BizJet,
Interesting thoughts, but I’m not convinced. I’ve seen 727 drag curves, and if I remember correctly, deploying even a bit of flap increased the value of minimum drag, not decreased it. I can’t think other aircraft would be any different.
I’d expect Smokey will jump in shortly. I think you bated him a bit with your response to his post..
But I’m not happy with your citation data:
1. Does the performance preamble anywhere say the final segment gradient speed is for best gradient? Because, as you know, final segment speed requires not ** LESS ** than 1.5 % gradient. Hence the manufacturer can choose any speed that meets this requirement.
2. I just can’t believe flaps 15 gives better second segment climb than clean. Take a look at the flaps 15 max take off weight for second segment limits (2.4%) and compare it to flaps up. This will tell us which configuration has the lesser drag. Can you get back to me on that?
And as for the “hot and high” situation reverting to the intuitive, I can’t see why minimum drag has anything to do with pressure altitude or temperature, except when compressibility comes into play. The reduced thrust available AS SPEED INCREASES occurs both when cold and low, as well as hot and high.
Merry Xmas to all
Hawk