When you order the EMS/Jomar twin engine sync unit you get a small populated circuit board about 1 1/4" square, a box to put it in, two Hall effect sensors, four magnets, a hank of wire, and a little bit of wire solder.

You have to make 14 solder connections to the circuit board, and except for the sensor wires, you have to supply all the wire and connectors.

If you assemble it as indicated in the instructions, you can cut one leg of a long wye connector and hard wire the unit into the cut leg, then with the sensors hard wired to the board this is the least expensive way to set it up.

The airplane I got the unit for has plug in wings, so hard wiring was not an option. Went to Radio Shack and got two miniature stereo jacks and plugs, used these for the sensor connections. I glued two female servo connectors to the top of the box, the result is a fancy wye connector with places to plug the sensors in. See first picture.

The second picture is one magnet, and the sensor. I had intended to put a size reference in, but forgot. The magnet is 1/4" diameter and 1/4" long. The sensor, as you see, is much smaller.

How it works:

The unit gets the throttle signal from the RX through a wye connector, with the "Master" engine servo on the other leg of the wye. It has no effect on the master engine throttle servo. Its other inputs are the rpm of the master and slave engines, its output is the throttle signal to the slave engine throttle servo to keep the engines at the same speed.

More to follow.

Bill.