What are Electric Ducted Fans (EDFs) aircraft?
EDF aircraft refers to a ducted aircraft, usually a jet.
The duct is the air flow channel of the turbine engine. From the front, the engine’s air intake is a large hole, and there is no gap between the fan blades and the casing. In fact, with such a thick inlet, the core machine inside is not so thick, so the air entering from the inlet is divided into two parts, one part enters the core machine, after being compressed by the compressor, it is mixed with fuel and burned, and finally sprayed at high speed Out, generating thrust, this part is the inner duct.
The other part only passes through the fan, and then flows out of the engine from behind, generating only a small part of the thrust. The passage this part passes is called the outer duct. The function of the outer duct is to cool the inner duct with cold air that has not been compressed, and to provide thrust for the reverse thrust when landing. The ratio of the air flow rate of the outer air inlet to the air inlet is called the bypass ratio or the bypass ratio.
For engines with a high bypass ratio, most of the power comes from the external intake air accelerated by the fan. This type of engine often has a short outer air inlet, and the exhaust of the inner air inlet is not mixed with the outer air inlet, but is discharged by the nozzle alone. The large bypass engine has very good energy efficiency at subsonic speeds, and is usually used in passenger aircraft, transport aircraft and strategic bombers. For engines with a low duct ratio, most of the power comes from the exhaust of the internal intake port that drives the core engine. This engine usually uses a hybrid nozzle, that is, the exhaust of the internal intake port is mixed with the air flow of the external intake port before being discharged.
The mixing nozzle can be deformed to adjust the magnitude and even the direction of the thrust. After the high-temperature exhaust gas is cooled by the airflow of the external intake port, it is also beneficial to reduce the infrared characteristics of the engine. Some small ducts are also equipped with afterburners than engines, which can get greater thrust at the expense of high fuel consumption. Small bypass ratio engines can be used for supersonic flight, usually for fighter aircraft.
Notes on buying EDF:
1.To confirm that EDF is a brushless motor, you need to look at the KV value.
2.Look at the controls, distance and model of the aircraft.
3. The aircraft’s ESC is best to 30A.
4. The battery of the aircraft should be lithium, otherwise it will not fly. Here are a few LiPo batteries that can be used for different EDFs.
And you can also find more RC aircraft lipo batteries on Ampow.
What are the advantages and disadvantages of EDF?
* Advantages of EDF propellers:
- Because the blade tip is restricted by the duct, the impact noise is reduced. The induced resistance is reduced and the efficiency is higher.
- At the same power consumption, the ducted fan will produce more thrust than isolated propellers of the same diameter. At the same time, due to the enclosing effect of the duct, it has a compact structure, low aerodynamic noise, and good safety in use. Therefore, it is used as a thrust or lift device in aircraft design.
* Disadvantages of EDF propellers:
- Good efficiency requires that the gap between the blade tip and the pipe is very small, and the three-dimensional shape design of the air duct is complicated, requiring high speed and minimum vibration.
- Higher prices
- Faster battery consumption
- The operation is not easy, and it is not so friendly to novices.
EDF is a different kind of drone, but it also has an irreplaceable role in some fields.