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Different setups performance

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tromic

Well-Known Member
Aug 13, 2007
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I also tried the best to worse. Because I can not upload the picture (I exceed the limit of attachment):
1 is Tomba slider and 1 mm mono.
2 is Tomba slider and 1,5 mm mono.
3. is Tomba slider and black nylon rope.
4. is Mares slider and black nylon rope.
 

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tromic

Well-Known Member
Aug 13, 2007
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Different set-ups performance
Interesting conclusion could be made from data on the link:
http://forums.deeperblue.com/pneumatic-spearguns/91753-different-setups-performance.html#post854027

Best "free shaft", fig. 11, is about 49% better in energy of the shaft on the target than the slider version of system using devoto line slide. That means that any vacuum barrel system using devoto like line slider is inferior to "free shaft". The exception is tomba plastic line slider, fig 4 and 12, that is same or better in energy on the target than the best "free shaft".
 
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tromic

Well-Known Member
Aug 13, 2007
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One can see a gun range (Cyrano 850) at 25 bar with a 7 mm shaft and vacuum systems:

According to Figure 19, with black nylon rope and the original mares slider - about 2.8 m.
According to Figure 18, with black rope and Tomba slider - about 3.3 m.
According to Figure 17, with mono 1.5 mm, and Tomba slider - about 4.6 m.
According to Figure 4, with a mono 1 mm and Tomba slider - about 5.2 m.

I took the lowest speed to be 10 m/s at which the energy of the shaft is around 16 J. I also took for starting speed the speed after shaft exit from gun 1 m (length of shaft). Is 10 m/s enough? It's as if you would shot from the same gun inflated to 2.5 bar into air at a target located 1 m from the tip of the shaft.



 
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Batman-alex

New Member
Jul 19, 2011
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Russia
Hi
Unexpectedly the high-speed of harpoon(staff) turned out for me.!!!
It would be very interesting to get results for Cyrano 850 without a vacuum system...

alex
 
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tromic

Well-Known Member
Aug 13, 2007
1,631
185
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Croatia
Hi
Unexpectedly the high-speed of harpoon(staff) turned out for me.!!!
It would be very interesting to get results for Cyrano 850 without a vacuum system...

alex
I already made that measurement last year and year before. With vacuum barrel gun the energy of the shaft is about 25% higher than with water barrel, on depth just below the surface. Deeper it is more than 25%.
 
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Batman-alex

New Member
Jul 19, 2011
6
0
0
Russia
I already made that measurement last year and year before. With vacuum barrel gun the energy of the shaft is about 25% higher than with water barrel, on depth just below the surface. Deeper it is more than 25%.
Thus, your gun without a vacuum has initial velocity of harpoon of approximately 26 m/s ???
Seems look like truth.... of:)

alex
 
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tromic

Well-Known Member
Aug 13, 2007
1,631
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Thus, your gun without a vacuum has initial velocity of harpoon of approximately 26 m/s ???
Seems look like truth.... of:)

alex
Not 26 m/s. About 29.5 m/s. Vacuum barrel is about 25% better than water barrel in energy, not in speed.
 
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tromic

Well-Known Member
Aug 13, 2007
1,631
185
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Croatia
I also tried the best to worse. Because I can not upload the picture (I exceed the limit of attachment):
1 is Tomba slider and 1 mm mono.
2 is Tomba slider and 1,5 mm mono.
3. is Tomba slider and black nylon rope.
4. is Mares slider and black nylon rope.
Dai risultati di energia ottenuta con 1 mm e 1,5 mm mono possiamo vedere che l'albero ha più energia del 33% con 1 mm mono, sulla stessa distanza, che con 1,5 mm mono. Ciò significa che con 1,5 mm mono la pistola dovrebbe essere sul 33 bar per avere le stesse prestazioni (energia) e con 1 mm mono a 25 bar.
Per il confronto sono il presente che il beneficio del barile vuoto su barile di acqua è circa il 25%.

From the results for obtained energy with 1 mm and 1.5 mm mono we can see that the shaft has 33 % more energy with 1 mm mono, on same distance, than with 1.5 mm mono. That means that with 1.5 mm mono the gun should be on 33 bar to have same performance (energy) as with 1 mm mono on 25 bar.
For comparison have on mind that the benefit of vacuum barrel over water barrel is about 25 %.
 
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tromic

Well-Known Member
Aug 13, 2007
1,631
185
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Croatia
This is a diagram of the speed of the shaft with Devoto slider (with and without a spring) and Tomba slider. Tomba slider was best in performance.

 
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tromic

Well-Known Member
Aug 13, 2007
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How pressure in gun affects effective range. In this example Cyrano 1100 was on 22 bar with 6.5 mm shaft and the range was about 5.6 m. How much more pressure is needed for longer range? 29 bar for 6.11 m. Even 36 bar would be neccesary for 6.5 m.

 
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Crispin

Spearfisherman ;=- --->
Sep 14, 2001
260
30
118
Auckland
www.blocksoft.co.uk
Just stumbled upon this Tromic - v.interesting.

I'm using a kara-yo tovarich with 2mm Dyneema.

I must admit i've not tried mono, but if I use anything less than 1.8 or 2mm dyneema, it tends to tangle when the gun is fired - I don't use a reel.

Any thoughts?
 
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tromic

Well-Known Member
Aug 13, 2007
1,631
185
153
Croatia
Just stumbled upon this Tromic - v.interesting.

I'm using a kara-yo tovarich with 2mm Dyneema.

I must admit i've not tried mono, but if I use anything less than 1.8 or 2mm dyneema, it tends to tangle when the gun is fired - I don't use a reel.

Any thoughts?
It would be much better with 1,5 mm mono and a reel. Do you use micro slider with free shaft?
 

Crispin

Spearfisherman ;=- --->
Sep 14, 2001
260
30
118
Auckland
www.blocksoft.co.uk
just a free shaft - i've got a micro slider but I don't use it. I have it at 20bar.

The shaft flies true without a slider i've found (although I havent tried a reel) , and I can take some pretty long shots with the gun.

I also don't think I like the idea of having the whole spear assembly with micro slider passing right through the fish and then having to deal with that each time I shoot one.

With so much power the whole spear goes through atm, and sometimes it can be a pain to thread back through especially with double flopper and a lengthways shot on a fish.

heres how it looks atm




How do your reel assemblies look then?
 
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tromic

Well-Known Member
Aug 13, 2007
1,631
185
153
Croatia
Ok, thanks for the picture. It is OK, but just try with a mono. It would be better. It is even better with a micro slider but is not so clean, simple. If you use a thin mono (1 mm) from the tip of the shaft to the slider and than 1,5 mm (or 2 mm) from slider to the gun it would be even better than with 2 mm spectra. You tie the mono, after 3 wraps, to some line (50 m) used for the reel.
Foxfish uses the same setup like you but with mono: http://forums.deeperblue.com/pneumatic-spearguns/91007-measuring-speed-shaft-3.html#post854223
 
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