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Old February 25th 08, 12:55 AM posted to rec.aviation.soaring
Eric Greenwell
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Posts: 1,096
Default Inter-thermal cruise speeds?

Bill Daniels wrote:
I really liked John Cochrane's paper "A little Faster Please".

The message I took from that was that the MacCready setting can be used as a
general "optimism setting". I tend to set MacCready with a "gut check"
about how I feel conditions will be ahead.

If you are bumping along above 17,000 feet, there's no thermal that's worth
stopping for since you don't want to go any higher so M could be infinity.
On the other hand, if you are low in tiger country, you'll take any thermal
(M=0). There's a sliding scale in between.

I use GPS_LOG which can average the last three thermals and automatically
set M. That almost always gives me a M setting higher than my gut says I
should use. Maybe that's why I fly slow.


Maybe, but probably not - I think a lot of good pilots do the same. My
experience is, if I use a MC setting the same as the average climbs I'm
making, two things usually happen:

1) My speed director tells me to fly scary fast in medium or stronger
sink (like 110-120 knots), and

2) I get low frequently!

So, I usually set it as high as I can without getting stuck low
somewhere, and that's generally around one-third of the climb average. I
flew contests for many years, and the really good pilots weren't flying
much faster, if any, than I was, but they sure chose better places to
go, and they knew when to shift gears sooner than I did.

--
Eric Greenwell - Washington State, USA
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