Aurum goes electric, The

Model Airplane News, Aug 1998 by Marshall, Larry

The Aurum looked to me like a great candidate for conversion to electric power. It is relatively light, and the interior organization would allow me to easily stuff 14 to 16 cells into it. By weighing all the parts, I determined that the airframe would weigh 46 ounces. Four servos, a receiver and a receiver pack add another 10 ounces, for a total of 56 ounces. To keep the wing loading on the 515-square-inch wing around 25 oz.-lb., I needed a power system that weighed 45 ounces or less. For that purpose, I chose a MaxCim MaxNeo-13D with a planetary gearbox (3.7:1). When it and 14-1700SCR cells are stuffed into the Aurum, the all-up weight is 5.8 pounds, and when propped with a 12x8 APC prop, the MaxCim provides more than enough power.

To do the conversion, I had to change a few things. First, I laid a 3/32-inch ply battery platform just ahead of the servo tray. Velcro-brand fastener was added to hold the battery in place. I opened up a hole in the firewall to allow some airflow through the fuselage to cool the cells and another just behind the wing as an exit. I simply used MaxCim's firewall engine mount to hold the motor in place. That was it for the conversion.

Like Gerry, I replaced the wing bolts supplied with the kit with largerdiameter nylon bolts. Unlike Gerry, I installed wheel pants, as they improve the looks of the airplane in my view. If you're flying off tall grass, however, it's best to leave them off.

I don't have many flights on the Aurum yet, but it seems to be an honest airplane. Right now I get 5-minute flights with the plane, but I expect to extend that a bit as I become more used to it and learn more about throttle management of this setup. Even at 6 pounds, the plane is capable of most sport aerobatic maneuvers. My plan at this point is to add at least one more cell, switch to 2000mAh cells and try an 11x10 prop. The switch to 2000mAh cells should increase duration by about 20 percent, and the extra cell and smaller, deeper-pitch prop should increase the flight speed. Besides, it's fun to do these little experiments. -Larry Marshall