Dart Shape v Performance
A few months back after reading a review on John Lowe style darts and the comments on them I decided to try a set in 21g.
Having previously thrown straighter, longer darts I was amazed at how well the Lowe darts flew through the air. I decided to try and understand why!

I subsequently purchased other sets of these bomber/torpedo shaped darts and compared them with other longer darts. To compare them I threw thousands of darts going around the board on targeting double and triples and recording the results. Sometimes I would do this 10 times to make sure the results were true.

On every occasion the shorter and in most instances fatter darts outperformed the longer darts by a huge margin, sometimes being 40% more accurate.

I also noticed that the shorter darts could be thrown with very small flights.

Why!

It appears that physics is the answer, in particular the principle of "Moment of Inertia". Once a dart is released its COG is kept in line with its parabolic trajectory by the force of the flight and its lever (shaft). The moment of inertia of the dart barrel is the force required by the combined effect of leverage (determined by shaft length) and the two dimensional force of the flight (determined by two dimensional flight size).
Inertia requires a greater force to start, accelerate or stop an object. Moment of Inertia is a measurement of the rotational force required to turn an object about a given axis, in this case the darts COG.

The formula for calculating the Moment of Inertia (I) of a rod is : Mass (m) x Length (L) x Length (L) divided by 12.

Darts that have different weights and lengths therefore have different (I) values, shorter dart barrels require less force to rotate around the COG than longer darts.
Put simply a dart barrel with a low (I) value will be more stable in flight (less fishtailing), will fly faster (due to less oscillation / drag) and be more accurate and consistent than a longer dart fitted with the same shaft and flight.

The following calculations and images are based entirely on the characteristics of dart barrels excluding the points. As most darts have standard points any difference
in the (I) values would be constant.
The following image shows how I have roughly eliminated the effect on (I) of the darts point. It also shows how I have determined the "True Length'' of a dart, this takes into account the effects of weight distribution such as hole depth and barrel shape. A forward weighted darts have increasingly lower (I) values the further forward the weight is distributed.

[Image: jhMCW92.png]

The following image shows a selection of darts and their (I) values.

[Image: UmQASvw.jpg]
A. Red Dragon Featherlite 10g. When comparing (I) values the comparison should be between darts of similar weights, I have no other dart in this weight range but would love to compare it to a "baby bomber" with a length of around 27mm, 95% tungsten and a hole depth of 15mm, would fly like a little rocket.
B. John Lowe 21g (red paint by me). A superb dart.
C. Harrows Bomber 21g. Superb dart and great value.
D. Elkadart Razor 21g. Good honest dart, not as accurate as a bomber.
E. Harrows Retina 21g. Similar to Razor.
F. Harrows Bomber 23g. A great dart that is probably the best, also great value.
G. Winmau Saracen 23g. Another great bomber dart.
H. Harrows Aero 23g. An average dart that is outperformed by most of the others.
I. Elkadart Razor 23g. Not for me.
J. Red Dragon Knight 24g. Superb dart in the 24g -26g weight range.
K Harrows Bomber 25g. A top, great value dart.
L. Bulls V8 25g. Good dart.
M. Red Dragon 26g. Reflex A superb dart.
N. Unicorn Bristow 26g. Not in the same league as the Reflex, would make a great fishing sinker.
O. Elkadart Rhino 29g. About as ugly as you can get but performs well.

The image below shows how changing a darts length and weight distribution effects (I).

[Image: bPVpWif.png]

The following image shows the dramatic effect on (I) when changing weight distribution.

[Image: nLvQJuw.jpg]


I hope the above information is helpful, I wish I was aware of the advantages of shorter darts when I first started.
The (I) value of a dart is the biggest factor in dart stability closely followed by forward weight distribution, the figures and testing of the above darts has convinced me that my straight longer darts will have to find new homes.
[Image: lWbm6R3.png]
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Very nice, my observations are the same

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That's a lot of over thinking just to determine that a Lowe style suits you. If one shape was the only answer for the best flying dart then why isn't all the pros using that one shape?
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What happens when you add the stem/flight in to the analysis though, presumably you need a small flight to get them landing flat (I think i would anyway) which re introduces the instability? I'll give a short dart a go though, seems a pretty inexpensive experiment.
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I have noticed that when I throw shorter darts that they are more stable in terms of flight, however, this is only taking into account 1 thing - stability.
All darts will oscillate to some degree (some more than others). The key factor for me is - how does it oscillate for me and when it gets to the board, has it straightened out and is it where I intended the dart to be.
If you look at Phil Taylor - his darts zig-zig with the point looking at the 6 and then snaps back central as it hits the board. And remember he used one of the longest dart setups in the game, with slim flights!

Very insightful post though, and definitely worth thinking about.
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First of all many thanks for this contribution, you really put a lot of effort into it.
But I can't at all agree with the conclusions.

(09-09-2019, 07:02 AM)Zazl Wrote: Moment of Inertia is a measurement of the rotational force required to turn an object about a given axis, in this case the darts COG.
If I've understood everything correctly, that's the essence of your theory.

And now comes my big point of criticism.
This is only true, if one would throw the bare barrel.
As soon as stems and flights are mounted on it, moment of Inertia in the sense of a rotational force doesn't play a role anymore.
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Wow talk about over thinking things - my thoughts are if a dart works for me then great, and if it doesn't work I'll just leave it lol.


As an aside, given that your samples are either ring grip or knurled, will you be doing a follow up study using other types of grip such as pixel, cortex, shark, atomised, smooth, microgrip, etc?

You have also based your findings on standard length points - what about those who prefer longer points of say 30mm, 36mm, 41mm, etc?

Then there's the way people actually grip and throw the darts that would need to be taken into account?
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(09-09-2019, 09:29 AM)mc1958 Wrote: Wow talk about over thinking things - my thoughts are if a dart works for me then great, and if it doesn't work I'll just leave it lol.


As an aside, given that your samples are either ring grip or knurled, will you be doing a follow up study using other types of grip such as pixel, cortex, shark, atomised, smooth, microgrip, etc?  

You have also based your findings on standard length points - what about those who prefer longer points of say 30mm, 36mm, 41mm, etc?  

Then there's the way people actually grip and throw the darts that would need to be taken into account?

His research is just looking at barrels in isolation, which is far enough. A shorter object will have a lower MI. 
Now if you throw your darts in a way that needs a level of correction, then a higher MI may suit best as it will pull back to centre more aggressively, or rotate more aggressively around its MI.
I believe level of correction is key in darts. We are not robots throwing here. So we need a setup that corrects our throws at the right point just before intering the board. This is why some people have darts standing up too much, pointing to the left etc....their correction is not tuned properly (stems, flights etc.).

Now, this is not taking into account barrel shape or grip profiles. I have a set of Andy Firdhams, and they fo fly straight as the dart and weight is smaller and it has a smaller moment of inertia. However, I cannot grip or hold darts of this size properly. 

So in my personal situatoin:
I have a 50-52mm barrel with correct stems and flights to suit my throw.
I have 2 sets that I can throw decently (50mm approx tapered stealth shape - Daytona Fire Original DF 03 and Target Carrera C12).

But here is the thing, I cannot have those darts with No6 of No2 flights. I have had to use TEN X and it must have a stem in and around 34mm with a 26mm point. Any deviation from this and my results change.  Darts tuning for corrections is key in my opinion. Most pros have adjusted around their flights, which are typically standard. However with a new generation of players coming through with more darts technology available to them, we may start to see some deviation.

Taylor with the Vapour S flights, Barney using the Sigma flights for a while too. I think the standard will change a bit over time, and perhaps those left using standard flights may be a legacy thing, or its what they grew up and adapted to. Either way, it works for them and their throw.
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(09-09-2019, 08:45 AM)Getagrip Wrote: That's a lot of over thinking just to determine that a Lowe style suits you.  If one shape was the only answer for the best flying dart then why isn't all the pros using that one shape?

I guess for mugs like me and many others any advantage we can get from a more stable dart is a plus. As for the pros I reckon they have such a consistent and steady throw that they could accurately throw almost any dart.
[Image: lWbm6R3.png]
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(09-09-2019, 09:26 AM)Cateye Wrote: First of all many thanks for this contribution, you really put a lot of effort into it.
But I can't at all agree with the conclusions.

(09-09-2019, 07:02 AM)Zazl Wrote: Moment of Inertia is a measurement of the rotational force required to turn an object about a given axis, in this case the darts COG.
If I've understood everything correctly, that's the essence of your theory.

And now comes my big point of criticism.
This is only true, if one would throw the bare barrel.
As soon as stems and flights are mounted on it, moment of Inertia in the sense of a rotational force doesn't play a role anymore.

Actually it does, but the section of the barrel behind the COG becomes an extension of the lever (shaft).
[Image: lWbm6R3.png]
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