The drag created by a windmilling propeller (torque force being provided by the wind rather than the engine) is equal to that of a solid disc of the same diameter being attached to the front of the aircraft. Feathering the propeller places the blades at the zero lift angle of attack (usually around negative 2 degrees). However due to the helical twist of the blade there will be only one section of the blade at the true zero lift angle. But it will still be at the setting for minimum drag. Form drag will also be reduced due to the smaller frontal area being presented to the relative airflow.
On a windmilling prop the total reaction is inclined rearward and slightly in the direction of propeller rotation. This force vector can then be broken down into windmilling drag (which opposes the direction of flight) and windmilling torque acting in the direction of rotation.
In a single engine aircraft the prop is feathered early in the checking process to ensure sufficient glide. In a twin feathering is completed only after thorough attempts have been made to achieve a restart on the dead engine as altitude can still generally be maintained on a single engine even though performance is reduced by around 75%. Just be prepared for a tired leg holding in all that rudder!
So in conclusion, feathering the propeller will give an extended glide range and endurance which will give the pilot more time to achieve his checks and plan the forced landing, if required.
2006-07-25 00:38:09
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answer #1
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answered by Glen 1
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When used in reference to a propeller on an aircraft engine........the prop will be variable pitch. This means that the angle of each propeller blade on the prop can be changed to either pull more or less air through it while running. When an engine stops running and the plane is in flight the prop is feathered meaning the blades on the prop are now turned to an angle that has the least amount of resistance allowing the plane to continue flying on remaining engines or to glide further before a forced landing.
2006-07-23 17:01:01
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answer #2
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answered by aer_tech 2
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To reiterate what most others have said..."feathering" or "feathered prop" means that the propeller is twisted parallel to the wind. It's like putting your hand out the window of a fast moving car...keeping your hand flat and parallel to the ground. This creates very little resistance and is essentially "feathered" like a propeller would be.
2006-07-26 18:48:06
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answer #3
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answered by larsonface 1
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"Feathering" is a term that is used in aviation when you turn the propeller of an engine to be parallel with the direction of flight to minimize parasitic drag. Also, if a propeller is not feathered, the engine would continue to turn. So, by turning the propeller's leading edge to be parallel with the direction of flight, the engine will not be turning by itself. Hope this helps you.
Ken
2006-07-23 17:08:07
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answer #4
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answered by RiderKen 1
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to add to the other responses, an unfeathered propeller can add nore drag than if you had gear and flaps down, wich is somthing you dont want if you are trying to climb or in other phases of flight, as you don't just loose 50% performance with an engine out, it is closer to 75% peformance loss, so drag is the enemy here.
2006-07-23 17:06:05
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answer #5
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answered by Anonymous
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It means to turn the propellor blades edgewise to the oncoming wind so they don't try to "windmill" the engine, which causes a lot of drag if the engine is shut down.
2006-07-23 16:59:18
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answer #6
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answered by Steve 7
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"Shallow" basically means that you judge people on their appearance rather than their personality and feelings. Example: Bob: "I'm only friends with her because she's hot." John: "You're so shallow."
2016-03-27 04:36:40
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answer #7
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answered by Anonymous
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A light touch.
2006-07-23 17:04:14
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answer #8
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answered by dudezoid 3
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dont know
2006-07-23 16:49:24
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answer #9
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answered by screwtape 2
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