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Aircraft should also take advantage of the wave of new energy, reduce dependence on traditional fossil energy, and help control the emission of carbon dioxide, nitrogen oxides and other gases.
However, with the increase of flight altitude and speed, the energy required by the aircraft is gradually increasing, and the addition of batteries will make the aircraft more bulky and unable to fly long distances, which is a bottleneck encountered in the development of new energy for aircraft.
In order to solve this problem, the United States company Electra has developed an extended-range hybrid aircraft, what is the concept?
How is the development of this aircraft, known as the "Goldfinch", progressing now?
If one day in the future you are going to charge on a plane, do you dare to sit there?
The take-off test of the range extender was successful.
In April 2023, an aircraft developed by Electra called "Goldfinch" completed a short take-off and landing test on the coastline of Rhode Island, marking the launch of Aircraft technology.
The eSTOL aircraft is an experimental aircraft, a distributed electric propulsion aircraft that can achieve short take-offs and landings by increasing lift.
The design of a distributed electrically propulsive aircraft features a turbofan consisting of multiple electric motors distributed at the appropriate locations at the front and trailing edges of the wings.
The Goldfinch, on the other hand, has two such turbofan arrays, one on the leading edge of the wing and one on the trailing edge of the wing, with a total of up to 20 motors.
The 20 electric vortex fans work by blowing airflow down from the surface of the ascending wing, creating a downward force that can significantly reduce the speed required for take-off.
The required take-off speed for this aircraft is only 56 km/h.
This take-off speed of 50 km/h is actually very slow, which requires the wing of the aircraft to generate sufficient lift, and the design of high-lift wings is very difficult.
But the designers of this aircraft had a very strong conviction that the aircraft did take off at a distance of only 52 meters on one occasion during the tests.
With a cruising speed of about 322 km/h and the ability to maintain a speed of 320 km/h in flight, the new model can even reach a range of 805 km, which has already met the operational expectations of the commercial plan.
What is a range extender motor?
The power system of this aircraft belongs to the extended-range hybrid type, and this electric motor is a device with a turbogenerator, which is combined with the electric motor to form a ternary system.
When the aircraft needs to take off or climb, the electric motor provides power for the electric motor and propeller to take off and climb, so that the aircraft can obtain power through the battery during takeoff.
After takeoff, the aircraft will reach a level flight state, at which point the generator will rotate and the motors and propellers will be charged, and the aircraft will no longer consume the power in the battery.
When the plane needs to land, the battery stores a certain amount of electrical energy, and the electric motor continues to power the electric motor and propeller.
This design not only reduces the battery capacity required by the aircraft, but also increases the range of the aircraft.
Advantages of extended-range hybrid aircraft.
The design of a pure electric aircraft is very difficult, because in order for the aircraft to take off, it needs to generate enough lift, and the generation of lift needs to have a certain speed.
But the faster the speed of the aircraft, the greater the drag in the impact air, which forms a contradiction between the two, even if the wing design of the aircraft is high enough lift, and the energy density of the battery is high enough, the aircraft still cannot reach the take-off speed.
However, the extended-range hybrid aircraft does not have this concern, and the battery power works at the output capacity of 270 when the aircraft takes off, and the battery is equivalent to a reserve medium of electrical energy.
The electrical energy during take-off and landing is mainly provided by the turbine generator, which has the advantage of being able to generate electricity as the fuel consumption increases.
This is because turbogenerators are powered by oil-fired turbine engines, which have a much higher energy density than batteries, and are even much lighter than the size and weight of today's batteries.
Based on the current energy density of batteries, an Airbus A220 jet would need more than a ton of batteries for short takeoffs and landings.
However, if the extended-range hybrid is used to achieve short take-off and landing, the take-off fuel required by the aircraft is no longer batteries, the weight of more than 100 tons can be saved, and the weight of liquid fuel is much lighter than that of batteries.
In pure electric aircraft, due to the need to carry a large number of batteries, in order to be able to meet the requirements of short take-off and landing, it is necessary to make the output power of the motor higher, and even change the design of the entire engine, which will inevitably have certain constraints on the design of the aircraft.
This is not the case with extended-range hybrids, which are more flexible due to the increased option of generators, so that the type of generator can be freely chosen, and the layout of the designed aircraft will also be more free.
Extended perspective
What will be the future of urban air mobility?
The concept of urban air mobility means that one day we will be able to place an order on our mobile phone and call a plane to take us from one location to another as easily as we can on a subway bus.
But the value of the aircraft will be greatly reduced, flying will become very popular, and the major aircraft manufacturers in the market will also launch low-cost aircraft for people to buy.
Future urban air mobility will use small, electric planes that are less valuable and cost about $200,000, or ten times the price of a Tesla.
And electric aircraft are also very low maintenance, so it is more convenient to charge while they are charging, and they may even be charged at home.
The aircraft is capable of a range of about 200 kilometers and has a landing distance of 500 meters.
Since the take-off and landing demand of these electric small aircraft is not high, it is equivalent to a runway that can take off and land multiple aircraft, which can maximize the value of the runway and make more reasonable use of the city's land resources.
So is there a possibility of all-electric short-haul flights in the future?
The faster the cruise, the longer the range, in this case, the energy density of the battery in the cabin needs to be higher.
When the energy density of the battery in the cabin gradually increases to meet the take-off conditions of this aircraft, the impact on the traditional aviation market can be very large.
But for now, such short-haul flights are still in the testing phase.
And the current battery energy density is far from meeting these conditions, and the battery used in this electric aircraft weighs 680 kilograms, which is equivalent to 300 kilograms of kerosene.
For traditional airlines, the value of the aircraft is generally very high, and the current value of the A220 jet is around $40 million.
If one day this electric small aircraft enters the market and brings higher economics to it, then traditional airlines may update their fleets.
At the same time, the R&D process of extended-range hybrid aircraft is very conservative, which is the least risky way, so that aircraft developers can explore the effects of new energy turbine engines without taking big risks.
At the same time, it can also give people more confidence that the hybrid will be safer, and the designers of the aircraft need to convince people that the aircraft they are developing is safer.
At the same time, thanks to the success of extended-range hybrid aircraft, it may make the road to new energy vehicles smoother.
epilogue
The road to new energy for aircraft is gradually coming to us, and although the research and development process is relatively conservative, it is also moving forward, and the future will be even better.