2.5" Fan Blade Propeller (2mm Shaft Hole, 4 Blades) - No.209

Description

The 2.5" 4-Blade Fan Propeller (No.209) is a lightweight, durable plastic propeller designed specifically for hobbyists, makers, and students. Featuring a highly efficient four-blade aerodynamic design, it provides smoother airflow and higher thrust at lower RPMs compared to standard two or three-blade alternatives. The center hub features a precision 2mm diameter hole, engineered to create a tight, friction-fit onto the shafts of standard hobby DC motors, such as the ubiquitous 130-size, 140-size, or 260-size motors.

Whether you are building a custom desktop summer cooling fan, a wind-powered generator model for a classroom science fair, or providing thrust for a DIY RC hovercraft or airboat, this inexpensive four-blade component is an absolute staple for basic electromechanical projects.

People also search for: 4 blade toy fan, 2.5 inch propeller, 2mm shaft propeller, dc motor fan blade, hobby motor fan, diy airboat prop, no 209 fan.

Specifications

• Model: No. 209
• Blade Count: 4 Blades
• Overall Diameter: 2.5 inches (Approx. 63.5 mm)
• Shaft Hole Diameter: 2.0 mm (Designed for a tight friction fit on 2mm motor shafts)
• Material: High-impact molded plastic
• Weight: Ultra-lightweight for high efficiency

Applications

• STEM Education: Perfect for classroom physics projects demonstrating wind energy, thrust, and basic motor circuits.
• DIY Cooling Fans: Building small, battery-operated portable fans for desks or camping with improved airflow.
• RC Vehicles: Providing smooth forward thrust for custom-built remote control airboats, hovercrafts, or lightweight foam airplanes.
• Generators: Acting as a wind turbine blade to spin a motor in reverse to generate small electrical currents.

Frequently Asked Questions (FAQ)

Q: Will this fit my small DC toy motor?
A: Most likely, yes. The vast majority of standard hobby DC motors (like the common rectangular 130 motor or the round 300 motor) use a standard 2mm metal shaft. This fan is specifically molded to press tightly onto that 2mm shaft.

Q: What is the advantage of 4 blades over 2 or 3 blades?
A: A 4-blade propeller typically moves more air volume per revolution and runs smoother (with less vibration) than a 2-blade prop, making it excellent for cooling fans and steady thrust applications.

Q: The fan keeps flying off the motor shaft when it spins really fast. How do I fix this?
A: If the friction fit has become loose over time, you can secure the propeller permanently by placing a tiny drop of super glue (cyanoacrylate) inside the shaft hole before pressing it onto the motor.

Package Includes

• 1 × 2.5" Fan Blade Propeller (2mm Hole, 4 Blades) - No.209