Power Absorption Design

081-07-03Pablo Asensio Martínez2026-04-011 min

The Problem

Powerful engines (turboprops) need to convert huge horsepower into thrust without the propeller tips going supersonic (which kills efficiency and creates noise).

Solutions

  1. Increase Solidity: Ratio of blade area to disc area.
    • More Blades: move from 3 to 4, 5, or 6 blades (e.g., C-130J has 6 blades).
    • Wider Chord: Broader blades.
  2. Scimitar Blades: Swept-back tips to delay compressibility effects at high tip speeds (like a swept wing).
  3. Contra-Rotating Propellers: Two propellers on the same axis rotating in opposite directions.
    • Advantage: Cancels torque, recovers energy from the slipstream (swirl), allows smaller diameter.
    • Disadvantage: Complex, noisy.