Chapter 344 smooth test

The final step before the test flight is to actually test the accelerated takeoff performance of the aircraft. The aircraft starts the engine at the beginning of the runway, and after the aircraft starts to move, it pushes the accelerator continuously to let the aircraft start to accelerate the sprint continuously. When the aircraft reaches the takeoff speed of the aircraft, the crew only needs to lower the flaps and increase the elevation angle of the aircraft to realize the takeoff process.

However, this acceleration test is not a test flight test. Therefore, after the aircraft accelerates to the takeoff speed, the crew should not put down the flaps, but should immediately receive the fuel to make the aircraft decelerate rapidly in the critical speed state of takeoff.

Through this test, we can test the approximate take-off distance of the aircraft, but it is only a rough one. If the wind direction and speed are different, the take-off distance of the aircraft will be different.

However, in the test airport of COMAC, when two aircrafts carry out acceleration test, the takeoff distance obtained is slightly shorter than that of ordinary aircrafts of the same type by about 200300 meters. Although this is an improvement, it is not significant for civil aviation aircrafts, because most of the airport runways meet the aircraft's enough takeoff distance.

It's not too much trouble to test the engine of the aircraft alone. The response speed of dc11 on these two aircrafts is even stronger than the original engine, and the thrust is enough. Therefore, after these days of lifting test, both the crew and the tester think that the two aircrafts have already met the flight test conditions, after all, the engine is only a power source, while the aircraft The main body of the aircraft is in the golden age, so as long as the reliability and sensitivity of the engine are guaranteed, the two aircraft will have the test flight conditions.

The commander in chief led the test personnel to work out five flight test procedures. The first flight test plan is a simple take-off and landing test. After taking off at the airport, the aircraft will fly 10 kilometers along the runway direction, and then start to turn around, implement the five side approach commonly used in the field of civil aviation, and return to the airport for landing.

In the second flight test plan, the aircraft climbs to a height of 3000 meters after take-off. After reaching the height, the aircraft flies at the specified altitude for 50 kilometers, then turns back and performs a five side approach landing over the airport.

In the third flight test plan, the plane needs to climb to a height of seven kilometers.

In the fourth flight test plan, the plane needs to reach an altitude of 10000 meters to 11000 kilometers.

The fifth flight test plan is not only to achieve the cruising altitude, but also to carry out a long-range test of 5000-6000 kilometers for the aircraft. The route of the range test should be strictly formulated to ensure that there is an alternate airport every 300 kilometers in the whole route, so that the aircraft can land at the nearest alternate airport in case of any abnormality If there is no problem with the flight, the aircraft can directly complete the whole route and turn back to the test airport.

All flight test procedures have been submitted to the air traffic control department for approval. Due to the special care of senior management, the priority of air traffic control over the test flight of Dongchen even exceeds the treatment of all civil aviation airliners. All procedures are approved soon, and all alternate airports are also informed, so they can meet the alternate demand of the test flight of Dongchen.

For the first test flight, the two planes took off at an interval of 10 minutes, and the first flight was Boeing 737. Zhang Yunfeng also boarded the plane himself, huddled in a slightly narrow cab with several test engineers. After the captain received the tower instruction and conducted routine inspection with the Deputy captain, the engine of the plane started and slowly pushed out the stand.

In the cabin, the engine roar was not loud. The captain was also very excited and said: "the noise in this low-speed propulsion state is much stronger than that in all medium and large airliners. The noise reduction of this engine is really super class. I believe that the noise in the cabin will be much smaller."

The tester nodded and said: "at low speed, there is a decrease of about 15 decibels compared with the engine of the same level. If the engine is running at high speed, the noise reduction can reach nearly 30 decibels."

The captain smiled and said: "today, I am the first captain to fly dc11. In the future, dc11 will surely become a classic in the field of civil aviation. It is a great honor for me!"

Said, the aircraft has entered the contact channel, which is 90 degree right angle to the runway. The captain gradually increases the thrust of the engine, so that the taxiing speed of the aircraft rises slowly. Soon, the aircraft has entered the final 90 degree angle.

Generally, the old pilots seldom collect fuel before turning the corner, then stop after turning the corner, and then take off again after aiming at the runway. In order to operate efficiently, the old captain basically starts to accelerate before entering the runway, does not collect fuel when turning, and then accelerates to take off immediately after completing the turning. In this way, the aircraft has a certain amount of fuel when entering the runway Without a long acceleration process, the take-off time of the aircraft can be shortened more quickly.

The same is true for the captain. The aircraft accelerates, and then turns at the turning point nimbly. After turning, the pilot does not stop at all. He pushes the accelerator of the engine engine at the same time with the Deputy captain. Then, the aircraft starts to accelerate continuously. When it reaches the takeoff speed, the captain laughs and says to himself, "OK, it's time to get up!"

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

At the same time when the elevation angle of the aircraft is off the ground, the captain said: "I have to say that the performance of dc11 is indeed excellent, not only its strong fuel economy and lower noise, but also its response speed and power feedback speed are much better than those of ordinary engines. It can be expected that this engine will take the lead in obtaining the airworthiness license of China. At that time, China's Civil Aviation The company should be the first customer to replace dc11. If the international peers know the performance of this engine, they may be envious of not sleeping. "

"That is, the cost of fuel alone has been reduced by nearly 40%, which is enough to make airlines around the world blush."

When the engine of the aircraft is strengthened to the maximum, the noise in the aircraft will be improved more obviously. Zhang Yunfeng can feel that the engine statement is much smaller than when he took the aircraft before, and he has taken the economy class with the worst environment several times at the beginning. He has also sat in the position where the economy class is close to the wing many times, knowing that the noise there is the biggest, Jane It's too big to bear.

However, when Zhang Yunfeng walked into the cabin, the noise level in the cabin was much lower than that of every previous ride. Even when he went to the seat beside the wing and saw the engine running under the window, the noise was already acceptable.

The plane soon began to turn, and carried out a routine five side approach. The landing process was also very smooth, and the engine did not show any abnormality during this short test flight.