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Level off from a Glide Descent

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Level off from a Glide Descent

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Old 19th Nov 2011, 15:39
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Level off from a Glide Descent

If you want to have some fun, read this thread which is running in Private Flying.

Methinks some of the posters require some remedial training - am sure you'll put them right!

Levelling off from a Glide Descent
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Old 19th Nov 2011, 17:53
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The ex-RAF instructor is correct!

The whole point of the student having been taught exercise 6(2) is to instruct them on the correct technique for acceleration and deceleration. This then comes into play for level-offs following climbs or descents.

The responses are great though - it's amazing how much mis-information there is in the world of aviation and, although I agree that there are many ways to achieve the same goal, the laws of physics do tend to stick their noses in on certain points.

If the aircraft is aiming from a 65kt glide to a 90 kt cruise, for example, and the 90kt cruise attitude is selected with a normal cruise power set, the aircraft will continue to descend until the speed picks up. While selecting full power would be more efficient it will probably be easier and less concerning for passengers for a cruise setting on the power to be selected. There is still a fairly large amount of excess power available and in a fixed pitch prop this power setting will creep up as the aircraft accelerates and maintain an excess in power required to accelerate. The reset of the power will be required but will be less obvious to the nervy passenger!!

Great fun reading though
high wing harry is offline  
Old 19th Nov 2011, 19:58
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Originally Posted by high wing harry
The ex-RAF instructor is correct!

The whole point of the student having been taught exercise 6(2) is to instruct them on the correct technique for acceleration and deceleration. This then comes into play for level-offs following climbs or descents.

The responses are great though - it's amazing how much mis-information there is in the world of aviation and, although I agree that there are many ways to achieve the same goal, the laws of physics do tend to stick their noses in on certain points.

If the aircraft is aiming from a 65kt glide to a 90 kt cruise, for example, and the 90kt cruise attitude is selected with a normal cruise power set, the aircraft will continue to descend until the speed picks up. While selecting full power would be more efficient it will probably be easier and less concerning for passengers for a cruise setting on the power to be selected. There is still a fairly large amount of excess power available and in a fixed pitch prop this power setting will creep up as the aircraft accelerates and maintain an excess in power required to accelerate. The reset of the power will be required but will be less obvious to the nervy passenger!!

Great fun reading though
Maybe a better way not to upset the "Nervy" passenger is to not descend from one altitude to another at idle power in your simple piston trainer/tourer.

How about leaving cruise power on and setting an attitude that will give you a 500 FPM descent. The increase in airspeed will recoup some of the time/fuel you used in climb and the only thing the pax will feel is a slight attitude change. That is what I teach my students.

The bigger issue IMO and the subtext of the original thread is an Instuctor who appears to be trying to use high performace T - Prop aircraft SOP's in a flying school Cessna. Flight Idle power descents are routine for turbines, but they are simply bad operational practice in piston aircraft except for some circumstances during the final approach to landing segment of the flight.
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Old 20th Nov 2011, 17:15
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Come on Bob say whats on your mind.
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