Hi Nuno,
i had sometimes trouble that one Maingear didnīt retract because the locking pin didnīt get back fast enough.
I tried most erverything to delay the air for the maincylinders with no 100% sucess. So i looked at the construction closely
and didnīt find a reason to left them on and removed them. Since then, every retract cyclus was perfect with no blockade or so.
If you look at Likais F16 1/6 maingear, there are also only the 2 maincylinders. If the air pressure is there, there is no problem because
all the force in landing came from the front. My F16 sits in my Hobbyroom for a while now without any air in the tanks and still stays perfect.
The maingear only gave up when i move the scissor on the main strut, then itīs time to fill some air in.
For the front gear, unfortunately you are absolutly right, i gave this unit to a friend to replace the soft materials to better ones, the construction itself is ok.
I hope to get this update soon because i mostely fly off grassurfaces.