Bowmen of Skelmersdale

Controlling Bow Behaviour with Stabilisers

Bows are simple mechanical objects in principle. But designing them for archers
makes life surprisingly complicated. Archers cannot shoot the arrow through the centre of pressure (at least, not without injury), so the arrow leaves the bow above the grip, and the bow is consequently slightly out of balance when shot. The riser is cut away on one side, so stresses in the riser are asymmetric, and vibrations complex and difficult to control. The ‘archers grip’ on the bow is hard to centre and reproduce, introducing variable torque. Muscles are best in motion, and perfect stability of aim is not humanly attainable. Different archers have different preferences for bow behaviour before, during and after the shot. All these things lead to a large range of bow movements, many of which are incidental to, or interfere with, the arrow reaching the target. So bowyer's and archers have gone
looking for ways to control bow movement.

Relatively early in modern bow design, it became clear that many movements could be controlled by adjusting the overall weight and the distribution of weight in the bow riser. This led by easy stages through ‘points’, lead or mercury inserts and  ‘bus- bars’ to short, weighted metal rods replacing ‘points’, longer rods replacing short rods, centre-mounted  ‘long rods’, counterbalances and V-bars, TFC’s, internally damped rods and oil-filled dampers to the range of stabilisers and attachments now available. The problem facing the archer is to sort through all the options to get good control of the bow.

That does not mean that stabiliser systems are a necessary first resort. On the contrary, though they can undoubtedly reduce the effect of poor technique.

Stabilisation is no substitute for good technique.

If bow behaviour is seriously and consistently faulty, the cause should be removed as far as possible before turning to stabilisation. For example, stabilisers can reduce the effect of torque, but it is a great deal better to adjust style or grip  to avoid torque in the first place.

This note is intended to show how particular stabilisers and attachments control different types of bow motion, and how their effect can be adjusted to suit the archer’s needs. The document covers different types of bow motion, then discusses the use of stabilisation to control them.

Reproduced by kind permission of Steve Ellison

What bow behaviour needs controlling?

Bow  movement

Timing - When is movement important?

Time and Motion

Controlling bow displacement

Weight, Mass and Inertia

Static and Dynamic properties

The misnamed TFC

Controlling bow balance

Centre of Gravity

Finding the centre of gravity

Changing the balance using weight

Weights and Distances

Rods, weights and risers

Controlling bow vibration

Causes of Bow Vibration

Reducing Vibration - Damping

Bow Resonance

Tuned damping - more on TFC’s