Comparison of Sliders for Spears

[Gazz]

Hi Guys i thought this might be useful, the riffe slider is the best for hydrodynamics in my opinion. Also it will hold a good fish.

 

[Gazz]

By the way the jbl slider and tang are holding up well on my Vouto air.

 

[Vov]

How about symmetry...? It would help maintain the direction of the shaft, no? That's why I would like to try first. Produce enough shots in a pool to compare shaft's behavior with various sliders and then make a choice.

 

[Gazz]

I agree but, many arbaletes have sharkfins with the mono attached and shoot perfect, i dont think symmetry is a major issue unless you are a sniper.

 

[popgun pete]

Mares claim that their line slide, or slider, introduced with the original "Cyrano" was developed after hydrodynamic design work and testing by the University of Genoa. You cannot always judge by the shape or size of the component, plus the line trailing behind has an effect as it sits in the wake generated by the shaft and the shape of its butt end. That is what science and engineering are all about, they don't just guess.

 

[Gazz]

I don't doubt that the slider on the cyrano is more hydrodynamic than their earlier guns or even the current sten, but if using plastic for a slider they need mass to obtain strength for the slider. This is the sacrifice of using nylon. There is no way the cyrano slider has superior hydrodynamics to the riffe. Adreno recommends the riffe slider when people come looking to replace their broken cyrano slider. Also look at mares's new race slider, same as the devoto.

Pelaj apparently employed university research to design their handle which proved to be ultimately a failure.

 

[Vov]

I agree but, many arbaletes have sharkfins with the mono attached and shoot perfect, i dont think symmetry is a major issue unless you are a sniper.

Sharkfins create a down force which lowers the back part of the shaft, which in turn (all other conditions equal) creates a lift - to maintain a more flat trajectory... So that asymmetry is helpful.
Sliders... maybe a different picture at various speeds. I am glad they have done R&D and testing... and hope it was done properly.
I would prefer a slider instead of crimping the very shaft, provided that it would not lead the shaft astray, or dramatically decrease speed. Easy to test.

 

[tromic]

Competitors - ready for the race!
Weights (slider with piece of line):
A = 3.1 gr
B = 2.6 gr
C = 7 gr
D = 2 gr
E = 1.8 gr

 

[tromic]

All results were pretty close, even for big Mares slider what was a surprise for me!
Actually the worst result was for Devoto slider, but I made a mistake because it was a slider for 8 mm shaft! I noticed that after finished the measurement.
I measured the time in which under the constant force carried out 15 laps.
The shorter the time, the lower the resistance, the greater the hydrodynamic.

 

[Vov]

Bravo, Tromic, great job, thank you very much. I believe since the mass of any slider is a tiny fraction of the mass of the shaft , what really matters is the shape (creating drag) of the slide and the reliability of the crimping it allows to be done.

 

[popgun pete]

Any test result numbers? I am wondering how large or small the differences are. The weight of the line side or slider has a bearing on the stop ring resistance to jamming on the shaft step which is usually small in height. Shock absorber tail springs decreased the impact when the shooting line pulled the shaft to a halt, but added to drag and weight, if the line anchor had no other shock absorbing element or a reel was not used (low or no drag setting). Sometimes people use the line slide with no stop ring, but that cracks the plastic line slides as the shaft step wedges into the line slide's bore forcing it open.

 

[tromic]

Any test result numbers? I am wondering how large or small the differences are. The weight of the line side or slider has a bearing on the stop ring resistance to jamming on the shaft step which is usually small in height. Shock absorber tail springs decreased the impact when the shooting line pulled the shaft to a halt, but added to drag and weight, if the line anchor had no other shock absorbing element or a reel was not used (low or no drag setting). Sometimes people use the line slide with no stop ring, but that cracks the plastic line slides as the shaft step wedges into the line slide's bore forcing it open.

The best measurement results would be only in real conditions, on shoot, in sea. All with same speargun, same line, only changing the runner! This "measurement" was just a rough estimation.

Here are some numbers for 15 revolutions of slider in water:
A-(Mares): 13.67; 13.45 sec
B-(Devoto for 8 mm shaft on 7 mm shaft): 16; 16.35 sec
C-(Omer): 13.68; 13.85 sec
D-(Tomba 1): 13.52; 13.53 sec
E-(Tomba 2): 14; 13.87 sec

At the end of the race the speed is higher because the water in the bowl rotates too!

 

[tromic]

Bravo, Tromic, great job, thank you very much. I believe since the mass of any slider is a tiny fraction of the mass of the shaft , what really matters is the shape (creating drag) of the slide and the reliability of the crimping it allows to be done.

The mass of the slider should be as low as possible. It does not effect the speed but will cause damage like in case of Omer microspeed slider, to slider itself and/or to other hammering side.

 

[popgun pete]

The "Riffe" sliders or slide rings are not line slides, but they certainly could be used as such. They are actually the tether cable connection ends that anchor slip-tip type detachable spear heads to the spear shaft, the base of the slip-tip being screw threaded onto the shaft nose and preventing the slide ring from pulling off the shaft. Riffe spearguns tie their shooting line to a cross-drilled hole in the front shark-fin tab for the wishbones or the tail of the eurogun type spears which use mini shark-fin tabs (thus too small for a transverse hole), so as such they do not use line slides. Photo is from the Riffe web-site www.speargun.com.

 

[Gazz]

Amazing effort Tromic!

 

[tromic]

Tomba 2 might be actually the best in performance. It was not in the test because I did a connection using dynema and mono line (additional knot). If mono had been tied directly to the slider the performance would be the best.
This test set up was not very demanding. I did it in maybe 1/2 hour, just to see how it would work and what could expect. I have another idea for test configuration... Maybe I would make it for fun, because I already know what is the best. It would be nice if I had some other kind of sliders to test them like STC X-runner, Pelengas, LG, Riffe...

 

[tromic]

Another idea for testing sliders perormance:

 

[popgun pete]

I thought that your first method was extremely ingenious and it produced some very interesting results. Maybe with this new one you could run the measuring cable right down the centre of the column to gauge the drag on the slider without having that side entry point to disturb the water flow. The cable could then run inside a vertical hollow shaft which does not need to be metal tubing, but would emulate the spear. There would be no water flow acting on exposed cable above the slider because it will be inside the tubing.

 

[tromic]

I thought that your first method was extremely ingenious and it produced some very interesting results. Maybe with this new one you could run the measuring cable right down the centre of the column to gauge the drag on the slider without having that side entry point to disturb the water flow. The cable could then run inside a vertical hollow shaft which does not need to be metal tubing, but would emulate the spear. There would be no water flow acting on exposed cable above the slider because it will be inside the tubing.

Interesting proposition Pete. Maybe an image of your proposal would be more clear to everybody.

 

[popgun pete]

Well here it is, but it would be a big project to build even something seemingly simple like this. The cable tension measuring gadget could be off to one side if the cable runs over a pulley rather than have it sitting right on top of the water tank/water column assembly.