I'm just about done building mine. Weather permitting, maiden could be this weekend. And I did install a Robart retratable tailwheel in the forward scale position. I'll try to attach photos of the install in a day or two if anyone is interested. The small plastic Robart tailwheel I used (part # 122) has several drawbacks: 1. All plastic, 2. very limited steering travel as designed, 3. even the tailwheel retainer (a small collet at the top of the tailwheel wire that prevents the wire from fallin out after tha aircraft leaves the graound) is plastic and fell off in my hand while installign the assy. Benefits are: 1. looks great, 2. helps balance cg.

The steering issue is created when the tailwheel is in the retracted position. If the steering pushrod were to continue to move in this position, the throw is very restricted (1/4" both ways?). Limiting the pushrod throw to this short distance would mean the tailwheel only turns a few degrees when lowered. My solution was to dial in as much steering as I wanted, then to TURN OFF the dedicated tailwheel steering servo when retracts were in the up position. I made a very simple and elegant switch by zip-tieing 1.5" of fuel tubing to the top of the retract servo arm. The tubing rotates with the retract servo. I threaded a piece of wire through the fuel tubing and soldered the end to a 1/2" piece of brass tubing, then inserted the brass tubing halfway into the fuel tubing. This made up the movable part of the switch. Then I simply screwed a long screw into the servo mounting tray such that, when the retract servo was in the fully gear down position, the brass tubing sticking out of the fuel tubing made positive contact with the long screw sticking up out of the servo mounting tray. This setup has benefits: 1. It's light. 2. contact is made throughout the last several degrees of retract servo travel (5 degrees or so). 3. contact is very positive and resistant to vibration, 4. Minor adjustments to the retract servo trim can be made without substantially affecting the tailwheel steering switch. 5. the flexing fuel tubing does not put the retract servo in a bind. Oh.. and lastly... the wire ends are soldered to the center wire (+ positive lead) of the tailwheel steering servo. This effectively turns the tailwheel steering servo on and off.

The retract servo itself is a standard HiTec servo (HD-325 I think). I use this one servo to actually lift and lower the tailwheel and to engage and disengage tailwheel steering. I have not yet decided if I'll use this same servo to throw the air valve on my Century Jet mains (scheduled to arrive tomorrow).