Servo - August 2016

The Lifter Add-On

As mentioned, the Lifter Add-On is equally simple to assemble, and again includes most of the needed additional tools to do the install. You still need a Phillips screwdriver, electrical tape or small heat shrink tubing, and an X-acto™or similar knife. The knife is to help remove the red wire from the servo connector, so a very small flat head screw driver might do the trick as well.

Assembling the Lifter Add-On all starts with putting together the main lifter arm. You start by screwing the lifter arms to the NutStrip. Make sure to use threadlock, and don't tighten them all together. This acts as the main pivot point of the lifting arm, so you want it to not bind, yet be slop free. You also want to make the two lifting arms symmetrical as you want the NutStrip on the outside of both arms.

You then need to connect the two lifting arms with the cross bar and linkage arm. Make sure the linkage arm is over the crossbar and should pivot on it smoothly once it’s together. The final step to the lifter arm assembly is to screw on the steel scoop. Like the armor on the bot, I like to put in all the screws, then tighten them after to make sure it’s all lined up. Take note that the screws just go into plastic, so don't go crazy on tightening them, and don't use threadlock. Remember threadlock products can actually damage the plastic.

With the lifter arm done, you'll want to set that aside and grab the servo and servo mounts from the kit and put them together. Remove the top plate from your completed Viper. Next is the most difficult part of the build. You want the servo to run off the 7.4V from the battery for more BEC in the tinyESC that is only 5V. To do this, you need to remove the red wire from the servo plug. This is done by gently lifting the little tab holding the pin in the connector. The easiest way to do this is to use an X-acto or similar tool and slide it under the little tab while sliding the pin out of the connector. There is no need to put any force on the wire as it'll slide right out unless the tab hasn't been lifted enough. If you never plan on using the servo for anything else, breaking off the little tab will make life easier and the wire will slide out, but you won't be able to put it back in. With that now done, use the little piece of included wire and slide it into the end of the pin on the red servo wire and cover it in electrical tape or heat shrink. The other end of the wire goes into a free slot in the red terminal block. You then put the servo plug into the throttle channel (ch3) and turn on the radio and bot (the radio always goes on first, and you always want the wheels of the bot off the ground when powering it on). Move the left stick all the way down and make sure the trim is centered. You can now power it all down. This is done so the servo goes where it needs to be when the lifter arm is all the way down. In a little zip lock bag, you'll find a couple different servo arms. You want the single arm that will have a bigger hole at the very end. Slide it on to the servo horizontally. This should be a snug fit, but you want to make sure the spline on the servo aligns with that of the arm. Before pressing it on, a slight rotational wiggle will let you almost feel where it needs to go in to avoid damage to the spline on the arm. The last step with the servo is to mount it in the chassis. The mounts are made to be universal, so there are five holes they can be mounted with. For the correct position, you want to use the second and fifth holes from the servo tabs for it to be in the correct position in the Viper chassis.

With all the electronics in the Viper now, you want to make sure all the wires are routed safely and away from the wheels and servo arm.

With all the electronics taken care of, it’s now time to mount the lifter arm you previously built to the top armor. To attach the lifter linkage arm to the servo, you can either power up the bot and move the left stick up, or with it all powered down, gently rotate the servo arm counterclockwise. You'll then be able to place the top armor on the bot with the arm sticking out to screw the linkage arm to the servo arm.