Shot Darts

An Omen and Some Sines - Flights affect on darts entry
Another interesting Uniboffin article on the science of the darts, this is about the flight and how it affects the angle of the dart in the board, click here to see the article on the Unicorn site: https://www.unicorn-darts.com/news/2015/...sines.aspx


Firstly, a belated Happy New Year, I hope you had a good festive season! For me, and quite possibly you too, it was, as usual, made all the more enjoyable by the darts World Championships being on TV. Many congratulations to Scott Mitchell, Lisa Ashton, and Unicorn’s very own Gary Anderson on their respective victories.

Although the BDO men’s final ran it close for sheer excitement and tension (unbelievable 158 finish, Scotty!), my pick of the many great matches on view had to be that PDC final in which The Flying Scotsman eventually triumphed over both adversity and a determined Phil Taylor in a performance that truly exemplified my last blog’s title, “The Mark of a True Champion”. In a fortuitous omen, that headline was even accompanied by a picture of Gary holding a trophy!

But now to my continuing topic of darts science. Apart from enjoying the sheer excitement of the matches, the high quality of the World Champs TV coverage, with its slow-mos and close-ups of dart release, flight, and impact, gave me its customary opportunity to assess the aerodynamics of different players’ set-ups.

One possible general conclusion that could be drawn from such observation is that there is some tendency for bigger flights to make a dart land more nose-down. And it’s the reason for this apparent correlation that I’m going to look at today.

In fact this correlation is somewhat tenuous as it’s quite easy to throw a dart so that the opposite will occur, but throwing actions that do so, at least for the relatively narrow range of most dart’s aerodynamic characteristics, seem less common than ones that don’t.

This is partly because it’s most natural to release a dart at an angle somewhere between slightly below horizontal (see the photo of Barney below) and the upward slope of the initial trajectory. If the latter, due to the rotation of the forearm, there can then be a tendency to pull the rear of the dart down at release, causing it to have an upward angular rate (see the photo of Kevin Painter).

Now to look at the other main factor in this issue, the dart’s aerodynamics. I’ve explained many times before, most recently in last time’s Q&A to Kevin, that a dart tends to take a fixed distance to correct in flight, irrespective of throw speed or angle (somewhat limited by that not reaching a level where the flights “stall”). The parameter that describes this distance is called yaw wavelength and for a typical dart might be in the 2.6 to 3.2m region.

So, using the two aforementioned different dart release conditions for two darts at either end of that stability range, let’s look at how stability affects the vertical impact angle at the board.

Ignoring things like “yaw damping” and “trajectory turn-over rate”, which would change the numbers a bit but not the principle, we can plot simple “sine waves” which model the vertical yaw (as I’ve also explained before, to an aeroballistician that’s the more correct term than “pitch”) of the two darts thrown in the two different ways. If we then take some account of the (near-parabolic) curve of the trajectory, we end up with the plot at the start of this blog.

This plot shows how the more stable red dart ends up more nose-down than the blue for both the dotted lines representing Barney-type release conditions and the solid lines representing Artist-type (albeit not by that much for the latter case).

So that’s why less stable darts with smaller flights (or heavier shafts, etc) can tend to land less nose-down (or more nose-up) than more stable ones. But, as I said, it is only a tendency and far from inevitable. If you’re experimentally minded, maybe you can have some fun testing the limits of the correlation.

Finally, just a quick comment on how you might want your darts to land, although it’s not going to be that helpful a comment because it’s pretty much personal preference. Flat darts provide less visual obstruction and can help players who aim each dart individually, but nose-down is more in line with the trajectory and may present less physical obstruction to following darts, perhaps suiting quick-fire “muscle-memory” players with close grouping.

OK, I’m off now to finish up the last of the Christmas cake – see you next time!


Q&As

Mr K and James Wade 24gm, etc
Glad to hear you’re a big fan of both Gary Anderson and Unicorn, Mr K, but given that the Silver/Black Stars “work wonderfully” for you, I’m not quite sure how well you’ll get on trying to recreate that same performance with the James Wade 24gm. Still, maybe worth trying them with Gripper 3 short shafts and Q 75 micron Big Wing XL flights (catalogue no 68606) as a start. The choice of these very large flights may seem a strange one given all I say in the above blog and your liking for your darts to land flat, but I’m going on your good experience with the Silver/Black Stars and the fact of your darts falling out when you use flight rings (by “angling down”, I’m assuming you mean tail-down?). Good luck with the search for the perfect set-up!


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