briefing about take off speeds v1, Vr, v2.

 

In most of the time if you watching videos or something related to the aviation pilot always say if they are about to take off just like

V1- rotate what that means actually, so let's get started.

This v1, Vr, v2 three speeds actually plays a major role during take off role. the speed definition either you are sitting  on twin engine Cessna and b747 are the same.

Ok, here is the definition of V1-

The speed beyond which the take off should be no longer aborted.

It actually means the if our plane has caught any trouble before take off then the pilot can immediately stop the plane. In the most of the cases the there is always emergency of engine failure. and low hydraulic pressure.

Here is one ex-

This aircraft a320 of easyJet has the problem with flight controlles. So the pilot decided to stop the aircraft immediately.

In such cases the use of reverse thrust is optional but the use of immediate Break system can caught fire also. So pilot has to slow down the aircraft in slowly manner.

The V1 of the aircraft has to be calculated before take off by considering the aircraft weight, runway length, wing flap setting, thrust reverser setting and much more.

This one off the major reason pilot in command put there hand on thrust levers. And after V1 they remove there are hand. 

If the snag is reported after the V1( speed is capable enough for take off) the pilot should go for the take off always otherwise it can lead to runway overshotting like this below.

**Another take off speed is Vr( rotate).-

The speed at which the pilot begins to apply control input to cause the aircraft pitch nose up, after leaving the ground.

This Vr also calculated before take off by considering the aircraft weight, environmental factor etc. At that point the lift on a wing is higher than the actual weight of aircraf on ground.

At that point the aircraft pitch rises and wing tip vortices/ turbulence begins to continue like this.

** Anthoer Take off speed is V2-

Take off saftey speed, the speed at which the aircraft climb safely with one engine inoperative.

The most of the airlines still operating V2 in there standard operating procedure.

Ok now imagine a situation if our aircraft in case of one engine failure that aircraft has to maintain height more than 35feet after V2. like below.

Ok,in 2008 there was b757 hit by the bird and failed it's engine when the aircraft is actually take off pilot decided to continue the flight with one engine by emergency operating procedure.

Then ICAO decided if the aircraft take from the ground i.e. at V2 speed then if the aircraft got in trouble then pilot has to continue the flight with the emergency procedures.