If you have ever thought, is the reason behind the aeroplane’s maintenance of balance, very carefully, you will be able to derive a conclusion that will lead all ways to a single object that promises to let out the fan’s counter energy in the form of heat and air motions, you will be surprised to know that you know the name of the object very well. The object is nothing but the duct fan. The duct fan is a propeller like fan object that helps movement of air above and below the aeroplane into a sideways motion first and then absolutely outside it. The duct fan is so called because there is a duct attached to it. The fan is connected to the main body part through a long channel called duct.
Mechanism of the ducted fan
The duct fan is a forward motion preparation in hug electronic and aviation gadgets. It has a kind of propeller mounted within a cylindrical shroud or duct. The duct is significant in balancing the thrust of the airplane from topmost vertex to the bottom and thereby affects airflow pressure and velocity from a crisscross section. This fan working mechanism follows the Bernoulli’s principle. Duct fans have shorter blades attached to it and therefore have a higher rotational speed that other fan types with longer blades. Such fan applications are present in aircraft, airboats, helicopters, hovercrafts etc.
Special utilisation of duct fans in aircraft
The type of duct fan used in aircrafts very commonly is the turbo fan engine. The turbo fan, in this case is driven by a gas turbine. But in other places where they are used like bombers, airliners and fighters, several source of power may be used to design the shaft and drive it. Such power sources are reciprocating engine, wankel engine, electric motor etc. in case of large aeroplanes, the duct fans are not so much in function. This is because the operating speed of the propeller in such a case is limited. Here, the tip speed approaches the sound barrier at a very lower speed hence nullifying the usage of duct fan in such a respect. The most common aircraft where duct fans are used in plenty is the VTOL aircraft like Lockhead Martin. In case of helicopters, sometimes a substitute for a ducted fan is used. Such fans are known as tail fans and the leading producer of tail fan is the Fenestron. It is usually used as a good replacement for tail rotors. The number of blades present in duct fas is usually in odd numbers as this facilitates the prevention of resonance in the ducts.
The advantages and disadvantages of the duct fans
The wide usage of duct fans signifies the fact that it is very useful device and has a lot of advantages. The first and foremost advantage of the duct fan is that it helps proper maintenance of speed and balance inside the aircraft. Also, it is more effective in production of thrust than ordinary motor fans.