Guy on the right doesn’t look like he has a free hand to shoot, plus he’s on what’s basically a portable version of one of the Mortal Kombat pit levels
If I had to guess at a glance, the pipe-looking things are to guard the rotor against striking the ground. If you mean the things hanging off them, I’d guess that they’re inflatated bladders to spread out the time of impact when landing.
EDIT: Rotor guy is apparently flying a de Lackner HZ-1 Aerocycle, and yeah, that’s apparently what they’re for:
The aircraft’s landing gear consisted of airbags at the end of each arm of the frame along with a large rubber float in the middle, providing amphibious capability,[5] although this arrangement was later replaced by a pair of conventional helicopter-type skids.[8]
According the the article linked it didn’t even pass the testing phase, because surprise-surprise guys kept crashing. That was the 50’s in peacetime, and the whole thing probably started because helicopters were the hype of the era and there was a lot of funding.
Glancing at Wikipedia, all hydraulic shock absorbers seem to use pneumatic compression. The oil is mostly a mechanical linkage, lubricant, and heat sink. I expect a liquid-only design could work, in a coilover monotube, but the spring would be taking all the compression, while the loose piston moving through oil simply resists change and smooths out the motion. There’s just not much reason to avoid adding a floating piston and some gas at the bottom of that. Underwater applications, maybe.
It is done by allowing fluid to flow through passages between chambers separated with a piston. Your car’s shocks and struts work the same way. There are also ones with external reservoir that may allow for more travel or that can be pressurized to alter resistance.
The fluid pushes on a reservoir of nitrogen that keeps the plane from bottoming out. It is a progressive pressure system, so it gets harder to move the more force is applied.
Ah! Yes, you didn’t mention the pneumatic component. I thought you just meant between two bodies of oil, which would only provide damping and some added moment.
The one on the right looks like it might plausibly be able to fly under extremely optimal conditions. The one on the left is a complete shitpost of an idea.