Why these hair wings dont twist leaders.

[Traditionalist]

 
Feathers have evolved to enable flight, among other things, and many of them have peculiar aerodynamic properties, even single fibres or bunches of fibres. Many flies dressed with feathers, either slips or bunches, will "Helicopter", most especially if they are not very carefully balanced in size and shape.  The weight distribution when flies are dressed "upside down" aggravates this propensity, and will often hopelessly twist and damage a fine tippet after a couple of casts. With few exceptions, feathers have interlocking fibres. like tiny zip fasteners, and these "catch the wind" It does not matter much what you do, this will always happen. Also, when on the bird, feathers are constantly preened to keep them in order, and reasonably waterproof. On water-birds this is absolutely vital. If you degrease a water bird, it becomes waterlogged immediately, sinks and drowns. This is why the major bird kills by oil spills are not caused by the oil itself, although this is shocking enough, they are caused by the detergent used to fight the spill, which degreases the birds, and so they drown.

Fur and hair  have not evolved to enable flight, otherwise pigs, and a host of other things might  fly!  They have evolved primarily to keep their bearers warm and dry. Of course there are specific hairs with specific properties on fur bearing mammals, but not in the same manner or diversity as with feathers. Also, and of primary interest here, is the fact that hairs and furs have no interlocking fibres. This means that air moving over them merely goes "through" a bunch, "over" a clump, or " around" a single fibre.  The hair does not offer resistance in any specific direction, and so wings and similar things on flies which are made from it don?t "helicopter".

There are some exceptions. If one makes the wings too dense, or completely unbalanced ( One heavy wing and one very light one) then they may twist somewhat, but still not as badly as feathers, and this is in any case then a design fault, and not the fault of the material. This also mainly occurs on "stiff" hairs like deer hair and similar. Which is mainly why I don?t like deer hair for these flies. It is also far more difficult to use. Of course it works, and so do feathers, but not as well. A steam engine works very well, but I bet you drive a car with an internal combustion engine?

That is the basic explanation. One could go on at length about various properties here, but it would not really serve any useful purpose.

TL
MC

[haresear]

Excellent post Mike. I have never bothered to use the dubbing loop/split thread technique in the past because I have never really had a problem with dubbing in the traditional fashion.

It looks like things are about to change. Anybody want to buy some capes?

Alex