Hi, everyone. It’s good to see that the spirit of scientific enquiry is alive and well amongst dart players, which means that there were again some good comments and questions after my last blog - and it’s no surprise that Sigma darts were the main topic.
As usual, I’ll respond to most of the questions in the Q&A section at the end, but it so happens that one of them was actually going to be today’s subject anyway. Neily B wanted to know why Sigma darts are more consistent for the average darts player.
To answer this, we first need to appreciate that, when darts are thrown from a standard 2.37m oche, the length of their flight path doesn’t vary from person to person quite as much as one might think. Don’t believe me? OK, let’s look at the factors involved:
Firstly, there will clearly be some variation in the position of different players’ release points due to their individual stance and throwing technique, but, for serious “dartists” who don’t generally lean so far forward they over-balance or so far back they need telescopic sights, this doesn’t often amount to more than a few centimetres.
The next factor to consider is speed of throw. A slower dart will have a more curved flight path and hence have further to go, but again the difference will generally be fairly small (by the way, despite what you might have read, this curve is not strictly a parabola, which is only an approximation that neglects aerodynamic effects).
Ah, I hear you say, but what about a player’s height? Your pal Lofty who plays down the pub is 2m (6ft 7) tall. How can his darts have as far to travel on their way to the treble twenty as the darts of his mate Little Len, who’s only 1.5m (4ft 11)?
Well, of course they don’t, but probably not by that much. Although Lofty’s arms are (hopefully) longer than Len’s and he might lean a bit further forward, their height discrepancy alone does not make all that much difference (and, for a similar reason, neither does whereabouts on the board they aim). This is all due to a Greek guy.
Let’s take Lofty’s longer arms out of the equation for a minute and imagine that both guys release their darts a convenient 37cms in front of the oche (convenient as that’s exactly 200cms from the board). How much further do Len’s darts have to travel to hit the 60, some 50cms above his release point but level with Lofty’s? 25cms? 30, maybe? No, the actual answer is only about 6cms. Because (as Pythagoras would tell us if he were rather less dead) 200 squared plus 50 squared is 206.15 squared.
Hence height, in itself, doesn’t alter flight path length hugely, and, although speed of throw, length of arm, and individualities in stance and release point will make some difference, for “the average darts player” (to use Neily’s phrase) throwing from a standard oche, their darts are usually going to travel somewhere near 2m. Now this is a useful piece of information for an enterprising dart designer, because the yaw cycle of a dart can then be tuned so that its wavelength is related to this distance.
But why should tuning the yaw wavelength to the flight path length help? (if you’re new to these blogs, or have forgotten about yaw cycles and wavelengths, see my earlier “Yaw Choice” blog). Well, most reasonable players can release a dart pointing fairly straight, but it’s much harder not to give it a yawing “rate” (to use the correct term) when so doing. This means that the dart starts off at low yaw, but this then increases up to a maximum after one-quarter of the yaw cycle. The yaw “pendulum effect” then causes the dart to pass through a minimum yaw point after a half-cycle before it hits another maximum (only in the opposite direction) at three-quarters. After a full wavelength, the cycle would be complete and the yaw back to a minimum.
Thus if the yaw wavelength is the same, even approximately, as the flight path length, the dart will hit the board pointing more-or-less in the direction it’s going, whatever yaw rate it was given at release. The dart’s point will hence tend to be in-line with the CG, which (remembering that only the CG has to stay on the thrown trajectory) is much better for consistent scoring than if the dart impacts at a variety of large angles.
Unfortunately, although this might seem like a great idea to help that “average player”, most darts have a yaw wavelength of much more than 2m, which means the match with flight path length is not achieved. But it can be if the dart has a very low moment of inertia barrel. And the perfect shaft. And aerodynamically-optimised flights. In fact, it can (finally getting to part of the answer to Neily’s question) if it’s a Sigma One.
Now that is only part of the answer because there’s still much else to explain, such as why a yaw wavelength of half-a-cycle wouldn’t work in the same way, and why the yaw wavelength of the Sigma Pro is something different again to achieve an effect (to quote Blackadder) “so cunning you could stick a tail on it and call it a weasel”.
But I think that’s enough trade secrets out of the bag for this time!
Q & As!
Chris, Irina Armstrong’s darts and Sigma barrels:
This makes me feel old, but the truth is the general design for Sigma dart barrels was formulated well before Irina had even left school! It’s just taken this long for the technology to come along so that they could be both made and marketed properly!
Z71pinkcadillac, abe and Warren on Sigma flights and shafts:
The bad news is that unprecedented demand for both Sigma Ones and Pros (which share the same barrels, abe) has caused spares to run low and the high-tec shaft materials means it’ll be a few weeks before new stocks come in. However, I’m told Mad on Darts (www.madondarts.co.uk) do still have some stock. It’s worth waiting for the real deal because it’s almost impossible to achieve a set-up with the same accuracy - at least as the Sigma Pro - using trial and error (for why have another look at my last blog, Warren). Just in case you get desperate, though, herewith my second-best recommendations for the aerodynamically closest alternative set-ups:
Sigma One: longer Checkout shaft (eg no 78565) / Maestro Xtra flights (eg 68253)
Sigma Pro: longer Aliflex II shaft (no 78247) / Hi-Lites Slim flights (eg 77346)