Inter-thermal cruise speeds?

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.

Bill D


"Mike the Strike" wrote in message
...
Stephen:

That is true if all thermals have the same strength. In reality,
thermals have a strength (and size) distribution. On a day with a 5-
knot average thermal strength you will find thermals as strong as 8
knots or as weak as 3 knots. More working altitude enables you to
pick the strongest thermals and maintain an effective MacCready higher
than the average thermal strength. The fastest pilots (which doesn't
include me) seem to be rather good at this.

Knowing when you can step up the speed and when to slow down is the
key to winning.

Mike

My understanding of the theory is that you will ALWAYS be worse off if
you set a MC higher than the thermal strength and therefore fly faster
than optimum. Flying slower however does have several advantages, as
others have described.

Stephen

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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