I need to calculate the increase in drag due to an airbrake, however the formula includes "semi span". I'm unsure if this is simply wing span/2 or is it the length of a wing in which case it would be (wing span - fuse width)/2. Any help would be good.
If I have a problem in which the laminar/turbulent transition point is said to be 50% the mean aerodynamic chord, how can I find the area of the wing over which there is laminar flow? Is it simply half the wing area?