If I replaced fan blades with congruent blades, the only difference being the second set has a higher density, would that affect the speed cap on the spin? I know it would affect acceleration, but I am talking about the speed ceiling.
P.S. Assume the blades are made of extremely rigid material and cannot change shape or break off because of a reinforced base.
P.P.S. And I was also wondering if, with the same scenario, except with a plane. Would it go faster/slower?
Best Answer
No. As you realise, this will increase the moment of inertia, which will reduce angular acceleration since the torque which the motor can supply is limited. However, the maximum speed which the motor can reach is not affected, since this depends (mainly) on the aerodynamic force, which is the same - it depends on the shape and size of fan, but not its mass.