I have been extolling the virtues of hydraulics for years now, I have five models which have been converted I don’t have the slightest problem with any one of them, one in fact is a quarter scale Jerry Bates Sea Fury has hydraulic landing gear wing folding mechanism and hydraulic doors.

The system depicted in that picture is the UMS system from India, the price looks comparable with what you would pay direct from the factory. In my view it has one weakness and that is the ECU, so I did away with it and made a simple accumulator from a discarded U/C ram, this ram has a spring fitted to the air/rod side (this spring determines the switch off pressure) the rod operates a micro switch which controls a radio controlled relay which operates the pump. This system is utterly reliable and doesn’t leak!

Right now I am flying the 1:7 FB F15e which has hydraulic gear and doors, the gear system has been converted to 4mm pipe and unions the doors are still 3mm and work perfectly. You can get away with two valves if you leave the doors open gear down although mine has three valves to enable three doors to close gear down. You can use a two cell LiFe (A123). I use a three cell which gives good speed and you won’t overheat the motor as it only runs for 7-9 seconds. The other good thing is I can get 30to40 cycles from one charge and the up and down speeds are the same.

If anyone is interested I can go into much finer detail as to how the transmitter is set up.

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