My Ultimate 40 will be easy to arm using the MPI [link=http://www.maxxprod.com/mpi/mpi-21.html]6970[/link] High Current Arming Switch. I am also adding an anti-spark feature to keep the arming pin from getting pitted. Any electric power system using a 6s LiPo voltage or higher creates a sizable spark when connecting the battery to the ESC. This can be eliminated by first connecting a 100ohm resistor across the line to charge the ESC capacitors and then connect the battery via an arming switch or direct Dean's Ultra plug.

Since my E-flite ESC came with an On/Off switch, I decided to use it for the anti-spark switch instead. It is not a fail-safe On/Off design for the ESC so it poses a weak link that could turn off the radio system in flight if the switch ever went bad. By removing the switch and soldering the On/Off wires together on the ESC, it will always remain on as long as power is applied.

The ESC was mounted to the bottom of the fuselage through a slot I created with a Dremel tool. It is held in place with servo tape on the top side and a wedge of balsa CA'ed inside the fuselage to keep it from moving. I will be creating an opening in the cowl for air to pass by the ESC as it exits. In this manner, air flow from the front of the cowl will cool both the motor and ESC. Additional holes into the fuselage will help cool the battery where an air exit will be made in the bottom tail.

To arm the system, simply turn ON the switch and then plug in the arming pin...spark free!