Pusher Propeller Problems

Although canard airplanes can have propellers in front, in the so-called tractor position, canard propeller-driven aircraft generally wind up with pusher propellers. Thus, in the context of discussing design, stability, and control problems of canards, it is appropriate to bring up some design problems of pusher propellers as well.

A tail-down landing touchdown attitude is often desired, for a minimum energy landing. In fact, many nose landing gears are not expected to take landing impact loads and are noticeably lighter and weaker than main landing gear assemblies. Pusher propellers tend to have relatively small diameters, just to provide clearance for tail-down landings. This is a constraint on propeller design, leading to lower propulsive efficiency. Alternatively, airplanes with pusher propellers tend to have relatively long, heavy main landing gear legs.

Pusher propellers generally act in the wakes of either wings or horizontal tails. While there may be no appreciable propulsive efficiency loss for such arrangements, a distinctive propeller noise generally results, which could be a problem for people on the ground. Pusher propellers have vibration problems, and their engines can have cooling problems.