You can fill in one or both of these fields. If you fill in both, the MotoWizard will consider only exactly that size propeller. If you fill in only one field, that measurement will be restricted but the other will not. For example, if you select Specific Size and select a diameter of 10 inches but leave the Pitch field blank, the MotoWizard can consider various 10 inch diameter propellers such as 10x5, 10x6, 10x7, and so on (this can be handy when you're trying to choose a propeller that looks right on a scale model). Click the Next button to go to the Battery options page... Battery Options On the Battery options page, you can choose the type of batteries that you want the MotoWizard to consider, or specify exactly the battery you want to use.
Spinning propellers are always a hazard on ground working, such as loading or embarking the airplane. Tractor configuration leaves the rear of the plane as relatively safe working area, while a pusher is dangerous to approach from behind, while a spinning propeller may suck in things and people nearby in front of it with fatal results to both the plane and the people sucked in. Even more hazardous are unloading operations, especially mid-air, such as dropping supplies on parachute or skydiving operations, which are next to impossible with a pusher configuration airplane, especially if propellers are mounted on fuselage or sponsons.