Post by LOU on Jul 10th, 2012 at 2:09pm
Windy,
Each plane has a recommended speed for turbulence penetration.
It's been a while, but I seem to remember Mach .78 to .80 was a good number in the 707 and 727.
What you don't want is to be at the edge of the operating range of the aircraft for that weight and available power.
A good example is mountain wave. If you're at high altitude and run into a wave, the plane my not have enough thrust to maintain altitude in the down portion of the wave.
As the plane enters the wave it is pushed upward causing the autopilot to pitch down in order to hold altitude.
The auto throttles pull the thrust way back trying to maintain speed.
Then (red plane) the plane enters the part of the wave pushing the plane down.
The autopilot pitches up trying to maintain altitude.
The available thrust is not enough to maintain speed and the aircraft approaches a stall. Mountain wave can be turbulent or smooth.
Either way, a plane at the edge of it's operating range is looking for trouble. :o
Lou
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Each plane has a recommended speed for turbulence penetration.
It's been a while, but I seem to remember Mach .78 to .80 was a good number in the 707 and 727.
What you don't want is to be at the edge of the operating range of the aircraft for that weight and available power.
A good example is mountain wave. If you're at high altitude and run into a wave, the plane my not have enough thrust to maintain altitude in the down portion of the wave.
As the plane enters the wave it is pushed upward causing the autopilot to pitch down in order to hold altitude.
The auto throttles pull the thrust way back trying to maintain speed.
Then (red plane) the plane enters the part of the wave pushing the plane down.
The autopilot pitches up trying to maintain altitude.
The available thrust is not enough to maintain speed and the aircraft approaches a stall. Mountain wave can be turbulent or smooth.
Either way, a plane at the edge of it's operating range is looking for trouble. :o
Lou
Uploaded with ImageShack.us