Hydrodynamics!!!!!

**Kleftiwallah** · 16-08-2006, 15:22

Nice easy question........what promotes the spoon of a spoon or spinner to spin? Cheers, Tony O-P.

**PanamaJack** · 16-08-2006, 20:49

Part one's easy Tony. A spoon doesn't spin it wobbles. Part two I'll leave for someone with a PHD.

**Steinbeisser** · 16-08-2006, 20:50

I would guess this is due to the Bernoullie effect. i.e. due to the shape of the spoon, etc. the water has to flow faster over one surface of the spoon (the convex side) and in so doing drops it's pressure. On the concave side, the reverse is true and pressure will be relatively higher, turbulence, eddies, etc. This pressure difference will force the spoon to move away from the axis of the lure and combined with the forward movement of the lure/or water current will result in the spinner/spoon/toby, etc. to spin or move erratically/wobble through the water.

Same principle as an aircraft wing or sail on a sailing dingy, etc. where differential pressure results in lift on the aircraft wing or a driving force on the sail.

Steinbeisser

**Kleftiwallah** · 17-08-2006, 13:10

I figured it had something to do with his theorum as an ex aircraft engineer and gliding instructor, it was the rotational aspect that has me flumoxed...can someone bring in a bit of propellor theory? Thanks for that Tony O-P.