Bill Daniels wrote:

I've flown airplanes with metric instruments (And Russian placards too).
The airspeed, rate-of-climb, RPM, manifold pressure were no problem.
Numbers is numbers I guess - fly with the needles in the green arc and
everything works. But that damn metric altimeter was impossible - no way
to
read trends on an instrument that insensitive. With an altimeter that
reads 1000 feet (304.8 meters) per rev of the big hand, you can thermal by
watching the trend of the needle.
I prefer to thermal on my "butt-feeling" and my audio variometer. I don't
need my altimeter for that. I guess that might be different in regions with
stronger thermals than we have to make due with here. I guess I could get
used to other scales as well (did fly a Sedhberg with Imperial instruments
once, real fun to fly 26 knots or so :-) !)
Personally, I would not trade by old, reliable mechanical primairy
instruments for a computerised system so easily. Not in a glider anyway.
Battery power alone is just not reliable enough for primairy
instrumentation in my opinion. It's fine for navigation, climb optimizing
and other stuff you don't really need to fly safely, but not for altitude
or airspeed.

André