Chapter 343 Dongchen hanggong (2)

The pilots who have flown civil aviation for many years are actually very sensitive to the cost control of civil aviation, especially the old pilots who have flown for more than ten or twenty years. They have personal experience in the rapid development period after the reform and opening up of civil aviation in the whole China until now. Since the development of civil aviation, the civil aviation industry in China has made great progress There are more and more airports, more and more routes, more and more flights, more and more airplanes, and the cost of airlines is also higher and higher.

Take the capital airport as an example. If the air traffic control orders an aircraft to push out the terminal stand, the aircraft will enter the queuing take-off link. From this time on, the engine of the aircraft must be in operation all the time, but in the busy period, some flights can not take off even for an hour. Every minute of delay, the airline will bear a huge amount of fuel consumption cost.

The same is true for landing, which will delay more than 20 minutes, and the fuel consumption cost will increase by 10000 yuan. The high cost will make the cost per kilometer of civil aviation much higher than that of railway and highway. However, the fuel surtax and airport construction cost alone will shut out a large number of potential users of civil aviation. The competitiveness of civil aviation has been unable to be improved qualitatively due to the cost reasons.

However, the comprehensive performance of dc11 is enough to reduce the cost of aviation by a large margin. If the airline adopts Dongchen's aeroengine, the whole field of civil aviation will usher in a rapid development.

The crew was very excited about the performance of the new engine. After 48 hours of non-stop operation, there was no abnormality in the whole process of the engine, which also proved that the engine has a reliable and strong ability of continuous flight, so the availability of the aircraft is higher. After hours of continuous non-stop operation, Zhang Yunfeng gathered all the crew members together. The code of international civil aviation is the offline test of the new engine. In addition to the strength test, swallowing test and inclusiveness test, it must meet 3000 hours of operation time before it can be approved for installation test. This process is too cumbersome for Zhang Yunfeng, while the second year is too complicated for this engine Institute Some of the parameters are very well-known. In a few minutes, all the parameters can be simulated for 10000 hours, and the results of the simulation experiment are infinitely close to the actual test. Therefore, Zhang Yunfeng is ready to play according to his own formula, that is, skip the application of airworthiness certificate and directly install the test.

Although this is a way to violate the rules, the rules are all formulated by people. Zhang Yunfeng uses the future technology and the super computer of the second child, which is extremely accurate. He has a very deep understanding of the performance and tolerance of any parts of the engine. Therefore, Zhang Yunfeng decides to let the engine hang on the plane first and directly enter the ground for hanging test.

Since it is necessary to hang the aircraft for ground test, it must be agreed by the crew, so Zhang Yunfeng just called the crew to discuss whether he would like to enter the hanging stage in advance.

The crew members have some concerns, but this concern is only an instinct for existing rules. At the beginning, everyone felt that there were risks in this way of not playing according to common sense. However, everyone understood that this engine, as far as the current performance is concerned, is definitely a brand-new engine with epoch-making significance. Therefore, the existing rules Then, it is not really suitable for this engine.

After negotiation, the crew agreed to carry out the lifting test first. However, the attitude of the crew was that there was no problem with the lifting test, but the test flight should not be too hasty. They need to be familiar with the ground performance of the engine first, and then decide when to actually carry out the test flight.

Zhang Yunfeng also has no opinion on this. Seeing that the engine has been offline for more than ten days, and has passed all tests except for the specified time, I'm afraid it will be delayed. I'm afraid that the engine will go to heaven, at least in the second half of the year. Hang it first, and talk about the flight test after the crew is familiar with and assured.

Four engines tested in the laboratory were transported to COMAC's test airport in the suburb of China Sea. This test airport has a super standard 4f runway, not only for COMAC's own use, but also for the military's large transport aircraft, which has been transferred to this runway for acceleration, deceleration test, takeoff and landing test and crosswind test for many times.

The standard of this runway is very high, with a length of 4200 meters and a width of an amazing 70 meters. Even the world's largest aircraft, the an225 giant transport aircraft of the former Northern crocodile nation, has taken off and landed here.

For the 737 and 320 small trunk airliners, the take-off distance is about 22002500 meters. On this runway, 737, 320 and other airplanes can accelerate to take-off speed without taking off. The remaining distance also fully meets the braking distance required by the aircraft from take-off speed to standstill. It is an excellent place for ground test.

The crew and technicians of Dongchen are stationed at the test airport directly. The technicians took two days to dismantle the engines of the two planes purchased by Dongchen from China Southern Airlines and install the dc11 engine of Dongchen. After two days' rest and hanging, the crew immediately entered the further test process of dc11.

The first thing to be tested is the sensitivity of the four new engines to the aircraft control system, the response speed of engine start and stop, the response speed and sensitivity to the throttle and other static state tests.

Although dc11 is a newly designed engine, in terms of compatibility specifications, it can be perfectly hung on the 737 and 320 series of full series models, just like all engines on the market.

After the engine replacement of the two aircrafts, the crew members boarded their respective aircrafts respectively, and the chief engineer of the test directed the engines of the two aircrafts to start at the same time. The response speed of the engine turbofan was very fast, and the speed was quickly raised, and the roar was heard. Then, the two crew members began to continuously improve the fuel supply of the engine, so that the engine could reach the target quickly When it reaches the full running state, the fuel supply will be recovered immediately, and the engine will be shut down when it drops to the low speed state.

The whole process is very smooth, the engine is very sensitive to the control response of the crew, and because of the advanced design concept and high material strength, dc11 is easier to enter the maximum thrust state in a short time than the general engine, which can relatively reduce the takeoff distance of the aircraft in practical application.

The whole process of ignition, increasing oil supply, reducing oil supply and flameout has been repeated by the crew for more than 60 times in a day. The four engines have been kept in a very sensitive response state without any accidents.

The next day, the crew got up at 5:30, and at 10 o'clock in the night, they cycled the test process of the previous day 90 times again, but there was still no abnormal situation.

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

Such a perfect and accurate response has greatly improved the crew's confidence in dc11. In the process of more than 200 consecutive starts and stops of an ordinary engine, it is inevitable that one or two starts fail or the response speed is slow. However, on dc11, each repeated test result is perfect.

The three-day test excited the technicians and crew of Dongchen, and the COMAC staff and leaders of the test airport were also very interested in the test of Dongchen. Because the production line used by Dongchen was transferred from COMAC to Dongchen, these people also regarded dc11 as half of COMAC's products and have been paying attention to the engine test of Dongchen.

On the fourth day, the crew was tired of repeating the test, but there was no abnormal start stop test. They asked to stop the start stop test of the original five days ahead of time to enter the next dynamic test.

The so-called dynamic test is to completely remove the aircraft's braking system and ground fixed devices, and then make the aircraft be able to propel normally at low speed on the ground. If the aircraft does not rely on the tractor to walk between the airport runways, it needs to independently complete the acceleration, deceleration, steering and other actions. In many states, the aircraft needs to independently complete these actions, such as queuing to take off, turning and so on When entering the runway, turning away from the runway after landing, etc., the most needed is the accurate response of the engines on both sides to the throttle.

If the aircraft finishes turning on the ground, it depends on the thrust difference between the engines on both sides and the rotation of the front wheel guide wheel. Therefore, once the aircraft needs to turn, it will immediately change the thrust balance of the engines on both sides, lift the thrust on one side, or lower the thrust on one side, or complete the lifting and lowering of the respective thrust on both sides at the same time. In this case, the engine sensitivity will appear Extremely important.

In fact, all the engines in service can meet the needs of sensitivity. Dc11, a super airliner with all the most advanced technologies, is not to mention a routine test. If this test passes, then the next step is to carry out the final acceleration test before the test flight. In the state of refined test, more than 200 start stop tests have been carried out. In each test, the fuel supply sensitivity test is included, and the performance of dc11 is very perfect. Therefore, in the dynamic test, all tests are easily passed. The whole process is very boring, that is, the crew drives the aircraft out of the stand, enters the contact taxiway, and then passes Turn to enter the beginning of the runway, stop at the beginning of the runway, and then turn back to the original road. The engine is in a low-speed state all the way, which gives the impression that it is powerful but unable to perform.

During the two-day dynamic test, the aircraft has completed a variety of designed operation tracks, which is equivalent to various internal road test projects in the driving school. Even the performance of Pusan can be easily competent, and there is no challenge for dc11.

In fact, dc11 has achieved excellent performance in all tests, and it is the best product over the years!