Remember, more fluid volume has to return to the pump, and the tank, than is being pumped out to the cylinder, during a retraction. This difference occurs because the cylinder shafts displace fluid on the high side only........................

Mike, Gerard, et al

 

Very interesting point.  Let's see, if the piston is 1 5/16" and the shaft is 5/16", the retract force has to be about 6% higher to move the same weight since the shaft reduces the area acted on by the hydraulic fluid pressure.

 

More interesting, when I next go to the airport, I will measure the door actuator piston and shaft and see why it takes so much more pressure to snug everything up - especially the doors that have now almost fully compressed the springs on the actuators by then.

 

My spool is correctly oriented yet sometimes (usually in the winter), there is a hiccup after no more than a second or two to finally tuck everything away after the takeoff retract.

 

Another thing I have noticed is the wear on the legs (slight dent) and door sequence valve's actuating screw heads (slight flattening) after about 700 in flight retracts and, I am sure, another 100-200 retracts whilst on jacks.  One should consider that those valves may not be completely opening and may need readjustment to achieve full flow of fluid.