DHA Day 3 – part 1

Just a quick post at this stage, it being 0130 and technically bedtime.  Today we had free practice on the Hungarian track before a lovely visit to a Viking longhouse in the afternoon.  This evening was the midsummer competition, which was run as a Swedish field track (like a Polish track but forming a circle around a field).  We finished at about midnight.  On any other day this would have been fine, but today it was very murky anyway so the last groups suffered a bit.  Still pretty light though!

I personally struggled with the speed of my horse but am happy with the way it went.  Claire came fourth but was the only person to you the bonus target: a box of chocolate on a stand.  She therefore won a box of chocolates!  Adam came for with his usual inimitable banzai run, somehow hitting the targets as they flash past.  The top two were separated by less than a point, with Emil Eriksson again demonstrating why he is, to my mind, the best in the world at this type of track, pipping Wojtek into second place.

Tomorrow we walk the DHA Hunt Track.  And I may post something a bit fuller…

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DHA Hunt Cup Day 2

It turns out that NowTV, the service by which we were going to watch Game of Thrones, is UK only, so we couldn’t watch the season finale.  I am not trying to shield Claire from Facebook spoilers (I’ve read the books, so I know about the big shock this episode).  She reads this so no comments here either!

Last night was spent companionably fletching arrows around a camp fire while we waited for our bows to arrive, which they did at 2330.  All present and correct!  In the meantime we had prepared an experiment in arrow design and impact damage, on which more tomorrow…

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Claire passed the time by riding Jeenial, Ylwa’s horse, bareback with just a neck strap.  She seemed to enjoy it…

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This morning we had 4 hours of riding, with the emphasis on balance and connection with the horse.  This included cantering while holding a cup of water (which gets harder if your horse is scared of the water drops), throwing an apple up and down while riding and finally cantering along while reading from Harry Potter and the Deathly Hallows (which is easier if you know the book like I do!  Probably harder if English isn’t your first language or if, like one poor person, you didn’t put your glasses on!).

We followed that up with a session on the Hungarian track.  My horse was a bit quick so I spent most of the time working on speed target than shooting, but when I did shoot the feedback was very helpful.

After another excellent lunch I went for another run (4.7km in 23 minutes: the 10km required for September’s triathlon keeps edging closer) and now I’m going to go and watch the second group.  Later we apparently have some games.  Our hosts are away and have left Emil on charge.  This could be interesting…

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DHA Hunt Cup, day 1

Having utterly failed to keep this blog up to date in Poland, I’m going to try to do it this week.  I’m in Rättvik, Sweden, for the DHA Hunt Cup, hosted by Dalecarlian Horse Adventures.  This is a trip I’ve wanted to make for a couple of years now.  Quite apart from the couple of days of clinics (this year run by Wojtek Osiecki, one of the best horseback archers in the world), the week culminates in the Hunt Cup competition, a 1km unroped track through the Swedish pine forest with targets at various ranges on both sides.  Those who haven’t seen the YouTube video posted last year by Emil Eriksson (two-time champion of this event), I recommend you give it a watch.  It looks like being not only one of the most challenging events in the sport but also one of the most fun.

Yesterday started at 4am for the drive to Gatwick, where Claire and I met up with Adam Snowball, the other Brit on the trip.  We were a bit worried by the staff at the outsized luggage belt: he needed quite a bit of help with the concept that the case contained bows that had been checked in by the airline and just needed to be put on the plane.  Still, we got past him in the end and settled in for a pleasant and on time flight.  On arrival at Stockholm we discovered that the answer to my rhetorical question “how hard can it be to put a plastic case on a plane” is “too hard for that guy”.  The bows were still in London.  Apparently they’ll be delivered later today (in the meantime we’re borrowing bows from the ever-helpful Emil, who also drove us from Stockholm to Rättvik).

After a very fine pizza dinner and a few drinks (we were reunited with soplica, the marvellous polish hazelnut vodka and with salmiakki, a Finnish liquorice vodka), I discovered that if you are tired enough then sleep is easy, even if it’s still broad daylight at 11pm.

This morning the clinics start.  I shall write more later.

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The clinics today focused on ground work with the horse.  In the morning we were shown how to connect with the horse using a rope halter a long rope, turning as though working in a round pen but without the pen.  After an excellent lunch we had a go at it ourselves, under the watchful eye of Wojtek.  Many useful things learned and a really peaceful feeling with the horse.

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The weather in the morning was bright but cold (after yesterday’s pouring rain) but this afternoon it warmed up just in time for a very pleasant run around the local roads to loosen my legs up after spending yesterday in the plane and the car.  The countryside here is beautiful, with rolling hills and dotted houses, which are all made of wood and painted a distinctive dark red colour.  This paint is locally made and the colour comes from the rich copper deposits (copper mining is a traditional industry here).  The houses are decades or even centuries old, the paint protecting them from the weather.  There is a definite homestead feeling to the area, comparable to that I saw in rural Oregon.

This evening’s plans include eating the dinner whose cooking smell is driving me mad, then fletching arrows until Game of Thrones comes on.  All praise the internet, which will allow us to watch the season finale in English…

Viking Series Sleipner Arrows

Recently, my thoughts have been on arrows.  In particular, they have been on carbon arrows.  I have so far tested three types; some time ago I wrote an article here comparing my Easton Apollos and my Easton PoweFlights.  At the Grunwald competition I took delivery of a dozen new shafts supplied by Emil Eriksson: the Viking Series Sleipners.

First, I shall declare an interest.  Emil is an old friend for whom I have immense respect and liking.  Plus he’s arranging to provide me with some excellent Finnish black vodka at our next competition – long story.  That said, I do not intend to let these factors affect my review and if I do then I shall say so.

Review

First thing’s first: the look and feel of these arrows is lovely.  They are a silky smooth carbon, without the slight abrasiveness of some carbon shafts.  The ones I have are decorated with a Viking broadsword, but I understand that in future they will bear the logo of Sleipner (I’m sure I don’t need to tell you, my erudite readers, that Sleipner was the 8-legged horse of Odin in Norse mythology.  And before anybody complains about the spelling, “Sleipnir” is the more common English rendering of the name but “Sleipner” is the Swedish version).  Both logos are pretty cool.

Weight: the arrows were cut to an AMO length of 29.5” (AMO measurement for arrows is the distance from the throat of the nock (i.e. the point of contact with the string) to the end of the shaft where the point emerges).  They come with inserts, 100 grain points (that’s what I chose but you can order higher or lower) and nocks and thus equipped they weighed 312 grains.  This weight was uniform across all the shafts (which is what you’d hope for but sadly not always what you find).  Once fletched with 3” parabolic feathers the mass was 321 grains +/-1 grain (being the variation in the mass of the feathers and fletching tape – it is essentially negligible).  By way of comparison, my Easton PowerFlights, cut to the same length and with the same fittings, weighed 351gns, making them 30gns heavier than the Sleipners.  The reason I weighed them already fletched, by the way, was that I was at a competition and had therefore fletched most of them straight away so that I could use them.

My preference is for a nock that fits the string relatively tightly.  Those supplied were too loose on my string for my liking (although probably about what most horseback archers prefer).  I therefore swapped them for the Easton nocks that I use in my PowerFlights.  This caused some minor (probably superficial) cracks in the carbon.  A dab of superglue fixed this with no further issues.  I am checking the internal diameters of the shafts to see whether the apparent difference is deliberate or not.

And so to flight.  The Sleipners fly beautifully.  Sometimes you shoot an arrow and just get a feeling that it is right.  So it was with the Sleipners.  This is hardly a scientific approach but it’s worth something in a sport like ours and in my defence I will add that I am not the only person to have come to this conclusion.  I know of at least one other person who shot a few arrows and immediately announced his intention to buy some.

Chronograph Testing

This afternoon I tested the arrows through the chronograph.  I shot Sleipners and Powerflights, all fitted with the same nocks and points.  I shot two groups of five of each type of arrow, so the average figures quoted are the mean speed of ten arrows shot in two groups of five (excluding a few arrows that came up as errors).  I shot one group of Sleipners first, then the Powerflights, then the Powerflights again and finally the Sleipners again.  I tried my best to keep a consistent draw and while this is not usually my strongpoint, I am encouraged that the difference between highest and lowest speeds in each group was no more than about 5fps.  The only exception was a single PowerFlight that was significantly faster than the rest of the group.  Since this raises the average speed of the PowerFlights, it does not favour the Sleipners, which was my main concern: I was actively trying to avoid unconscious bias towards the new arrows.

The results were startling: the PowerFlights averaged 178.25 fps (the two groups averaging within 3fps of each other, suggesting good consistency).

The Sleipners averaged 193.11 fps.  The consistency wasn’t so good here: the first group were all within 5fps of each other but the second group contained three errors and the two results it gave an average of 186.19 fps.  This is still significantly faster than the Powerflights, but is worryingly lower than the other results for the Sleipners.  I suspect that the lower result is due to a change in the light conditions at about that time.  As a matter of fairness, however, I have included those two scores in the overall average speed of the Sleipners: the first, consistent group gave an average speed of 195.87 fps!

As a matter of curiosity, I also tested my Easton Apollos at the end: a single group of 8 arrows gave an average speed of 171.95 fps (with just under 6 fps between fastest and slowest, the light having steadied again).

Conclusions

The Viking Series Sleipners are beautiful arrows to look and they feel and fly nicely as well.  They are significantly lighter than the Easton PowerFlight and that seems to translate into increased arrow speed – despite allowing in the upwards outliers of the PF and the downwards outliers of the Sleipner, the Sleipner is nearly 15fps faster than the PowerFlight.

I personally intend to buy a load more of these arrows and use them as my main arrow.  I thoroughly recommend giving them a go.  To get some, speak to Emil Eriksson on Facebook or message me and I’ll put you in touch.

Grunwald 2015 – Training Course

A week ago I got back from the first stage of the European Grand Prix in Grunwald, Poland.  The whole time I was there I kept thinking “I must update the blog”.  And then I’d either fall asleep or be handed some Soplica (Polish hazelnut vodka), which I would drink until I fell asleep.  So here, somewhat later than anticipated, is the first part of my review of the week.

I actually flew to Poland knowing that there was no space for me in the competition but intending to watch and support.  More importantly, however, I was going for 4 days’ training under the watchful eye of Michal Choczaj of AMM Archery.  This would be the first formal coaching I had received in this sport since I first took it up some 5 years ago.  That time it consisted of a quick demonstration of the thumb draw and a few riding lessons.

The program for the training days was intense: a relatively civilised start time of 10am led on to 2 hours of ground archery training, followed by a half-hour break and a further 2 hours of horseback work (including Ana Sokolska’s rather gleeful insistence that we take our feet out of the stirrups and use our thigh muscles to “stand up”.  For somebody who rides as rarely as I do, that gets old really quickly.  Lunch was served at the beautiful house where we were staying, followed by a repeat of the morning’s program in the afternoon, often not finishing until after 8pm, at which point a collection of knackered horseback archers would collapse back in the house, eat dinner and sit back to enjoy the roaring fire and the free-flowing alcohol.

Speaking personally, I learned a huge amount in those few days.  My riding in particular is much better now than it used to be (for which a fair amount of thanks must also go to Simon Harding and to Oisin Curtis, the BHAA’s Development Officer, who is also a riding and horseback archery instructor at Old Mill Stables in St Ives.  I have always known that I hunch over my bow more than I like but by the end of the training week I was sitting noticeably straighter, drawing further and was generally more relaxed.

Standing tall!

Standing tall!

The pivoting wooden horse is a fantastic training aid.

The pivoting wooden horse is a fantastic training aid.

I heartily recommend AMM training courses to anybody hoping to improve their horseback archery.  Closer to home, I also recommend Oisin’s lessons.

Photobombing level: ninja.

Photobombing level: ninja.

And so to the competition.  Those who read this blog last year will be familiar with the Grand Prix, in which GB took silver last year.  This year the competition has expanded with the addition of France, Germany and Hungary bringing the number of teams to 7 (although Finland were unable to field a side this week).  To accommodate these numbers, the teams have been reduced from 4 to 3 people.  Otherwise the concept remains broadly similar: 3 stages spread throughout the year; 3 events per stage (Korean, Hungarian and another chosen by the host nation) and points scored for your placing as a team within each event.

On the eve of the competition I was informed that there was a space for me after all, riding Irys, my war pony from last year.  I would not be in the Grand Prix team (since we already had a full team) but I would get to ride.  Given that the third event was to be a combination Grunwald Battle and Polish event, getting to ride was a big plus – it’s one of the most fun events out there.

War Pony!

War Pony!

As to how the competition went, I’ll deal with that in my next post.

Arrow Speed – Graphic Predictions

In my last post I wrote about the testing of my various arrow through my shiny new chronograph.  Since then I have bought two different types of all carbon shaft to try: Easton Apollo 560 and Easton PowerFlight 500.  For the PowerFlights I have a choice of points: 60gn or 100gn points (the Apollos have 100gn points).  Is it possible to predict the speed of these arrows?  Since I have had a flare-up of an old back injury and for the last 48 hours haven’t been able to stand upright or walk without a limp (and ideally a stick) I am going to attempt to do exactly that.

The first big caveat is the one pointed out by Steve Ruis in his comment to my last post: correct arrow spine is critical to speed.  In particular, dynamic spine is important.  As regular readers will know, this is the extent to which the arrow bends as it is shot, as opposed to static spine, which is how much it bends when a weight is suspended from it at rest.  These three variants (Apollo, PF with 60gn and PF with 100gn) are going to have different dynamic spines.  The Apollo, as a .560 spine, is weaker in static spine than the .500 PFs (I am going by the marked spine for these purposes).  With their 100gn points they are likely to remain weaker than the PFs.  The PFs have the same static spine (being identical shafts) but the 100gn points make the dynamic spine weaker than the 60gn points do.  This may well have an effect on speed.  I shall be able to correct for this factor to a limited extent by shooting each variant as a bareshaft first (I am also going to do this with the other arrow types I tested in the previous article).  Having shot the Apollo bareshaft already, I can say that they are a touch weak but not too bad.  They are stiffer than most of the aluminium arrows I tested in the last article (though not than the A/C/Cs, which might explain that arrow’s slightly high performance).

Leaving spine hypothetically to one side, what predictions can we make?  Well, the new arrows weigh as follows (+/- 0.5gn):

Apollo: 360gn

PF w/100gn: 350gn

PF w/60gn: 310gn

We would therefore predict that they would all fly faster than even the fastest (and lightest) of the arrows in other test (which weighed 372gn).  We would expect the PowerFlights to be faster still, with the 60gn tips being fastest (subject, as I say, to the effect of spine).

What is the relationship between mass and speed?  Applying our favourite formula, F=ma, we should expect a linear relationship.  That is to say, since a=F/m, where F is a constant (the stored energy in the bow), we should expect speed to rise in inverse proportion to the drop in arrow mass.  Note that this does not mean that if we half arrow mass we double arrow speed.  The mass that is being propelled by the bow includes the mass of the bow’s limbs and the string.  With that clarification in mind, however, we should expect to see a straight line if anybody were to be sad and geeky enough to draw a graph of arrow mass against arrow speed.  Like the one below, for example.

Arrow speed graph

As you can see, the arrows I tested last time form a straight line, subject to some pretty sizable error bars caused by poor shooting form, variations in spine etc.

I have added dotted lines to represent the three new arrow variants that I intend to shoot in the next few days.  The prediction from the graph (apologies for the unclear numbers on the y-axis: it was late when I drew this graph) is that the Apollos will fly at 192fps, the PF with 100gn points will go at just under 195fps and the PFs with 60gn points will be around 204fps.

As you will have gathered from the various caveats (variations in spine; less than perfect consistency in my shooting technique; differing nocks; drawing a graph at midnight in a childrens’ drawing pad etc) mean that this is not exactly perfect science.  I am not, as one should do, isolating one variable.  My prediction, however, is that factors such as spine difference will not affect the speeds to an extent that trumps weight.  I expect to see the order of speeds as predicted and I do not think that the actual speeds will be out by more than about 5fps.

And as soon as my back heals, I shall test it and let you know!

My New Chronograph

I have just bought myself a chronograph.  Specifically, a Chrony F1 with lighting set.  The lights let you use it indoors but I have no intention of so doing.  It’s just that it was on sale and getting it with lights worked out cheaper than getting it without.

For those who don’t know, a chronograph is a device for measuring the speed of an arrow (or bullet, pellet, paintball etc).  It’s basically a long box with a laser at each end that beams upwards.  It starts an internal stopwatch as the front of the arrow goes through the first beam and stops it as it goes through the second beam.  Using the recorded time and the distance between the beams, it works out the speed of the arrow.  This is a brilliantly useful tool: every time you change something – fletchings, brace height, string material, arrow shaft etc – you can shoot before and after through the chrono and see what effect the change has on your arrow speed (and therefore on your trajectory and point of aim: see earlier posts on arrow speed).  I explained all this to Claire, my loving and long-suffering wife.  She replied “you want it because you’re an archery geek and it’s a cool new toy”.  She was, of course, entirely right; but it is also a really useful piece of kit.

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The chronograph is famous among archers for its disappointments.  We all expect our favourite bow to be whipping arrows out at 200 fps or faster.  Then we get to a chronograph and discover that we are barely touching 180.  Like all good science, it can be a cruel destroyer of our cherished illusions, but one that should lead us to make informed changes to improve our situation.

Today the chrono arrived and I took it down the woods for a play, together with my Border Ghillie Dhu and a variety of arrows to test.  I ended up comparing the following (all made by Easton and listed: type; spine; mass in grains; grains per pound of draw weight (gpp)):
XX75 Platinum Plus; 2016; 431gn; 11.65gpp
XX75 Tribute; 2016; 429gn; 11.59gpp
X7 Eclipse; 2014; 372gn; 10.05gpp
X7 Eclipse; 2114; 390gn; 10.54gpp
A/C/C; 3-39; 384gn; 10.38gpp

Note: I have assumed for these purposes that I was drawing 37lbs.  This is the marked weight of the bow at 28″.  I did not measure the draw weight or my draw length for these purposes, since the aim was to compare arrows rather than necessarily give accurate gpp readings.

Judging purely by arrow mass, therefore, we would expect the Platinum Plus and the Tribute to be of similar speed, with the Tributes maybe a tiny bit faster.  We would then expect the 2114 Eclipse to be faster than those two, with the 2014 faster still.  We would expect the A/C/C to be somewhere between the two sizes of Eclipse.  Sounding a note of caution here, I will say that I had limited numbers of the X7 Eclipses and had a few error readings (basically I missed the beam).  This means that the speeds for the X7s may be less reliable than the others.

There are other variables beside mass.  One is the nocks.  Nocks can be tremendously important to arrow speed.  The nocks on all of these arrows were the same, except for the A/C/C, which has a rather better (and more expensive) nock.  The remainder all used the same nocks.  The situation is complicated a little by the fact that the nocks on the aluminium arrows (i.e. all except the A/C/C) have been splayed and this can mean that they vary slightly in fit.  We shall keep this at the back of our minds while remembering that I shot at least 3 of each type of arrow and then took an average, which should mean that differences in nock splaying cancel each other out.

Air resistance can be a big factor in arrow speed.  It is determined by a variety of factors including thickness or shaft and size/setup of fletchings.  The aluminium shafts all have the same fletching but in any event we would not expect resistance to make a significant difference at the short range here (I was standing about 3ft from the chronograph).

The average speed of the arrows is noted below (in feet per second):
Platinum Plus: 173.53 fps
Tribute: 177.59 fps
2014 Eclipse : 188.16 fps
2114 Eclipse : 182.38 fps
A/C/C: 194.42 fps

As we expected, then, the Tribute marginally outshoot the PP.  Both are outshot by the  Eclipses, with the lighter Eclipse faster than the heavier one.  The anomaly is the A/C/C.  This went faster than expected from the simple masses.  One explanation may be the nocks.  Another can be seen when the raw data is examined.  On one shot I really went for it, nailing the release, pushing the bow hand forward and probably drawing quite a bit further than usual.  The result was an arrow that went at 208 fps!  If you remove that arrow and stick with a fair comparison of regular draws, the A/C/Cs drop to 187.65, which is in the expected range, slightly higher than we might expect, but that’s likely to be the nocks.  This removal of the faster arrow is not some form of special pleading, by the way: it is perfectly sound to remove an anomalous result from a set of statistics.  This result varied from the mean by more than twice what any other arrow did and produced a result at odds with all of the rest of the data.  Keeping it in would be poor science.

The final adjusted results, therefore, are:
XX75 Platinum Plus; 11.65 gpp: 173.53 fps
XX75 Tribute; 11.59 gpp: 177.59 fps
2114 X7 Eclipse; 10.54 gpp: 182.38 fps
4/40 A/C/C; 10.38 gpp: 187.65 fps
2014 X7 Eclipse; 10.05 gpp: 188.16 fps

This is in accordance with our expectations of reduced mass bringing greater speed.  What lessons have I learned?  Well, for starters I shall stop buying Platinum Plus and go back to Tributes as my basic arrow.  I shall also look at investing in another set of X7s.  Quicks Archery very kindly sponsored me and Claire by giving us reduced rates on X7s before Korea last year.  These have gradually vanished into the undergrowth or been bent around trees or target frames and the time has clearly come to replace them!

I do not claim that this is anything approaching a perfect experiment.  There are various things that should be (and will be) addressed.  One is shooting more arrows so as to get a better idea of the average speed.  Another is getting somebody else to shoot it, to try to obviate any unconscious bias (although I did this to some extent by not weighing the arrows until after I had shot).  My draw length is not as consistent as it should be, although this should have evened out between the different arrows.

This is the first in what will be an ongoing series of articles where I get to play with the chronograph.  I shall set out more detailed and scientific findings in future posts, in which I hope to deal not just with the effect of changing other variables such as brace height but also to try a variety of bows and do some kind of comparison (I am intrigued by the number of relatively inexpensive bows out there that advertise speeds over 200 fps without giving a draw length, draw weight, arrow weight etc.  After reading this post, I hope that you will share my cynicism of such claims).