Pilots who have flown civil aviation for many years are extremely sensitive to the cost control of civil aviation, especially the old qualified pilots who have flown for more than ten or twenty years, and have personal experience in the entire period of rapid development after the reform and opening up of China's civil aviation, until now the whole process, with more and more airports, more and more routes, more and more flights, more and more aircraft, and the cost of airlines is getting higher and higher.

Take the capital airport as an example, if the air traffic control orders a plane to push out of the terminal stand, then the plane will enter the queue to take off, from this time on, the engine of the aircraft must be in operation all the time, but during the busy period, some flights can not even take off for an hour, and every extra minute of delay, the airline will have to bear a huge amount of fuel consumption costs.

Landing is the same, delay more than 20 minutes, fuel consumption cost will increase in 10,000 yuan, high cost, so that the cost of civil aviation per kilometer is too high than the railway and highway, and only the fuel surcharge and airport construction fees, will be a large number of potential users of civil aviation turned away, trapped by the cost reasons, civil aviation competitiveness has not been able to get qualitative improvement.

However, the comprehensive performance of DC1-1 is enough to reduce the cost of aviation by a large margin, and if airlines adopt Dongchen's aero engines, the entire civil aviation field will usher in a rapid development.

The crew was thrilled with the performance of the new engine, and after 48 hours of non-stop operation, there were no abnormalities in the engine, proving that the engine is reliable and capable of continuous flight. The availability of aircraft is also higher.

After 48 hours of continuous non-stop operation, Zhang Wenhao gathered all the crew, the international civil aviation regulations are the new engine off the assembly line test, in addition to the strength test, swallowing test, inclusive test, but also must meet 3,000 hours of operation time before the approval of the installation test, this process is too cumbersome for Zhang Wenhao, and Xiao Er knows all the parameters of this engine well. More than 10,000 hours of simulation experiments can be performed on all parameters in a matter of minutes, and the results of the simulation experiments can be simulated. It is infinitely close to the actual test, so Zhang Wenhao is ready to play his cards according to his own routine. That is, skip the application for the airworthiness certificate and directly install the test.

Although this is a way to violate the rules, but the rules are made by people, Zhang Wenhao uses future technology and Xiao Er, an extremely accurate supercomputer, to have a very in-depth understanding of the performance and endurance of any part of this engine, so Zhang Wenhao decided to let the engine be hoisted on the plane first, directly into the ground hanging test.

Since it is to be hung on the plane for ground testing. Then it must be agreed by the crew, so Zhang Wenhao convened the crew to discuss whether he was willing to enter the hanging stage in advance.

The crew had some apprehensions, but they were instinctive against the existing rules. At first, everyone felt that this unconventional way of playing cards was a bit risky, but everyone understood that this engine. In terms of the performance that has been embodied so far, it is definitely a new engine with epoch-making significance, so the existing rules must really be suitable for this engine.

After negotiation, the crew agreed to conduct the rigging test first, however, the attitude of the crew was that there was no problem with the hoisting test, but the test flight should not be too hasty, and they needed to familiarize themselves with the ground performance of this engine before deciding when to actually conduct the test flight.

Zhang Wenhao has no opinion on this, seeing that the engine has been off the assembly line for more than ten days, and has gone through all the tests except for the specified time, and if it is delayed, I am afraid that when this engine really goes to the sky, at least it will have to wait until the second half of the year.

The four engines that have been tested in the laboratory were transported to COMAC's test site in the suburbs of Zhonghai, which has a 4F runway with an ultra-standard design, which is not only used by COMAC itself, but also by the military's large transport aircraft, which has been transferred to this runway for acceleration and deceleration tests, take-off and landing tests, and crosswind tests.

The runway is of a very high standard, with a length of 4,200 meters and a staggering width of 70 meters, where even the world's largest aircraft, the former Soviet Union's An-225 giant transport aircraft, has taken off and landed.

For the 737 and 320 small trunk airliners, the take-off distance is about 2200-2500 meters, on this runway, 737, 320 and other aircraft can fully accelerate to the take-off speed without taking off, and the remaining distance is also fully meet the braking distance required by the aircraft from the take-off speed to the standstill, which is an excellent place for ground testing.

The crew and Dongchen's technicians were stationed directly at the test airport, and the technician team spent two days disassembling all the engines of the two aircraft purchased by Dongchen from China Southern Airlines, and installing the DC1-1 engines in place, and the crew immediately entered the further testing process of the DC1-1 after two days of rest and the suspension was completed.

The first thing to be tested is the test of the four new engines in the aircraft, the sensitivity of the aircraft's control system, the response speed of the engine to start and stop, and the response speed and sensitivity to the throttle.

Although the DC1-1 is a newly designed engine, in terms of compatibility specifications, like all engines on the market, it can be perfectly hung on the full range of models of the 737 and 320 series.

When the two aircraft completed the engine replacement, the crew boarded their respective aircraft, the chief engineer of the test commanded the two aircraft engines to start at the same time, the engine turbofan reaction speed is very fast, the speed is quickly raised, and there is a roaring sound, immediately, the two groups of crew began to continuously improve the fuel supply of the engine, so that the engine quickly reached full operation, and then immediately retracted the fuel supply, and when it was reduced to low speed, the engine was turned off.

The whole process is very smooth, the engine response to the crew control is very sensitive, and due to the advanced design concept and high material strength, the DC1-1 is easier to enter the maximum thrust state in a short time than the average engine. This, in practical application, can relatively reduce the take-off distance of the aircraft.

The whole process of ignition, increasing the fuel supply, reducing the oil supply, and stalling the ignition was repeated by the crew more than 60 times in a single day, and the four engines remained extremely responsive without any incidents.

The next day. The crew got up at half past five and worked until ten o'clock at night, re-circulating the previous day's test process 90 times. Again, nothing out of the ordinary.

On the third day, 90 times, everything was fine.

Such a perfect and accurate response. The confidence of the crew in DC1-1 has been improved a lot, and ordinary engines, in the process of more than 200 continuous start-stops, will inevitably have one or two start-up failures, or slow start-up response, but on DC1-1, each repeated test result is very perfect.

The three-day test made Dongchen's technicians and crew extremely excited. The COMAC employees and leaders at the test airport were also very interested in the test of Tecton, because the production line used by Tecton was transferred by COMAC to Tungchen. These people also regard DC1-1 as half of a commercial flight product, and have been paying attention to Dongchen's test of this engine.

On the fourth day, the crew was tired of repeating the start-stop test without any anomalies, and they took the initiative to stop the original five-day start-stop test early and enter the next dynamic test.

The so-called dynamic test. It is to completely remove the aircraft's braking system and ground fixtures, and then let the aircraft be able to advance at low speed on the ground normally, and the aircraft does not rely on the tractor to walk between the airport runway, it needs to independently complete the acceleration and deceleration, steering and other actions, and the aircraft needs to complete these actions independently in many states, such as queuing up to take off, turning into the runway, turning away from the runway area after landing, etc., at this time, what is most needed is the accurate response of the engines on both sides to the throttle.

If the aircraft completes the steering on the ground, it mainly depends on the thrust difference between the two engines and the rotation of the front wheel guide wheel, so once the aircraft wants to steer, it will immediately change the thrust balance of the engines on both sides, one side will increase the thrust, or one side will reduce the thrust, or both sides will complete the lifting of their respective thrust at the same time, at this time, the sensitivity of the engine is extremely important.

In fact, all active engines can meet the sensitivity requirements, not to mention DC1-1, this kind of test, is only a routine test, if this test passes, then the next step, can be the final acceleration test before the test flight.

DC1-1 has carried out more than 200 start-stop tests in the state of exquisite test, and each test includes the test of fuel supply sensitivity, DC1-1's performance is very perfect, therefore, in the dynamic test, the tests are also easily passed, the whole process is very boring, that is, let the crew fly the aircraft, drive out of the parking stand, enter the contact taxiway, and then enter the runway after steering, stop at the beginning of the runway, and then turn to the original way back, the engine is out of a low-speed state throughout the whole process, It gives the impression that it is powerful but cannot be used.

In the two-day dynamic test, the aircraft has completed a variety of designed running tracks, which are equivalent to various internal test items in the driving school, even if it is Poussin's performance, it can be easily competent, and there is no challenge for DC1-1.

The last step before the test flight is to actually test the accelerated take-off performance of the aircraft, the aircraft starts the engine at the beginning of the runway, and after the aircraft moves, it continuously pushes the throttle to let the aircraft start to accelerate and sprint, and when the take-off speed of the model is reached, the crew only needs to put down the flaps and increase the elevation angle of the aircraft to achieve the take-off process.

However, this acceleration test is not a test flight test, so the crew should not lower the flaps after the aircraft accelerates to the take-off speed, but immediately collect the fuel to let the aircraft quickly slow down in the critical speed state of take-off.

Through this test, the approximate take-off distance of the aircraft can be tested, but it is only an approximation, and if the wind direction and speed are different, the take-off distance of the aircraft will also be different.

However, at the test airport of commercial aviation, when the two aircraft carried out the acceleration test, the take-off distance obtained was slightly shortened by about 200-300 meters compared with the ordinary aircraft of the same type, which is an improvement, but it is of little significance to civil aircraft, because the vast majority of airport runways meet the sufficient take-off distance of the aircraft.

Aircraft engine testing alone is not a hassle, and the DC1-1 responds quickly on both aircraft. It is stronger than the previous original engine, and the thrust is sufficient, so, after these days of hoisting tests, the crew and testers believe that the two aircraft have been ready for test flight, after all, the engine is only a power source. The main body of the aircraft is in the golden period, so as long as the reliability and sensitivity of the engine are guaranteed. Then these two aircraft are ready for test flights.

The commander-in-chief led the testers to formulate five sets of flight test procedures, and the first set of flight test plans was a simple take-off and landing test flight. After taking off at the airport, the aircraft flies ten kilometers in the direction of the runway, and then begins to turn, performing the five-sided approach method commonly used in the field of civil aviation, turning back to the airport for landing.

In the second set of test flight plans, the aircraft climbs to an altitude of 3,000 meters after takeoff, and after reaching the altitude, it maintains the specified altitude and flies for 50 kilometers, then turns back and performs a five-sided approach and landing over the airport.

The third set of test flight schemes. The plane needs to climb to an altitude of seven thousand meters.

For the fourth set of flight test schemes, the aircraft needs to occur at an altitude of 10,000 meters to 11,000 kilometers.

The fifth set of flight test plans not only has to reach the cruising altitude, but also has to carry out a range test of up to 5,000 to 6,000 kilometers for the aircraft, and the route of the flight test must be very strictly formulated. Ensure that there is an alternate airport every 300 kilometers in the entire route, so that after any abnormality occurs, the aircraft can land at the nearest alternate airport, if there are no problems throughout the journey. The aircraft can directly complete the entire route and return to the test airport.

All the test flight procedures have been submitted to the air traffic control department for approval, and because of the special care of the senior management, the air traffic control has given priority to Dongchen's test flight even more than all civil airliners, all the processes have been approved quickly, and all the alternate airports have also been notified, so that they can respond to the diversion needs of Dongchen's test flight aircraft at any time.

The first test flight, the two planes took off ten minutes apart, in the order of the first flight, is the Boeing 737, Zhang Wenhao also personally boarded the plane, together with several test engineers, crammed into a slightly narrow cab, the captain received instructions from the tower, and after a routine inspection with the co-pilot, the aircraft engine started, and slowly pushed out of the parking stand.

In the cabin, the roar of the engine was not too loud, and the captain was also very excited to say: "The noise in this low-speed propulsion state is much stronger than that of all medium and large passenger aircraft, and the noise reduction of this engine is indeed a first-class level, and I believe that the noise in the cabin will be much smaller." ”

The tester nodded and said: "The decibel number is about fifteen decibels lower than that of engines of the same level at low speeds, and the noise drop can reach nearly thirty decibels when operating at high speeds." ”

The captain smiled slightly and said: "Today, I was ranked in the first flight position, and I became the first captain to fly DC1-1 into the sky, in the future, DC1-1 will inevitably become a classic in the field of civil aviation, for me, it is indeed a great honor!" ”

As he spoke, the plane had entered the contact channel, which was connected to the runway at a 90-degree right angle, and the captain gradually increased the thrust of the engine, so that the taxiing speed of the aircraft slowly increased, and soon, the plane had entered the last 90-degree corner.

The general old pilot, few in the corner before the oil and then stop after the corner, after aiming at the runway and then re-throttle to take off, the old captain in order to operate efficiency, basically before entering the runway began to accelerate, do not collect fuel when turning, and then accelerate the take-off immediately after the completion of the turning, in this way, the aircraft has a certain speed when entering the runway, without going through a long acceleration process, can shorten the take-off time of the aircraft faster.

The same is true for the captain, the plane accelerates, and then deftly completes the steering at the turn, does not pause after turning, and pushes the accelerator of the engine engine at the same time as the co-pilot, and then, the plane begins to accelerate continuously, and after reaching the take-off speed, the captain laughs and says to himself: "Okay, it's time, get up!" ”

Immediately, the nose of the plane began to rise, and the plane took off smoothly.

At the same time as the elevation angle of the aircraft off the ground, the captain said: "I have to say, DC1-1 performance is indeed excellent, not only its strong fuel economy and lower noise, even the response speed, power feedback speed is much stronger than the ordinary engine, it can be expected that this engine will be the first to get China's airworthiness license, by that time, China's civil aviation company, should be the first to replace the DC1-1 customer, if the international counterparts know the performance of this engine, I am afraid that they will be jealous and can't sleep." ”

The co-pilot on the side nodded and smiled: "That is, the fuel cost alone has been reduced by nearly 40%, which is enough to make airlines all over the world red." ”

In the case of the maximum afterburner of the aircraft engine, the noise in the aircraft is more obvious, Zhang Wenhao himself can feel that the engine sound is obviously much smaller than when he took the plane before, and he has also taken the worst environment of the economy class several times at the beginning, and he has also sat in the economy class close to the wing many times, knowing that the noise there is the largest, it is simply unbearable.

However, when Zhang Wenhao walked into the cabin, the noise level in the cabin was much smaller than every time he had taken it before, even when he got to the seat next to the wing, seeing the engine running at full strength under the window, the noise was already within the acceptable range.

The plane soon began to turn, and the routine five-sided approach was performed, and the landing process was very smooth, and the engines did not show any abnormalities during this short test flight. (To be continued.) If you like this work, you are welcome to vote for recommendation and monthly passes, and your support is my biggest motivation. )