>I don't like to see Tony K getting all this flack, (although I enjoy
>watching the fireworks) so I'll divert some of the fire by sticking my nose
>above the parapet. Some very fast Europas exist although none of them have
>contributed to this discussion. I sometimes wonder how many Europas, when
>trimmed for level flight in the cruise, have tailplanes flying out in a
>straight line, and how many are undulating, because the angle of incidence
>at which they have been set isn't actually the optimum given the possible
>other vagaries in the rigging of the aircraft. I personally believe Tony's
>figures, because I know he has gone to endless lengths to verify them.
So do I. ( although 10 l/hr is exceptional, )
Laminar flow ships like the Europa do exhibit great variation in the extent
of laminar flow, and it doesn't take much to upset it, with a big increase
in skin friction drag component.
Drag of the fuselage can be grossly affected by air flow into and out of
the various holes and gaps. Its worth remembering that because overall drag
is quite low, drag caused by extraneous features like unfaired outriggers,
big gaps around the mainwheel and anything else not perfect, (like the
pilot's left hand?) can be a large proportion of the total drag, and
therefore have a big effect on performance. I suspect this is why there is
so much variation in the fleet.
While I think about it, a badly balanced prop and spinner will cause a lot
of vibration, with consequent disruption of the laminar boundary layer.
Perfect balance of a prop is a revelation. Feels like a different airplane.
Tony Consonant's prop will be very well balanced, I would think?
Graham
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