av8r76-
You got quite a discussion started here. Very simply, after the min speeds are met, V1 will increase as weight increases. But as you see, there are many other factors. Is "balanced field" clear now?
V1 MIN will decrease with higher temperatures, V1 BASIC will increase due to the lesser thrust to accelerate to Vr.
streamline-
V2 doesn't necessarily = 1.2 Vs. AT lighter weights, it is often driven by the Vmca requirement. V2 can't be any LESS than 1.2 Vs.
The spread between V1 and Vr will vary signifigantly with density altitude. For example, in my a/c with a t/o weight of 300,000 lbs, at sea level the spread is 14 kts. At 7000 feet the spread is only 8 kts.
All the t/o performance charts I've dealt with use IAS and CAS. What charts are you referring to in mentioning EAS?
twistedenginestarter-
For purposes of this discussion, can we agree that derate and assumed temperature procedures accomplish the same thing? It's the takeoff weight that is reduced by the runway requirement if using assumed/derate. The V1 speed won't change all that much.
If using reduce/derate and I lose one on t/o, I know that all my obstacle and climb requirements have been met. I also have the added performance of the engines really eating colder air than the assumed, so my performance will be better than planned. I'm not an advocate of pushing up the power to get a more "decent" climbout. Why stress the remaining engine(s) at red-line if I've already cleared the obstacles? Once I'm past the obstacles, I'd rather have speed than altitude anyway.
(I know that will take some flak).
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[This message has been edited by quid (edited 30 September 2000).]