smokinbarracuda

Hi guys, I'm currently trying to wire up the recoil in my Abrams (with rx18 and HL electronics) and I just want to check a few things before I start and fry something! Basically its a Hobby Engine recoil unit as seen below which I have modified to work the right way with a servo which I have also modified to work in one direction with just the two motor terminals. I want to have constant power from the smoker jack which is broken by a contact switch when the barrel returns to the front. Then to fire I will use the left stick up function.

Am I correct in the following: Break the positive smoker wire and route through the contact switch, then connect to the servo motor terminal along with the black smoker wire to the other terminal. I'm now left with the red positive wire which used to be connected to the bb gun and still is also connected to the elevation motor. Am I right in connecting this to the servo motor terminal where the red smoker wire is attached? Do I need to use the old bb gun black wire or will the the smoker ground be used for the left stick up function? Sorry for the non technical terms!

I'd appreciate any help, thanks

YHR

HL use common positive wiring. This means the Elevation motor and recoil motor are fed by the same positive.

I beleive what you have done is correct. The negative wire from the RX 18 (pin 4, where Pin 1 and 2 feed the turret rotation motor) is used to trigger the recoil. Up on the left stick provides the negative connection to power the recoil motor and that closes the contact in the microswitch to allow your smoker jack to supply power to the recoil motor to finish the cycle.

Panther G

Yeah this is where i get all mixed up too. I need a ladder diagram. this is the problem we where talking about YHR. I did no realize they both work off the same common +

smokinbarracuda

Hmm, thanks YHR, I seem to be a little confused, I thought the red wires for the smoker and the fire function were the positive with the black wires being the negative. Therefore I thought I would attach both red wires to one motor terminal and the smoker black to the other as the negative or ground for both functions. Is this wrong because you say its the negative connection that is caused by the left stick up function when I assumed it to be the positive ie red wire. Please help!

YHR

The elevate, and fire functions on the 8 pin connector are negative. The color of wires in a Heng long should not be considered accurate as to what polarity they are carrying.

Common positive wiring is used between the recoil and elevation motor, and the negative is supplied from the pin connector.

smokinbarracuda

ok hopefully i think i can work with that now. Thanks again for the help. If successful i'll try to get a vid of my abrams in action. Cheers

Panther G

Be sure to take some good pics of the wiring and connection points. I still need to get mine sorted out when I get some time. I'm still trying to use the HE recoil and elevation.
At the moment , that's the plan but I may just go for it and do a mod with a Tamiya recoil and elevation. That actually simplifies things a little.

smokinbarracuda

Success! at least with the wiring anyway. Another issue has arisen though where the gun now recoils twice when I press the fire button (flash and speaker function) and left stick up at the same time which will be a problem when I do the transmitter mod. It recoils perfectly when just using the left stick up function. Any ideas how to solve this? Would it be possible to activate the recoil off the flash led wire instead of the left stick? By the way I'm using the modelbau ARM module with flash.

Panther G, Ive taken a few pics of the wiring, not great but might help. Its very simple, The wire that is triggered by the left stick up function is the black wire that used to be connected to the bb gun. You just connect that to the correct side of the servo motor. That wire isn't actually used in controlling the elevation at all.

Panther G

Well, you haven't gone into any description of the servo mod so yeah not much help. I do appreciate the pics though. Not sure how I'm going to go about this. <div>  Most likely will have too use a Tamiya recoil mechanism of one type or another.  I also havent decided on what electronics package to go with. Currently it is an HL conversion but I aint too thrilled with this, so it will be a Tamiya conversion or a full Elmod. The Elmod would be nice because i could get all the correct sounds , but i will have to think about it.</div>

smokinbarracuda

modifying the servo was easy. I just took it apart, removed the circuitry and the tab on the final gear that acts as a stop. So you are just left with the two motor connections which connect to the smoker via the contact switch. Then its just a matter of connecting the black bb gun wire to the motor where the black smoker wire attaches. Let me know if there's anything else i should elaborate on and should be made clear

smokinbarracuda

Well I finally succeded in getting it all working, flash, cannon sound and recoil all at once. I'm very happy with the result but a couple of things could be better. The flash that is connected to the modelbau unit stays on for about 2 seconds so I may have to upgrade to a high voltage flash. The only other problem is that with this version of the rx18 the cannon sound is very weak, much quieter than on my old rx18. Not much that can be done about that though. I'll shoot some video of it working and try to figure out youtube! Cheers