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All About Guns What's your weapon of choice, and why? Discuss the beloved speargun here! |
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06-11-2017, 12:56 PM | #91 |
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Re: Alemanni Demultiplied Rollerguns
They shoot low? I never heard that one before-
a 3 band gun shoots better than any rollergun in real world testing? Holy crap! I am screen shot-ing this thread for use later. Majd - you are such an asset! You rule!
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06-11-2017, 01:12 PM | #92 | |
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Re: Alemanni Demultiplied Rollerguns
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And please tell me how do you define "technically advanced materials"?Wich is more advanced-pure carbon,glued wood,aluminium?And how advanced can be a roller when we are looking for maximum simplicity on spearguns? And also when came the super advanced "inverted" adition to the new Alemani Vella? Last edited by seal77; 06-11-2017 at 01:22 PM. |
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06-11-2017, 03:13 PM | #93 |
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Re: Alemanni Demultiplied Rollerguns
Seal, I agree with you in that it is important to have a gun that feels good to you in the water and that it can be totally fine to give up some ultimate power in order to have other things be better (sight line, recoil). If that is your philosophy, then that is super cool and I respect that. There is such a thing as "enough power" for most hunting situations. But it just seems a rare thing for many of you builders to actually "admit" this, perhaps to yourselves, too. Which is a pity as it overshadows the stronger sides of your designs.
I am speculating that these situations arise when Majd tests a gun and it doesn't shoot as powerful as others - or that it doesn't shoot as accurately if really powered up to match his benchmark guns and people get offended about the result. But if you said your gun was built to do other things, not for outright max power, then that could save some frustrations. It is a shorter gun, that is fast and accurate, perhaps with a little bit less power - and it should be tested accordingly. If that is actually the DNA of the gun, then say that upfront. But of course, if you say it shoots powerful and accurate at 8-9m, Majd will test it against the very best gun he has. And if it falls short, then he will say so and then we have all this frustration. It might still have been great if not pushed as much. No matter what, I have a lot of respect for your ideas, building and the energy you put into it. The math is on your side, so that breakthrough on the maximum power side should come some day. I will say this though, if you do care about power then just get the same brand and density of foam as Majd and if the foam manufacturing tolerances are OK, then you can actually compare apples to apples. Last edited by Diving Gecko; 06-11-2017 at 03:45 PM. |
06-11-2017, 08:56 PM | #94 |
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Re: Alemanni Demultiplied Rollerguns
If you want to compare band gun configurations then you need to start with the band energy storage, that is why I created all those “green triangle” energy diagrams. What the diagrams don’t show is the effects of inefficiency which absorb some of the energy during the shot, so a gun that starts off with more energy storage may not shoot as well if the extra energy is gobbled up by the movement and drag of all the extra moving parts used in that gun. There is no magic involved in any of this, a rollergun will always be less efficient than a classic band gun, but the roller system can allow longer bands than those which could be accommodated on the classic form of band speargun in that same stock length. The mobile sub-pulley systems can halve the length of these longer bands, but then the number of bands have to be doubled to achieve the same energy storage because you have halved the stroke of the band battery in what is now a “cable rollergun”. Every inch that the band battery contracts in length moves the wishbone by two inches as the cable wraps the sub-pulley and is therefore doubled up in the length of cable being moved. What the latter arrangement allows, as the bands are now shorter than classic bands, is that they can be drawn out with a pre-stretch to use up more of the now available gun body length. This pre-stretched or tensioned band battery approach uses the top end of the band energy storage for the shot (the thick end of the triangle) with the energy balance remaining stored in the gun. If you leave the bands in that state then they will eventually crack due to ozone cracking (oxygen preferentially attacks stressed rubber), therefore such guns need a demounting system to take the stress off the bands when the gun is not in use. Without pre-stretch such guns will not outperform classic guns because the bands are too short, having been halved in length and are also propelling moving pulleys which need to be added to create the drive train to the shaft.
The idea of the energy storage diagrams is you view them in sequence as they build up a story, they assume you look at the prior ones rather than just go to the layout that you are currently interested in. Any band speargun can be simplified down to its energy storage diagram, but thicker diameter bands will increase the slope of the “green triangle” used for that band. This diagram shows how the triangles were sized for the stretch length shown on the various guns depicted in the diagrams. Last edited by popgun pete; 06-11-2017 at 09:07 PM. Reason: added a diagram |
06-11-2017, 10:18 PM | #95 |
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Re: Alemanni Demultiplied Rollerguns
[quote=popgun pete;2143597 a rollergun will always be less efficient than a classic band gun.[/QUOTE]
That's a pretty broad statement. A classic gun has more drag from the bands than an invert roller for the same shaft speed because the bands need to contract twice as fast. Infact, one of the claimed benefits of the invert roller is that the shaft speed is faster because the bands are running in a higher gear. If using ball bearings with rope around the pulleys the losses are probably not high. |
06-12-2017, 01:33 AM | #96 |
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Re: Alemanni Demultiplied Rollerguns
If you have a roller gun that you have confidence with while hunting, then great I think you should stick with it. I recently had one of the most experienced spearos in the world spend 2 days with me in my home pool testing all sorts of guns and configurations. He brought in several guns and we compared guns and setups. He does a lot of spearfishing safaris all over the world and has one of the biggest online spearfishing shops in europe ... and on a spearfishing trip we had this big roller - classic discussion. He would always tell me that the big name rollers were in a class of their own in terms of power and performance, but he would not use them often because they took too long to load and on many of his trips they are in remote areas ... and if something went wrong you were out a gun. Your double roller gun was one of the guns tested and we had another big name roller gun as well. Let me tell you that he went back home with a completely different opinion to what he had before. The best word I can describe when he shot the guns side by side was shock and amazement. I have the video of this testing, but I need to find a way where I can make it more diplomatic to post the video as a lot that was said was very undiplomatic. He was still perplexed to how that kind of power was possible from a 3 banded classic gun, and he seemed to think that the small changes I made to my Albacore 130 had a dramatic effect on performance and that a factory model would not perform like that. Personally I think there is not much difference once you mod the handle. The only change I did on that gun to the one I tested in the Albacore 130 test I posted was that I cut the first 2 bands 2cm shorter because I figured they had stretched out (they were old and I had over 250 shots in them) ... so on those 2 bands the stretch would have been around 390% ... shit ... now I want to try 400% . I was quite surprised at how much of a difference that made as the gun had much more power than the one I tested @ 380%. The increase in power had zero effect on accuracy or controllability ... gun was shooting the same but with more penetration. After passing the 8 meter test and feeling the yank of the gun as the shaft ran out of line ... he tried an accuracy test and at 6 meters he was hitting within 2cm of the bullseye every shot exactly where he was aiming. This is what I mean !!! Power + Flat Shooting + Extremely accurate + Quick loading + Few moving parts ... his words not mine!
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06-12-2017, 01:56 AM | #97 |
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Re: Alemanni Demultiplied Rollerguns
The Albacore 130 weighs about 3.5 kg which is around 7.7 lbs. I added CF but I removed all the lead pellets that were in the muzzle and handle ... so it probably comes out to about the same. With an 8mm shaft I have to put a little lead to keep it perfectly ballasted ... with 8.5mm shaft it is slightly negative in pool but perfect in saltwater with zero added lead necessary. There is a huge chunk of lead that is in the stock that is not accessible ... maybe that is for the better as I am sure if I would have been able to remove that, I would have ended up spending more hours modding this gun.
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06-12-2017, 06:42 AM | #98 |
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Re: Alemanni Demultiplied Rollerguns
Pete, those Energy Storage Diagrams don't take into consideration the great Robber of Range and Accuracy which is Recoil. So much is lost to recoil.
Majd, could you weigh that Carbon covered Albacore and get a precise weight? Sometimes it's not a simple exchange when replacing metal etc. Plus there is the handle mod adding weight. I know Mass and Weight are different but it would be interesting to know the actual weight.
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06-12-2017, 08:52 AM | #99 | |
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Re: Alemanni Demultiplied Rollerguns
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The best that Majd claims to have are the Abellans and they are just well set simple wooden guns.I only replaced the Abellan with a classic gun made by me,set like the Abellans and shooting like them(this is for sure,I have explored all Majds tests).Dont forget that Abellans sizings are different and Im talking about more compact guns than his Albacore. If somebody builds a 200 sm gun and shoots at 15 meters will you say that its a miracle? Would you hunt with it? I doubht... For me this is perfectly enough,I dont pretend to satisfy whole sperafishing world's interests. Last edited by seal77; 06-12-2017 at 09:05 AM. |
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06-12-2017, 09:58 AM | #100 | |
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Re: Alemanni Demultiplied Rollerguns
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I will repeat what I think you and I actually agree on, though in your frustration you might not have noticed: Not every gun needs to have crazy power or be compared to a long Abellan. If you goal is something different then that is cool, too. |
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06-12-2017, 11:08 AM | #101 | |
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Re: Alemanni Demultiplied Rollerguns
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06-12-2017, 11:36 AM | #102 | |
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Re: Alemanni Demultiplied Rollerguns
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This reminds me the story about fin bladesI was listening to the old champions who was advising: get the hardest blades,thats why we are champions!..I was punishing myself for some time And after i found the soft blades couldnt find words to thank them |
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06-12-2017, 05:58 PM | #103 |
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Re: Alemanni Demultiplied Rollerguns
I'm only a part-time builder, and my knowledge is anecdotal or pulled from second-hand sources, but I think one of the BIGGEST advantages of rollers is the line of sight, whether or not the guns are more powerful, accurate, and/or having the same power as a longer less maneuverable traditional gun.
When you are diving with a big three, four, or even five band traditional gun, and you shoot at a moving target with less then perfect visibility, you pull the triggers, then a bunch of stuff happens, bands go flying into your field of view, and then you either hit the fish or you don't. Sometimes you see the shaft flying, sometimes you don't. With a roller (my experience is with a double roller based on an Alemanni design with a very simple loading procedure), the recoil is so low, and there is no rubber in your field of vision, AND YOU CAN SEE WHERE YOU MISS. Shooting in a pool is great and all, but taking a shot with one hand at an awkward angle at a fish wiggling off in a separate direction involves a ton of variables. Being able to learn from your mistakes, see every miss, and compensate for future shots has GREATLY increased my accuracy (above and beyond whether the roller itself is more accurate/powerful than my traditional gun). Also, the one "improvement", for me at least, of my guns over other rollers is using small ID, 14.5 mm bands stretched at 350+ percent. The whole point of a roller is steady acceleration over the full length of the track (instead of rapid acceleration initially in a traditional gun). I'd much prefer using thinner bands at a higher stretch to get the most out of the roller design, even if I have to change the bands more often. I see no reason to use a 16mm or 18mm band at less stretch, except for preserving the lifespan of the bands. And if you're spending this much money and time to get things perfect, might as well spend the extra hour or two once or twice a year tying bands. Also, regarding the shaft deflecting downwards, I took a file and a dremel and scraped away the sharkfins until they are nearly 90 degress. That way when the wishbones rise up on the muzzle risers, they don't pull the sharkfins up and deflect the shaft low. It was a little dodgy finding out how much I could get away with (at a perfect 90 degrees the wishbones will slip off the sharkfins), but I haven't noticed any downward deflection. |
06-12-2017, 08:31 PM | #104 | |
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Re: Alemanni Demultiplied Rollerguns
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I did notice on the Andre Roller guns the shaft being used has fins that are less angled. |
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06-12-2017, 10:07 PM | #105 | |
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Re: Alemanni Demultiplied Rollerguns
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