Mark,
A most thoughtful metric.
It might lead to a very interesting way of valueing the gider market as
opposed to $perL/D.
This might be a way to determine various cut off points for gliders under
consideration.
Have you extended the reasoning to other aspects?
Cheers!, Pete
"Mark James Boyd" wrote in message
news:413ce507$1@darkstar...
Owain Walters wrote:

How do you define your 'Personal performance limit'?
And why do you need to acheive this before you buy
a better glider?

I've been using sink rate at 80 knots as a metric for a while.

SGS 1-26 700
AC-4 500
LS-4 320
ASW-20 300
PIK-20B 280
ASH-25 220

And it looks like the

square of 700 49
------------- = -- = ~5
square of 300 9

So an ASW-20 costs about 5 x what an SGS 1-26 costs.

Blanik L-13 550
PZL PW-5 500
DG-100 375
Grob 102 CS 360
Grob 103 350
Libelle 201b 350
SGS 1-35 321
Cirrus Open 318
Pegasus 101A 270

It seems to me that the low perf. trainers are in the 700 range,
medium performance and non-retract are in the 500 range,
and higher performance in the 300 range.

And from what I've seen, a lot of even fairly experienced soaring
pilots are pretty happy with anything better than 300fpm sink
at 80 knots. Well, some will insist on ballast and flaps at that
point too, but a lot seem ok 300fpm sink.
--

------------+
Mark Boyd
Avenal, California, USA