Dear friends and followers, welcome back to my channel and to a video I was so eager to make for you guys
I am sure many of you have seen these panels being
Extended during landing and maybe during flight we'll be looking at the different types of these panels and what the space shuttle and the bugatti
Veyron have table to do with it. So this video is packed with great information. So let's get started
If you've been sitting in a window seat close to the wings
I'm sure you have seen these panels being extended just after the plane has touched down
What you see here are the flight control spoilers well to be exact at this moment
They act as the ground spoilers, but I'll come back to that in a minute
Now the flight control spoilers have three different purposes
We're going to have to look at to get a better understanding on most jet airliners
The flight control spoilers are operated hydraulically as the aerodynamic loads onto these spoilers can be very high
Plus most of the planes have more than one hydraulic system backing each other up in case one of them fails
So we'll take my beloved a320 as an example today
If we look at the wing from a top perspective
You see the ailerons close to the wingtip on either side which act as the primary flight controls rolling the plane along its longitudinal
axis now for your interest each aileron is
Operated by two hydraulic actuators one powered by the blue and one by the green hydraulic system
Making the system very redundant in case one other system fails next to the ailerons. You see these panels
Those are the flight controls spoilers acting as a secondary flight control surface
Which can be deployed manually by the pilot or under given circumstances
they extend automatically each flight control panel is
Operated by one hydraulic actuator and each hydraulic system is taking care of at least one spoiler panel on each side
So if one system fails, they're matching spoiler on the other side of the wing will fail as well to avoid an assembly
but you get my point about redundancy right now bear with me because we're going into a little
Aerodynamics lesson right here now
So let's say we were to be flying at high speed and you want to make a turn to the left
So the aileron on the right-hand wing will go down
Increasing the lift as the wing can burn out just got longer
Similar to the flaps operation and at the same time the aileron than the left-hand wing goes up
Decreasing lift now picture this cardboard as the upgoing wing now as I said
We're flying at high speeds only minor
deflection in the aileron will cause a lot of stress on the wing creating this nasty twisting and bending moment as
Now there's more lift generated just at this part of the wing. This will go up first, right? So bend the wing now to
counteract that planes with large wing spans such as the Boeing triple7 for example have
inboard ailerons which are used during high speed to reduce the stress on the wing and for low speeds the
Output ailerons are used or a combination of both now in this video here
You can see the outboard ailerons are barely deflecting compared to the inboard ailerons. This is all great to know Joe
But what about the flight control spoilers?
So here we are again and we are in a left-hand roll or turn
So the right-hand wing goes up the left-hand wing goes down
But in actual fact the plane has the tendency to do this
Meaning the nose points to the right so it's an opposite. Yaw moment
but at the same time it is rolling so you get this left turn but it is sort of a
Smearing shearing turn so better known as the adverse aileron your now to counteract this adverse
Yaw moment
You could just increase the drag on the downgoing wing and that's where the flight control spoilers come to action
so by increasing the drag on the downgoing wing the yawing moment is reduced and the rolling moment is
Increased and that's one of the reasons why smaller Cessnas?
Etc have to use the rudder to do a control turn as they don't have roll spoilers now to sum
One or more spoiler panels will deflect in harmony with the aileron on the associated wing to enhance roll
Authority and response I admit it needs some time to understand all of this not even to mention the induced and parasite drag
Etc
But I'll be very happy to do a very detailed video about this topic including even the droop the ailerons and much much more
I'll post a comment about it
And if that gets at least 2000 thumbs up, I'll be very happy to create that video for you guys
Does that sound like a plan?
Now the second purpose is the speed brake function
Now you've all tested the speed brake function as a kid
Remember when sitting in your parents car and you were holding out your hand out of the window and you did that
You tilted your hand and the passing air pushed your hand rear woods. Now you hand acted as a speed brake
Well, it didn't really slow down your dad's car, but imagine using a much larger surface
So if you move the speed brake control lever in the cockpit
It creates that tilting moment you do with your hand and it deflects the spoilers two
Three and four, once you extend the speed brakes, they create drag and decrease the lift over the wings
This automatically will lead to a pitch down momentum
so you will pull back on the side stick or yoke and
therefore reduces the speed now by far this is the best way to quickly kill speed during level flight and
You will feel and hear that as a pilot or passenger as the deflection
Causes the air to become very turbulent and passes over the horizontal stabilizer
Which will start to shake the plane as if you were flying through minor turbulence
Besides that it creates this really cool howling sound
I always have to smile about noise abatement procedures airports have put in place due to sensitive residential areas
If I extend a speed breaks it is as loud as I'll be hurting by with 300 knots
Now just to go back to the rolling purpose of the flight control spoilers
Let's say you were to be in a turn and would have to extend the speed breaks for whatever reason the spoiler elevator
Computer will give the role function higher
Priority over the speed brake function and deflect the spoilers accordingly
so the speed brakes are a
Fantastic help to reduce the airplane speed or increase the vertical speed during descent and they come in all sorts of shapes and sizes
Just to point out a few really cool ones. This tiny one right here is an add-on
You can have installed on a Mooney works fully electrical and doubles the airplanes drag and descent rate
Also most military jets come with a distinctive speed break or as they call it an air brake system
here you see the massive air brake on an
f15 slowing her down just prior to touchdown and this is what a speed brake hand look like on an f-16 and
This is one of the more extraordinary ones mounted on the tail cone of the British Aerospace Avro one four six
Pilots told me it's very effective, but it definitely has a weird look to it
But even cooler is the speed brake on the space shuttle Discovery if you closely monitor the tail fin rather
You can see it is split in half and extends to either side if that ain't cool. I don't know
What is now the third and most?
noticeable action of the flight control spoilers is the ground for the function as
The plane comes in for landing and touches down all spoiler panels are extended to their maximum angle
And by the way, this is the only time spoiler number one on the episode twenty actually gets to work
It has only a ground spoiler function
So the primary purpose of the ground spoilers is to maximize the will brake
Efficiency by dumping the lift generated over the wing and at the same time
forcing and
Pressing the full weight of the aircraft onto the landing gear and to come back to our hand outside of the car scenario it also
helps slowing down the aircraft by creating aerodynamic drag very similar to the air brake on the bugatti veyron it
Pushes the weight of the car towards the ground so that the rear brakes become more effective and adds
Aerodynamic drag now depending upon aircraft type the ground spoiler extension works fully automatic in most planes nowadays now
Deployment is most often
triggered by weight on wheels and the throttle lever position in idle all reverse a door opening other aircraft may require the pilot to
Manually select the ground spoilers after landing, but they have become a very rare sight now doing the research for this video
I couldn't find a single play where you need to extend and manually but they're still out there
So, please comment below if you actually fight such a plane
I remember playing around with the ground sport as it stood got airport as wrongly 2-5 has an uphill slope
we very often didn't even use the auto brake function nor reverses and just
coasted uphill and
then we disarmed the ground sport is a few seconds after touchdown and you could literally feel the plane being sort of let loose and
Always reach taxi speed at the last exit that was a lot of fun and we save lot of brake. We're on fuel
So the next time you see the speed brakes being deployed
Think about your hand being in an Airstream as you hold it out of the window in your car. That's it for today
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See you next week all the best your captain joke