I have been on a roll making tow/bomb releases for my arfs lately. Last week I added functional drop tanks to my alfa f-86 edf jet, now my cx2 has a functional "multi purpose" release. I used a slack line with a spring return, since a standard rod would bind given the cramped quarters inside the cx2 shell.

I used a hxt500 servo, "80" cf rod, kevlar thread wraps, spruce, 1/16th ply, a spring from a ballpoint pen, 25lb test fishing line, and a few bits from a Dubro micro control rod set. Any suitable materials can be substituted, but please note the spring must be "light" enough for the servo to compress it far as it needs to go. Mine has 3 positions that can be locked/released separately, and the rod clears all three; if the servo is too weak or the spring too strong, the servo could stall before the rod is fully retracted.

The servo obviously plugs in to the free ch5 port on the cx2's 4n1. To operate the release, rotate the ch5 knob CW to release the loads sequentially, or CCW to lock loads on to the heli. Be aware the servo is under stress while compressing the spring. To prevent premature servo failure it is best to return the servo to the full lock position (CCW) immediately after dropping each load . If you forget to do this, you'll likely be reminded after you land and the rotors stop, by the loud buzzing sound coming from the release servo!

Enjoy!
Kev

[edit: I almost forgot the most important detail. The latches for the loads are placed directly under the rotor shaft so trim is the same after the release.]