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  • Install the prop with the curved side of the blade facing forward and tighten the prop nut or bolt with the proper size wrench.
  • Recheck the tightness of the nut or bolt often, especially on wood props which tend to compress and loosen more often.
  • When starting the engine, keep spectators at least 20 feet clear of the model and out of the path of the propeller. The safest place to stand is behind the aircraft, except for pusher propeller installations .
  • Keep hands away from the prop as much as possible. Use a chicken stick or and electic starter.
  • Keep face and body out of prop arc as engine is started and run.
  • Make all adjustments from behind the prop except on pusher prop installations.
  • Never throw anything into the prop to stop the engine. Use a kill switch or pinch off the engine's fuel supply.
  • Discard any prop with nicks, scratches, splits, cracks or any other sign of damage. Never attempt to repair, alter or bend a prop.
  • Don't run an engine in areas of loose gravel or sand for the prop can throw such material into your face and eyes. It's not a bad idea to wear eye protection.
  • Keep loose clothing, shirt sleeves, and other such items away from the prop and avoid carrying objects that can fall into the prop such as pens, screwdrivers, etc.
  • Be sure to keep the glow driver wire out of the prop path.
  • If a spinner is used, be certain that it's edges are not in contact with the propeller blades.


This is the theoretical distance travelled along the axis of rotation of a propeller during one revolution.

This distance is purely a theoretical one. If a propeller has a pitch of 6 inches it means that the model would advance 6 inches through the air for each revolution of the screw, provided that the propeller blade were mounted in solid guides, like a nut on a bolt with one thread per 6 inches. In a fluid such as air it does not practically advance this distance, there is slip.

See also: Engines, Multi-Bladed Propellers, Propeller Manufacture, Propeller Sizes