the slider/slide ring is completely centered it helps guide the tang through the shock absorber without hitting it.
Finally, I think you accidentally deleted your very first post here? Now, I only see the two posts with the pics as your very first posts.
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I only really shot it on one prolonged Indo trip, perhaps for something like six weeks.
It was all good except for the parts I made, haha.
- Dima's piston, muzzle and shock absorber have handled it all beautifully. So has his line sliders though stocking up on them has not been easy with his move to Belize. What the limit is for his parts, I don't know yet. I would be surprised if I could not do high thirties with them.
- The very affordable Chinese carbon fiber tube has been fine, too.
- The Evo handle fine, except the high friction line release. A plastic version of it would alleviate the issue.
- The 3D printed bulkhead with one-way valves clogged up and ruined the Mirage loading ability - likely due to some bits of plastic I hadn't deburred properly, not sure. I ended up pulling it from the gun completely and using the pulley loader instead, but a redesign with larger internal airways in the bulkhead would probably reduce the risk substantially of this happening again. I think this part in particular is a great candidate for resin printing.
- The nose cone, also 3D printed, deformed and spilled all the air on a day where the gun was unintentionally left cooking in the sun. I used PLA which has very low heat resistance, but a change to a better material would solve this problem. It could still be printed, just change to HIPS, ASA, ABS or PC and I think it would suffice for another prototype. Or it could be CNC'ed out of Delrin or alu. If I simplified it a lot, I could even turn it on the manual lathe holding it with a four jaw chuck to get the off center bores done. Wouldn't look swank at all, but for a proto, it would be fine.
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The gun that was described by Iyadiver from my recollection was a wet barrel gun and had a relatively large piston diameter. The muzzle had a removable fitting which was replaced by the pump which was screwed onto the remaining section of the muzzle. The lever operated water pump had a check valve so that water was pushed in, but could not flow back. You operated the water pump handle and water was progressively forced into the inner barrel like jacking up a car with a hydraulic jack. At a certain point the piston clicked on the sear lever tooth, so the barrel was then depressurized by turning a screw which dropped the hydrostatic pressure in the inner barrel immediately. Then you unscrewed the water pump and replaced the muzzle fitting. All that remained was to insert the spear in the barrel and press it back to jam in the piston. I assume when the water pump screwed in any muzzle relief ports were covered by the nose end of the pump seeing that the bore size was large. Such a gun would win no safety awards!
Basically the shooting power of the gun was based on the big piston and not super high pressures, much like the "Dreamair" in that respect. No one could muzzle load a big piston gun without some sort of gadget and that is how the water pump idea developed. I doubt that the inventor knew anything of hydropneumatic guns.
Basically the shooting power of the gun was based on the big piston and not super high pressures, much like the "Dreamair" in that respect. No one could muzzle load a big piston gun without some sort of gadget and that is how the water pump idea developed. I doubt that the inventor knew anything of hydropneumatic guns.
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Yeah, I have been thinking about this method too lately. What's cool about @quakeos approach is that he is trying to do all this with as few custom parts as possible. He could eventually sell or share plans for a new front of the muzzle and an adapter for the pump.
I guess he hangs the pump on his float between shots but personally, I wouldn't mind a smaller pump, perhaps a lever type one. I wouldn't mind an increase in pump strokes if it gave me a much more storable pump.
If I was having a go at making this work for me, I would probably make a pump half the length of the Salvi pump perhaps with some sort of better hand grip at the muzzle end of the pump so I could really put some force into it. But I would want the pump small enough that I could stick it on the belt.
While the safety issue is certainly present, I think the least attractive part of the "muzzle pump" setup is that I would have to lift the gun upside down out of the water when inserting the shaft. I'd really like not having to do that with a 150ish cm long shaft in bluewater and waves. I suspect that's how Chris is loading this gun and if not, then that's probably why he had water behind the piston.
I guess he hangs the pump on his float between shots but personally, I wouldn't mind a smaller pump, perhaps a lever type one. I wouldn't mind an increase in pump strokes if it gave me a much more storable pump.
If I was having a go at making this work for me, I would probably make a pump half the length of the Salvi pump perhaps with some sort of better hand grip at the muzzle end of the pump so I could really put some force into it. But I would want the pump small enough that I could stick it on the belt.
While the safety issue is certainly present, I think the least attractive part of the "muzzle pump" setup is that I would have to lift the gun upside down out of the water when inserting the shaft. I'd really like not having to do that with a 150ish cm long shaft in bluewater and waves. I suspect that's how Chris is loading this gun and if not, then that's probably why he had water behind the piston.
Aside from the fact that this is an interesting idea and realization, it still seems to me to be too complicated to use and the reduction in force required for loading is small, 1.6 to 2.6 x, if pumping barrel would be 10 or 8 mm compared to 13 mm barrel of pneumatic speargun.
Using Easy loader is much more efficient, faster and safer. Reduction in force is at least 20 x for winch diameter 14 mm and lever handle 140 mm. This could be suitable to use with 3 mm Spectra Dyneema rope (300 kg braking strain).
I thought about this some more and since I like what @quakeos is trying to do I don't want to see him get burned on misunderstandings once he starts sharing his articles with a wider audience. So, in case we haven't scared him off already, I'd just share some comparisons.
I tested the very popular Small ID in 14mm and it took about 24kg to pull it by 300%, or factor x4 (in SpearoSpeak this is often called 400%...). This was actually a tad more than Primeline's own force calculator had predicted, but that might be because my bands were 14.2mm and not 14mm.
Anyhow, it's very close to Triton's tests here. I run my bands at around 3.7 as a lot of us do with the thinner bands, so that's probably about 22kgf which on a circular band is 44kgf and since I have two of those, we end up with a total of 88kgf.
I don't even think this is high for a two banded gun but it is 2.6 times more force on the wishbone than what a 25bar (13mm) gun would put on the piston of its shaft (34kgf). Now, 25 bar is about the upper limit of what most oleo spearos can manage to load at (I can't, but a fair bunch can).
What's interesting is that your 45 bar gun - which to us in the know is incredibly high - still puts less force on the shaft than a normal two banded gun: 61kgf for the 45bar gun and 88kgf for the two-banded gun.
So, long story short, it's def all about efficiency as even a 45 bar super gun stores less energy than all BW bandguns and even less than most reef guns. Heck, even a one banded gun easily stores 1.3 times more energy than a highly charged 25 bar airgun.
As always, I might have gotten something wrong as perhaps we can't equate stored energy to force on the wishbone? But at least, it was nice for myself to do this comparison. I never actually had done so and never realized how crazy efficient even normal oleo at about 20-22bar is.
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As often before, your posts make very little sense.
Your barrel is not 13mm, it’s a lot smaller, so unless you state your barrel diameter or the force on the spear tail, your 50 bar “information” is irrelevant and/or misleading. If your barrel is ø10mm, then your friend in the picture is strong - that equates to 30bar on a 13mm gun and I don't know anyone who can load that.
I expect your gun is very efficient in really short sizes but then again, I personally and affectionately call trevallies for “stupid fish” - they are some of the easiest fish in the ocean to shoot as they are too curious for their own good. Besides coming too close, they are quite skinny so you don’t actually need a powerful gun to penetrate them. Hence, your pic doesn’t really show much. It certainly does not show a gun capable of shooting heavily rigged shafts on thick bodied +30-40kg fish which is what the premise of this thread is all about. Your pic shows that a man who smokes likely shot a fish in China using your gun.
But thanks for sharing the picture as it’s always good to know which guns sink and which ones are neutral - I vastly prefer the latter.
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8mm, I see...;-). If i feel like spending more energy on replying, I’ll do the math tomorrow but it just means your friend in China is not miraculously strong and the gun does not have much more force on its shaft than a regular gun. And that once again you barge into a thread with no real idea of what people in it are talking about. It’s very much the same as when you didn’t listen to the premise of my thread about the Evo Mirage.
So, to help you out: In this thread we are talking about guns which can shoot heavy 9mm or bigger shafts that carry heavy tackle such we dyneema or cable shooting line and can still punch through really big fish that don’t always come right up to you.
We are talking about guns that can’t be loaded normally since they have 50-60kgf of loading force needed.
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