Fairing continues on the 66-021 #Gunproject

Fairing the incut displacement tail on the '66'. 



Release is a circlular vortex generating low drag anular tip.

The '66' is a development or extrapolation of my existing displacement tail designs ( or 'sinker tails' as they are sometimes called).

There are three 'features' of this shape:

1) The tail sinks

 under pressure, this has a similar effect to increasing the rocker and it has some nice effects on the handling,... it keeps the pitch fulcrum ( rather like the hinge on a seesaw) of the board in a stable position, so the rider doesn't feel chop as much and the board's reaction to input remains predictable.

Planing surfaces increase lift by the square as speed increases, with conventional designs this has the effect of shifting the wetted surface area and planing area back on the board as speed increases, this moves the fulcrum back towards the tail, making the board unbalanced and causing handling issues.

With displacement based lift speed makes no difference, the tail response stays more or less the same.
That's the basic idea of the displacement tail, this '66' series shape makes the effect more extreme by reducing planing area even more.

2) Water exit or 'release'.

 With a displacement tail the water leaves at the very tip of the tail, in this case a smallish circle, rather than over a horizontal hard planing edge as is the case with conventional boards.

By having an incut on the tail the rails of the board are more parallel at the exit ( this makes for more efficient flow mixing as the water leaves) and the 'stream' in the direction of the water flow more closely.

3) A hip in the planshape 

caused by the incut, which should give a nice turning section of the rail close to the rider.

I could say that the board is like a pig shape complete with pigtail but I won't.



I haven't ridden a planshape with incut yet so we shall see, I can say with confidence that she'll float, paddle well, and will definitely catch waves, for the rest I'll report back when we get the machine wet.