Electricus 205 (oz14544)

About this Plan

Electricus 205. Radio control electric-powered sailplane model.

Quote: "Here's a really super 2-meter, direct drive, 05 electric sailplane that climbs like the proverbial 'homesick angel' and handles aerobatic maneuvers like a champ. Perfect as a first electric model. Electricus, by Larry Jolly.

As I promised in my last article, this month we are going to build an electric sailplane. Whether you are a novice electric flier or a veteran power jockey, pay attention and you can have a most satisfying model that you can fly literally anywhere, anytime, and you won't get caught, because the Electricus 205 flies very high, very easily, and of course very quietly.

How did the Electricus 205 come about? Well, it's a long story that started back in January of 1982. I had just flamed out of the Leisure Grand Championships with an overloaded micro-switch. Mike Charles went on to win with his two-meter design, Ultra II (featured in January '83 MB). I liked the looks and characteristics of Mike's airplane - and the fact that it won didn't hurt, either. Anyway, like any experienced modeler, I went home and slept on it.

As I fell into a deeper sleep, I started to dream. I found myself in a tunnel of darkness. I looked left, then right. To the right I saw a glimmer of light at the end of the tunnel. I started walking, then running, until I got to the end of that tunnel. As I peered out I saw that this was a strange land, not unlike a desert - with rocks, and cactus, and all that good stuff. A little ways out I saw a man standing on a ladder, working on what appeared to be an adobe house.

I walked over to the man and greeted him. Upon asking his name, he replied that he was: 'The Bearded One, Guru of Sandia Crest, Keeper of all Knowledge pertaining to model airplanes.' I thought to myself, what a break. This guy can tell me everything I need to know about my next electric project.

I told the Bearded One of my dilemma. He knew a lot about free flight power models, and suggested I steer my thoughts in that direction. He reminded me of the basic rule: More wing more glide, less wing more climb. Like any truly great Guru, he preferred for me to think out my design rather than have him draw the picture for me. I thought to myself, if I could get my model high enough, theoretically it wouldn't need to glide at all. If it started from enough height, it couldn't fall fast enough to touch down before the max time had elapsed. What I needed was something in between a balloon and a Saturn V.

As the parameters were laid down, the Electricus 205 started to take shape. Light weight was a key factor, for as you physics majors know, mass has a lot to do with acceleration. If I could build a model to 35 ounces all up, I could shorten the span and still have a reasonable wing loading. I asked the Guru about airfoils. I told him I was thinking about an under-cambered section to improve the glide. Looking at me like I was nuts, he replied: Any good free (lighter knows thin, flat bottoms climb faster than under-cambered sections. Didn't you ever hear of Carl, 'The Wizard of the Chicago Armory,' and his 8% flats that set the world on its ear in the late 30s? You know, he was right.

Now, I was ready to build. I chose the Eppler 205 airfoil because of its excellent handling characteristics, flat bottom, and its ability to cover ground. The Guru informed me that a place called Dukes was out of Jet, so I would have to go back where I came from to complete my model. Bidding me farewell, the Guru went back to finish his house. (You figure it out? Yes, the Guru in this case is Dave Thornburg!)

So this is how the Electricus was born. It has an exceptional climb and a wide speed range. If your idea of fun is contest flying, this is the model that is going to be hard to beat. The Electricus 205 is designed to take full advantage of a hot 6-cell, OS motor and a small 2-3 channel radio. For SEAM 2-meter rules, I would recommend a Leisure OS racing or an Astro 05XL. Use a Rev-Up 7x4 prop for this class. For F3E or 7-cell contests, use the Astro-Cobalt Challenger and a 7x6 Rev-Up. But before you fly, contact NASA, otherwise they'll think one of theirs got away! If you want to fly an Electricus 205 you have to build it, so Let's Go!!!

Preparation:I have found it much easier to scratch build if you start out by cutting yourself a kit. Check the plans over to see what you'll have to buy, in addition to what you now have. All wood should be 'contest wood' for the best possible performance.

Cut the fuselage sides from two pieces of 3/32 x 3 x 36 matched C-grain, if you have it. The ribs are made by the sandwich-and-sand method. If you have trouble making your ribs, check the back issues of Model Builder, Dave Thornburg proved he knows more about making ribs than your local barbecue house ever thought of.

If you have a table saw at your disposal, make the leading edge by splitting a piece of 1/4 x 5/8 with a 30-degree cut. Follow this with a 10-degree cut on the bottom. If you don't have a saw, rough sand a piece of 1/4 x 1/4 to shape.

When you have everything prefabricated, set it out on a table and see if it looks as good as those photos the guys send in for their 'before' pictures in their kit review articles. Now you're all ready, right? You have a straight, true building board at least 36 inches long, T-pins, knives, sandpaper, plus thick and thin instant glue, Let's do it. if we start now, we can chase the thermals Sunday morning!

Building the Electricus 205: The wing is the most time consuming construction to build, so let's start on it first. Let's begin with the left center panel, so we don't cover the internal construction detail...."

Direct submission to Outerzone.

Quote: "Hi Mary & Steve, Please find attached plans and article for the Electricus, designed by Larry Jolly. From Model Builder, Vol 13, Number 134. March 1983... Special thanks to Robert W for scanning the plan in hi-res from his copy of the magazine. Kind regards,
Ian Salmon."

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