Many thanks to members for all the good ideas on why my mains tend to hang down when retraction is selected.  Particular thanks to those that suggested investigating the "shuttle valve" on the back of the landing gear structural box as the likely source of retraction failures that keep both  mains in the wells.

 

We may well have two things going on intermittently: shuttle valve ball flopping to the wrong side occasionally which would stop both mains from going up and we have a couple of incidences of only one main coming up which must arise from some other cause. 

 

So we have made the decision to jack up the airplane, cycle with some careful observations, hand pump gear down while listening carefully for bubbles in the hand pump line when pressure is released, pull the actuators and shuttle valve out (valve first), and carefully investigate and document.  We also plan to replace all O rings, check O ring compressions (piston to cylinder O ring compression), and look for signs of locking pin wear or damage and locking slot possible damage.  It was also suggested that we rotate both the locking pins and hydraulic pistons to shift the wear point at pin/slot to another location.

 

Will document carefully, take photos where it makes sense, and report.  Teardown won't be until mid-March due to schedule conflicts.

 

Sadly an inquiry to Lancair was received and acknowledged by MIchelle, promptly forwarded to tech support, and thereafter.... Silence..... Which seems increasingly common from anecdotal reports collected from various builders contacting the factory with questions. 

 

Having no part numbers for O rings, we will have to take them to a hydraulics specialty shop and get or order replacements.  Of course since we are out in the boonies, this means sit and wait time before reassembly since we can not pre-order anything.

 

More to follow.

 

Fred Moreno