yeah they're eating me alive over on TikTok, but I'm used to it because I respect the knowledge. I was just writing a quick catchy title, knowing it might get me into hot water. So here we are!
Spoiler and reverse thrust are both a type of air braking mechanisms/systems. Functionally speaking, OP isn't wrong. Both systems enables the aircraft to functionally "brake" it self by redirecting the airflow, inducing drag, hence the slowdown.
Changing pitch of the propeller is how turboprops brake as well. On the ground if you've ridden in something like a dash 8 or even a king air you hear a frequent back and forth "roaring" noise when the prop changes pitch to go into "beta range" as it's called
I would critique the use of the term “air brake”. Because reverse thrust is the correct term. Air brakes are on the wings and can be deployed to rapidly slow the airliner in flight. Thrust reverse on the engines can only be enabled once landing gear sensors have told the flight system that the aircraft is on the runway. Different engines have different thrust reverser systems also, what’s described here is a modern, high bypass turbofan, such as a GE 90. But other engines can have pivoting door type. Or even older, low bypass engines which have vanes right at the back to redirect the gas flow from the engine, hot and cold. I just needed to correct a little bit of miss-info here, I’m sorry.
Just so I'm understanding this right, the air coming from the sides of the engine is whats slowing the plane down? Like is the air coming from the sides creating drag?
Most of the thrust produced by commercial jet engines is what's called by-pass air. It's air that does NOT go through the core of the engine; there is no fuel dumped into it, no combustion done on it, nor is it used for anything other than thrust generation (aside from a little bleed taken off for use internal to the plane). It's this air that is redirected forward by the thrust reversers, helping to slow the plane down just after touching down.
The air coming from the sides is also slightly angled forward 😊 and I would imagine the friction picked up from the mechanism (forcing air in the turbine, letting it slam against the angled flaps, then spun around to fire out the sides) helps as well
For those wondering. The thrust produced by the N2 or core of the motor, is not significant enough to propel the aircraft while the N1 fan is reversing.
Sometimes in tail mountes engines it's possible, but wing mounted engines will kick up a lot of dust and particles which could fly into the engine, plus it isn't particularily pleasant for anything on the ground.
Some military planes like C130 and C17 do it. But generally it's bad because it pushes debris into the engine. They turn off thrust reverse when they get below a certain speed for that reason.
Making the engine fan spinning the opposite direction will cost a hell load of money to do so, the equipments and the engine must be strong enough to resist the force on the engine fan
Nope, there's way too much rotational inertia to overcome to stop such an engine, and restarting isn't quick either. Just like your car's engine doesn't spin the other way around when reversing, it makes a lot more sense to just redirect bypass air in a turbofan engine. Also, there's no way to brake the engine shafts, take a look at how long they take to spool down after turning the engines off. And you usually get two shafts running in opposite directions on those engines. And the blades on the rotors and stators are designed to generate thrust one way only. Designing such an engine to be able to work "backwards" would be very hard and very inefficient.
This is ABSOLUTELY WRONG. Reverse thrust is used daily by all airlines. Please don't comment on things you have no idea of. Turbine blades are in the rear of the engine. You don't even know that the COMPRESSOR blades are in the front and would therefore be subject to FOD. Except that reversers are retracted while the aircraft is still rolling forward thereby stopping FOD. A typical Rolls Royce Trent is designed to use reverse thrust thousands of times between shop visits.
Is this why there’s a big roaring sound when slowing down on runways after touchdown?
yes
yes
yes
yes
Yes
Awesome! I was looking for an explanation on how "sliding" reverse thrusters work, and this visualization is perfect!
You are truly amazing person. Your capabilities to make things easy to learn is unique!! Thank you!! ❤
There is a massive difference between air brakes and thrust reversers.
yeah they're eating me alive over on TikTok, but I'm used to it because I respect the knowledge. I was just writing a quick catchy title, knowing it might get me into hot water. So here we are!
@@animagraffs I figured, I just commented that so others don’t get confused, you don’t usually get stuff wrong.
I mean, he didn't get it wrong. Unless he changed the title. He put "air brakes" in quotes implying it was not correct.
Spoiler and reverse thrust are both a type of air braking mechanisms/systems. Functionally speaking, OP isn't wrong. Both systems enables the aircraft to functionally "brake" it self by redirecting the airflow, inducing drag, hence the slowdown.
Understood.
Interesting - I always assumed they changed the pitch on the turbines or something - very cool to see how it actually works!
Changing pitch of the propeller is how turboprops brake as well. On the ground if you've ridden in something like a dash 8 or even a king air you hear a frequent back and forth "roaring" noise when the prop changes pitch to go into "beta range" as it's called
Once the blocker doors close, the air travels through a set of cascade vanes to direct the thrust forward. Good job though!
I always wondered how that worked thanks : )
I would critique the use of the term “air brake”. Because reverse thrust is the correct term. Air brakes are on the wings and can be deployed to rapidly slow the airliner in flight. Thrust reverse on the engines can only be enabled once landing gear sensors have told the flight system that the aircraft is on the runway. Different engines have different thrust reverser systems also, what’s described here is a modern, high bypass turbofan, such as a GE 90. But other engines can have pivoting door type. Or even older, low bypass engines which have vanes right at the back to redirect the gas flow from the engine, hot and cold. I just needed to correct a little bit of miss-info here, I’m sorry.
Air brakes and thrust reversers are 2 separate things. This is talking about just thrust reversers not air brakes
Isn’t the same effect, if just turning off the engine or its shafts residual rotation ???
No, using reversers is directing airflow, and therefore thrust, forward.
Awesome.
Reversers are not to slow the plane down, its to make the brake cooling time lower then when you are not using reverse thrust.
It is very much also used to slow the plane down. Huge difference between no reverse and full reverse on a landing.
Awesome
Just so I'm understanding this right, the air coming from the sides of the engine is whats slowing the plane down? Like is the air coming from the sides creating drag?
None, is creating thrust in the opposite direction
Most of the thrust produced by commercial jet engines is what's called by-pass air. It's air that does NOT go through the core of the engine; there is no fuel dumped into it, no combustion done on it, nor is it used for anything other than thrust generation (aside from a little bleed taken off for use internal to the plane). It's this air that is redirected forward by the thrust reversers, helping to slow the plane down just after touching down.
The air coming from the sides is also slightly angled forward 😊 and I would imagine the friction picked up from the mechanism (forcing air in the turbine, letting it slam against the angled flaps, then spun around to fire out the sides) helps as well
For those wondering. The thrust produced by the N2 or core of the motor, is not significant enough to propel the aircraft while the N1 fan is reversing.
@@djmorin8745 that checks out! I assume on lower bypass types, such as old turbojets, the bucket type reversers do block that core thrust then
@@hotshot4512 typically clamshell and not target or cascade “cold stream”
Why can we use reverse thirst for pushback process
Because Pilots can't see what's behind the airplane
Sometimes in tail mountes engines it's possible, but wing mounted engines will kick up a lot of dust and particles which could fly into the engine, plus it isn't particularily pleasant for anything on the ground.
Not fuel efficiencnt for pushbacks
Some military planes like C130 and C17 do it. But generally it's bad because it pushes debris into the engine. They turn off thrust reverse when they get below a certain speed for that reason.
It also may cause a compressor stall and ingest FOD into the engine, both of which cause costly damage
Oo
This design is for Boeing’s aircraft, and Airbus has flaps that come out to deflect it
This is from the A220 Airbus design, actually.
Oh my bad, good video tho
Foggy plane windows
0:05
Not what I thought reversed thrust was, I thought the fans just spun other direction 🤔
Making the engine fan spinning the opposite direction will cost a hell load of money to do so, the equipments and the engine must be strong enough to resist the force on the engine fan
Nope, there's way too much rotational inertia to overcome to stop such an engine, and restarting isn't quick either. Just like your car's engine doesn't spin the other way around when reversing, it makes a lot more sense to just redirect bypass air in a turbofan engine.
Also, there's no way to brake the engine shafts, take a look at how long they take to spool down after turning the engines off. And you usually get two shafts running in opposite directions on those engines. And the blades on the rotors and stators are designed to generate thrust one way only. Designing such an engine to be able to work "backwards" would be very hard and very inefficient.
Compressors can’t be reversed, combustion will stop, hot air will come out through propeller, everything will be destroyed.
This throws runway debris into the engine, brakes are cheaper than turbine blades, most airlines now have policies in place to prevent using them.
Wrong
This is ABSOLUTELY WRONG. Reverse thrust is used daily by all airlines. Please don't comment on things you have no idea of. Turbine blades are in the rear of the engine. You don't even know that the COMPRESSOR blades are in the front and would therefore be subject to FOD. Except that reversers are retracted while the aircraft is still rolling forward thereby stopping FOD. A typical Rolls Royce Trent is designed to use reverse thrust thousands of times between shop visits.
This happen in touchdown and Speed Breakup level 🎚️