Mark James Boyd wrote:

Getting lower fpms seems to also have at least one downside
too: higher stall speed. I personally would like something
like a Russia AC-4c, with a fairly low stall speed, but
with ballast too. Short wings and slow stall speed when I want it
are good. I wonder about getting one with a motor and
then just putting a big water bag in the hatch instead

30 knot stall vs. 40 knot stall is
900 vs. 1600 energy units at landing.
Almost twice as much energy to dissapate at touchdown.

Your arithmetic is right, but the Russia stalls closer to 40 knots than
30 knots at the weight I flew one several years ago (180 pounds with
parachute). It landed noticeably faster than a Blanik or PW5.

Once the unballasted stall speed of a glider gets past
40 knots, I'd be a little hesitant to be "happy'
about the great penetration...

There is a world of difference landing off field with a glider that
touches down at 30 knots vs 40. I've known pilots that got spooked by
the faster landings when they moved from slower speed gliders to a "high
performance" one. Landing in a field just didn't seem like a such a good
idea anymore. Training can overcome this, but some just quietly slipped
away from the sport.


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Eric Greenwell
Washington State
USA