Aerospace Hydraulic Systems

the aircrafts operating manual will have simpified hyd system schematics..as far as operating pressure for the s/o valves , pressure relief valves , reservoir capaciticy. and type of fluid to be used. for the technician, you need the maintence manual.

how are you working on aircraft hyd systems without the benifit of having an FAA a & P license ??

We are an FAA license hydraulic repair shop and we make those components too... Sad to say that only few people( I am not sure though) maybe knew about the applications. I have some thoughts because I can analyze hydraulic components based on the principles and can even do some calculations. I just need to confirm some... because I like to do something that I really understand (fully).

i'm still confused.. assuming you have a landing gear door actuator on your bench, the application is known, the operating pressure is set , : what else could you be looking to understand?

Actuators are not a problem to me... what I am trying to find out is the reservoir/cooler assembly. This is a cylindrical reservoir attached and piped to an air cooled oil cooler(1 unit assembly). My question is... is this the main reservoir of the entire system?

with out knowing what type of AIRCRAFT...whos knows..but sticking the entire system reservoir on the actuator?..got a pic?..russian design?..

No, American... BTW the cylindrical reservoir(kind of like a double cylinder) has a piston inside that tries to keep the reservoir a little bit pressurized to avoid entrenched air(something like a pressurized reservoir). An LVDT monitors the reservoir volume.

sounds like a landing gear oleo to me...

My experience is with Vertol helicopters but it sounds like you're describing a utility hydraulic system accumulator. This is a 3000 psi system with a nitrogen pre-charge to keep air out of the system if the pressure bleeds down during non-use and to act as a shock absorber during system operation.

On Chinook helicopters this was also the utility hydraulic system reservoir and had a double action pump attached to it to manually charge up the system so we could use it to start the APU. Once the APU system got up to speed it recharged the accumulator and provided pressure for the system. Lots of other parts operated off that utility system, like brakes, power steering and rear ramp and ramp extension door.

The flight hydralic systems, though similar and also 3000 psi were separate in terms of reservoir and coolers.

If you can get hold of military -20 and -30 maintenance manuals for the aircraft you will get full descriptions of these systems.

Hope this helps,

Hooker

sounds a little like the tail -cargo door open closing actuator on a cl - 44 as well...but w/o knowing the a/c type.. never seen the ships sys reservoir exposed to potential FOD.. so i' d rule this out as being the complete ships primary hyd sys reservoir. the likelihood of this being placed downstream of any fuses placed between the reservoir and the component is my guess..enough fluid to give a couple of emergency actuations.. but it's just a guess w/o a photo or ship type

I did some units for probably smaller helicopters. It is just a small reservoir that is connected to "GTP pump"( i dont know what GTP means) suction and pressure then supplying the flight servo and utility systems. And it is very small... it means the pump is a variable(small displacement) and teed to the accumulator? The pump is just charging/recharging the accumulator? The pressure switch dictates the charging and recharging?