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.
Depends on the aircraft if it has gas or hydraulic shock absorbers. Some lightweight aircraft just have torsion based shock absorption.
How would hydraulic ones work? The entire concept there is that liquids are almost incompressible.
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.
Ah! That makes sense.
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.
You’d still need some kind of restoring force. Visibly, some cars use metal springs for at least part of that.
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.