Kristian,
welcome to the discussion!
"T*sin (a) - D*sin (a) + L*cos (a) - W"
Almost correct. You included all the factors but forgot the condition, as specified by the requirement for a steady-state climb:
T*sin (a) - D*sin (a) + L*cos (a) - W
= 0
"This would give a fixed lift for any given speed regardless of pitch-angle"
Sorry, it will not. T will increase while D will remain largely constant for small changes of a, especially at high airspeeds (see the answer to OP Q2!). W will, obviously, remain constant. L will reduce, and the condition of vertical force balance as specified by the equation will remain satisfied.
BTW, you defined
a as
climb angle and then proceeded to make conclusions about the effect of
pitch angle from the (half...
) equation including
a but no reference to pitch angle. Easy to mess up in this, innit?
