Beppe, this is really interesting because now we get a history.
This is (the fuse of) the 'Kosmo 3' wich is kitted and delivered by Mantua (IT):
The '73 mainly uses a differnt canopy, yes. The '7 Bello' ...the Profile seems to be
modded, it has a bigger chamber than a 'clean' NACA.
Interesting ist the step to the 'Kosmo 2'. Thicker profile and it looks like an also
modded root profile wich streams to a cleaner NACA at the wingtip.
If the root rip defines let's say 2/3 of the wing than you have a reduced drag and
less uplift. So you can fly faster with a light plane even if you have worse
stall characteristics. But since you fly airy you do not need a superior stall
characteristik or you even don't want it to have a better spin entry. This is
what Fritz Bosch did, later Ed Katzmirski followed by Kirkland and others. Is this
right and was this Benito's intention?
The 'Kosmo 3' is goin' back to the thinner profile and the wider wing design.
Ok, it's a Kit and so it maybe will come out heavier by the customers.
The rudder/elevator was ready, not much changes there. Interisting is
also the elevator on the '7 Bello', I havn't seen such a narrow cutout so far.
Just my two Cents...