At 11:26 09 July 2008, Dan G wrote:
I'm crewing this season, and no doubt my pilot will be expecting me
out at 7am with Mer in hand.

My question is (and I'm sure it's been debated before, I did search,
but want fresh input) how worthwhile is polishing?

I can understand keeping the fuselage as slippery as possible to
reduce skin drag, but I've heard that glider wings would still work as
well as possible if their surface was 40 grit sandpaper! Also take a
look at a golfball -- it's dimpled specifically in order to reduce
drag, again implying that a smooth surface may not be perfect.

On the other hand I realise that bugs, chips in the gelcoat etc. are
bad news as they locally seperate the boundary layer, so you don't
want those around.


Dan


I believe the difference between the wing and the golf ball is a result of
low reynolds numbers ,you get some strange affects when you increase the
size of aerofoils .
With regard to crewing in my competition flying I like to rig,water
ballast,grid and polish while grid squatting.It gives you something to do
and moves any finger marks .
Jon