Flying on the step?

When people talk about being "on the step" they are talking about their
being a cruise speed above that which can be obtained by accelerating in
level flight. It is a bunch of BS. You are correct that there are two
speeds achievable at any given power setting, one above L/D max and one
under. There are not TWO speeds above L/D max.

In the case of any airplane, if you have power to climb, you have power to
accelerate. There is no case where you can climb to an altitude and not
accelerate to whatever cruise speed is availible (and there is only one).

Mike
MU-2


"Corky Scott" wrote in message
...
On Sun, 31 Oct 2004 14:05:51 -0800, "Peter Duniho"
wrote:

Bottom line: if there were really something to it, it would be wide-spread
industry and military practice. And yet, all those folks continue to
climb
to their altitude, accelerate to cruise speed and then throttle back to
maintain that speed.

Perhaps there is something to it then, check out this blurb from a 747
discussion group, the subject for this discussion was started by
someone asking about flying on the step:

***Begin quote***
As for flying 'on the step', I believe Jetguy's on the money. For a
given power setting there will be two speeds available (ie: the two
points on the curve where power available = power required). Being 'on
the step' is when you're flying at the higher of the two speeds.

On a video today I saw a demonstration of how to get 'off the step'.
The scenario was a CX B747-400 simulator with RB211-524H engines. The
aircraft was placed at 40,000' and at a weight which gave a margin of
approximately 30-40kts between the stall and high speed buffet. At a
speed ~ 10kts below the high speed buffet the thrust was reduced,
decellerating in level flight until the onset of the pre-stall buffet.
By this time the aircraft had gone past the lower speed at which level
flight could have been maintained with the initial power setting (ie:
the 'off the step speed'), and was so far up the back side of the
power required curve that full power was needed to maintain level
flight, and stop the IAS from reducing further.

The only solution was to descend, trading a bit of that potential
energy to accelerate the aircraft onto the right side of the drag
curve, and then recapture the initial altitude (if you wanted to test
your luck in coffin corner).

A very interesting demo which certainly highlights one of the major
differences between putting around in a Cessna and high altitude jet
transports.
***end quote***

This would appear to be specific to swept wing airliners only.

My father, who flew PB4Y-1's and -2's told me about the climb above
and dive down to cruising altitude technique which he used for his
long range patrol. The PB4Y-1, called the "Privateer" by the Navy,
was the navalized version of the B-24. Loaded for patrol, it would
have been substantially overgross. The B-24 also had a wing called
the Davis Wing, which had a very narrow cord (high aspect ratio) and
it's likely that it had a narrowly defined best cruise angle of
attack. I think it's possible that if you did not accelerate to the
proper airspeed, you could spend a long time wallowing along behind
the power curve before enough fuel burned off to allow the airplane to
nose down to the proper angle of attack. I agree though that finding
that proper cruise attitude and speed could be achieved by the diving
down method as well as leaving climb power on and throttling back once
the proper speed has been reached, or slightly exceeded. The point is
to exceed it slightly before throttling back, I doubt the airplane
cared which way you managed that.

Corky Scott