Yes, looking at Vilas’ link again I see that the thrust loss between V1 and Vr at 15C is 4027 lbs while that at 38C is 3998 lbs. That’s a difference of only 29 lbs. That’s not enough to make any significant change to climb gradient. But it is curious that the thrust loss is greatest at the lower of the two temperatures.
The figures in the link also look a bit dubious in that at both temperatures the thrust decreases a lot between V1 and Vr (by 4022 lbs at 38C and by 4042 lbs at 15C), then these losses are almost completely recovered between Vr and V2. Given that the differences between V1 and Vr are only 2 knots and the difference between Vr and V2 are only 7 knots, these effects look very strange.
Last edited by keith williams; 4th Nov 2014 at 19:34.