It seems to me that this would preclude the use of massive windmills (i.e., flywheels), such as the one on the craft. Later, the rules specifically prohibit flywheels:
First, the total weight of the vehicle is only 450 pounds (204 kg).
Secondly, the "windmills" are indeed sails which are (considering the total weight of the vehicle) fairly lightweight and have trivial kinetic mass (ie. not massive). Also relevant is that for a flywheel to be efficient, the mass should be as far from the axle as possible.
So in this case no, rotating sails =/= flywheels and the spinning mass of the sails is a "trivial force", especially considering the weight of the vehicle against the weight of a driver, since the driver would most likely counteract any intentionally or unintentionally placed flywheel of a mass relative to the total weight of the vehicle.