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Making Flight Arrows
Arrows specifically designed for Flight archery cannot be bought. If you want
to shoot competitive Flight, you must make your own arrows (or find a willing
soul to do it for you). This actually has the advantage that you win or lose by
your own efforts.
When it comes to materials for arrows, you really have three choices: carbon
target arrow shafts, solid carbon rod or wood.
a. Target shafts . The British compound record of 817 yards was shot in 1996 with 480 mm (19 inch) Flight arrows made from 4.5 mm Easton PC carbon target arrow shafts. These were the smallest diameter arrow shaft Easton's made. The advantages with this material are that it is stiff and, because the shaft is hollow, it is light (5.49 grains, or 0.356 grams, per inch). It is also very easy to make nocks and points that can be fitted into the ends. But the interior diameter is 2.7 mm, and the arrow's walls are less than 1 mm thick so, when barrelling the arrow for better aerodynamics, one has to be very careful not to weaken the side walls too much.
b. Solid carbon rod , introduced into Flight archery by American archer Rulon 'Ike' Hancock in 1975, is what most Flight archers use today. For low poundage recurve Flight bows, with arrow lengths around the minimum 14 inches, 3 mm diameter is sufficient; for heavier recurve or compound Flight bows, 4 mm is preferable. With 3 mm carbon rod, barrelling is not practical and the shaft is left with parallel sides. The use of 4 mm rod allows for a fair degree of aerodynamic shaping. I taper the ends to 3 mm and make 3 mm points and nocks.
c. Wood . Until Ike introduced carbon, cedar wood was used exclusively for Flight arrow shafts. And cedar is still used by some archers today. Cedar is light and, unlike carbon, clean and easy to shape. Its one disadvantage is that to get a stiff enough spine, it must have a larger diameter than carbon — and that means more friction through the air. Shooting wooden arrows is a distinct disadvantage in competition with archers shooting carbon. Even so, Flight archers with wooden arrows still manage respectable distances.
For my compound bows, shooting between 25kg (55 lbs) and 33 kg (72 lbs) I use
either 4 mm solid carbon arrows at 15 inches long or 4.5 mm hollow arrows at 19
inches long.
I get my 4 mm solid carbon rod from:
RBJ Reinforced Plastics Ltd
Woodcock Hill Industrial Estate
Harefield Road
Rickmansworth
Herts WD3 1PE
UK
Tel: +44 (0) 1923 778853 / 777532
Fax: +44 (0) 1923 896080
The rod is sold in 5 metre lots but they will cut it into any lengths you want
at no extra cost. I get them to cut it into 380mm lengths. This way I get 13
arrows out of each 5 m length. They have a minimum order that they will supply
based on price. You will probably have to buy at least two 5 metre lengths.
Weight of arrow
The aim when designing a Flight bow is to get the maximum speed out of it. One
of the parameters which determines speed is the weight of the arrow: the
heavier the arrow, the more energy it takes to overcome its inertia and the
slower it will leave the bow. So the lightest arrow possible is desirable. But
it can be taken too far. There are two trade-offs: firstly with arrow friction
through the air, and secondly arrow to bow tuning.
If an arrow is too light, it may leave the bow very fast but have insufficient
mass to pull it through the air. For example, a feather is extremely light. If
one could be shot, it would leave a bow as fast as the bow's limbs could
recover. But it wouldn't go very far because of the air friction. This point is
well illustrated in practice when one compares distances shot in Yorkshire,
which has heavy, humid air, with distances shot with the same equipment in the
high salt flats of America. The small, light Flight arrows go considerably
further through the thin, dry US air, but heavier Target and longbow arrows get
better distances in Britain.
A very light arrow also necessitates a very thin arrow. This lowers its spine
rating which can cause excessive oscillations in the arrow as it tries to
absorb the energy. It's a case of trial and error.
As a guide, arrow weights range from as little as 3.5 grams (55 grains) for a
light recurve Flight bow to over 6.5 grams (100 grains) for an unlimited
Aerodynamics
So your bow is efficient, your arrows leave it fast. After that, it is up to the arrow to make the most of that speed. This is where aerodynamics comes in. I have divided this aspect into three: Drag coefficient, Centre of Gravity and Fletching, all of which are interdependent.
Drag coefficient
The ideal shape for an arrow is similar to that of the javelin. By making the
arrow a very elongated, slim oval, pointed at both ends, you can decrease its
drag coefficient, and thus air friction, by up to fourteen percent while at the
same time reducing its mass (weight) by nearly twenty percent compared to a
parallel-sided arrow with a similar spine. (The nock spoils it slightly.) This
minimises the trade-off for the Flight arrow of mass versus drag coefficient:
we reduce the drag by reducing the mass ? with no loss of spine.
In theory, the shaft of the arrow should be symmetrical point end to nock end
and with the thickest part exactly in the middle. In practice I find that
making the thickest part slightly nearer the front is just as good and it helps
me with getting the Centre of Gravity (CofG) in the right place.
All the arrows I make for my compounds are made from 4 mm carbon or 4.5 mm hollow carbon tube. Held in an
electric drill, which itself is held in a vice, the shafts are shaped with
wet-and-dry abrasive paper followed by T-Cut. To minimise air friction still
further, the shafts are then polished. A suitable polishing abrasive is carbon
dust collected during the shaping process. The shaping of the hollow shafts weakens the ends. These are strengthened by supergluing short lengths of solid rod into them. The solid rod is allowed to protrude 5 mm and the point and nock are fitted over this.
Centre of Gravity
The next consideration is the Centre of Gravity (CofG). A Target arrow's CofG
is usually in the order of 8% to 13% in front of the centre
point of the arrow. This is to make the Target arrow stable which is necessary
for consistent groups on target. In Flight we are not interested in groups, but
in distance.
There is some debate about where a Flight arrow's Cof G should be.
Many Flight archers prefer the CofG to be at or just in front of the centre of
the arrow. These Flight archers hope that they will get a 'floater' — an arrow
which will float on the air so that it goes further, with a flight path as
shown in Figure 1.
Figure 1
The disadvantage is that such an arrow is highly unstable. An arrow with a
heavy point and a CofG well in front of the arrow's centre will shoot in stable
flight without fletches. But put the CofG at or behind the mid-point of the
arrow, and it won't shoot without fletches at all. So as the CofG approaches
the centre of the arrow, fletches have to be bigger to stabilise the arrow. And
the bigger the fletches, the more friction there will be through the air.
There is also a belief that the heavier point of an arrow will drop faster than
the lighter fletched end. But this misconception forgets that Newton's First
Law of Apples — gravity — acts equally on all weights. And at 32 ft per second
squared, gravity's affect in the vertical plane is very small when compared to
the arrow's horizontal speed. Figure 2 traces the trajectory of a forward
weighted target arrow.
Figure 2
In an attempt to resolve the debate, an American engineer and archer, Dr
Clarence Hickman, conducted a series of experiments in the 1930s with a hollow
metal arrow. Dr Hickman fitted a moveable weight inside the shaft which allowed
him to vary the arrow's CofG without changing its overall weight. The arrow was
shot using an 11 kg (24 lb) bow mounted at 45E in shooting machine. The results
he achieved showed clearly the advantage to be gained from having the CofG
forward.
He tried seven CofG positions from 32%, to 57% of the length of the arrow,
together with six sizes of fletch ranging from 100 x 25 mm to 15 x 10 mm. With
all fletch sizes, distance fell slightly as the CofG moved backwards. With the
CofG behind the centre of the arrow, the distances achieved fell markedly. The
greatest distance he achieved was with the CofG at 32% and the arrow
unfletched.
On a 15 inch carbon Flight arrow, I try for a CofG about an inch in front of
centre — which is 43%. It is difficult to get the CofG much further forward as
to do so would require too heavy a point, making the overall weight too much.
To achieve the weight I am after and to get the CofG in the right place, I use
a variety of points which I make from either 3 mm silver steel or 3 mm
aluminium rod (for which my wife's size 11 aluminium knitting pins are ideal).
Fletching
From what has already been said, you will appreciate that fletches should be as
small and light as possible. The most popular material until the advent of the
computer age was razor blades. These were easy to shape and fix onto the then
popular wooden arrows. Today, pieces of floppy disc are the norm.
Fletches are fitted to stabilise the arrow. Their size is determined by two
considerations: The more stable the arrow is without fletches, the less work
fletches have to do and the smaller they can be. And the straighter the arrow
leaves the bow, the smaller they can be.
When I made my first Flight arrows, I had seen those of other archers but not
paid sufficient attention to the size of their fletches. As a consequence, when
I turned up next year, it was immediately obvious that I had made them much too
big. So to give some idea of size, I find that a 15 inch, 4 mm arrow with a
CofG at 43% needs fletches about 6 mm long by 3 mm tall.
If you have the facility to cut tiny slots in the arrow to take the fletches,
that is ideal. I haven't, so I stick them on with Superglue.
When testing arrow designs, there are two measures of their effectiveness. If
they are incorrectly spined or incorrectly tuned, you will get such arrow
damage as torn fletches. You can test for this by shooting into a 150 mm (6
inch) thick polystyrene butt at a distance of as little as a couple of yards.
The other test is to see which goes furthest. For this you need a much bigger
area.
One last point. In Britain, Flight is invariably shot over grass. This makes
finding arrows difficult. So spray-paint them in fluorescent colours. If
shooting on the salt flats of Nevada, it is better to leave them black.
Target class arrows
The Target bow classes are for archers to shoot their standard Target equipment
— and that is what they should do. However, some Target arrows are better than
others for Flight. The simple rule is: the lighter the arrow, the faster it
will leave the bow and the further it will go. Any archery shop catalogue will
tell you the weight of arrows, from which it is easy to work out the ACEs
should be the best.
But the most important consideration is that the arrows are the correct ones
for the bow. Even a badly shot Target arrow straightens up relatively quickly,
but when it leaves the bow it is travelling at its fastest. For Flight, this is
the most important time as speed lost here has the greatest effect on overall
distance. Thus a heavier arrow, but well tuned to the bow and shot cleanly will
travel considerably further than a lighter arrow which is less well tuned or
badly shot.
Last updated 30 January 2003
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