The following methods can be used to distinguish between the forward and reverse propeller blades of model aircraft:
1. Distinguish by the windward side of the propeller blade: Place the propeller horizontally, ensuring that the side with the letter on the blade faces upwards. Observe the windward side of the right blade: If the windward side of the right blade is behind, then the propeller is a positive propeller. If the windward side of the right blade is in front, then the propeller is a counter rotor.
2. Distinguish by engraving on the propeller blades: The propeller is usually engraved with model and specification words, such as "10X5.5MR". If the lettering on two propellers is different, one of them may contain additional letters or markings, such as "MRP": Propellers with multiple P characters or specific markings are usually anti propellers. The differentiation methods of different manufacturers may vary, some may be distinguished by "CCW" and "CW", while others may be distinguished by "L" and "R". When making a purchase, it is important to inquire with the seller about the specific differentiation method.
3. Direction of rotation judgment: For propellers already installed on model aircraft, the direction of rotation can be observed to determine whether they are positive or negative propellers: propellers suitable for clockwise rotation are called negative propellers. A propeller suitable for counterclockwise rotation is called a positive propeller.
The above methods are only applicable in most cases, and specific judgments need to be made based on the actual design and usage scenarios of the propeller. When installing and using model aircraft propellers, it is necessary to carefully read the product manual and correctly distinguish and install the forward and reverse propellers according to the requirements to ensure the safety and normal operation of the model aircraft.