Integrated gearless and non-lubricated auxiliary power unit

An auxiliary power unit (APU) (100) includes a compressor (102), a turbine (106), a combustor (106), and a starter-generator unit (108) all integrated within a single containment housing (110). The turbine (106) has an output shaft (114) on which the compressor (102) is mounted, and the starter-generator unit (108) is coupled to the turbine output shaft (114) without any intervening gears. The rotating components are all rotationally supported within the containment housing (110) using bearings (122d) that do not receive a flow of lubricating fluid.