Pakystunt

Good idea !!! It would be good to leave little wood between rubbers to get some extra strength in body of gun. With 3x17,5 i have some incurvation of gun body Try renforce the body with some fibers .... without changing a lot .... my suggestion to you, leave it like it is just renforce if you can, add two knots where they Should be a central and rubber for the initial pretension and precharging ..... and you transform your sailing into Volcan (sailing Vacondised version hihih) The simple sailing is for pussys (joke) Tnx for idea, with this setup 2x17,5 + 1x16 (all sailing) i have 27ms on

Good idea !!! It would be good to leave little wood between rubbers to get some extra strength in body of gun. With 3x17,5 i have some incurvation of gun body Try renforce the body with some fibers .... without changing a lot .... my suggestion to you, leave it like it is just renforce if you can, add two knots where they Should be a central and rubber for the initial pretension and precharging ..... and you transform your sailing into Volcan (sailing Vacondised version hihih) The simple sailing is for pussys (joke) Tnx for idea, with this setup 2x17,5 + 1x16 (all sailing) i have 27ms on

Good idea!!! It would be good to leave little wood between rubbers to get some extra strenght in body of gun. With 3x17,5 i have some incurvation of gun body

I made some changes on gun, now i shot with rubbers only down 2x17,5+1x16 all on paranco. Speed on 4m is 26,5ms This is target when i was shooting from 5,5-6m, water visibility is low hard to see target well and water is cold. I figured that I make rotation in my hand when pressing triger, (maybe that gives shoots bit to left) here is video of recoil and shoots https://www.dropbox.com/s/252fsi78drnblmr/Produce55.mpg?dl=0 ciao

I like dynamic targets ! Stefano this guy is grendpa of rollerguns in Croatia =D I understand !! So he is the "Orvac" of Croatia. Yes something like that

I like dynamic targets ! Stefano this guy is grendpa of rollerguns in Croatia =D

Problem is only when gun is loaded to first sharkfin and on 50% pre-tension, when loaded to last sharkfin and normal pretension 20% no problem gracie Habanero

on first picture you can see that gun is not loaded with dyneema, there is piece of spectra which goes to sharkfin to reduce shoots going down

2.

some photos

Gracie Stefano When pretension is 50% and dyneema on first sharkfin shots are low because recoil moves head of gun up before end of spear is out of gun. Gun kicks up rear end of spear and you get low shoot

video of test, dont know why is precision with 50%preload bad... always 5-6 cm down. Precision on 4m is perfect, on 5,5 is very good maybe 3cm to left for better view download video !!! https://www.dropbox.com/s/rsdirl1coyj4d12/Produce5.MP4?dl=0

speed at 5,5m with only 2x17,5 on paranco and 16 up was 23,8 when pre-load is set to 50% pulling way is shorter 20cm and speed is almost same i will put video tomorow

Today I made some test with pre-load ..load 2x17,5 from paranco on first shark fin in the midlle of spear and classic rubber 16 up avarage speed is 26ms on 4 meters... here i have shortened dyneema and pre load was about 50% because I wanted that rubbers be on 100% than I put preload to 20% and hooked dyneema to last shark fin and classic rubber up to last shark fin to and speed was 27ms at 4 meters

You are right. Thus the closer to the center of mass you will apply the force, the smaller will be the bending of the shaft. I have a question for Stefano: how can you get the initial kinetic energy from average speed? Come fai a trovare l'energia cinetica iniziale dalle velocità medie? Devi fare una stima approssimata della balistica interna. M yes, sounds right but... if the pulling way is shorter will the kinetic energy be smaller ?

I agree !!! Stefano, what do you think about this: When the gun is loaded with 2x17,5+16 on paranco and 16mm up, dyneema from paranco is hooked on shark fin in middle of spear not on end i have speed of 27ms on 4m... what is strange because rubbers are on much lower % elongation( maybe 300 %) and shaft speed different is only 3ms ? I think you're focusing on the concept of speed rather than kinetic energy of the shaft.I did a quick simulation of your speargun.In order to have an average speed of 30.1 m / sec on 4 m and 26.8 m/sec on 5.5 m with the shaft 8x130, you must have an ini

I agree !!! Stefano, what do you think about this: When the gun is loaded with 2x17,5+16 on paranco and 16mm up, dyneema from paranco is hooked on shark fin in middle of spear not on end i have speed of 27ms on 4m... what is strange because rubbers are on much lower % elongation( maybe 300 %) and shaft speed different is only 3ms ?

That is superb for 3 rubbers 16 , is it hard to load the gun with you system. For first 10-15cm you are loading full power of bands, without paranco? Tnx

TNX Dan There are many small things, I will make some good photos of gun that all of you can see. Maybe someone will make it more powerfull than me and my friends... and evolution will continue...

I dont understand Italian so god... what thing ? =D

Tnx for answer In hunting I didnt notice that gun is shooting low, I only notice that on long range shots (5-6m) I miss few centimeters to left because of recoil. I will make new video when water will not be so murky. Volcan is great gun, what is speed without rubber up ciao

results from test on 4m with 135x8mm : 2x17,5 on paranco + 16 up: 24,5ms 2x17,5 on paranco ,no rubber up: 20ms 2x17,5+16 on paranco +16up : 30,1ms 2x17,5+16on paranco ,no rubber up: 26,3ms 5,5m with 135x8: 2x17,5+16 on paranco +16up : 26,8ms When the gun is loaded with 2x17,5+16 on paranco and 16mm up and dyneema from paranco is on middle of spear not on en

Great shot!!! :D I hope the latter is true... haha, this was on 3-5 meters ... small fish but no low shots

shoot is not low, i have shoot low becouse target has many holes in center and I didnt want spear goes to same hole... than i dont have sound when spear hits target Precision of gun is very good, on 6meters 2cm in left due to recoil, but thare is one thing left to fix and it will be center-center you can think thats not 4m, but why should i lie... i make guns for myself not for selling

Shaft is 8mm 135. Now without 16mm rubber up i have 26,3 I think that I can reach 34-35ms on 4 meter with 3x17,5 on 360-370