Well, if you haven’t seen them , the electric powered planes are here and are here to stay! From small indoor airframes to large pattern and scale birds, the electrics are really gaining on the gas jobs. If you have any doubt about this, just hit any hobby shop and you will find a large section of the store is for electrics.

The push to electrics has come as the battery technology has improved. The use of lighter ni-mh and lithium polyimer packs have made possible the advances in the capability of electric powered aircraft. You no longer have to carry around a battery that could weigh as much as the airframe. The main battery of choice is the li-poly packs and their capacity and discharge rates just keep going up. Li-poly’s are different from the batteries that we are used to, as they are not enclosed in a metal tube, but are made up of a sandwich of lightweight plates in foil package. This construction saves a lot of the weight and makes for easier installation in the airframe. This advance does come with a price though as you will have to upgrade to a newer style charger that is capable of charging Li-Poly packs. These packs if charged wrong WILL cause fires. One of the other problems is that your good old speed controls from NiCad days will not work safely with the Li-poly’s as the cutoff voltage will be too low for the Li-Poly packs and could cause damage to the packs. Newer speed controls will generally have selectable cutoff voltages for either 2 or 3 cell Li-poly’s and some are even adjustable by the owner.

Ok so now you have seen what's new in batteries, wait to you see the working end , the motors! The good old “can” motors like the speed 400 and the 540 are being replace by brushless motors that are 1/3 the weight but put out even more power with less amperage. This means better performance and longer flight times. These brushless motors are basically 3 phase A/C motors that are driven by a brushless speed control. The motors range from small, modified cdrom motors for indoor plane to very large motors that will pull a 10 lb pattern ship straight up swinging 20” of prop. The motors come in a couple of designs classed as “outrunners” and “inrunners”. Basically the outrunner design is a outer bell with permanent magnets that spins around outside of the stator and windings, while the inrunner is the opposite with the magnets on a center armature and the windings on the outside. There are various types of winding patterns and stator designs but the concept is the same. The motors came be homemade, kit form or perassembled. Info on modifying cdrom motors can be found all over the internet while sites like www.gobrushless.com offer kits based on the cdrom motors for as little as $10. They also have a great tutorial on their site explaining how to make the motors and the different winds and how they work.

One of the other advances is in the airframe itself. New building material and construction techniques can create very light and tough aircraft. Light weight foam material combined with the fact the equipment is lighter means that new ideas are constantly being explored. One of these foams is called Depron and is used for underlayment for laminate flooring in Europe. This foam is available in 1mm, 2mm, 3mm, 5mm, and 6mm thick sheets. This material is very light but pretty stiff and cuts like butter with a good old Xacto knife. There is a world full of plans out there for depron airplanes with places like www.3dfoamy.com offering kits AND free downloads of plans for every kit they sell. Plans out on the net range from 3D indoor , to jetfighters for pusher or electric ducted fans with just about everything in between!

If you want more info on this aspect of the hobby, post a message on the forum and we’ll see if we can’t get you headed in the right direction.