Ollie,

I don't have Simon's book with me at the moment, but if you look at the diagram in question, you will see a short line segment which represents pylon racers. At the left end of the segment is the 'turning task', and at the right end of the segment is the 'straight speed task'. The left end of this segment certainly does not correspond to level flight, and shows that induced drag is a small component of total drag. While a pylon racer is generating a lot of lift during a turn, I think that the wing is not that close to its maximum CL, because the speed remains high, and because it would be very risky to approach maximum CL during a turn. I completely agree that there is a limit to the benefit of clipping wings for a plane that must turn, because drag goes up in turns. It is not clear to me whether the induced drag penalty is worse than the profile drag penalty however. I suspect that as long as speed remains high, the profile drag increase resulting from increasing the angle of attack is larger than the induced drag increase. In particular, I think it is a mistake to assume that it is better to reduce chord than span when reducing wing area in search of top speed.

banktoturn