Should spear shafts be tapered like a pool cue?

[Dan Howard]

For a thrusting spear this makes sense to me but for a throwing spear?

I specifically said that it would not be suitable for a throwing spear.

[Marcus Mummius]

For a thrusting spear this makes sense to me but for a throwing spear?

I specifically said that it would not be suitable for a throwing spear.

Woops, my mistake, sorry :roll:

[Marcus Mummius]

Will the barrel-shape do much to increase the aerodynamic qualities of a spear? Does it really help? Or are there better ways?

Vale,

[Dan Howard]

Arrows were barrelled to increase range. Some thought that it was because of aerodynamics, but it is possible that the shape simply prevents the arrow from flexing as much - allowing more energy to be imparted into the flight.

[tlclark]

Will the barrel-shape do much to increase the aerodynamic qualities of a spear? Does it really help? Or are there better ways?

Vale,

I don't know if barrelling helps aerodynamics but it does help in hafting the spearhead. A tapered socket seems to fit better and there's no raised edges where the butt and spearhead touch the shaft, meaning that there's nothing to catch on clothes or cause abrasions against the hand etc.

Travis

[Marcus Mummius]

@Dan: thanks for the explanation!

@Travis: Yes, it's clear tapering is useful at the ends to ensure a nice snug fit for the butspike and the head. A barrelshaped shaft however is more extreme than just some tapering at the ends of the shaft.

When I get my jav heads from Matt L. I think I'll make barrelshaped shafts for them...

Vale,

[tlclark]

@Dan: thanks for the explanation!

@Travis: Yes, it's clear tapering is useful at the ends to ensure a nice snug fit for the butspike and the head. A barrelshaped shaft however is more extreme than just some tapering at the ends of the shaft.

When I get my jav heads from Matt L. I think I'll make barrelshaped shafts for them...

Vale,

As an art historian I have to make a case for just aesthetics.:wink: Having held a straight shafted spear and a barrelled sphere, it just feels better. Also a barrell shaft has an inherent tactile quality to it that a straight shaft lacks. A barrell shaped spear has a belly a throat and a tail. Just by feel you know how to position the hand. You can tell instantly what part of the spear you are holding. That's a tactile clue missing in a straight shaft. Maybe it's an ergonomic thing.

Just speculating.[/i]

[Matt Lukes]

Will the barrel-shape do much to increase the aerodynamic qualities of a spear? Does it really help? Or are there better ways?

Vale,

I would wonder if it's mainly a matter of making the center of gravity of the missile as well-centered as possible as opposed to streamlining. It makes no sense that a pilum, for example, could benefit from streamlining the haft below the pyrimidal block as that part itself would cause a great disruption of airflow- but if the benefit of the taper Sean reports simply improves the balance, THAT I can see helping the flight. Of course that could be affected easily by adjusting the length of the haft as well.

[Matt Lukes]

As an art historian I have to make a case for just aesthetics.:wink: Having held a straight shafted spear and a barrelled sphere, it just feels better. Also a barrell shaft has an inherent tactile quality to it that a straight shaft lacks. A barrell shaped spear has a belly a throat and a tail. Just by feel you know how to position the hand. You can tell instantly what part of the spear you are holding. That's a tactile clue missing in a straight shaft. Maybe it's an ergonomic thing.

Just speculating.[/i]

Funny, I'd have the opposite reaction- I'd find the straight haft rather more pleasing visually and from a tactile perspective. Any taper beyond an inch or so from the end of the socket and buttspike seems to me to be making the weapon more flimsy and less- weaponlike :lol:

[mcbishop]

Will the barrel-shape do much to increase the aerodynamic qualities of a spear?

Probably not because it is symmetrical in cross-section. An airfoil relies upon asymmetry to generate lift (pressure differential caused by airflow speed differential, Bernoulli's theorem usw), although angle of attack comes into the equation.

Dura catapult bolts are a different matter, however, as the overall longitudinal profile is indeed that of an airfoil: they may well be aerodynamic, rather than ballistic (but that needs to be tested in a wind-tunnel).

Mike Bishop

[Matt Lukes]

Quite so- which is why I thought that drag on the back end could be the only aerodynamic consideration for a spear or small javelin, and the drag caused by the pyrimidal block of a pilum...

Actually, I'd think the pointed buttspike would minimize the airflow disruption at the back end (which I really can't see being significant at the short range these weapons would be thrown anyway)

[ShaneA]

I'm coming into this a bit late...

We do have Celtic finds that has spears that are the pool cue style of taper. It does bring the balance point back, and isn't all that shocking considering the size of some of the spear heads we use.

With javelins the taper and balance point is critical to getting them to throw and fly right. From what I have found you usually want to have the POB to be around 3/4 of the way down the shaft towards the head. It will vary depending on a few things though. You want to make sure that it is flying in a good arc. Too far forward and it can cause the point can drop, shortening its flight, plus you want the center of mass to be inline with the point when it makes impact. If the point drops below the center of mass when it makes impact, it won't transfer into the target for one, and shaft will try to rotate over the top of the point and can snap. If the POB is too far back on the javelin it can pull it down and shorten the flight, as well as not transfer as much on impact.

Mainly at this point I have been working with javelins, bigger throwing spears will be a bit different. Probably not going to be throwing them the same kind of distance and a more flat arc would work better.

Don't really have a clue about all your Roman stuff though...

Shane Allee

[Matt Lukes]

Interesting- now would these tapered Celtic spears be rather long? That's where I can see the taper being quite important to keep the point from drooping on a long spear held near the butt

[ShaneA]

I would imagine that they would be longer spears, but I don't believe the article gave any exact numbers. I'll go back and translate that bit again and see if they mentioned anything about the length of them.

One thing I forgot to mention the first time about doing a taper like this is that you can more or less follow the natural taper of the tree/sprout.

Shane Allee

[Matt Lukes]

Yes of course- choosing an appropriate piece of wood would certainly reduce the amount of work necessary to prepare the haft and maximize its strength...