×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Generic Aircraft hydraulics (LOW SYS PX, VIBRATONS THROUGHT AIRFRAME)

Generic Aircraft hydraulics (LOW SYS PX, VIBRATONS THROUGHT AIRFRAME)

Generic Aircraft hydraulics (LOW SYS PX, VIBRATONS THROUGHT AIRFRAME)

(OP)
I have a scenario:
"pilot reports No1 Hyd sys showing low px. vibration experience throughout airframe. px indication fluctuates between 100 & 1000 psi"

I have put this down to pump cavitation or air trapped in the system. As I forestated this is a generic a/c hyd sys but can anyone advance on my fault diagnosis?

thanks for your attention

merry christmas

RE: Generic Aircraft hydraulics (LOW SYS PX, VIBRATONS THROUGHT AIRFRAME)

Check the hydraulic system accumulator for, e.g., bladder failure, no/wrong nitrogen precharge, stuff like that.

Mike Halloran
Pembroke Pines, FL, USA

RE: Generic Aircraft hydraulics (LOW SYS PX, VIBRATONS THROUGHT AIRFRAME)

(OP)
Thanks for your input

merry christmas

RE: Generic Aircraft hydraulics (LOW SYS PX, VIBRATONS THROUGHT AIRFRAME)

Not sure what kind of system you are working on---G/A, military etc but here's some food for thought.

I work on 60 GPM 3000 psi systems so bear that in mind

Airframe vibes sounds pretty drastic--how is the pump driven? Check the pump, accessory drive or gearbox that drives it for problems.  Sounds like something could be getting ready to come apart

air could account for flux in pressure but generally speaking should go away as air bubbles are broken down and go into solution unless you have a massive amount in the system---this would then manifest itself as low reservoir volume---maybe then you keep running low on hydro hence the pressure flux.  Operate the system and look for reservoir level drop.  Another symptom is servicing a low system just after operation then hi reservoir levels or dumping overboard just after shut down.  The major airframe vibes don't seem consistent with this though.

obvious to have checked the filters and part number of the filters

you could look for bypasses---hydraulic equivalent of a short circuit.  fluid passing from a pressure line into return or sometimes another system (fluid transfer between system).  This can result in hot--really hot components (the ones that are bypassing.  For your problem you would most likely have to have one hell of a massive bypass from pressure to return.  The constant unlimited demand for flow would have an effect on pressure throughout the system---hook up a gage to return (on the servicing port QD)  while looking for big return pressures.  a bypass can overpressurize return  while normal movement will give you a modest rise and fall from static return pressures.  looking at the flowmeter on a hyd test stand will also help.  You could also test suspect components by pressurizing them and reading return pressures on a gage


hope that helps--be great to hear what you find









Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources