Tomba - All in One barrel sealing

[tromic]

This is mine latest project for Cyrano and 7 mm shaft. Adapter to muzzle is not necessary. I made it using only drill and grinder because I have not lathe. O rings are 6x2mm and 7x2,5 mm.

 

[settingsteel]

Very interesting. So you did not add the tubing to cover the holes at the muzzle? And I notice 2 o-rings one fits in a ring and the other just wraps around the shaft, did you make the ring the o-ring fits into also?

 

[settingsteel]

Another question, could you not just use the white "plug" alone as a plug and attach the regular line retainer piece that comes stock with the cyrannos on top of the plug?

 

[settingsteel]

And one more, could not an o-ring be fitted to the white plug, or is it better to have them directly on the shaft?

Tromic, do you notice a substantial difference in power with this setup as opposed to just keeping it simple, without any type of tomba, mamba etc. I ask because alot of spearos (here in miami) think the difference it makes is minimal compared to the price/process of getting one installed in their guns.

 

[tromic]

Very interesting. So you did not add the tubing to cover the holes at the muzzle? And I notice 2 o-rings one fits in a ring and the other just wraps around the shaft, did you make the ring the o-ring fits into also?

I made plastic tubing insert 12 mm long, 11 mm diameter for the piston and 14,6 mm outer diameter to fit the muzzle inside. Then I just put silicon to fill the holes in the muzzle from out side.

 

[tromic]

Another question, could you not just use the white "plug" alone as a plug and attach the regular line retainer piece that comes stock with the cyrannos on top of the plug?

No I could not. White plug alone would not be enough for air tight condition for longer time.

 

[settingsteel]

OK, sounds good....but by now you should know me:duh.....PICTURES please.

 

[tromic]

And one more, could not an o-ring be fitted to the white plug, or is it better to have them directly on the shaft?

Tromic, do you notice a substantial difference in power with this setup as opposed to just keeping it simple, without any type of tomba, mamba etc. I ask because alot of spearos (here in miami) think the difference it makes is minimal compared to the price/process of getting one installed in their guns.

I think it is better to have O ring on the shaft if possible because of less profile, better hydrodynamic properties and easier to make.

Really I have not notice a substantial difference in power.
What I noticed:
-it was more difficult to load the gun with vacuum in barrel - it should be;
-the gun was more quiet with tomba;
-there was more recoil with tomba - this indicate some more power in the gun;
-it was difficult to see substantial difference in shaft speed, even at video; I need better camera.
[ame="http://www.youtube.com/watch?v=th1HtSW-zrQ"][/ame]
That is way I decided to put plastic tubing inside the muzzle. This should give some better performance because there would be initially less air and/or water in the muzzle.
Substantial difference in speed is if you use thinner shaft: 6,5 instead of 7 mm.

 

[settingsteel]

hmmm interesting input, I saw the video but did not really see much comparitively speaking.

 

[tromic]

This is very simple solution. But, this would, maybe, work also with only one metal ring and one O-ring over the shaft. I haven't try it yet.

 

[martinbar74]

This last simple version if works , will make revolution of vacum kits , please let us know when you have result
Thanks
Martin

 

[tromic]

This last simple version if works , will make revolution of vacum kits , please let us know when you have result
Thanks
Martin

I am sure this version at the picture works. I had testing similar versions and they were working. If you thing about the version with only one o ring that would work also but it has some disadvantages so this present version is better.

 

[tromic]

This is a short overview of all tombas (mamba) I use with my Cyrano.
Holes in the muzzle are sealed with plastic tubing inside and silicone outside. The last picture is for 6,5 mm shaft. Sealing device stays in the adapter at the muzzle, after shooting.

 

[tromic]

This is very simple solution.

Few days ago I tried this version of dry barrel. It is now my favorite choice for Cyrano and 7 mm shaft. Easy to operate, reliable. Performs excellent.
One another important think what I find out in general concerning dray barrel systems: it is very recommended to empty the water from the gun before inserting the shaft and sealing it, and after that loading the shaft in the water. If not doing so the water that remains in the muzzle would, under high pressure, enter the barrel between the barrel and the piston. The oil on piston becomes milky what means water and oil mixture. I think, this is especially true for dry barrel systems that have small diameter hole for the shaft (tovarich, some kinds of tomba) so the water could not easily escape.

 

[Old Man Dave]

Nice work as always and nice testing vid. What was the range from speartip to target in the video?

Dave.

 

[tromic]

Nice work as always and nice testing vid. What was the range from speartip to target in the video?

Dave.

About 4 m.

 

[tromic]

For 6,5 mm shaft width Cyrano this is my favorit. Easy to use and reliable.



The rubber tubing should not be firm around the shaft (6 mm inner diameter) and it is good to empty the water before loading the gun. One should tie the body of the tomba to the muzzle (piece of dyneema) to prevent losing it in the water after shooting (in case water is in the muzzle) If there is no water in the gun, after shooting tomba stays in the muzzle.

 

[foxfish]

Tromic can you show us how you actually make the components & what materials you use?

 

[tromic]

Tromic can you show us how you actually make the components & what materials you use?

Foxfish, it is at the 2. page of this post. There was shown all one need to make tomba. Piece of plastic, maybe teflon or similar, and rubber tubing for sealing the shaft (6 mm inner diameter), plus a O-ring 6x2 mm for sealing tomba to muzzle. Annular groove for O-ring is 9 mm in diameter.
Regards, tromic

 

[tromic]

All the results are at 20 bars with Cyrano 850 in the shallow water, near the surface.

The results for factory gun (water barrel).


This tomba with tubing had 19% better performance to the factory gun at 3,5 m from the gun.
Making the tomba's body more slim, using O-ring instead of tubing over the slider, result is about 23 % better performance to the factory gun.


With my mamba like adapter (I made it myself) with the same gun I had 26% better performance to the factory gun. The reason for better mamba result to tomba was higher drag of tomba's slider.
Using better - more hydrodynamic, harpoon than got with the gun I had 15% better performance with 7 mm shaft and mamba vacuum barrel than with the factory equiped harpoon - all together about 48 % better than with factory water barrel.


This tomba with the "spring slider" had more than 48% better performance to factory gun at 3,5 m from the gun.


With this setup factory gun had 110% better performance to the tomba equipped gun. The reason was very high drag of the piece of the spectra.


With this "knot slider" I got the same result as with "spring slider", about 48% better performance to the factory gun.


So I could conclude from the best case:
1. About 25% of improvement is due to vacuum barrel, and 25 % to the better (more hydrodynamic) shaft.
2. Even the best vacuum system could give very poor performance if not used right way.

Improvements due to vacuum barrel would be even higher in deep water. Look at:
http://forums.deeperblue.com/pneuma...uum-barrels-aka-dry-barrels-3.html#post788275