How about this?
Hey guys…came up with a slightly different design using 2 different motors
One standard DC motor to use for rotation of the flywheel, speed set through PWM
The other a servo with an arm on it that rotates in a 90 degree arc. the arm is under the flywheel with the servo above. the the stroke length of the piston can be changed by adjusting the angle of the arm relative to the line between the servo motor and the axis of the fly wheel. Heres a bad picture of my thought
Would a servo motor have enough torgue to maintain its postion while the flywheel is spinning and a resistance force is being applied to the piston?