Benjamin Gawert wrote:

Well, the difference is not *that* huge. The only thing that is done
in the F-35 is to move the complete display part from the HUD to the
HMDS (which IMHO does make sense, I wonder why this hasn't been done
before already).

It all got started in South Africa of all places; they hooked the
tracking systems of their Kukri IR AAMs into the helmet so that the
pilot only had to look at the target to slew the optics of the missiles
around and let them lock onto it.
From that point forward, it was simply a matter of getting the mass of
the helmet down to the point where it wouldn't snap the pilot's neck if
he had to eject, while adding more and more to its capabilities.
I'm sure our Huey gunner's helmets with their automated gun-slewing
mechanisms also played a big part in the overall history; but you don't
pull high Gs in a Huey unless you crash.

Pat