TWA757 From United States of America, joined Jul 2007, 179 posts, RR: 0
Reply 2, posted (15 years 4 months 2 weeks 6 days 20 hours ago) and read 2452 times:
During takeoff, V1 means that the aircraft is comitted to a takeoff, and there is not sufficient runway left to stop in case of an engine failure. Before V1, the pilot can close the throttles and abandon the takeoff. V2 means that the aircraft has cleared the ground, and that a posisitive rate of climb has been established. Also, VR is called at the rotation speed. So it goes: V1, VR, V2.
AAR90 From United States of America, joined Jan 2000, 3526 posts, RR: 44
Reply 3, posted (15 years 4 months 2 weeks 6 days 12 hours ago) and read 2434 times:
From my MD80 Performance Manual, FAR Section (with some minor deletions for brevity):
V1 is takeoff action speed. It is the speed at which the engine is assumed to fail (Vef) plus speed gained during the interval between engine failure and the instant the pilot recognizes and reacts to the engine failure.
VR is rotation speed. It cannot be slower than V1, 105% of Vmca, or a speed that results in a lift-off speed (Vlof) slower than Vmu plus a margin.
V2 is takeoff safety speed. It must not be slower than 1.2 Vs (stall speed), or 110% of Vmca.
So what's the above mean in english to pilots? Assume you are limited by pavement available.
If braking action has not started prior to V1, you're not gonna get it stopped on the remaining pavement. Hence the "action speed" name.
VR is speed at which rotation begins.
If engine failure occurs prior to V2 and you continue takeoff, climbout at V2 speed. If engine failure occurs faster than V2, procedures vary between aircraft and airlines, but basically you'll fly some speed at or above V2 during initial climb-out.
*NO CARRIER* -- A Naval Aviator's worst nightmare!