I was wrong

[adb]

I admit it. I was wrong. Spine for war arrows does matter. I didn't think so, but practical experience tells me otherwise.

I've been doing a fair bit of warbow shooting this summer. 12 shoots so far. Mostly practice, but 1 officially scored competition.

I've been using birch, ash and oak shafted arrows, and have been paying no attention to spine values. I am unable to come up with an accurate way to measure spine on a 1/2" arrow shaft. I've only been concerned with the weight of the finished arrow, to fall within the guidelines of CWBS and EWBS rules.

Long story short... the stiffer spined birch and ash shafts will consistently fall up to 20 yards short of the softer spined oak shafts for arrows of the same size/weight. The stiffer shafts are also not flying as well, with major fishtailing on loose. I am only judging spine by flexing the finished arrows, and the oak shafts are noticeably softer.

Anyone else with experience in this regard? Of course with target arrows, I'm following the general practical guidelines for arrow spine. 

[Dag]

I wholeheartedly agree with you adb.  For the longest time I've read that spine on heavy war arrows does not matter.  I could never bring myself to believe that.  However, I've never had an opportunity to test it. 

I used to shoot red oak war arrows, 1/2" tapered to 3/8", that felt like trying to launch a telephone pole.  Then I received some 3/8" diam Hickory arrows that left the bow like lasers.
 
Although it was a very small sampling, and albeit with different wood types.  It still seemed clear to me that spine does play a role.

So, perhaps more proper tests can be done.  I feel like most of us warbow archers have taken this bit for granted and never REALLY looked into it.

As a student of science I am more than willing to change my ideas given the proper evidence.  I am intrigued on the findings of this topic.

[unkieford]

Disclaimer!!   I don't have a war bow (yet!) to work with, so I'm just guessing here, but I suspect that the heavier your bow is, the wider range of spine might work, but it will still matter.
My gut instinct is that spine variance should fall within a certain percentage of draw weight, but darned if i know where. 
For example, a 50# bow might seem OK with a spine variance of about 5#, or about 10% of draw weight. If that relationship stays linear, then a 100 lb bow would work OK with about 10# variance.

but that might all be completely dished by an actual scientific test. 

As for measuring spine on shafts that thick, I wouldn't even try to match 'em to a chart anywhere. I'd measure deflection (with a dial gauge or something) on your best arrow, and just try to get others as close as possible. You might need something heavier than a 2# weight to really see any bend.

---Ford---

[Joec123able]

It seems like most of the guys who shoot warbows shoot for distance more then any thing so maybe when there shooting 200+ yards spine isn't an issue when laser accuracy isn't important I don't know just my thoughts as a person whose never shot a warbow

[WillS]

The more movement a projectile has in the air, the less efficient that projectile is.  Crucial energy is being wasted on vertical and horizontal movement, so the arrow just doesn't go as far which for distance is important!

[adb]

It seems like most of the guys who shoot warbows shoot for distance more then any thing so maybe when there shooting 200+ yards spine isn't an issue when laser accuracy isn't important I don't know just my thoughts as a person whose never shot a warbow

I think you've missed my point... spine is an issue! With arrows having less spine (all else equal), I'm getting 20 yards more cast.

[WillS]

Adam, what spine are you actually finding works best for your particular bow?  If you're shooting a 100# bow, are you getting best results with arrows spined at 100#, or are you just finding that weaker spines in general are performing better?

I've recently finished up a sheaf of EWBS Standards, which are ash spined 85-90#, so I'm curious how they'll come out of a bow around 110-120#.  If I'm honest, I was of the "spine just doesn't matter" opinion until your post, so I wonder if they'll be too weak.  Need to find time to let them rip asap.

[bumppo]

I asked this question about spine and warbow arrows back in 2010 when I was just starting out with bigger bows and it seemed for the most part people didn't worry about it. I pretty much ignored that attitude and after some R&D I developed a spine tester for my bigger shafts. It took me a while but eventually I came up with a pretty consistent scale for spine vs. bow weight. How it relates to how others measure spine I couldn't tell you, it just basically tells me that one shaft's deflection is more or less than another and by how much.

What I found: of course spine is important....... shooting shafts that are way too heavy for a bow quickly shows in distance and accuracy, plus, this may be just me but.... too heavy of an arrow just doesn't "feel" or "sound" right when loosed. Also goes the opposite way, my lighter shafts that fly great with my #90 bow are terrible for my heavier bows. I'm only shooting up to #120 so above this weight may be different.....

[Joec123able]

It seems like most of the guys who shoot warbows shoot for distance more then any thing so maybe when there shooting 200+ yards spine isn't an issue when laser accuracy isn't important I don't know just my thoughts as a person whose never shot a warbow

I think you've missed my point... spine is an issue! With arrows having less spine (all else equal), I'm getting 20 yards more cast.

Ok I don't shoot warbows so don't take what I say toO Serious

[adb]

I asked this question about spine and warbow arrows back in 2010 when I was just starting out with bigger bows and it seemed for the most part people didn't worry about it. I pretty much ignored that attitude and after some R&D I developed a spine tester for my bigger shafts. It took me a while but eventually I came up with a pretty consistent scale for spine vs. bow weight. How it relates to how others measure spine I couldn't tell you, it just basically tells me that one shaft's deflection is more or less than another and by how much.

What I found: of course spine is important....... shooting shafts that are way too heavy for a bow quickly shows in distance and accuracy, plus, this may be just me but.... too heavy of an arrow just doesn't "feel" or "sound" right when loosed. Also goes the opposite way, my lighter shafts that fly great with my #90 bow are terrible for my heavier bows. I'm only shooting up to #120 so above this weight may be different.....

Thanks! So... how are you measuring spine on 1/2" shafts? Care to share your results?

I've also noticed a difference in 'feel.' The stiffer spined shafts don't release very clean, and the release is always more noisy. The arrows usually fishtail horribly as well. I know sometimes that's, but not always. With the softer spined oak shafts, there is little or no fishtail, and the loose is much quieter and cleaner.

[adb]

Adam, what spine are you actually finding works best for your particular bow?  If you're shooting a 100# bow, are you getting best results with arrows spined at 100#, or are you just finding that weaker spines in general are performing better?

I've recently finished up a sheaf of EWBS Standards, which are ash spined 85-90#, so I'm curious how they'll come out of a bow around 110-120#.  If I'm honest, I was of the "spine just doesn't matter" opinion until your post, so I wonder if they'll be too weak.  Need to find time to let them rip asap.

I'm not currently measuring spine on these heavy arrows. I have yet to come up with a way to do it consistently. I'm just finding that the oak shafts flex more when I bend them between my thumbs. The birch and ash shafts basically don't bend at all when I try and flex them by hand. They are noticeably stiffer and don't fly nearly as well.

We don't shoot many EWBS standard arrows. We're shooting mostly livery and a few 1/4# arrows. I currently shoot 90# and 100# bows. My buddy is shooting 120#. The stiffer arrows definitely cast the same out of his bow... not as well as the oak.

[adb]

It seems like most of the guys who shoot warbows shoot for distance more then any thing so maybe when there shooting 200+ yards spine isn't an issue when laser accuracy isn't important I don't know just my thoughts as a person whose never shot a warbow

We shoot for cast, but we also shoot for accuracy. We set a mark at 200 yards, and compete for closest to the mark. So, accuracy IS important.

[Del the cat]

Alan Blackham on his 'Back street bowyer' site has some slo mo video af an arrow leaving a warbow ...the damn thing was going sideways!
Yup spine does matter and IMO weaker is generally safer than too stiff.
Del

[Yeomanbowman]

Adb,

Was the FOC similar with birch and oak arrows?  I find a good amount of FOC is beneficial for distance.  I once made 2 very dense birch arrows with very light Tudor bodkins so a lot of the weight was in the shaft and found them disappointing but the FOC was quite low. These were shot from a very fast 155lb yew bow.

[adb]

Adb,

Was the FOC similar with birch and oak arrows?  I find a good amount of FOC is beneficial for distance.  I once made 2 very dense birch arrows with very light Tudor bodkins so a lot of the weight was in the shaft and found them disappointing but the FOC was quite low. These were shot from a very fast 155lb yew bow.

I make all my heavy arrows strongly FOC. 60/40... even 70/30. I usually use reasonably heavy heads... mostly no lighter than 20 grams. Shaft tapers are also bob-tailed, leaving them point heavy.

Have you had an experience with barrel tapered shafts?