[English Longbow] Spine Charts for Longbow

blakey

Active member
Because of another thread (about recurve spine) I've been thinking about the standards for spining ELB. If you shoot an arrow where draw length brings the point to the back of the bow, with no overhang, then what spine charts do you use? Am I right in thinking that ELB spine deflection is measured at 26" ? Cheers
 

Simon Banks

Active member
Yes I think 26" is right for static spine. Flights stiffen and the pile weight softens dynamic spine..
Never got my head around how my arrows work perfectly with both my 50# and 42# longbow.. Bit of a black art if you ask me..


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Raven's_Eye

Active member
Ironman
I'm not sure a spine chart for longbow would really work. recurves are more consistent with how they work, and with the arrow being central to the bow it can be calculated more easily.

With longbows the bow is a factor. Ignoring the material of the bow spine depends not only on the poundage and draw length, but also the speed of the bow and it's width. For example an Aidy Hayes bow is thinner than a Bickerstaff bow so an Aidy bow would been a stiffer arrow as it doesn't have to curve around the bow as much.

Simon I have a similar thing, I have a 65lb bow and a 50lb bow but the arrows fly just as well out of each, due to the different characteristics of the bows.

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I'm not sure a spine chart for longbow would really work. recurves are more consistent with how they work, and with the arrow being central to the bow it can be calculated more easily.

With longbows the bow is a factor. Ignoring the material of the bow spine depends not only on the poundage and draw length, but also the speed of the bow and it's width. For example an Aidy Hayes bow is thinner than a Bickerstaff bow so an Aidy bow would been a stiffer arrow as it doesn't have to curve around the bow as much.

Simon I have a similar thing, I have a 65lb bow and a 50lb bow but the arrows fly just as well out of each, due to the different characteristics of the bows.
 

Simon Banks

Active member
My advice is find somebody like Carol Archery who has hundreds of ready made arrows and the experience/eye for seeing of the are flying true and given 30 mins of shooting different arrows you'll find your perfect arrow.
 
D

Deleted member 7654

Guest
A lot will depend on the bow.
A tired old 40# Ash ELB made by a beginner will require a totally different spine from a 40#Boo backed Yew that is made by a good bowyer.
Spine charts are nothing more than a very rough guide to a starting point.
Things that effect arrow performance.
Length,
Spine
Point weight
Fletchings
Brace height
Bow
Draw length (many people don't actually know how far they draw. So their 40# @28" bow is only really being pulled to 35# because they draw about 26#)
Loose
Tab!
Del
 

BillM

Member
I got a chart from Stan at Aim4Sport which is based on arrow length while most other charts are based on draw length. while most recurve archers will use a clicker so the draw length will be measured to the riser. Most longbow archers will have a few inches forward of the hand so the characteristics will be different compared to draw length. This chart basically indicates that for every additional 2" of arrow length the spine moves to the next column of the chart - a stiffer shaft is needed for the arrow to perform like the shorter one. If anyone wants a copy, PM me and I'll make up a spreadsheet which I can email to you.

BillM
 

russ1980

New member
It's been said many times before, the charts you see are just a guide. The only real way of getting perfectly matched arrows is to shoot various spines and weights and find ones that suit your bow and you. Also it depends on where you anchor, your draw length, your arrow length etc etc. Also as mentioned in a previous reply not all bows shoot the same even if there the same poundage. But my own personal opinion is that you can have the best made bow with a perfectly matched set of arrows but if your release isn't up to scratch none of the above matters.
 

jbridges

New member
There is a somewhat fundamental problem with spine charts. They are all in units of 'bow poundage'. Arrow static spine is really a deflection when a fixed weight is applied. Unfortunately the people who produce spine charts convert deflection to bow poundage (because it is more convienient as bow poundage is written on your bow). The problem with this is that this conversion depends on the type and speed of your bow and no one knows what type or speed of bow was used to do the conversion on the chart being used. Easton arrow spine charts demonstrate this because there are different columns for recurve, soft cam, hard cam bows etc.

We also have to remember that the manufacturer/retailer of wooden arrows may be selling predominantly to the American flatbow or hunting recureve market. To keep most of their customer's happy, the arrow spine charts used will be matched to laminated carbon fibre limbs. If you find someone with an arrow spine meter from the 1940's, chances are it is more matched to an ELB.

What I have describe contributes (in my view) to the feeling that getting the right spine for an ELB is a black art. It also implies that swapping arrow retailer (they may use a different spine meter to your last retailer) might prove problematic as might swapping the manufacturer of the arrow shaft. You will still get variation but it would be less (in my opinion) if we all request arrows of a certain deflection.

I know there is the AMO standard but I have compared (using Excel) it to my own spine meter and other spine charts I have found on the web and there are differences. Another interesting point about static spine is that everything is more sensitive for light weight bows. Once you get towards 70lbs, the curves flatten out menaing that the same arrows will come out of a wider range of poundages. Might be why some archers have more of a problem with spine than others.
 
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