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The Unicorn of Accuracy

Posted by UniBoffin at 11:52 on 29th March 2010 in UniBlog

The Unicorn of Accuracy

Despite an unfortunate tendency for allowing flights of irrelevance to interrupt my explanations of the flight of darts, I do realise that the most likely reason for anyone to read these blogs is simply because they want to be a better dart player. They may even hope – no doubt with a healthy dash of scepticism - that the appliance of science might just help them in the hunt for that legendary darting beast, the more accurate “arrer”.

So, let’s cut to the chase. Is such a beast not just legend but myth? Can an arrer really be more accurate? After all, a dart’s not a guided missile. It doesn’t know where it’s supposed to go. Whether designed by a rocket scientist or not, throw it in the wrong place and it’s going to myth, sorry, miss. That’s just common sense, isn’t it?

Well, yes and no. Although no amount of clever aerodynamics can compensate for a dart being thrown in the wrong direction, unclever aerodynamics can easily send one thrown in the right direction off target. And exactly what constitutes clever aerodynamics I have explained before in “The Adventure of the Three-Quarter”.

So it’s to that epistle that I would refer any diligent Holmes who is prepared to wade through a Grimpen Mire of scientific verbiage to track down the fabled unicorn of darting accuracy (see what I did there?). But, for the benefit of all Watsons, it seems it would be helpful if I covered the subject again, this time foregoing scientific rigour in favour of understandability. Just don’t tell my old college maths professors (although I expect they’ll have lost their faculties by now!).

OK, we’ll start with what you do when you throw a dart. You apply two things to it, a force and a moment (a turning force). The force accelerates the dart so it leaves your hand with a certain speed and direction. After that it’s mostly gravity that determines the trajectory of its balance point (hence centre of gravity), with some meddling from aerodynamic forces, mainly lift and drag. The more important of these two is usually lift and, unlike gravity (which is pretty much fixed for non-astronauts), its effect will vary considerably according to how straight the dart flies and its design – for example a 40gm dart will lift half as much as a 20gm one of the same shape.

In flight, the wobbling and spinning of the dart about its centre of gravity, which was set off by the moment applied during the throw, is solely at the mercy of aerodynamic terms, with the most important of these again being related to the lift acting on the flights, although this time the dart’s length as well as weight also plays a part.

The point now is that most people find it much easier to control the force applied when throwing than to control the moment. To prove this, try throwing a nail (which won’t be much affected by aerodynamics) at a dart board. It’s not difficult to accelerate it the right amount to get it to hit more-or-less where you’re aiming, but it is difficult to put the right moment on it to get it to hit point first, let alone straight (although it can be done - check out Joe Hitchcock on YouTube!)

So, let’s say you accelerate a dart perfectly but apply a bit of unwanted moment when doing so which causes the dart to wobble in flight. The centre of gravity might be cheerily on its way to treble 20, but it’s stopped short when the dart hits the board at an angle with the point sticking in treble 1.Unlucky!

Ah, no problem, you say. I’ll simply tune my shaft and flights so that my darts hit the board straight. That way, whatever angles my darts may experience in flight, it won’t make any difference to my scoring.

Nice idea. In fact, the same nice idea that virtually every serious dart player, professional or amateur, holds dear. But there’s a catch. Those angles that the dart experienced in flight caused lift, and it’s very likely that the lift sent the dart’s centre of gravity – and therefore, as it’s hitting straight, its point - off course. Not by much, just a few millimetres probably, not enough to notice directly, but enough to miss the target.

But let’s say some geeky aerodynamics-type can come up with a sneaky trick. Design a dart so that it hits the board straight only if, in flight, it wobbled one way and then the other so that the lift in each direction cancelled out. If it wobbles so that the lift doesn’t cancel out, make sure that the angle of the point when the dart hits the board is in the opposite direction to the lift and exactly compensates for it.

If that can be done, the dart point will always hit where its centre of gravity was going when it left the player’s hand, whether the dart hits the board straight or not, or lifts or not. This means the player will only need to be precise with their throwing force, not their throwing moment.

And that, I hope you’ll agree, would indeed be a more accurate arrer.

So here’s the crunch question. Can that be done? Well, as those diligent Holmeses will know, the answer is again yes and no. If the in-flight wobbling of the dart is too great, the sums can’t be made work and the player is usually better off with conventionally well set up darts that tend to hit the board straight (maybe Sigma Ones). But if the wobbling is only relatively slight – as it usually is with high standard players – the numbers can be made to fall into place pretty nicely.

Unfortunately, the problem here is that it’s almost impossible, even for a professional player, to tell by trial and error whether darts which land at mildly varying angles are helpful compensating for invisible lift or not - and statistically it’s much safer to assume not. Unless, that is, they’ve been scientifically assessed or designed by some sort of darts boffin, like a set of Sigma Pros.

So the Unicorn of Accuracy isn’t a mythical beast after all!

There are 3 comments to this post

Posted by Jeff at 15:04 on 29th March 2010


I must say reading your UniBlogs has helped my game. After reading these, I was better able to disect my playing, and tune my equipment to elevate my performance.

Thank you and well done!

Posted by Dave Burgess at 10:07 on 31st March 2010

The Andy Hamilton darts look almost identical to Sigmas. What is the difference?

Posted by Victor at 16:15 on 7th July 2010

I've found these blogs to be most helpful. I enjoyed how in depth this article goes into the momentum and angle of the darts, and how they impact the accuracy of the darts. I love my Unicorn Darts and would not give them up for the world.

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