I have seen different videos and people do these things in different ways and I wanted to make sure I understand the proper speeds to use.

 

Prior to takeoff I have seen people setting their speed to the v2 speed on the MCP, while others have set the MCP speed to v2+20. Is this influenced by the wind at the time of takeoff like the vref speed on landing? 

 

In determining vref the speed should be set to vref +5 in calm winds and it is my understanding that the fmc number is the vref number +5. I get a bit confused though in the calculations when it gets windy with gusts. In a situation where the wind is 20kts my understanding is that in that situation the speed would be vref +10 (1/2 of the wind speed). Where I get confused is when there are also gusts. For example, let's say the winds are 10kts with gusts up to 30. Would that be vref + 20 or something else? Would the calculations be different if I had a tail or cross wind vs a head wind? Sorry for the basic questions. 

MCP should be set to v2 for takeoff.

I have seen different videos and people do these things in different ways and I wanted to make sure I understand the proper speeds to use.

 

Prior to takeoff I have seen people setting their speed to the v2 speed on the MCP, while others have set the MCP speed to v2+20. Is this influenced by the wind at the time of takeoff like the vref speed on landing?

 

In determining vref the speed should be set to vref +5 in calm winds and it is my understanding that the fmc number is the vref number +5. I get a bit confused though in the calculations when it gets windy with gusts. In a situation where the wind is 20kts my understanding is that in that situation the speed would be vref +10 (1/2 of the wind speed). Where I get confused is when there are also gusts. For example, let's say the winds are 10kts with gusts up to 30. Would that be vref + 20 or something else? Would the calculations be different if I had a tail or cross wind vs a head wind? Sorry for the basic questions.

Half of the steady headwind and all if the gust. No more than 20 knot over Vref.