On Jun 6, 10:06*am, Andy wrote:

Got it - sounds a bit uncomfortable since moving the velocity vector
around in the vertical axis takes a lot more aggressiveness then
horizontally. I assume it also helps to know where the boundaries of
the gradients are before you reach them. If you miss you just mush and
lose altitude fro all the induced drag.

Yes, as you have properly shown in the still air case- only now the
penalties are even higher than in still air.


It's the exact opposite technique from what I see and hear from most
top racing pilots who advise flying slower than McCready theory and
maintaining laminar flow over the wing with only modest maneuvering.
How do you decide when to use which technique when you are cruising
along at 15,000 feet and 85 knots and run into a 6 knot thermal?

9B

Well. that's the trick, isn't it? I would say that if you're at
15,000', full of water, but only going 85 knots, it must be pretty
spotty overall and would recommend sticking to the conventional
approach. For one thing, you only have a little over a second of
deceleration time at that speed. When the conditions allow, it is much
better to have more maneuvering time through higher velocities.
However, it has also been shown that chasing MacCready through a
thermal will usually yield poorer results than stick-fixed excursions
(Braunschweig Tech. University, 1982). Chasing any of this with the
vario is futile due to lag times.

In any event, much of this does run counter to the normal "racing"
protocol. E.g., Moffat's final turn at the top of a climb when it is
tightened and you accelerate across the thermal core before exiting.
Exactly opposite to the best total energy/dynamic maneuvering
scenario, apart from tightening the turn in order to be right at the
center of the core for the straight line flight.

I only entered a contest once as an individual, and chose to fly it
without a computer (or even a speed ring). I did effectively use these
techniques, and lateral dynamic maneuvering as well.

Best Regards,

Gary Osoba