flomulgator

mental exercise here:
can a rotary engine impart gyroscopic stability for pitch? Does an eccentrically rotating mass impart gyroscopic inertia in the same way that a spinning disk would? How would this affect the dynamics of a car if it was a measurable and considerable quantity? My thoughts are that it would make it difficult for the car to change pitch....piledrive the dips and be light over the humps. If you transversely mounted a rotary would it then impart roll stability?

olddragger

iTrader: (3)

its a triangle not a circle thing.
OD
I am probably stupid

rb67

Yeah, but the moment of inertia of the rotors compared to the moment of inertia of the car is so small that it is likely you won't be able to measure it from performance. The drive train is probably worse as well as the tires. If anyone has the mass and dimensions of a rotor, we can estimate the rotational inertia rather easily.

We can simplify it as a disk which would be relatively close and good enough for a first order approximation. So we have

(1/2)M*r^2 + M*R^2

where r is the rotor radius and R is the radius from the center of the rotor to the point about which the rotor spins.

We can then model the car as a cuboid. (1/2)m*(h^2 + w^2) where h and w vary depending on the size of the car.

The drivetrain is simply 1/2 M_1*R_1^2

From there we can use find the angular momentum and torque generated by the rotors and figure out what kind of forces we are experiencing in the car. I would reckon that the rotors themselves contribute so little it is a non issue when compared to wheels and drivetrain rotations.

flomulgator

I see, so you are treating the rotor as a non-rotating orbit. However, where does rotational speed come into play in that equation? That is what imparts gyroscopic torque (which is different than angular momentum, correct?). I would think that at lower speeds the driveshaft would not matter as much because it's rotational speed is reduced considerably compared to the rotors due to the transmission.