If I would want to create a visible wingtip vortices on a given plane, what are the conditions that I would need to meet?
Wikipedia gives the following explanation:
The air cools adiabatically in the center of the turbulence at the end of the wing, as this is an area of particularly low pressure. The air often reaches temperatures below the dew point temperature, which leads to the condensation of the water in the air to water vapor / mist and a vortex is visible. When approaching with moisture-saturated air, you can see such vortex heads even at several points on each wing, in addition to the outer edge often, for example, at the respective end of the buoyancy aids (flaps).
Now to the question: What conditions would be needed the have them built on a oltimer plane like the Douglas SBD Dauntless or the Douglas TBD Devastator?
I would assume Ideal conditions would be a tropical climate near the Ocean with a high humidity near ground level.