by mosumo » Mon Apr 19, 2010 9:11 pm
this is my explanation:
the basic four forces are: lift and weight, thrust and drag.
During acceleration, thrust is greater than drag. it means that we feel the inertia - our body try to remain at rest but somehow it is pressed back to the seat that we seat in. (consider the passenger seat that installed facing forward.)
During deceleration: reverse the above condition.
Constant Speed, Level flight: The lift and weight is equal. Same with thrust and drag. so we feel no force acting on our body.
During climbing or descent: if it is done in constant speed, you will also feel no force acting on you. Be careful, the lift and weight are equal during climbing. the lift exceeds the weight during the moment of a/c rotation, either nose up or down. after that everything is equal provided there are no turbulence etc.
usually when travelling in a n airliner, in a fair weather condition- usually you would feel the acceleration during take off roll and a moment when the pilot is doing rotation (to bring the tail down so that wing will increase it's angle of accident). you'll feel the 'floating' moment just about few second where the lift is so great. after the lift and weight, drag and thrust have settled down, you feel no more force pushing your body. the only thing you will notice is the a/c is climbing - due to the tilted horizon.
The other event is during descent and approaching runway. you might come across where the pilot extend spoilers to reduce lift and speed and you can feel the deceleration . during approaching, landing gears are down, flaps are down - the drag is greater where the a/c is decelerate much more that you can feel the inertia.
e747, the image you got is a fixed trim tab. it means that pilot cannot adjust it during flight. the only way to adjust it is during a/c is at ground. the pilot will tell maintenance personnel how much the drift during flying and the engineer will bend the fixed trim tab either side enough according to his experience and knowledge - this is much more to trial and error method.
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