Originally Posted by
PETER01
Reading up on planes for quite a few years now, I think that reverse thrust panel is part of the Cold stream type system used on 777's and other jet engines. Of course there are many other types so you can now confidently tell someone the answer to the question if anyone ever asks you
"What's that blue thing/door doing go backwards on landing?"
https://en.wikipedia.org/wiki/Thrust_reversal
Yes the air being diverted forward for reverse thrust on a high bypass turbofan will be the cold bypass air - i.e. the air which doesn't go through the core of the engine and isn't part of the combustion process.
I have heard the same as
Globaliser that reverse thrust is not included in landing performance calculations. Also often unless it's a short runway reversers may not be used or are only used at idle level rather than at maximum..