Hi Gents,

I hope I am not abusing this site, so far your advice has been invaluable.

Gavin

I was stydying bird’s feathers the other day. I discovered that a feather when on right side in the wind has a tramendous lift force and yet it is stable by itself. When inverted it is still stable, but negative lift force pulls it down.

Spitfire wing is close to a bird ( wing tip ) feather shape..that is why it has also a need for smaller tailfeathers. IMHO !