good day

for a two way boat we need a profile
for daggers or fins
providing lift in both direction

ruders can be either one way
or also two way
depending whether they move trough 360°
or not

two way profiles need to be symetrical lenghtwise
so it is difficult to create a section
not stalling on the front
or having to much drag on the rear part

www.tspeer.com

what is missing there
are asymetrical sections

because like on a dagger or fin
we want lift at about 0° angle of attack

on the vectorfin I have tried all
proa 1 - 3
but with a flat surface on the lw side

like www.tspeer.com shows
the proa 3 section seems also
the best for asymetrical sections
but the proa 2 can also be used
if not to much load
is at the starting phase present

what kind of experience has anyone
had with this ?

regards fritz


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