This example shows an epicyclic gear drive with overall ratio of 256:1 and verifies its transmission efficiency given the individual gear meshing efficiencies. The example is based on Tuplin, W.A. "Designing Compound Epicyclic Gear Trains for Maximum Speed at High Velocity Ratios", Machine Design, April 4, 1957. The drive is built of two ring-planet elements as shown in the gearbox schematic. The example confirms the transmission efficiency value of 0.22 as predicted by the analytical analysis presented in the paper.