I am having trouble understanding a seemingly contradictory explanation.
When the centre of gravity is beyond its forward limit the tailplane is more effective due to a longer moment arm. [I understand this to mean that there is more downforce from the tail and more of a (nose) pitch up moment. - perhaps I am wrong]
My book tells me that:
"with the COG outside the forward limit, the elevators may have to be permanently displaced upwards in order to provide sufficient balancing download from the tailplane for straight and level flight."
This seems to contradict the first paragraph ? Can anyone help ?
They go on to explain how the opposite occurs with the COG beyond its aft limit with the opposite - that the tailplane is less effective [which I understand to mean there is less downforce from the tail and thus more of a net (nose) pitch down moment.]
They continue that:
"the elevators may have to be permanently displaced downwards to provide sufficient balancing upload from the tailplane for straight and level flight"
Would love some help!
