Q-61: I’ve already built your Scratch One RC electric trainer that was featured in your “From the Ground Up” series in the November 2003 and January 2004 issues of MA. The wood package from Aerocraft Inc., along with the components from Kirk Massey at New Creations RC, made my first scratch-built model a complete success. In fact I like the Scratch One so much I’ve been wondering if it might be possible to scaled it up or down in size to take a variety of electric motors?
A-61: Funny you should ask that question! Several weeks back I was asked to review a set of micro RC components being offered by Global Hobby Distributors Inc. The specific components are known as the Cirrus Micro Joule, consisting of a micro receiver, servos, and several tiny ESCs. The weight of this equipment (receiver, two servos, and ESC) came to only 0.37 ounces; can you believe it?
I decided that a simple aircraft design might be in order to provide some application for these micro RC components. To get the job done quickly, I scaled down my Scratch One design to 65% of the original size. The resulting model which I have named Scratch 65, has slightly more than 100 square inches of wing area and ended up weighing only 2.69 ounces ready-to-fly on two FMA/Kokam 145 mAh Li-Poly batteries. The little version of the Scratch One proved to be an excellent flier and was constructed in only one day from basically a single sheet of 1/16 balsa and a half sheet of 1/32 inch thick balsa. How cheap and fast can it get!
I just released a full construction article on this new design which hopefully will find its way into print as soon as possible. This size model would be ideally suited as your first indoor RC flier.