"Kyle Boatright" wrote in message ...
" wrote in message
hlink.net...
I'm reading "Fate is the Hunter" and just read something interesting.
Gann
states that they would climb to 100 feet above their cruising altitude and
then descend the 100 feet back down. He called this "flying on the step."
He claims that it bought them a few more knots of airspeed.

Has anyone heard of this? Is it normal practice? Or is it one of those
practices that have been disproven?

Personally, I've never heard of this practice.

There is no "step", but the perception is probably based on achieving cruise
speed as quickly as possible after climbing to altitude. The most efficient
cruise occurs at a specific airspeed (in reality, angle of attack). Below
that speed the airplane is on the back side of the power curve, and faster
than that speed, the airplane is wasting fuel...

It wouldn't surprise me at all if the transports and bombers in WWII and
before tried to cruise at this "sweet spot" to maximize range. So, if they
climbed to altitude, set power at cruise, and waited for the airplane to
accelerate to cruise speed, they were in for a relatively long wait, and
(in theory, at least) would never quite get to the ideal speed. On the
other hand, if they accelerated to cruise speed before the power reduction
(whether by climbing through, then descending to the cruise altitude, or
just by flying to the desired altitude and keeping the power up), they could
pull power back to cruise and be right at the sweet spot from the get-go...

KB

We see pilots (trained elsewhere) that regularly level off at
altitude, pulling back the power as they do so, then trimming. The
airplane continues to accelerate and more fooling with trim ensues, as
well as with power (in fixed-pitch) since the RPM comes up as well.
This continues for a long time, with altitude fluctuations and other
distractions completely messing up the flight.
In the Flight Training Manual (Canadian) the proper sequence is
Attitude- Power-Trim, when levelling off. Get the airplane level,
leave the power in until cruise speed is reached, reduce it to the
power that will maintain that speed, and only then is the trim set. It
requires forward pressure which some don't like (some airplanes will
require some trim to keep it manageable), but after the proper process
is followed the airplane will hold altitude properly and the pilot can
get on to other things like navigating. I've sometimes made a student
sort out altitude excursions by rolling in lots of nose-up trim and
forcing him to hold it until the other things settle down.

Dan