today I'll be answering another very important question

Joe, in many videos I can hear the pilots say this while performing a takeoff

"V1"

"Rotate"

"V2"

So what is all these ?

These three speeds play a major part during takeoff roll

so let's look at them in closer detail

Okay first to know this again is a basic introduction about takeoff speeds

The speeds we're talking about today will always follow in that order:

V1

Vr or rotate

and V2

and these speed apply no matter if you sit in a little twin engine Cessna or a Boeing 747

The speed definition is for either plane the same

Okay let's look at V1

Imagine yourself in the cockpit of your plane and apply takeoff thrust to your engine

and as you gently accelerate down the runway

you come to a point where you reach V1

So by the book

V1 is defined as the speed beyond which the takeoff should no longer be aborted

Meaning that in case you experience any trouble with your plane before reaching V1

The classic example would be an engine failure, you would immediately abort your takeoff

and would apply all necessary matters to bring the aircraft to a stop

Although the use of full reverse thrust is not mandatory

I'll come back to that in a second

So in this video here this Airbus A319 applied takeoff thrust

and due to a technical malfunction had to abort to takeoff prior reaching V1

Just listen to the sound of the engines

Now the autobrake system comes active and immediately

applies pressure to the brake cylinders

the ground spoilers are deployed so are the reversers

and the plane and crew come to a safe stop on the runway

The smoke you can see here is coming from the brakes

as they are the primary force slowing down the aircraft

Now let's say there were to be an engine failure

so one of the reverses would be inoperative

and therefore full reverse thrust can't be added to the braking measures as mentioned before

Because V1 needs to be calculated prior every takeoff

taking into acount airplane weight, runway length

wing flaps setting, engine thrust used, runway surface contamination

and environmental factors and even the aircraft brakes

to assure yourself that any given failure prior reaching V1

you'll have enough runway leftover to come to a complete stop

Now if it's just a minor failure you can continue to takeoff

but that's a whole another video about the stop or go decision making

and besides that this is one of the reasons why the captain

keeps his hand on the throttle until the pilot monitoring calls out V1

and then he moves his hands away from the throttle

to not inadvertently abort the takeoff after V1 in case of a failure

So in case you experience any serious malfunction after V1

You'll have to commit yourself to continue the takeoff

otherwise a takeoff abort will lead to a runway overrun

and could severely damage your plane

Next speed to call out is Vr or better known as Rotate

By the book, Vr is defined as

the speed at which the pilot begins to apply control inputs

to cause the aircraft nose to pitch up

after which it will leave the ground

Again Vr is also calculated prior takeoff in accordance

with aircraft weight, environmental facts etc.

And it's the point where the generated lift over the wings

becomes higher than the aircraft weight keeping it on the ground

Easiest way to memorize Vr is the point where the nose will leave the ground

and vortexes are created at the wing tips which rotate behind the aircraft

And the point where the main gear leaves the ground

that's the point where you have reached Vlof, the liftoff speed

Next speed is V2

Now some airlines still have the standard operating procedures to call out V2

Please comment below if you fly with such airline it would be great to know

Okay, again, by the book

V2 is defined as takeoff safety speed, the speed at which the aircraft

may safely climb with one engine inoperative

Okay let's go back to all engines operatives

Now imagine all is normal

you takeoff and someone would measure your height

above ground at the end of the runway like in this picture here

The height measured is the so-called screen height

Now let's go back to V2 and our engine failure situation

In case one engine fails you need to maintain the speed of V2

in order to leave the runway at a screen height of 35 feet or higher

and maintain the climb rate at V2

to be clear of obstacles in the departure sector

and you should be able to maintain that speed and climb rate

until reaching one engine out acceleration altitude

where you then gain speed and retract the slats and flaps

and continue with the emergency procedures

This video here is a great example for V2

As you can see the Boeing 757 hit a bird just after liftoff

and the engine was severely damaged

The pilots maintained V2 and the respective climb rate

retracted the gear and performed all the necessary emergency procedures

flew a traffic pattern and landed the airplane safely

The reasons therefore is when local authorities design departure routes

including obstacle avoidance procedures

They predict that your aircraft is at least capable of maintaining V2 with one engine

and the gear retracted and guarantee obstacle collision protection

But trust me there's a little bit more to it so this was just a basic explanation of V2

Okay I hope you enjoyed this short little video about the takeoff speeds

next week's video will be all you need to know about ram air turbines

so stay tuned for that and tomorrow I will be uploading

my 100,000 followers thank you video

so please make sure to check that out

because I need your feedback on that video you'll see why

Thanks for your time, see you next Thursday

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All the best your Captain Joe