@Pilothead I think you meant length cubed, not weight cubed, because weight cubed doesn't make sense in a cantilever beam deflection -- also deflection is an effect, which I already ran its numbers, the cause (torque / bending moment) is enough to figure out how much potential was left unused and how much help was gained from the quad engines

further reading: Euler–Bernoulli beam theory: cantilever beams

I personally think just the first section of the answer is satisfactory, the rest including the 330's history is going extra miles, if you still need more information you can attract attention to the question by adding a bounty if you wish

Yes, of course it is length cubed. No need for extra miles.