Abstract: Two-stroke, fuel injected internal combustion engines for unmanned aircraft and associated systems and methods are disclosed herein. Engines configured in accordance with embodiments of the disclosure can include, for example, (a) an electronic fuel injection system configured to provide a desired low fuel rate by injecting fuel every nth compression cycle rather than every cycle (so-called “skip-cycle” operation), (b) one or more pressure sensors configured to measure fluctuations in peak crankcase pressure and use such fluctuations to control fuel injection delivery, and (c) a multi-cylinder configuration having a common crankcase with a fuel injection arrangement configured to mitigate or eliminate problems with mixed redistribution.

Abstract: One advantageous embodiment of the present invention is an integral clamping-and-bucking apparatus (12) for a system (10), which is utilized for applying rivet fasteners (56) to two or more panels (14a, 14b) and forming a joint (24) therebetween. The integral clamping-and-bucking apparatus (16) includes a clamping foot (46) for clamping the panels (14a, 14b) in a predetermined configuration and for drilling a hole (54) in the panels (14a, 14b) the panels (14a, 14b) at the joint (24). Also, the integral clamping-and-bucking apparatus (12) further includes a bucking bar (48) for bucking a rivet tail (62) that extends from the hole (54). The clamping foot (46) and the bucking bar (48) are coupled to and actuated by a controller (32). This controller (32) actuates the bucking bar (48) and the clamping foot (46) for transferring power between the clamping foot (32) and the bucking bar (48) while maintaining a substantially constant total force applied to the panels (14a, 14b).