00:00When you are in the sky, you can take a look through the skylight and see the engines just below the wing.
00:07A thought crosses your mind, how fascinating it is.
00:10It's this little thing that keeps us in the air at 11,300 meters of altitude.
00:16And after that, you go back to your movie, your book or your iPad.
00:21Of course, it's pretty cool, but we expect it to work.
00:25We consider that it goes without saying and we don't pay much attention to it.
00:29But know that to get to this result that has become so ordinary, it took a lot of work.
00:34Fasten your seatbelts.
00:36Today, we will discover everything that is necessary for an airplane engine to work properly.
00:41Before you board your plane and its pilot turns on the engines,
00:45the aircraft must pass many tests and prove that it is safe.
00:49One of these tests, for example, consists of injecting very high pressure water into the engine.
00:55Most engines evolve over time.
00:58Engineers always seek to build something new,
01:01to improve certain characteristics and, in general,
01:05to modernize the machines to ensure that they work as best as possible.
01:09And for them, it's very fun, at least until the engine in question meets Mother Nature.
01:15To ensure that it remains efficient and stable,
01:17experts must ensure that it resists violent storms with rain, ice and snow,
01:23extreme heat and many other things.
01:26An engine must be ready to face all this before its production even begins.
01:31Engines can absorb huge amounts of water.
01:34There are special tests to test this.
01:37During one of these tests, a team projects water into a running engine.
01:42You will be surprised.
01:43They send nearly 3,000 liters of water per minute directly into the engine.
01:48These tests confirm that you will be safe on board the plane,
01:52even in the event of heavy rain or a storm of immeasurable power.
01:56If the engine is designed correctly and meets safety standards,
01:59the water will come out without damaging it.
02:02Let's continue.
02:03When the temperatures are very low and the weather cools down,
02:07everything becomes icy.
02:09This can damage the engines and cause major problems for the planes.
02:13These tests are particularly difficult.
02:16Experts have to send all kinds of ice particles into a running engine.
02:21After all, you never know what you're going to run into in midair.
02:25Let's continue.
02:26When the temperatures are very low and the weather cools down,
02:30everything becomes icy.
02:32This can damage the engines and cause major problems for the planes.
02:36These tests are particularly difficult.
02:39Experts have to send all kinds of ice particles into a running engine.
02:44After all, you never know what you're going to run into in midair.
02:48Hot and cold tests are also fun.
02:51To check whether an engine will continue to operate in extreme heat conditions,
02:55manufacturers will run it at maximum temperature
02:58and keep it in this state for a long time.
03:01During a flight, the temperatures can be excessively high,
03:05but also very, very low.
03:07To test the effect of glacial temperatures,
03:10engineers must go to a place where it is very cold.
03:13For example, the Canadian Arctic region of Nunavut.
03:17Cover yourself well because the temperatures there are not very pleasant.
03:21They go down to minus 28 degrees Celsius.
03:24Once there, you let the engine go through flight tests and on the ground for a week.
03:30It's nice to stick your face to the window
03:32to watch a plane take altitude, isn't it?
03:35Well, if a plane manages to take off, it's thanks to its rotating blades.
03:40They are super important and rotate at an incredible rate of 3,000 rpm.
03:45The engine reaches its full power thanks to their rotation.
03:48But these blades must be secured.
03:51Something can always happen
03:53and one of them could come off.
03:56This is why tests are an essential part of the process.
03:59They allow us to know if certain blades are not fixed firmly enough
04:04and to remedy it, if necessary,
04:06in order to avoid any problems,
04:08especially when the plane is in flight.
04:11By detaching, a blade could hit other parts of the aircraft.
04:15This has already happened in the past with some planes.
04:18This is why tests are now very strict.
04:21They allow specialists to determine
04:23if the blades are well adjusted even before their final assembly.
04:27During the test, the engineers place a small explosive at the base of one of these blades.
04:31When the engine is turned on, boom!
04:34And this is how we see if the blade will stay inside its compartment or not.
04:38If it comes off, the team goes back to its plans.
04:41It knows that it must review its entire design before making a new test.
04:45Even a blade is so small that a finger can cause huge problems to the engine
04:49and, consequently, to the entire aircraft.
04:52Speaking of blades, have you noticed these little white spirals that we can see here,
04:57in the center of the engine?
04:59They are rather cool, but they also have a function.
05:02They are primarily used to ensure the safety of the crew on the ground.
05:06Crew members generally cannot hear them when the engine is running,
05:11because they wear hearing protection most of the time.
05:15Thanks to these spirals, they can know when the engines are running
05:19and stay at a safe distance.
05:21Another reason why they are so important,
05:24although this has not yet been proven,
05:27is that they frighten the birds
05:29and prevent them from getting too close to the plane's engines.
05:32So you are in the air, relaxing with a good book,
05:36and you feel rather calm.
05:38You don't like to take the plane, especially because of...
05:41There you go, the on-board commander tells you that you are going to go through some turbulence
05:45because the plane is going through a storm.
05:48He says there is nothing to be afraid of.
05:50It's normal.
05:51Even if the risks of lightning striking your plane are very high at this altitude.
05:56On average, a airline receives a lightning strike about once a year,
06:00and it can be very difficult to manage.
06:02In the past, some planes, having done the experiment,
06:05even had to perform an emergency landing.
06:08Engineers therefore had to create a test system
06:11to ensure that lightning would not stop the engines.
06:14They now use lighter materials, such as carbon fiber.
06:18As these materials do not conduct electricity well,
06:21they are used both in the engines and in the structure of the plane.
06:24Manufacturers also add a layer of aluminum foil or metal mesh,
06:28which further reinforces the protection of the aircraft against this type of accident.
06:32Thus, when the on-board commander asks you not to worry,
06:36he does not seek to reassure you while knowing that there is danger.
06:40Thanks to the materials used,
06:42it is very likely that you did not even feel the lightning strike your plane.
06:46A finished plane is tested in three stages.
06:49During the first, the system is checked without turning the engines.
06:54During the second, the engines turn on a special support.
06:58The ultimate step, and in a way the most important,
07:02during which we check that everything works correctly,
07:05is the flight test.
07:07Various tests are carried out on all this equipment.
07:11Once the plane is in the air,
07:13the engine must prove that it can produce a thrust.
07:16Do you remember the blades we mentioned?
07:19It takes about two years to build an engine and prepare it for these tests.
07:23One might think that then the process takes place quickly.
07:26But in reality, it can last up to five years for a single model.
07:30When the builders launch a new aircraft,
07:33they use the first engine built only for the tests.
07:37This means that it is a final prototype,
07:40but that it will never be used in commercial aviation.
07:43There are many other tests, of course,
07:45such as wing flexion tests, for example.
07:48The wings flex in the event of turbulence,
07:51which allows us not to feel anything or almost during storms.
07:55Wing flexion is tested at almost 150% of the maximum flexion
07:59that a plane undergoes during a normal flight.
08:02Then there is the acceleration test.
08:05The different parts of the plane are subjected to constraints
08:08and very high pressures throughout the flight.
08:11Imagine that you rush onto the runway to take off
08:14and that you suddenly have to stop the flight and stop the plane.
08:18Acceleration tests involve applying significant forces
08:21to all internal elements and to the entire external structure of the aircraft
08:26to ensure that it resists all these constraints.
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