Airplane Things You Don’t Know The Purpose Of
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Airplane Things You Don’t Know The Purpose Of

September 6, 2019

– [Presenter] Ever since
Orville and Wilbur Wright flew at Kitty Hawk airplanes have had wings,
controls, and some kind of motor. But planes have evolved
over the last 100 years. The commercial airliner
you fly in now has features that Orville and Wilbur
wouldn’t have dreamed of. In this video, I’ll show you
10 things you might not know about modern aircraft, from the mysterious to the curious. – Amazing! – [Presenter] Number 10. The mysterious triangle
symbol over your seat. When you board a modern jet aircraft you’re probably looking
for your seat number and for the nearest emergency exit. If you look more closely you might notice a small triangle over your window. That’s not a secret society symbol. It’s a reference mark for the flight crew. There is a triangle at
the front or leading edge and back or trailing edge of each wing. The center of the wing is
ideally the center of gravity of the plane for balancing the controls. Imagine balancing a long
tray with a glass on it on your finger. It’s easiest if the
glass or downward force balances the upward
force from your finger. If you move the glass
to away from your finger the tray will want to tip. So if the flight’s not
full a flight crew member might ask you to move between these rows to distribute the load for
easier control of the plane which translates to less drag and better fuel efficiency as well. It’s also a quick way to spot
which window shade to pull up if the crew needs to inspect
the wing during flight. Number nine. The flange sticking out of the wing. While you’re waiting to leave the gate you’re probably staring out the window at the wings that are going
to carry you off this earth. On some aircraft like the A320 you might notice some metal stubs sticking out of the middle of
the wing like a sore thumb. No, that’s not for lifting the plane. This is part of the evacuation system. If the plane is forced to land somewhere that you can’t use the stairs or the terminal boarding bridge the crew will deploy inflatable chutes from the emergency exits. But if you use one of the over-wing exits you’ll have to step out onto
a slippery metal surface. Those stubs or wing flanges are anchors for tying guide ropes. That little stub will guide
you safely off the wing without stubbing your toe. Number eight. The hum when you board the plane. Have you ever noticed that
there’s an omnipresent drone when you’re waiting for the last passenger to board the plane? (droning hum) The engines aren’t powered up yet but something is running. That’s the sound of the
auxiliary power unit or APU. The APU is what provides electricity to the plane temporarily between the time the plane
unplugs from the terminal until it is ready for take-off. The APU is usually a small turbine that powers a generator for electricity and a compressor for air pressure. The APU powers everything
from the cabin lights and fans up to starting the main engine. It even provides a fire protection system. This system uses less fuel
than running the main engine since it’s only designed
for cabin operations not for driving the plane. The flight crew will start the APU before letting any passengers board so you can sit in comfort and safety while they prepare the
plane for departure. If you pay attention you can
see the lights dim temporarily and hear when they switch
from terminal power to APU. Now you know why your
movie was interrupted for a few moments. Number seven. Tomato Juice. Do you find yourself
ordering a tomato juice when you’re on a plane? Ever wonder why you suddenly
crave a salty vegetable drink that you wouldn’t give a
second glance to on the ground? It’s the same reason you
think airline food is bland. Everything on board a plane is conspiring against enjoying the food. Scientists have studied this and it’s not just your imagination. First, the noise of the
engines dulls your ability to taste sweet things. Food scientists at Cornell
found out that sound levels at 85 dB, the same level
as airplane engines, reduce the effect of
sweetness on tastebuds. And that fan over your head is blowing air that is much drier than you’re
probably used to at home. Lower humidity means
you can’t smell as well. On top of that, as the plane
climbs to cruising altitude the pressure inside drops. You feel that when you pop your ears. That pressure drop affects
your sense of taste too. So next time you wonder whether to order the fish or the chicken, just order a Bloody
Mary with extra Tabasco and savor that serving of tasty tomato. Number six. Opening window shades for
landings and take-offs. I bet you thought the window
shades were installed on planes so you could sleep during long flights. But then the flight attendant
asks you to open the shade before take-off and when
they’re going to land. Ha! Why don’t they just
look out their own window? Yes, the shades are there
to give passengers control over their own environment, but safety takes priority over comfort. The most critical part of any flight is when it’s near the ground. Those windows aren’t just
there for sightseeing. If something happens to the power on board the only light besides the
illuminated arrows to the exits will come from the windows. And if someone has to
open an emergency exit then need to check outside
for debris, fire, water, or other hazards first. The Federal Aviation
Administration requires that planes can be evacuated within 90 seconds. So remember that window
shades work both ways and make sure yours is up
whenever taking off or landing. It will give you a great view before you’re too high to see the sights. And it might just help you
see your way to the door in an emergency. Number five. Winglets. Airplanes are always a tug of war between the thrust of the
engines and aerodynamic drag. One big source of drag is
something you might not see unless the temperature and
humidity are just right. Have you ever noticed little
swirls of mist trailing from the wingtips. Those are wingtip vortices. These little whirlwinds tug
at the tips of the wings as the smooth layer of
air flowing over the wing that gives it lift breaks away. Every tug is like a dog
pulling at your pant legs as you’re trying to walk. Slowing you down and wasting energy. On a plane, that translates into fuel. Those little winglets sticking
up at the end of the wing stop the vortex from forming which reduces drag and saves fuel, which saves you money. Number four. Side stick. Back in the day of the first planes pilots were known as stick and rudder men steering the plane by the
power of their arms and legs pushing on control cables. Those planes were much smaller and flew much slower than
your modern jet though. Commercial aircraft are
designed with electronic systems that take fingertip commands
from the flight deck to massive ailerons that would dwarf that first balsa wood plane at Kitty Hawk. These fly by wire systems are
controlled using a side stick that looks like the joystick
from a computer game, giving today’s pilots
an ergonomic replacement for battling that old steering column. The side sticks are
actually linked together so the pilot and co-pilot can
both roll and pitch the plane. Now don’t think they’re
battling each other like a video game. There is a button to choose
which pilot is in control. It’s got a few more buttons including a push to talk button
for talking on the radio and another for switching
the autopilot on or off. It has built in sensors
that allow the pilot or co-pilot to take immediate control by applying sufficient pressure. Don’t worry. It’s also connected to warning lights and alarms to notify the pilot when the autopilot is disengaged and which pilot has control. Number three. Bleed air system. While the Wright Brothers’
flier barely flew above the dunes at Kitty Hawk, today, jetliners fly higher
than the tallest mountains. Climbers talk about the death
zone above 3,000 meters. So when the plane reaches
cruising altitude, it has to keep enough pressure inside for people to stay alive. Without pressurized air you’d soon be sounding a little drunk before falling asleep as your
brain is deprived of oxygen. Now to fly at these rarefied heights part of the design of
any high flying airplane is how to keep the air flowing. One source of the pressurized
air on jet airliners is called the bleed air system. Bleed air comes from a side
port on one of the jet turbines. It is only a small percentage of the air blasting through the jet and is controlled to keep
a comfortable atmosphere in the cabin. The air is also heated as it
passes through the turbine. Otherwise the cabin would drop to the outside air temperature which is around minus 60 degrees Celsius at 10,000 meters cruising altitude. So that engine hanging off the wing isn’t just propelling you forward, it’s also supplying you
with enough air pressure so you and the flight crew won’t pass out. Number two. The eye level indicator on cockpit window. Pilots come in all sizes,
and just like your car, planes have adjustable seats for them. And just like you might
use the hood ornament as your reference when you
adjust your car seat and mirrors pilots have a reference
for pilots to make sure they’re in the right spot to
see their controls and outside. It’s called the eye level indicator and it’s just a small knob
on the cockpit window. While the pilot operates
the seat adjustment levers he or she keeps their eye
on the little red ball on the indicator until it
lines up with the white ball. So that 50% of their view
covers outside the window and 50% on their instruments inside. Not only that, this ensures
the pilots are positioned so all the controls and
switches are in the same place every time they sit down. This low-tech solution
is all that’s needed to make sure your pilot can
gauge approaching objects and reach the appropriate
controls to react without taking their eyes off the ball. Number one. The hole in your window. Since cabin pressure is so important you might think a hole in
your window is a good thing but if you look closely you’ll
see every window has one about the size of a strand of spaghetti. That hole let’s the
pressure between the cabin and the air between the panes equalize. Like your house windows
the layers insulate from the extreme cold
of high altitude flight. But unlike your house airplane
windows have to deal with large changes in pressure as
the air climbs and descends. There are actually three
layers in an airplane window. The inner pane is plastic and just protects the
glass from scratches. The middle pane has the
small hole that let’s the air between the panes expand and contract, but still provides insulation. If you didn’t have the middle pane you’d be looking through a layer of ice as the moisture in the cabin air condenses on the cold outside glass. That’s just a few things
you might not have known about airplanes. Do you know of any other
interesting features of planes? Let me know in the comment
section down below. Also please be sure to like
this video if you enjoyed it and subscribe, hitting that bell icon to
never miss another video. Thanks for watching.

Only registered users can comment.

  1. At the start of the video you said that all planes have a "motor", but gliders don't and they are still planes

  2. OMG thank you soooooo much!!! I always wondered why the lights flickered and in the first time I was flying, it scared me to oblivion because I thought there was something wrong somewhere. Then I just accepted it and got used to it, although I had no idea why it happened. Also, I always wondered what was the hole at the end of the plane and if the engines could run on the wings without actually making the thingies there turn, since I always heard the noise, but saw no movement 😀 you answered this all 😀

  3. You should probably investigate better in your content. Only Airbus uses a Sidestick on their planes. Boeing is still using the normal yoke. And before anyone asks Boeing uses Fly-by-wire too. Other than that, great video!

  4. The sidestick can be a problem because the pilot and co-pilot cannot see what each other is doing. That is what brought down a perfectly good Airbus over the Atlantic, I believe in 2009. The co-pilot held the plane in a nose high stall all the way from 40,000 feet down to below recovery altitude before the captain figured out what the moron was doing. By that time however they were already doomed. Those joystcks should be forced to move in unison ALWAYS like the traditional control columns and joysticks do.

  5. Bleed air is taken from the compressor, not the turbine.

    uncombusted fuel pumped into the cabin; yeck!

  6. I wasted my time watching this because i know all the things there and more. But hope it helped you learn something. The apu also helps with the hidrualic system. English isnt my first language so sorry for any bad spellings

  7. If the windows are so important then why do planes still have that stupid blanked out section next to the engine cowling? I have never heard of a plane killing a passenger by flinging a blade through the cabin walls. I see no advantage in safety as small pieces of metal can easily go through the blanked out area so why bother removing the window? American Airlines is quite paranoid about this. Their 777s almost all have a blanked out section next to the engine. The last two times I had to fly American, their planes had the window removed in that exact spot. Why does Air France's A380 NOT have a blank section next to the engine cowling? Lufthansa also doesn't do this. Is this just only on US airliners?

  8. Don’t they tell you to lower your window during take off and landing……..that’s what they do in my airline

  9. I literally laughed out loud when at 5:28 he’s talking about wing tip vortices and then shows an airplane dumping fuel

  10. The window shade one is wrong. Planes are most likely to crash during take off and landing, so of they do, you need to keep the shades open so whoever helps you, can easily see where u are

  11. Sorry, but the APU has nothing to do with the fire suppression system. It has it's own and is independent of the one for the engines.

  12. Tomato juice has another use; it's the best cure for airsickness I know. As a small kid, I was on a flight to Tehran when I became violently unwell. The Stewardess gave me a tomato juice and within seconds I was right as rain. I still drink the stuff on flights, but also? It's handy when you're 'on the sauce' to drink between 'proper' drinks. Gives you second wind, so to speak… btw, due to the effects of pressure etc, one alcoholic drink in the air hits you like three on the ground. I don't advise 'pissing it up' on a plane.

  13. An interesting one is the ashtray in the lavatory, which is still there even though smoking on planes has been illegal for decades. Some thinks it's because it would cost too much to design a new door without the ashtray and have it type-approved. While some thinks it's because the regulations requiring an ashtray are out of date.
    The actual reason they have ashtrays is that, if someone decides to break the law and have a smoke, it's MUCH better to discard it safely in the ashtray than in the trash where it can start a fire.

  14. i have never once, ever in my life… in all the hundreds of flights i've been on, had the craving to order tomato juice. Never even realized it was a thing.

  15. If you bleed air into the cabin right out of turbine and you will be roasted !

    Bleed air is actually taken out of low pressure compressor where the air has appropriate temperature and pressure , conditions roughly similar to those at ground level or above up to 9000 ft.

  16. Trash collected from international flight originated from outside the USA to USA has to be incinerated and not just thrown away. This is to prevent "bugs" or anything harmful from just being tossed in garbage.. When Air Force 1 fly's to a foreign country say in Africa jet fuel is flown in for the plane along with the Presidential limo aka"Beast" and the Marine Corp helicopters are put into C-5 Galaxy planes.. A lot of logistics..

  17. I always drink Bloody Mary's when flying. You never stated what the little hole in the window is for.

  18. Im sry to say, but the side stick is really only used on Airbus's (i think)
    and most planes use a yoke or stick as you say.

  19. Where in the world did you get the idea that the center of gravity is ideally over the center of the wing, or that the center of lift is the center of the wing? And how does moving passengers around in the fuselage that size reduce drag? As far as the sidestick replacing that "old steering column" – check out the 787 control yoke. Oh – and you can fly around all day long at 3000 metres without a pressurized cabin or supplemental oxygen. Entertaining video, but a bit of research would help.

  20. Really cool video, I gave it a like. Thanks so much for narrating this with a human voice instead of one of those annoying computer ones…

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