Yeah and when you want to get airborne despite hot, high and heavy, this is how to.
- Flaps up during the runway backtrack.
As you turn around the aircraft, increase power so the aeroplane turns with as much speed it can take during the turn.
- Start rolling.
Once the speed has built up enough, select full flaps and.... off you are airborne.
Flaps retraction to be done using your fine touch veeery slowly until they are up and you have sufficient speed to climb away.
If you have mountain experience, that's how you would do it there as well.