Home | Tournaments | Calendar | Weather | Merchandise | Sponsors |
|
All About Guns What's your weapon of choice, and why? Discuss the beloved speargun here! |
|
Thread Tools | Rate Thread | Display Modes |
04-17-2022, 06:12 PM | #16 |
Registered User
Join Date: Mar 2006
Posts: 4,245
|
Re: Fusion Rollers vs Standard Rollers
If your rollergun is built on a tube gun body then the physical routing of the bands and cables for the drive are more restricted because everything has to run parallel to the body tube. In a timber or carbon fiber gun there can be troughs and channels sculpted in the stock that bands and cables can travel in and these don’t have to be parallel to each other as the gun body can be a wedge shape with a wide but slim profile muzzle. Thus the muzzle rollers need to size for the run of the cables top and bottom on your gun or you use more than one to direct the cable, but that requires another slave axle in the tube gun muzzle which adds to weight. An interesting example of cable routing considerations is this madcap design for a rollergun which uses a pneumatic storage battery and hence is built on a tubular body of large diameter which dictates the run of drive cables. Note the tilted rollers at the muzzle.
|
04-18-2022, 06:56 AM | #17 |
Registered User
Join Date: Dec 2012
Location: Bali
Posts: 80
|
Re: Fusion Rollers vs Standard Rollers
I have done quite a bit of accuracy and penetration testing of roller gun and inverter guns with stopper tube. I found by adding a second longer wishbone, to load on the shark fin and a short wishbone for the stopper. I got very flat and accurate shots and more penetration compared to just the one wishbone for the stopper.
The second wishbone stops shaft lift. I built a 165cm overall length (Band stretch 148cm) inverter, 21mm bands going through the back rollers and 3 sets of 19mm band on the botom of the gun and a mono roller 160cm overall length (145cm band stretch) 16mm bands through the front rollers, 19mms bands through the back rollers and 1 x set of 19mms bands as booster on the bottom. I had the double wishbone setup for both guns. Both these guns have stopper tube setup. I used the same 9mm shaft and got the same penetration with the 3 x 50mm foam that Spearq8 uses. The test was at 6 meters. I was surprised with this result as the inverter has more band and larger diameter band compared to the mono. I believe inverter system is slower than a roller gun setup, also the double wishbone gave the mono a flat shot. Such a easy fix to add a second wishbone to a roller gun or a inverter gun that has a stopper tube to get accurate shots. Last edited by Satdiver; 04-18-2022 at 08:22 AM. |
04-18-2022, 08:43 AM | #18 | |
Registered User
Join Date: Mar 2006
Posts: 4,245
|
Re: Fusion Rollers vs Standard Rollers
Quote:
|
|
04-18-2022, 08:48 AM | #19 |
Registered User
Join Date: Dec 2012
Location: Bali
Posts: 80
|
Re: Fusion Rollers vs Standard Rollers
|
04-18-2022, 09:50 AM | #20 |
Registered User
Join Date: Mar 2017
Posts: 25
|
Re: Fusion Rollers vs Standard Rollers
Sounds really interesting, I wonder if the bigger inverter set up you had was loosing energy due to the second set of rollers?
Or perhaps it is a case of what Majd often says: shafts have a terminal velocity, once you reach that, adding more band power doesn't result in more speed? As an aside and a slight derail; Pete, you mentioned your love of pneumatics, are there any production pneumatics that you would recommend, round the 100cm mark? I have always been interested in them, but no one in my neck of the woods uses them so it has been hard to figure out what to get. Maybe start a new thread if you have a few options. Sent from my SM-G930F using Tapatalk Last edited by Kiwizach; 04-18-2022 at 10:14 AM. |
04-18-2022, 02:31 PM | #21 |
Registered User
Join Date: Aug 2008
Location: Big Island
Posts: 5,098
|
Re: Fusion Rollers vs Standard Rollers
SATdiver, Did you limit the band stretch on the 16mm bands on the top of the Mono Roller?
So I understand, this was an Inverted Mono Roller with (Poliplast) Rollers in the back of the gun. 16mm on top and going around the Rollers (Limited Band stretch with dyneema core?) 19mm bands on the Poliplast 19mm Bands on the Bottom Were all of these bands Small ID? Thanks. Interesting.
__________________
https://www.facebook.com/Ulusub/ |
04-18-2022, 04:18 PM | #22 |
Registered User
Join Date: Mar 2006
Posts: 4,245
|
Re: Fusion Rollers vs Standard Rollers
The problem with these discussions is proprietary names are not universal and different people will read something else into the descriptions. In my posts I stay with mechanical terms that state what they are. Demultiplied is a gearing term, for examples multi-part triggers are demultiplied as is a block and tackle hoist, so it is a basic description. Terms like polipast and fusion carry the problem that their definitions may only be local to the areas that they are used in. Diagrams or detail photos dispel any such problems.
|
04-18-2022, 04:37 PM | #23 | |
Registered User
Join Date: Mar 2006
Posts: 4,245
|
Re: Fusion Rollers vs Standard Rollers
Quote:
https://www.seawolf-sub.com/shop/velair/ Last edited by popgun pete; 04-18-2022 at 06:58 PM. Reason: more info |
|
04-18-2022, 09:24 PM | #24 |
Registered User
Join Date: Aug 2008
Location: Big Island
Posts: 5,098
|
Re: Fusion Rollers vs Standard Rollers
Is there a Reason to use Double Sheaves? If you are going to use them, does it make more sense for them to be inline? I saw this muzzle recently.
This Muzzle Stop certainly looks nice, I like the concept. I'm not sure if there is an upward vector on the Shaft fin. I like the idea of a Spring or some kind of Slowed reaction. R=F/T But if you can extend that T it delays and reduces the disturbance.
__________________
https://www.facebook.com/Ulusub/ |
04-18-2022, 11:16 PM | #25 | |
Registered User
Join Date: Mar 2006
Posts: 4,245
|
Re: Fusion Rollers vs Standard Rollers
Quote:
Actually I was just looking at the same web page. Last edited by popgun pete; 04-18-2022 at 11:43 PM. Reason: added a photos |
|
04-19-2022, 01:57 AM | #26 |
Registered User
Join Date: May 2009
Posts: 3,292
|
Re: Fusion Rollers vs Standard Rollers
I think Paul Hutchins (Satdiver) probably has the most experience with the big roller guns. He has been working on improving the performance of the biggest Alemmani multi roller guns for a while, and I have watched the progress through videos he has kindly shared. I think even 3 or 4 years ago he was one of the few that understood the tail lift problem and was working on several ways to address that ... so it would not surprise me if he has managed to work things out. Even the test videos of a year or two ago were huge improvements over the best that Alemmani had. Defintely would be interesting to see what the latest he has come up with.
There is also another person working hard on sorting out the tail lift problem on the bigger roller guns and that is Albattar spearguns. He has moved away from invert rollers and ironically ... is back to normal coupled double rollers. The guy is a real speargun addict and very experienced spearo. He actually travelled a large distance just so he could try out some spearguns in my pool and see what could be improved. I do have his latest gun and plan to give it a try in a couple of weeks. In our pool sessions his roller guns had the typical tail lift problems when gun was powered up. I helped him re-design the muzzle by lifting the rollers up in hope of cancelling out tail lift ... and according to him the latest version does that even fully powered up. If so then that would really be a huge breakthrough. I have the gun, and as soon as I have time I will test it out. As for power saturation of shafts. Considering you have a perfect Classic setup with high handle and correct handle shaping ... I think 6.5 to 7.5mm shafts with around 120cm of band stretch and 2 x 14.5mm small ID bands are above or very close to Terminal Velocity. Moving to 8mm shafts the 2 x 14.5mm small ID bands and around 130cm band stretch you are about 85% to 90% Terminal Velocity ... so yes you can gain a little more power with a 3rd band ... but probably not worth the hassle ... better is just improve loading technique and crank up the band stretch. With 8.5mm to 9mm shaft and say 135 to 140cm band stretch and 3 x 14.5mm small ID bands you again are very close to Terminal Velocity ... my guess is also around 85% to 90% with 8.5mm and maybe 80% on 9mm ... so a 4th band is just not worth it as recoil can start to become a problem for many ... this is where I feel where a good roller gun can become an advantage. I mean loading 4 classic bands can take quite a while ... so quick loading is obviously not a requirement there so no advantage for Classic. With those big guns, power or controlled power becomes the main requirement ... and I can see how a well setup roller can get to the 100% of Terminal velocity on the heavier 9mm or even 10mm shafts. Of course you are talking about an insane amount of power that probably is only needed for hunting giant Dogtooth Tuna at distance. IMHO even that can be dealt with using an 8.5mm shaft and 3 bands and the correct slip tip. But for that to happen, the tail lift problem has to be sorted out otherwise you just can't power up the gun and keep things stable. Last edited by spearq8; 04-19-2022 at 02:17 AM. |
04-19-2022, 05:40 AM | #27 |
Registered User
Join Date: Mar 2017
Posts: 25
|
Re: Fusion Rollers vs Standard Rollers
Ok guys, let's get this thread back on track, have loved the yarns so far though. Incase there is still some confusion as to the definition of a "fusion" gun as defined by the OP, I took some screen shots from the video they linked. Please see them below.
Note: These are NOT demultiplied Now, is there anyone with experience with these gun set ups in particular? Sent from my SM-G930F using Tapatalk |
04-19-2022, 07:23 AM | #28 |
Registered User
Join Date: Mar 2006
Posts: 4,245
|
Re: Fusion Rollers vs Standard Rollers
I watched the video, this rollergun is basically a two stage loading gun, or three if you count pulling each of the separate lower bands separately onto the metal prong anchors that project laterally on each side just in front of the rear handle. It reverses the usual method of pulling the wishbone onto the shaft tab first and then moving the rear anchor on the bottom of the gun last as here you do the bottom first and then pull the wishbone back on the top deck. The advantage of doing it this way is the lower band tension is held by the stopper knots at the muzzle while you get ready to pull the top band back to the shaft tab. The disadvantage is you don't drive the shaft right up to the rollers during the shot. The philosophy is while a standard gun does not drive when the bands reach slack length this gun compensates by using prestretch in the bands to elevate the force level with the gun loaded even though it still stops pushing before the muzzle is reached. The guy didn’t say whether the top bands were stretch limited with internal cords, if they are the same diameter then they don't need to be. An advantage of the setup is you can use cable type muzzle rollers and the bands sets don't have to lose energy as they fold around rollers because they stay on their respective decks of the gun.
|
04-19-2022, 08:14 AM | #29 |
Registered User
Join Date: Mar 2017
Posts: 25
|
Re: Fusion Rollers vs Standard Rollers
Yeah, we get how it works. And in use it is just single stage as you leave the bottom bands in tension throughout the dive. Do you have any experience with them Pete? In terms of optimal pretension etc, or different band combinations top and bottom?
I have one set up with two bands below, so it does have an internal cord stretch limiting the top band to 340% Although I would love to I just don't have the resources to test a bunch of set ups. Sent from my SM-G930F using Tapatalk |
04-19-2022, 08:51 AM | #30 |
Registered User
Join Date: Mar 2006
Posts: 4,245
|
Re: Fusion Rollers vs Standard Rollers
No, I have never used one of those, you can think of it as a standard rollergun where the cable to the lower deck rear anchor point is now inserted into the band run with band segments now at either end of the cable. When you pull back the top band you will feel the pretension as soon as you drag the cable stopper knots off the muzzle bridge. That could be more of a reach at stretch than pulling the cable back on the lower deck to a second rear anchor point in two stage loading where a rollergun adds more tension after its first cocking. Not much of a problem on a short gun though as you don't have very far to reach.
Guns often have a sweet spot where it performs best with a certain band load, exceed that and the gun does not perform as well. Usually the manufacturer works this out for the guns he sells, but not always. I will not mention any names. Divers are often tempted to power up a gun to shoot further, but in my view you move up to a longer gun which are easier to aim in long shots. Last edited by popgun pete; 04-19-2022 at 09:06 AM. Reason: more info |
Bookmarks |
Thread Tools | |
Display Modes | Rate This Thread |
|
|