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: A pneumatic valve (10) for selectively controlling fluid flow through a pneumatic system of a vehicle is disclosed. The valve (10) includes a housing (12) having a cavity (28). The cavity includes an inlet (16) and an outlet (18). A flow controller (40) is disposed within the housing (12) for selectively controlling fluid flow through the housing (12). The flow controller (40) is actuatable to an open position, where the inlet (16) is in fluid communication with the cavity (28) and the outlet (18) is in fluid communication with a pneumatically operated device. The flow controller (40) is also actuatable to a closed position, where the flow controller (40) substantially impedes fluid from flowing through the housing (12). The flow controller (40) is actuatable between the open and closed positions in response to a predetermined fluid pressure within the pneumatic system.