Hey, John... I'm not AS good with Photoshop as my Brother was... :-/
let me see if I understand this correctly, (then I will at least attempt to work up a decent diagram for this....) first I want to make SURE I understand correctly.
assume a standard tricycle gear setup, 3 servoless retracts, all being powered by a 5 cell NiCad, (6V) which is SEPARATE from the battery used to power the receiver and all other servos.
1) 'Y' together all 3 retracts. (one single plug would now control all 3 gear.. it wouldn't really be a 'Y' cord, but you know what I mean...
call this one 'Y1')
2) using a separate 'Y' cord (this one really IS a 'Y'..) call it 'Y2'. plug the male end of Y1 into one female leg of Y2.
3) plug the 5 cell nicad (used ONLY to power the gear) into the OTHER female leg of Y2.
4) snip the MIDDLE (RED) WIRE from the MALE leg of Y2 (insulating it completely) and plug the male end of Y2 into the gear channel of the receiver.
5) make all other receiver and flight battery connections as normal.
did I get that right?
ORIGINAL: JohnBuckner
This is very easy to do and you need nothing special.
First you start with a common standard Y cord. Next you plug the leads from the electric retracts into one of the female legs of the Y cord and the next step will be to plug the lead from your second or retract battery or the second batterys switch/charge harness into the second leg of the Y harness.
Hold on now for the last step before everyone starts chanting this cannot work! it does. The last step is to take the male plug of this Y cord that you have the gear and second battery plugged into and carefully snip the center wire (the red one) then remove a quarter inch or so contact cannot be made. Do this only on the plug from the Y cord that is plugged into the rx,s retract channel.
Your retracts will now be powered by only the second battery, they cannont dump the flight battery or affect it in any way and the sense lead of the plug now has the ground plane for the sensing circuit to function. You mearly plug this into whichever channel you desire for retract selection.
John
This is a photo of one of my ships that is a hard working airplane and is intended to serve its whole life just shooting arrested landings and I used a glow driver to help assure smooth throttle ups circuit after circuit. I powered the glow driver in exactly the same way simply to avoid the danger of draining the flight battery excessively from this repetitive use so it has its own isolated pack as you can see. You can also see the second batterys charge/switch on the side of the fuselage in tandem with the flight battery charge/switch.