Probably on a large civil aircraft the large voltage spike required to get the gear moving is uneconomical to implement. Having said that the 787 is one of the first large designs shedding pneumatic in favor of electric so it can be done. Probably in the heyday of Piper / Cessna design people thought " if the gear on a B17 is hydraulic well shurely there is no other way" whereas nowadays one could probably have a stepper motor per TB20 gear leg at 0.10 of the hydraulic system cost.
What hydraulics gives you is simplicity.
If you use a single electric motor then you need long linkages to operate the three lots of mechanisms. If you use three motors then you get the difficulty of doing the emergency release because you have to somehow release the gear in three places.
And motors can be
Whereas if you chuck in one of these you are done with all the electrical stuff which causes such problems in light aircraft.
Do passenger jets have an emergency gear release? I thought they just had multiple hydraulic pressure sources.
What jets do have however is the gear coming up all at the same time. I wonder how they do it?
The Mustang has a hydraulic system which drives the gear and is also used for the braking system. Obv electrically pressurised. It also has pneumatic emergency release which operates with nitrogen blow down to supplement the gravity drop down after the mechanical interlocks are released. There is a second nitrogen bottle to allow braking in the event of hydraulic failure.
Hydraulics are simple, light and efficient.
No reason to stop at “the electrical stuff that causes so many problems in light aircraft” – modern (stress on modern) electrical stuff doesn’t fail so often. How often did your windscreen wiper fail in your car? Am willing to bet it sees more cycles than a gear motor.
DC brush motors that fail don’t seem to be that much of a problem on Mooneys.
The PC12 from 2014 has gone electric.
Does the mustang have symmetrical operation and if so how is it implemented?
A RG can be easy as that
Always symmetrical operation, no electrics, no hydraulics 
Indeed, the Europa monowheel is just a mechanic retractable gear. Very smooth and extremely easy!
You just need to master it on the ground :-)
Peter
Most airliners only have the landing gear on one hydraulic system, the gear engages in up locks when fully retracted. Should the hydraulics fail the gear is dropped by mechanically releasing the unlocks and the gear falls under gravity.
I did fly one airliner that had a peunmatic actuation of the gear, it is the only aircraft I have ever had any landing gear problems with and the only aircraft I have been forced to land with a gear leg unlocked………… The whole air system was less reliable than a Narco ADF.
I wonder how airliners implement the concurrent retraction… I can think of several ways.
