As far as I know the 201b designation involved several items: foam skins,

new tailplane, revised brakes, ballast bags as standard and increased Vne

and Mtow limits.

Anybody who is interested can see exactly when these changes occurred
because all the TNs are available on Hansjörg Streifeneder's site,
http://www.streifly.de/

Also, you mentioned it in passing but the 201b had dive brakes on
the top surface of the wing only.

That's correct. Lower surface brakes is the easiest way to tell a 201
from a 201b. Everything else apart from the tailplane change are internal

and I, for one, can't walk up to a lone Libelle and tell which tailplane

it has.


201 has a sharp radius to the leading edge tip (15mm radius?) the 201b
tailplane has a much larger radius (50mm?)