dear friends and followers welcome back
to my channel today I'll be answering
another very important question Joe in
many videos I can hear the pilots say
this while performing a take-off thank
you so what is all this these three
speeds play a major part during takeoff
roll so let's look at them in closer
detail ok 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 speeds
apply no matter if you're sitting in a
little twin-engine Cessna or a Boeing
747 the speed definition is for either
playing the same ok let's look at v1
imagine yourself in the cockpit of your
plane and applying 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
we want the classic example will 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 1819 applied take
off' rust and due to a technical
malfunction had to abort to take off
prior reaching v12
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the brake system comes active and
immediately applies pressure to the
brake cylinders the ground spoilers are
deployed so are the reverses and the
plane and cool 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 account airplane
weight runway length wing flap 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
left over to come to a complete stop now
if it's just a minor failure you can
continue the takeoff but that's a whole
nother video about the stop or go
decision-making and besides that this is
one of the reasons why the captain keeps
his hands 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 would have to
commit yourself to continue to take off
otherwise a takeoff aboard will lead to
a runway overrun and could severely
damage your plane next be 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 to
takeoff in accordance with aircraft
weight environmental factors etc and
it's the point where the generated lifts
over the wings becomes higher than the
aircraft weight keeping it on the ground
easiest way to memorize
Villar is the point where the nose will
leave the ground and vortexes are
created at the wingtips which rotate
behind the aircraft and the point where
the main gear leaves the ground that's
the point where you have reached V loss
the liftoff speed next speed is v2 now
some airliners still have the standard
operating procedures to call out v2
please comment below if you fly for such
airline it would be great to know ok
again by the book v2 is defined as take
off safety speed the speed at which the
aircraft may safely climb with one
engine inoperative
ok let's go back to all engines
operative now imagine all is normal you
take off 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 get 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 reason 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
guarantee obstacle collision protection
but trust me there's a little bit more
serious so this was just a basic
explanation of v2 okay I hope you
enjoyed this short little video about
the take-off speeds
next week's video will be all you need
to know about the ram air turbine so
stay tuned for that
and tomorrow I'll be uploading my
100,000 follower 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 make sure to
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all the best
your captain Joe
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