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  • It is complicated because, to do the job of horizontal stabiliser, the tailplane has to sometimes produce downforce and sometimes upforce, depending on speed, CG position, configuration, power setting and so on. So tailplane alpha could be positive sometimes, and negative at other times.
    An increase...
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  • Ben W
    replied to Yawing moment
    Kam, is this a question you saw in a recent exam? If so, I wonder if there might be a couple more words in the actual question. If it asked about total yawing moments or the sum of the yawing moments it would point towards your third answer....
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  • Yes. It assumes CL max, air density and wing surface area are unchanged when we enter a turn from level flight. Because this formula is used to calculate the change in stalling speed it is CL max that we use.
    The value of lift has to rise when we enter a turn and, after making these assumptions,...
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  • As we roll into a turn, we will have to increase alpha to increase CL in order to stay level. In a steady speed level turn, CL will then remain constant at its new level, the value of which will depend on our speed and bank angle. If we try to apply too much bank it may increase beyond CLmax in which...
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  • Ben W
    replied to thrust on blade angle
    Thrust will tend to be low at to the root, due to the low rotational speed. High thrust at the tip may give problems with large blade bending moments, and will create large tip vortices which decrease propeller efficiency.
    So your middle answer looks best, but can anybody offer more feedback on...
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  • Ben W
    replied to Question 810462
    Initial reduction in CL will result in the aircraft descending if the pilot does nothing. But question says LF remains constant so he is maintaining level flight. To achieve this he must raise the nose and increase alpha, so maintaining constant CL. Another ATPL trick question!
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  • The short answer is yes, your last sentence is correct. EASA has found it necessary to clarify its definition of angle of attack in their Learning Objectives. Translated Into plain English: - When they are considering a real aircraft, angle of attack (and so critical alpha also) is the angle between...
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  • The picture you get in the link in Binners post is good. Note that immediately above and below the top of the inversion layer, the temp is similar, and, in this case, the highest that is found throughout the climb, giving the lowest performance. For the exam, assume Inversions always give a sudden...
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Ben W
Ben W
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Last Activity: 11-12-2017, 07:05
Joined: 13-05-2014
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