Hi all,

I've flown all the Cessna RG singles as well as the 337 and the gear is not as complicated as you all imagine. Yes, it is cleverly designed and is kind of unusual in its looks, but it all gets back to positioning of the gear mounts and the angles involved during retraction. When the pilot selects gear up, the lever he moves in the cockpit simply releases hydraulic pressure that has been holding the gear in the locked position. It then freefalls due to gravity and "dangles" until the hydraulic pump builds pressure on the other side of the actuator and moves the gear back and up into the wells. Hydraulic pressure is then trapped and holds the gear up. Extension is simply the reverse procedure. I've had situations where there was a leak in the system and the gear has sagged out of the fuselage until the hydraulic pump has cut in and reestablished pressure. Most light aircraft are like this and have no uplocks as such.

Years ago, I build a Pilot kit of the F16 and although I eventually sold it unfinished, I had installed standard 90 degree mechanical retracts in it and they worked just fine. Although in that situation, the gear legs were straight, whereas the Cessna ones are bent just near the wheel, there should be no real problem getting it all to work. The secret is to just play with the geometry until they retract into the wells and then bend the axles to suit the extended position.

I will note that the 337 gear goes further (ie rotates more than 90 degrees) but the principle is the same. Just try and steer away from the older Cessna 210 as it had doors and you don't need that complication. Cessna found that themselves of course and deleted them from later models as they only improved the speed by a few knots but added a bunch of maintenance woes. The 337 gear of course always had doors so if you're building one of those you'll be unable to avoid them... good luck.