planeDesigner.part with n>1 calculates lift wrong

[tko]

AFAICT the following two constructs should result in identical results, but don't

plane(part(lift.deltaDeluxe, n=2),
      ...)

plane(part(lift.deltaDeluxe),
      part(lift.deltaDeluxe),
      ...)

[numerobis]

Uh oh, that implies I missed a multiplication somewhere.