(a) V1/VR can be made whatever you like within AFM permitted, and specific runway environment, numbers, the higher end limit being V1=VR, ie V1/VR=1.00. . .. .Generally, presuming adequate ASDA, V1 needs to be pushed higher if you . .. .(i) have obstacle problems .. to minimise the TODR . .. .(ii) are going for an overspeed (increased performance) V2 schedule ... to maximise WAT-limited RTOW and/or improve distant obstacle performance .. again by controlling the TODR.. .. .(b) If the intent is to push V1 up, stopway helps a little bit, clearway is not relevant. Clearway becomes of use for runways with reduced ASDA where a reduced V1 can be contained within the ASDA while the clearway extension helps the TODR figures at the lower V1. The TOR restrictions generally limit the utility of clearway.. .. .(c) Sometimes the intention is to go the other way and push the V1 down .. for instance on wet runways or where the overrun is undesirably hazardous ... a matter for company policy and whether the flight standards people carry more weight than the back office bean counters. A problem here is to consider the effect of crosswind on the Vmcg (ie min V1), a matter which the AFM ignores and is not required to be considered (unless the flight standards people prefer to operate conservatively).. .. .Where some pilots get confused is in regard to ill-explained rules of thumb which one sees from time to time for balanced field operations ... generally where some of the related assumptions and restrictions are not well explained. . .. .Most of the time the performance engineer wants to go unbalanced to maximise the scheduled RTOW. The problem which then arises is that pilots often tend to believe the RTOW figures at face value without thinking about THIS particular takeoff and its particular problems on a takeoff by takeoff basis ... a sensible part of the pretakeoff emergency briefing.. .. .There have been numerous discussions on this subject and it would be worth while doing a search and reviewing some of these.. . . . <small>[ 30 March 2002, 07:58: Message edited by: john_tullamarine ]</small>