Interesting to know that some aircraft have a 5th segment. What would be the difference then?
Only seen the one I can recall at the moment (AW650 Argosy - Britain's Queen of the Skies) .. allowed for a final acceleration to enroute climb.
Pugachev Cobra
Much better diagram .. however, one trusts that the originator intends the aircraft to be several seconds off the ground before selecting wheels up ?
The original question is interesting but has no definitive answer .. very much a case of "it depends" ...