There have been some drones and experimental air vehicles where quadrotor-type electric props do the VTOL operation, and then a fuel-powered propeller and wings take over for efficient forward flight. This is one way to build a VTOL drone with serious range. (This is a big deal for the military, where limited range means fighting for and holding a string of bases to get to the area of interest.)

It seems wasteful to carry both systems, but it's simpler. The mechanical complexity of transition-type VTOLs is far worse. See the Osprey.