Kitfox Aircraft Stick and Rudder Stein Air Grove Aircraft TCW Technologies Dynon Avionics AeroLED MGL Avionics Leading Edge Airfoils Desser EarthX Batteries Garmin G3X Touch
Results 1 to 6 of 6

Thread: Relocate Oil Reservoir to Prevent Hydraulic Oil Lock 912 Model 3

  1. #1

    Join Date
    Jan 2018
    Location
    Vernon, BC
    Posts
    59

    Default Relocate Oil Reservoir to Prevent Hydraulic Oil Lock 912 Model 3

    Has anyone relocated the oil tank to have it lower, and less likely to cause hydraulic lock? There is enough room on the people side of the firewall, where the header tank used to be.

    Have other owners with early 912 installations experienced hydraulic lock?

    I just went through the hydraulic lock recovery process on my other ultralight. It too has the oil tank bottom at the upper design limit of about equal to the crankshaft / oil pump. Hydraulic lock was never an issue, until I dismantled the plane for ground transport. During disassembly the fuselage was on a slope, which must have been enough to start the syphoning. Not what you would want to happen anywhere else than your home base.

    So as I rebuild this model 3, why not add a few more weeks to design and fabricate yet another better way of doing things? <many times I envy the new kit builders>

    If the oil tank moves behind the firewall, there will be a huge open cavity over the motor, as I have scrapped the hot air box in favour of heat probes in the carburettors. mmmmm, will that mess with the air cooled cylinders?

  2. #2
    Senior Member Dusty's Avatar
    Join Date
    Dec 2012
    Location
    Christchurch, New Zealand
    Posts
    378

    Default Re: Relocate Oil Reservoir to Prevent Hydraulic Oil Lock 912 Model 3

    I would recommend leaving the tank in the stock position as access for checking is good. If you are getting hydraulic lock there may be a problem somewhere else, possibly non standard filter? Keeping the oil lines short is more of a priority as the oil feed is mainly suction. 5 years with my current fox I haven't experienced a hydraulic lock yet.

  3. #3
    Super Moderator Av8r3400's Avatar
    Join Date
    Jan 2009
    Location
    Merrill, WI
    Posts
    3,044

    Default Re: Relocate Oil Reservoir to Prevent Hydraulic Oil Lock 912 Model 3

    X2 what Dusty said.

    I've been flying 912 powered model 4s for over 10 years and have yet to have a hydraulic lock situation. Rotax filters have a check valve in them that prevents this problem.
    Av8r3400
    Kitfox Model IV
    The Mangy Fox
    912UL 105hp Zipper
    YouTube Videos

  4. #4
    Senior Member
    Join Date
    Mar 2009
    Location
    Pittsboro,NC
    Posts
    299

    Default Re: Relocate Oil Reservoir to Prevent Hydraulic Oil Lock 912 Model 3

    I agree with Dusty and av8r3400. It's not worth the effort. Hydraulic lock doesn't happen unless your plane sits for months at a time. I completed my model 4 late 2015 and I've never had a problem. I just pull the prop through by hand for a few turns if I'm not able to fly.

  5. #5

    Join Date
    Jan 2018
    Location
    Vernon, BC
    Posts
    59

    Default Re: Relocate Oil Reservoir to Prevent Hydraulic Oil Lock 912 Model 3

    Good to hear of no problems with the model 3 layout. I don't want to fix a problem I won't have!
    On my other ultralight it has the official oil filter, but it never sat for a 16 months without turning a prop. It was only supposed to be 4 or 5 months, covid made it another year.
    oops, did I start another debate - how to store a 912.

    thanks for the comments

  6. #6
    Senior Member Eric Page's Avatar
    Join Date
    Jun 2020
    Location
    Toledo, WA
    Posts
    863

    Default Re: Relocate Oil Reservoir to Prevent Hydraulic Oil Lock 912 Model 3

    There's also the issue of putting oil through the firewall. A leak of hot engine oil onto your feet and lower legs in flight would be catastrophic. The tank would also be a significant and uncontrollable source of heat in the cabin. That might be nice in the winter, but not so much in the summer.
    Eric Page
    Building: Kitfox 5 Safari | Rotax 912iS | Dynon HDX
    Member: EAA Lifetime, AOPA, ALPA
    ATP: AMEL | Comm: ASEL, Glider | ATCS: CTO
    Map of Landings

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •