Experimental EDF Glider

I wanted to see how a glider-type design would fly with the addition of a powerful EDF. Here's how the project went.  

One reason why I love flying machines is that there's simply so much variation; you can find aircraft in all shapes and sizes, in many different configurations and combinations. You can also sometimes find mixtures of two entirely different concepts. This week, I wanted to try a crazy hybrid of my own - an EDF glider.

Aims 

To find out as much as I could from this project, I thought it might be a good idea to set out some clearly defined targets for this airplane. It was built to investigate three specific unknowns: 

1. Configuration - Does a plane with a jet mounted above the wing produce desirable characteristics? 

2. Wingtip design - Do downward drooping wingtips do anything to affect the flight experience?

3. FPV - How does this configuration lend itself to First Person View flying with a camera? 

Video

To see how the whole project panned out, here's a video. Once you've viewed it, read on to discover how this project went down in more detail.

Design 

Like most of my projects (because I live in the dark ages and have rather limited CAD skills), this plane started life as a collection of sketches in my book of ideas. Doing many simple drawings really helped to develop ideas from my head in a short space of time. 

To get the build underway, I grabbed a spare MiG 3 wing I had lying around and used it as my guide to the rest of the airframe. Using predesigned parts like this can really help you when it comes to designing your own models: not only does it save time, it ensures that the part is tried and tested. With this EDF glider, it was one less thing to go wrong and, subsequently, one less thing to worry about!

The fuselage was cut out of our favorite water-resistant foam board here at Flite Test. It's a simple boxy design with a curved front. These are quick to design and easy to assemble. 

The EDF was mounted atop two supports. These were made from doubled up (laminated) foam board. Two strips of thin plywood were then glued above this to screw the EDF unit onto. This means that the whole unit is removable. You just have to unplug the ESC bullet connectors to pull the whole thing out. 

Testing 

The first flights of this new bird were surprising, to say the least! Despite the aircraft weighing in at nearly 600g, which isn't exactly that light for a model of this size, the model performed really well. It cruized around without much power needed and generally flew with the handling of a much larger, docile airplane. 

As you poured on the beans, though, this thing really rocketed along. It was pleasing to have come up with an airplane that could float much like a glider and yet accelerate to much greater velocities with a mighty whoosh. The configuration didn't seem to have any negative effects, with the EDF being mounted up high on the wing. 

When it came to changing up the wingtips, I found that the modifications really didn't affect the flight handling much, apart from making the roll rate a little more responsive. The downward dropping anhedral canceled out some of the polyhedral designed into the MiG wing meaning that, without becoming unstable, the model could rotate much faster around its lateral axis. 

With the addition of a GoPro and a 25mw FPV micro cam, the fun factor went to even greater heights with this aircraft. I was slightly worried that airflow disturbance from the rather square GoPro would affect the efficiency of the EDF, but it seemed that the top speed of the model remained much the same. Whizzing over treetops, punching it up to altitude and then cutting power completely to glide down was an exhilarating way to fly from a first-person perspective.

Results

In all, this aircraft proved itself a capable, well rounded and versatile platform for experimentation. It's actually very easy to fly, probably thanks to its high wing and in build stability. The thing is such a blast, with a massive amount of power available that you never need to rely on; the aircraft glides like a glider yet fires up like a fighter.

The wingtip mod effects seemed negligible. There was a slight improvement in roll rate, and it potentially helped to create a small ground effect on landing, yet the main benefit to the airplane is in the aesthetics - the wingtips just look darn cool. 

I feel that this concept could be developed further to turn this plane into a super easy to build and straightforward flying RC jet. If you make one like this, let us know in the comments or by writing about it on the Flite Test Forum! 

Article by James Whomsley

Editor of FliteTest.com

Contact: james@flitetest.com

YouTube Channel: www.youtube.com/projectairaviation