A duct is a tube or channel designed to guide airflow from one point to another.
- In aviation or RC models, ducts are often cylindrical or annular structures around a fan or propeller.
- The duct reduces airflow loss, improves thrust efficiency, and can also protect the blades.
Example uses:
- Ducted fan engines on jets or VTOL aircraft
- Air conditioning vents (same principle)
- Marine thrusters
2. What is a Ducted Fan (涵道风扇)?
A ducted fan is a propeller or fan enclosed in a duct.
It is a common propulsion method in:
- RC jets
- VTOL drones
- Small electric aircraft
How it works:
- Fan or propeller spins inside the duct.
- The duct accelerates the airflow and reduces tip losses.
- The result is more thrust per rotation than an open propeller of the same diameter.
3. Advantages of Ducted Fans
| Advantage | Explanation |
|---|---|
| Higher efficiency | Duct reduces tip vortices and wasted airflow |
| Safer | Blades are enclosed, reducing risk of injury |
| Quieter | Noise is reduced compared to open propellers |
| Compact design | Fits better in jets or VTOL aircraft with small airframe |
4. Common Applications
-
RC Jet aircraft (EDF – Electric Ducted Fan)
-
VTOL drones (quadcopter with ducted fans)
-
Hovercraft propulsion
-
Experimental aircraft using ducted lift or thrust
Notes:
- Ducted fans are different from propellers because the duct improves airflow efficiency and often increases thrust at high speeds.
- Duct shape, fan diameter, and tip clearance are critical for performance.