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Old 28th Nov 2013, 19:42
  #223 (permalink)  
Pace
 
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So much comes down to energy management and control forces. When I was involved in developing a MSFS flight model I took measurements in a Seneca to try and get better flight dynamics and control feel in a gamey MSFS.
Trimmed in the cruise 1/2 inch deflection on the yoke was required with quite a force to pitch the aircraft 10 degrees.
We all know at just above the stall on landing the column will come back several inches to its stops and to almost its maximum deflection.
the same goes with the rudder the faster you go the less movement of the rudder for a given effect the slower you go the more movement is required for a given effect until there is no more rudder movement available for a desired effect!

We have two energy sources to tap into! From the engines and from the potential energy in the airframe.
with any minimal performance aircraft whether it be a single or twin the less energy source available from the engines the more pilots are reqired to tap into the potential energy in the airframe by pitching for energy or speed.

Hence the old argument of pitching for speed or power for speed. Low time pilots are taught to pitch for speed in low powered draggy aircraft.
neither argument is correct as you have two throttles one to the engine/s and one to the airframe in the form of a column and it is a blending of the two sources not one which maybe required.

What has this got to do with VMCA and engine out on twins? Quite a lot really.
VMCA is literally the point like the elevator where the speed of air over the surface of the rudder is so slow that maximum rudder movement is required for a given effect.IE to counteract the effects of asymmetric power from one side of the aircraft only.

In this case to counteract the effects of unequal power from one engine rather than two. In that situation there are only two choices increase the speed i.e. pitch for it or reduce the power from the live engine or bank against those forces to reduce the requirement for rudder.

but banking brings its own problems especially in a minimal power (engine out in a twin)
We all know what happens if you take a 150 and go into a 45 degree level bank maintaining altitude without adding power from a low power setting?

so for me its all about energy management especially like in draggy low powered singles where you need to pitch for potential energy in the airframe.
The Twin engine out is the same, a low powered draggy aircraft where the pilot needs to tap into the airframe potential energy more and not get into high drag situations.

Hence why I see light twins as minimal performance aircraft especially engine out and why far greater lateral thinking needs to come into the equation rather than climb at all costs at blue line. That is great if the pilot can peg blue line regardless of a climb level flight or descent but sadly few rarely do.

Pace

Last edited by Pace; 28th Nov 2013 at 20:06.
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