Wing tip stalls

Consider also that it is partially irrelevant whether the taper results in a
forward or backward sweep.
As the wing chord reduces so the Reynolds number changes (for any given speed),
and the behavior with it for any given airfoil. The lower Reynolds number at the
narrow chord will result in more tetchy behavior for the laminar profiles
preferred for the overall wing. I assume that this is one of the reasons the
aerodynamics types make quite substantial airfoil changes on the tapered
sections of the wings. This is probably a larger factor in design than the
minimal degree of sweep forward or back possible in a high aspect ratio
sailplane wing.

Depending on what you want from your airplane it may be a desirable compromise
to live with the more interesting high AOA behavior of a compound taper wing.
For the performance improvements possible it is presumably worth the effort for
high performance XC ships.

Presumably this is one reason why the Piper Cherokee has it's "hershey bar"
wing. Only washout effects, so easier to predict behavior. The other reason to
go with simple wing planforms is the cost involved...

Bruce

mat Redsell wrote:

thanks for your fine reply on wing tip stalls,

I tend to concentrate on the flying and building... and leave the book work
for late at night.

I have produced a number of DVD's on the Pioneer which to me is a most
interesting glider that needs a lot more study.

As to the root stalling first -yes that is as we found it but it is very
gentle. Dave Wells tufted the wing root and yes it progressed from the root
to the tip. In my movie it readily shows that when the one attempts a stall
the Pioneer stays at a certain angle of attack but it can slowly go off to
one side but it can be controlled by the rudder.

If you would like to view this for yourself I will send you a DVD of a
cross country flight with a save from 700 ft agl and include a number of
attempt stalls and a high speed run to 95 mph. I would like your input.

In a turn the Pioneer will not drop a wing tip... I think this needs further
investigation and the new Pioneer III with a modern arifoil, that should fly
this year, will be another glider to study.

-mat