TOPCAT and choosing a derated take-off

[Guest kelvind80]

I've recently downloaded this programme. And it's very good, I must say!I've just got one question with it. Once I've put in all my data, and received back some computed assumed temps for derated thrust take-offs, which one do I choose from the list?There's a list of 10-20 assumed temps, so I'm wanting to know how to arrive at a good assumed temperature to use?Thanks,Kelvin

[jordanal 70]

I usually choose the derate that gives me around 600 to 1000 ft of room before running out of concrete. The slower spool-up and longer rotate times really make for some nice smooth takeoffs.Regards,