Recently, with the C919 large passenger plane becoming popular again, the video of C919 completing a large slope roll in the test flight two years ago was also popular again. I wrote a short article about this that year, thanking my friends for their love. This time, it has been slightly modified and released again to commemorate.
C919 aircraft completed large slope rolling
Recently, the domestic C919 large aircraft completed 105-degree large slope rolling during the test flight. The video was heard, and the Chinese people were excited and netizens were even more ecstatic. This also leads to a question: What does the C919 aircraft complete a large slope rolling mean?
, share some opinions on this.
1. Large slope rolling shows the excellent lateral handling performance of the C919 aircraft
fuselage coordinate system
aircraft operates in three-dimensional space, theoretically with 3 degrees of movement freedom and 3 degrees of rotation freedom. In fact, for land-based aircraft, there is only 1 degree of movement freedom and 3 degrees of rotation freedom. If the fuselage coordinate system is established based on the pilot, one degree of movement freedom is forward movement along the longitudinal axis (X axis) direction of the aircraft, and cannot be freely moved along the horizontal axis (Y axis) and vertical axis (Z axis) directions of the aircraft. The three degrees of rotation freedom are rolling movement around the vertical axis (X axis) of the aircraft, pitch movement around the horizontal axis (Y axis) of the aircraft, and yaw movement around the vertical axis (Z axis). The video of
shows the rolling movement along the longitudinal axis of the aircraft (X-axis). In about 4 seconds, the test pilot first made a left roll of about 105 degrees, and then made a reverse right roll of 105 degrees. The average rolling angular velocity of the entire process reached more than 50 degrees/s. In actual use, the maximum rolling angle of of civil aviation aircraft generally does not exceed 35 degrees, and the maximum rolling angle speed does not exceed 20 degrees/sec. Obviously, the C919 is much higher than these data, showing excellent lateral handling performance and more than enough to cope with daily flights.
Of course, based on this video, it is not enough to make more evaluations of C919.
2, civil aviation aircraft is a civil aviation aircraft. C919 is not necessary and cannot compete with fighter aircraft
For this video, some netizens directly wrote a text: The domestic passenger plane flew out of the fighter aircraft's maneuvering action. The deep love and the deep affection are beyond words. However, civil aviation aircraft are civil aviation aircraft, each with its own positioning. There is no need and it is impossible to compete with the fighter . The C919's rolling angular speed exceeds 50 degrees/sec, which is a very excellent result among civil aviation aircraft, but it is still far behind it compared to fighter aircraft. For example, the maximum rolling angular velocity of the US F/A-18 fighter is 225 degrees/sec, while the J-10 fighter in my country is even higher. Obviously, in terms of rolling angular velocity alone, the two are not at the same level, let alone the others.
aircraft circling diagram
Somersault roll
Go deeper, you might as well talk about the maneuvering movements of the fighter. Rolling is just a pilot. The actions connected to the subsequent actions can be a large slope, continuous scrolling, and other actions can be made. Just doing a large slope roll of 105 degrees is not enough to represent the maneuvering movement of a fighter, and at most it makes people think about it. Of course, the C919 can make large slope rolls as a civil aviation aircraft, which is enough to show its excellent lateral handling performance, and it is not necessary or impossible to make a series of more complex maneuvering actions similar to fighter jets.
3. How to view Boeing 707 aircraft completed the maneuvering action of the air drum that year
aerial roller diagram
With the popularity of the C919 large slope rolling video, someone found out the old past events of the Boeing 707 flying out of the air drum more than 60 years ago, and proudly claimed that it was unprecedented and there will be no one to come in the future. We look forward to the early appearance of the later generations.
This is what happens. In the 1950s, humans entered the jet era. However, the jet passenger aircraft market has been sluggish due to the world's first jet aircraft and the two consecutive air disintegrations of the British Comet.In August 1955, in order to open up the sales of Boeing 707 aircraft, Bill Allen, then president of Boeing , decided to take advantage of the opportunity of hosting a watercraft competition in the local area to give the Boeing 707 a low-altitude open field in order to leave a deep impression on the audience. I never thought that the test pilot Johnston made a good idea and made two rolling in the air! He was about to suffer from Allen's nervous heart disease, so he hurried to find medicine. Fortunately, everything is safe and the outcome is just right. This almost crazy suicide behavior left a deep impression on the maneuverability and reliability of the Boeing 707 aircraft. A large number of orders followed one after another, creating a sales miracle of Boeing aircraft.
Although Johnston's "shocking flight" objectively saved Boeing, Boeing's senior executives have always been negative about this. Johnston's son recalled that the day after the incident, Johnston received a "teaching". Although he argued that the purpose was to help the company sell planes, Allen still warned him: "Don't do this in the future."
40 years later, when the first flight of Boeing 777, the last sentence Boeing executives explained to the test pilot was still: "Don't be a roller!" It can be seen that the shadow of this matter is so deep. The test flight of the new aircraft is an extremely rigorous task. What to fly, when to fly, what conditions to fly, where to fly, how to fly, what results to achieve, etc. must be fully demonstrated, and there is a complete set of processes and work plans. The entire test flight will take several years, and all extreme situations that may be encountered during use must be flew one by one. Any mistakes during the test flight may delay the test flight progress, and in severe cases, even lead to the test flight failure. Therefore, in the test flight work, we must strictly abide by the rules and plans, and we must never act spontaneously. For civil aviation aircraft, the aerial roller is not only useless, but also extremely dangerous, which destined that the Boeing 707's aerial roller can only become a "master song". Johnston's behavior cannot be allowed, nor can it be praised or encouraged. On this issue, the media must assume their own social responsibilities, not promote fuel or sensationalism, nor should they mislead the public.
