|Quoting KingFriday013 (Reply 8):|
and maybe someone can clarify about classics) they have a skid kinda thing but looks more like a hump, and it's fixed (does not extend/retract).
The B737-400 was the first. Not fitted or needed on the -300 or -500.
It is a fixed skid, attached by a crushable cylinder. I have never seen one crushed.
The Tristar had a retractable tail skid. As usual on the Tristar a clever device that extended using hydraulic power and then used the same fluid as an oleo device. It was meant to cushion the impact. But I have only seen one contact, and it nearly ripped the whole strut off the fuselage.