APC AP205205E propeller 20.5x20.5E contra drive CW (F3A pattern)  [AP205205E]

Propeller for electric pattern aircraft

This APC propeller is an RC-scale 20.5x20.5E contra drive unit presented in a clockwise (CW) rotation form and designated for F3A pattern use. The write-up focuses on fitment checks, installation considerations, and how this prop plays a role in throttle response and trim adjustments for pattern flying.

Fitment: confirm motor shaft diameter and spinner or prop adapter type before installation. Contra drive props require matching mounting hardware and correct thread or collet sizing to secure the blade set to the motor shaft.

Installation notes: ensure correct rotation direction for CW contra setup, tighten hub hardware evenly, and verify clearances to airframe surfaces and control linkages. Balance the propeller assembly dynamically or statically as part of final setup to reduce vibration transmitted to the airframe and electronics.

Tuning role: a 20.5x20.5 profile affects static thrust and pitch behaviour; use incremental changes in pitch and motor timing (on your ESC) to refine vertical response and slow-speed precision during pattern maneuvers.

This propeller serves as a direct replacement or upgrade for electric pattern aircraft requiring a 20.5x20.5 contra drive CW blade set; verify mechanical fit and balance before operational use to achieve predictable pattern performance.