Abellan Powerband problems help please help

[Andreas Simos]

Hello alltogether
its me again Andreas from germany , finally i bought my first wooden speargun an >>Abellan Albacora << on ebay spain for a lot of money and it came here with a broken handle :yack (first thing is fixed already) and maybe wrong powerband dimensions , i tried to reach the manufacturer by email and by phone but no reply :vangry,

i want o go to greece on holydays very soon and time runs away ...:crutch

so i come to the exact description of my problem:
i dont know how long the powerbands have to be and what thickness they should have ( i guess 17mm is ok)
.
dimensions an measurments i made are:
.
overall length of the gun : 135,5 cm ( 53,34 inch)
Shaft length about : 115 cm (45,27inch)
wheight : about 6,5 kilos
length of the spear : 141cm (55,51inch)
diameter of the spear : 8 mm (0,31inch)
wheight of the spear with slip tip : >500 gramms

distance from muzzle hole end (shortest distance to sharkfin measured with dynema line ) to first , second , third sharkfin are exact
1. 86cm (33,85inch)
2. 96cm (37,79inch)
3. 105cm (41,33inch)

how long have to be the powerbands exactly overall length, from constrictor knot to constricktor knot , and how long should be the wishbone length

what i have is: 3 quite good looking powerbands 17 mm (0,66 inch) diameter in the length 61,5cm (24,21inch)/ -62,3cm (24,52inch) /-62,7cm (24,68inch) from constrictor knot to constrictorknot, is it possible to use them by using different wishbone lengts?

i hope someone of you can help me
Regards Andreas

 

[Old Man Dave]

I have seen the videos of the making and use of guns made by Victor Abellan. Not sure which model yours is but most of his guns seem to use 2 bands.

The size of bands is fairly easy to work out. When the band is stretched it should be between 3 and 4 times its normal unstretched size. 3 times is an easy load but 4 times needs a lot of strength and high quality bands. Go for 3.3 to 3.5 for an average.

To measure the length of bands for your gun use a thick piece of string or some small rope and rig it in the gun as you would a band. Make the rope reach to 2 inches (50mm) in front of the skarkfin or spear notch. Remove the rope and measure it. Divide by 3.5 and thats your band length. Repeat for the other bands. Allow an extra 1.5 to 2 inches onto the length of band when you cut it for the portion of rubber beyond the constrictor knots. This is for a typical 4 inch (100mm) between beads dyneema wishbone.

I don't see why you couldn't use longer wishbones and shorter rubbers if you have them but it wont look nice and seems a shame for such a nice gun.

Good luck.

Dave.

 

[Andreas Simos]

thanks for your fast reply old man dave..
my speargun is the little bit olderand havier Model Albacora 115 they say it can use 3X 17mm or 2x
19,5 or 2x20mm rubber bands, i like to use 3x17mm powerbands because they are easier to load .

ok, 100mm dynema wishbones i understand ..

...could you give me an example for the calculation....

Andreas

 

[Old Man Dave]

This blue rope is being used to measure the stretched band length. It stops 5cm short of the notch on each side of the spear.

The rope measures 130cm (this is a short gun and this is to the front notch). Using a 3.5 stretch factor then 130 /3.5 = 37cm. Add 5cm to the total length of the band for the ends after the constrictor knots.

For this gun with a rubber stretched 3.5 times you need a piece of rubber 42cm long. The constrictor knots are tied 2.5cm from the ends and the wishbone is 10cm long between beads.

Your gun is going to be bigger but that's how you do it. You need to try it to see whether it suits you but it will be about right.

Dave

 

[Andreas Simos]

thank you dave
i think i understood ... so i will try it out as you said ... the thre powerbands are long enough to do so one other question is howmuch i have to add for the overlay of the powerbands first one 0 second one 1cm ? third 2cm ?
and how do you think can i pass the knots of the wishbone into the powerband the easyest way ? is there any good description of making powerbands by my own ? means, how do i make a constrictor knot or how do i pass and so on
Andreas

 

[Old Man Dave]

You can try searching making bands in the search function at the top of the page or use google on the internet for a general search. I used this site recently. How To Make Your Own Speargun Bands/Slings .

Dave.

 

[Lannabulls]

V. Abellan sold his businness to an italian guy, now the Abellan company and its new production is over there in Italy, Brescia city.

I never heard an Abellan gun named "albacora", however here the Abellan web site
http://www.abellansub.com/productos.php?op=2

Can you post a photo of your arbalete? So we can understand better wich model we are speaking about, it will be easier to crrectly answer your main questions, the power band thickness and the length.

Fishing in Greece in summer: a mono or double power bands is the way to follow, commonly the mono it's the right solution, it depends on the games you are going to hunt and your favourite tecnique.

 

[GreekDiver]

i have a Denton 110cm that i just got recently. I love it.

Email Victor. info@abellansub.com

He responds fast if he is in town.

 

[Lannabulls]

Hi GreekDiver,
nice gun, what about the steel muzzle shape?
After several shooting did you notice any problem as cut on your power bands?

Despite that kind of muzzle , i had a home made gun with that muzzle shape and i got the above mentioned problem, i like very much the Abellan productions, they have a lot of the Dapiran ideas!!!!!

 

[GreekDiver]

Hi GreekDiver,
nice gun, what about the steel muzzle shape?
After several shooting did you notice any problem as cut on your power bands?

Despite that kind of muzzle , i had a home made gun with that muzzle shape and i got the above mentioned problem, i like very much the Abellan productions, they have a lot of the Dapiran ideas!!!!!

It wont cut your bands.

 

[Andreas Simos]

hi alltogether i calculated as old man dave told me phoned with a dealer in chania crete if he can make me some powerbans i hope calculated right ,, the abellan albacora is shown on this site: Bluworld - News dal Forum di Bluworld
her reported that the 106 cm version can shooot over 7m but i have the bigger the 120 version wonder how far it can shoot ;-))

 

[Lannabulls]

Hi Andreas,
Bluworld is a really nice forum, i'm on of its member and it's the most technical forum in Italy today, a lot of home made arbaletes, excellent works!!!

In order to calculate our power bands lenght:


PBL = [(L*2) + F] / K

PBL = Power band Length
L = Our gun length from the muzzle power band hole to the 2nd notch or sharkfin
F = Power band length inside the muzzle hole
K = Powerband Strength %


K = 300%- Power band with average performances, easy to charge, the most
common % of strength good in most common situations
K = 350%- Medium high % of strength, not easy to charge
K= 400%- Very High % of strength, a lot of us are not able to charge it cause it takes a lot of strength. Only some power band brands are able to withstand this %


You got a 120 Abellan, let say that F is about 5 cm and we decide for a 300 % of strength:
[(120*2) + 5] / 3 = 81.5 cm from knot to knot
Cut a power band piece 83.5 cm long, add 1 cm to each power band ends in order to tie them.

With a new gun never used before, always begin with a 300 % of strength, test it first in order to understand if you got a right % or you have to shorten it, it also depends on the shaft and power band diameter that we are going to use.

Your abellan 120 in Greece:
depending on games that you decide to hunt, try a 6.5-7 mm shaft with a 16-17.5 mm mono or double power bands, test different lay out in order to understand what's working better for you.
Ciao

 

[speareasy]

Not all rubber bands have the same modulus of elasticity. I would stick to 3 X the modulus of elasticity to start, you can always cut your bands shorter later. It is very easy to tie your own bands if you have the proper materials. Here is a chart from www.spearitco.com to band size according to your gun conditions. I find it is a good starting point but you most likely will want to go higher or lower a bit depending on how easily you can load the gun. The people at this site have all the stuff you can ever need to load your own bands and fantastic customer service.

● Calculate Speargun Band Size : Spearitco.com, The worlds largest selection of Speargun Bands and Do-It-Yourself Spearfishing Supplies

 

[shaneshac]

As an mentioned on the post in the other section, i used to have an albacore and used 64, 62 and 60cm

Colour code the wishbones as they sometimes switch over during the shot

another option is 4x14mm

 

[spaghetti]

As an mentioned on the post in the other section, i used to have an albacore and used 64, 62 and 60cm

Colour code the wishbones as they sometimes switch over during the shot

another option is 4x14mm

OT:
Shane!
Cool to have you posting on DB again: this makes me really happy. Welcome the comeback guy! xxx

 

[shaneshac]

heheheh its been a while ;-)

Will pop round a bit more often :martial

 

[Old Man Dave]

OT:
Shane!
Cool to have you posting on DB again: this makes me really happy. Welcome the comeback guy! xxx

I was just thinking the same. Don't be such a stranger, as we miss you.

Dave.

 

[lopen79]

hi guys
ok in case i am going to use dyneema wishbones in double circular bands should they be the same length (the dyneema) ?

 

[hteas]

Much easier to stick with wishbones of the same length. Less to think about.
If you want to squeeze every little bit of power out of the gun, you can go with slightly different band lengths custom tuned for the actual stretch of each, but with the same wishbone length. But, doing so will give very little increase in power, and you have to keep track of which band to load first.

 

[mundial]