hot gases leaving the lp and hp compressor turbines are accelerated again as they expand through the power turbines 20 the power turbines 20 provides rotational energy to drive the gearbox via the power turbine output shaft 22 a gearbox 30 130 reduces the speed of the power turbine 20 to one suitable for the propeller in the present invention the gearbox can either be a u201c standard rotation u201d gearbox 30 or an u201c opposite rotation u201d gearbox 130 depending on the desired direction of rotation for the propeller the gearboxes 30 130 of the present invention advantageously may both be provided from substantially the same components as will be explained further below referring to fig2 the u201c standard rotation u201d gearbox 30 is shown in more details a gearbox housing 32 front cover 34 and accessory drive cover 36 forms a casing containing the various gearbox components a flange 37 on the gearbox housing 32 provides the turbomachinery gearbox interface a flexible input drive shaft 38 couples the gearbox 30 to the turbine shaft 22 an output shaft 40 includes a flange 42 to which the propeller is attached the output shaft is supported by a front ball bearing 68 and a roller bearing 70 which are mounted in the front cover 34 and.