Hi All,
I've been experimenting for a while now with an electric replacement for a good .15 size IC engine. I had used many of the MVVS .15 twin ball race engines through the years because I was the local agent out here for 11 years or so. I was involved in the training of kids in the late 90's and early 2000's and I always believed that a .15 size stunt trainer was a better deal than the usual .049 or Babe Bee size planes. After trying quite a few designs I came up with a simple trainer that flew our Novice pattern really well. It was relatively easy to build and this started me out on my EZE series. The Eze-1 that I built for one of my kids, is still flying today about 16 years later, and has been rebuilt a few times by my young friend Theo Kleynhans.

I have quite a few small motors that do not work and then I figured out that I need a motor that weighs 65 to 75 grams with a Kv of 1400 to run on a small 3-cell lipo. Our Novice pattern is similar to the full pattern but leaves out the outside squares, triangles, square eights and hourglass. It takes around 3.5 minutes to complete so I worked on a flight of 4 minutes with a 1300 mAh 3-cell lipo. They are nice and compact these days so I set about building a plane to do the testing. I also wanted to try a few other idea's on how to make an electric installation that was neat, and an undercart that could be changed for a hard circle or grass. Something like a "one size fits all sorta thing"!

I decided to use a built-up fuselage and bolt the motor straight on the nose, so that I could test different motors easily. The motor that looked like the real deal to me was one of the new Black Tiger 3530C motors from RSM. These motors are nicely made with decent bearings and a nice open front end on the drum for air to go through. I used one of my Compact timers with the small pushbutton, and for this one I used a switch with a longer actuator rod on it. Everything worked out reasonably well, and I called the design the "Elec-Trick"..........for want of a better name at the time.

I wanted to use an 8" prop for good ground clearance so I chose the APC 8 x 6 E and set the rpm at 11 000. I made a set of Spiderwire lines to exactly the same length as Theo's cable lines for his EZE-1. You can see the pics of the two planes below. It flew at very much the same lap times as Theo's Eze-1 with the MVVS .15 and Master Airscrew 8 x 5 prop. It also flew the 4 minutes with around 18% left on the Hyperion battery checker. I later tried an APC 9 x 6 E prop set down to 10 000 rpm. It uses a little more power but can still make the Novice pattern with ease. I would say that the bigger prop flies with a lot more authority. This was a really successful project and I'll now make a simpler profile model to share with the budding novice pilots.

I have included pics of my reversible undercart that's made with a block of hard wood (I used pine), and you simply unbolt, swing it around and it places the wheels more forward or more backward. I cut the slots on the block with a handsaw and it really works well. The little girl holding the model is one of my neighbours kids named Juanita. The Elec-Trick looks quite big when she holds it. Oh, and just btw, the Spiderwire lines work really well and I would say that they are easier for newcomers to get as well, especially out here in Darkest Africa! I did managed to prang this model and the nose broke off, but I found that it was a little tail heavy so when I fixed the nose I made it a little longer and it's now working very well.

I have made a neat and simple winder for the handle and lines out of 3 mm Corregated plastic like Coroplast. I'll post some pics and details later.

Keith R

Interesting planes.
keep the pics going.


Warren

Looks like the battery wipes out the leading edge but, does the spar go all the way through?


MM

Keeping the control system accessible is a good idea in and of itself, in my opinion.  Once you get good, then bury the thing!

Thanks very much for the nice comments. I've since found that it needs even more nose weight so maybe I made the rear end a bit heavy. I want to make a simpler profile now the same size for beginners to build and then I'll post all of the details and a plan.

Keith R

Hi Chris, I was trying to make this a "low-tech" project, and a 4mm dowel is pretty light and available from most local hardware stores around here. Sure you could use flaps on this system as well, but for this sort of stunt trainer, it isn't necessary. The wing is also quite flimsy when built like this, so the covering does the stiffening up job. When I was teaching kids it was a good training system to teach them how not to warp wings when using the shrinking iron, and also how to "bend them straight" afterwards. 

Keith R