My Caproni A21S Calif is an all-metal side-by-side twoseater. Finish is in a
way that you don't see any rivets, L/D is 41.5.

You pay an additional 10% of strucrural weight increase for having it in
metal (comparison to a janus C model - about the same wing span, the same
airfoil and pretty exactly the same polar). In a serial production, the cost
of a Calif is *way* higher than the cost of a Janus (that's why Calif's are
no longer in production).

If you want higher performance, it would mean more aspect ratio and less
airfoil thickness - and then metal would get really heavy.

--
Bert Willing

ASW20 "TW"


"Mark James Boyd" a écrit dans le message de
news:3fa6166d@darkstar...
Hmmm....

I was wondering if metal gliders have an L/D disadvantage
due to the metal, or because of the lousy rivets and
poor wing airfoil and draggy struts (of the SGS gliders,
for example).

Is it possible to make a retract gear metal glider with
flush rivets and a carry-through spar which would give
40:1 ratio, or is metal just a substance that won't
allow the shapes or fine tolerances needed to make such
a wing?

Vans seems to do an excellent job selling very high
quality kits with very nice wings (metal). I wonder
if they'd consider selling a Quickbuild glider kit?