Master Airscrew 2.5:1 for S400 RC Gearbox - MAS3425

The Master Airscrew 3425 gearbox is a 2.5:1 gear reduction unit built for S400-size motors in electric RC aircraft. It steps motor speed down to a 2.5:1 ratio, letting you swing a larger, slower-turning propeller for more efficient thrust on park flyers and small electric models. If you're running an S400 motor and want a direct geared drive rather than a direct-drive setup, this Master Airscrew gearbox (MAS3425) is the part to fit.

Key Features

• Fixed 2.5:1 gear reduction ratio for matching larger props to S400 motors
• Designed specifically around the S400 motor format common in electric RC aircraft
• Geared drive allows a bigger, slower prop for improved static thrust over direct drive
• Compact RC gearbox suited to park flyers and lightweight electric airframes
• Sold as a spare and upgrade unit for S400-powered propulsion setups

Compatible With

• S400 Motor

What's Included

• Master Airscrew 3425 2.5:1 gearbox unit for S400 motors