A DIY approach to electronic servoless retractable gear for a DJI 550. I decided I was going to try and create a set of retractable gear for my 550... When I was done, I decided to share it :) Updated: 20131020 - included the step files so that you can tweak the design if needed. Also added a cap that can be placed inside the down leg if you used the new style plastic leg skid to down leg fitting. This reinforced the inside of the leg there you run the set screws into to keep it from turning.What you'll need: 2 - dynam 75 degree, 4mm hole servoless retracts (picture included) 2 - 4mm x 70mm socket head screws (cut off the heads as close to the head as you can). File a flat on one side of these 2 - 38mm long by 12mm OD, 11mm ID carbon fiber tubes (Align 450 tailboom work just fine) 1 - Tarot landing gear kit (includes all the other parts needed and you won't use the top mounting tube, or leg ends. 2 each of the top and joint printed parts 4 each of the 550 spacer 1 - main mounting plate 3mm bolts, nutz, washers 1 - Y servo connector Unfortunately, the dimensions of Carbon tubing vary and I've done my best to match printer dimension production to meet those size criteria, but you may need to sand things to fit. The bottom plate is built to support countersunk screws, the ones that the retracts came with to mount the retracts. The 4 corner bolts are 3mm and are spaced to match the 550 frame. you'll need the 550 spacers to match the slot size and keep the bolt centered and away from the circuit board contact area. The 4mm screws need a flat filed on one side, they are inserted into the 4mm opening on the servoless retracts and then a set screws which come with with retracts are used to hold the screws in place. I used epoxy to stop everything from rotating that and the flat on the 4mm screw should do the job. As a further modification, the mounting plate is setup to support the Tarot gimbal, the spacing will meet the dimensions of the mounting standoffs for that gimbal and the small 2 hole spacer will again center the screws to keep them from touching the circuit board. Another modification and I may make this to mine... the Tarot legs are a bit long... I'll have to measure them, but it's probably worth taking a couple of inches off of them before assembly. The entire thing stands approx 200-220mm off the ground and it could be shortened to 170-180mm and still have plenty of room, maybe even 150mm total height. Play around when you build and decide which height is right for you or your gimbal.