This is what I know:
- $V_1$ is the takeoff airspeed after which the aircraft must take off, no matter what happens after $V_1$ has been reached. That's the easy part (I think).
- $V_R$ is the rotation airspeed
Are there any other $V$-speeds?
What I'm specifically curious about:
- Is $V_1$ related to runway length?
- Is there an absolute maximum $V_1$ for each aircraft type? If so, can it vary based on conditions (takeoff weight, density altitude, etc.)
- Are there circumstances where $V_1$ is higher than $V_R$? If so, does that mean that $V_1$ is never called on a normal takeoff? (this is the case for most light aircraft, but I guess the whole concept is not applicable in that case)
- What exactly is $V_2$?
- Is there a $V_3$? (and so on)
Anything else worth knowing about $V$-speeds?