Efficient Speed Control for Electric Power

A WHILE BACK I bought a Kraft Chipmunk at a greatly reduced price on impulse. I assumed that the low price tag couldn't possibly include the motor, so I'd have to put in my trusty TD .049. To my surprise, the Chipmunk arrived with an 05 electric motor and prop all ready to go! Being somewhat of a "purist," I decided that I just had to have proportional control on the throttle. I asked around and checked out the electric motor speed controllers that were already on the market. I found that they were all a bit on the expensive side, many were bulky or heavy, and most were less than 90% efficient. After a few test flights, I knew for sure that the last 10% of the power really meant a lot to the climb-out performance! The weight of the motor battery pack must already be contended with by fliers, and total weight must be kept to a minimum for maximum flight performance.

S2 B2: (Solid State Battery Backer

WITH THE ADVENT of "big-buck" modeling projects in the 1/5, 1/4, and larger scales, a lot of concern has been placed on the batteries that operate the airborne control system. We've analyzed, conditioned, cycled, and plotted performance of the Ni-Cds that we treasure and trust to power our equipment. This is all well and good, but Murphy's Law says that if a battery can fail in flight, it will! Until now, I'd managed to avoid the use of a "battery backer" system for several reasons. First, I personally feel that a high-vibration environment like a model aircraft is no place for a relay. I also didn't want to have to switch to nonstandard five-cell packs, because my charger and ESV (with load) are set up for 4.8-volt, four-cell packs, and I feel comfortable with them. Never having analyzed or used any of the systems currently available, I was able to start this project with an unbiased opinion of what the specs should be for the S2B2.

Glitch Buster

HAVING BUILT my first really large aircraft, the Nosen Cessna 310, I was finally exposed to some of the problems that begin to crop up when using long wires and heavy-duty servos in airplanes; there may be a serious hazard to the model and environs when a glitch occurs. This article will deal with my experiences, ideas suggested by just about every major source in the RC hobby, and my personal "layman's" interpretation of what's really going on. The second part will present an "ultimate" solution to the problems which most often crop up in large aircraft with fairly complex airborne systems, especially those with lots of long wires.