Craft the Rotational Dynamo and place it in the world, and supply it with Shaft Power to generate Redstone Flux. The ratio of conversion is 520 Watts = 1 RF/t. This engine can take a maximum of 8192 rad/s and 1024 Nm of Torque (with no upgrades). This will produce 16,132 RF/t. Any further shaft power added will be wasted. When upgraded, the dynamo has the capacity to output a whopping 32,263 RF/t.
As of v10 of RotaryCraft, the rotational dynamo can be upgraded using the Flux Amplitude Upgrade which will double the amount of Torque the Rotational Dynamo can take in, effectively doubling the amount of RF this engine can output.