Foam Glider Conversion To EDF
I use what I have
With last summers successful conversion of an Air Hogs foam glider I decided to do another hand toss foam glider conversion, this time using electric ducted fan (EDF) units from 2 Kyosho Illusion kits I once owned. The concept for this build comes from my own fascination with NASAs B-57 Canberra research plane and the eerie similarities of a Lifoam Ultra Flyer hand toss glider that was given to me.
As is standard fare, this build was purposely created on a tight budget. The goal was to make this conversion happen using as much of my own existing materials as possible. The total build cost was approximately $45. The cost was much higher then my last build but, this was because I had to purchase two (2) 30amp brushless ESC speed controllers to ensure my 2 motors ran in sync.
The primary build materials I used were:
- (1) Lifoam Industries, Ultra Flyer (youtube video)
- (2) 45mm EDF motors (former Kyosho Illusion units)
- (2) Hobby King 30A ESC 3A UBEC
- (3) Hitech micro servos
- (1) 2200mAh 11.1 LiPo Battery (any brand)
- Scotch Heavy-Duty Strapping Tape
- 5-minute epoxy (hobby grade)
Again, I hope you find my how-to build information useful when venturing to create your own foam-to-rc conversion. Cheers!
Fuselage Build Gallery
The fuselage design was more complex because the Ultra Flyer has a much thinner fuselage profile then my previous Air Hogs kit. To accommodate the required room for electronics and battery, I had to build a belly pod. This worked to my advantage because the belly pod not only created a perfect grip for hand launching it also keeps the motors clear from ground debris on landing.
I strengthened the pod with balsa wood sides because after coring the foam for the battery and electronics, it became too thin an brittle. Coupled with wrapping it in packing tape, the belly pod is now very strong and very durable.
Engine Build Gallery
I decided to use two 45mm ducted fan units (EDF) as my power plants for this build which were left over from past Kyosho Illusion kits that I owned. Although it looks simple, coming to a solution was not. The challenge is that most EDF systems I’ve seen were installed inside the aircraft or inside a large foam housing unit. I had neither.
Additionally, I wanted to be able to quickly remove the EDFs for other projects so adhering the motors directly to the fuse was not an option I wanted to entertain. My solution for a motor mount came in the form of a paper towel cardboard tube that I wrapped around the motor.
Wing Build Gallery
The wing build followed the same approach as my Air Hogs wing build. Until aerodynamics becomes an issue (not likely), I plan on using rubber bands to mount all of my wings. It’s easy to execute and is extremely durable versus other methods I’ve tried in the past (e.g., screws).
Elevator Build Gallery
Nothing too fancy here. Again, I used a similar approach as in the past and have had great success. Unfortunately, the Ultra Flyer’s tail is more flexible then I anticipated. To increase its stiffness I cut out a slot under the fuselage and glued in a 14” wooden spar.
The following photos show close up shots of the battery bay, the ESC installation for the motors, and how I made my own servo horns from small craft popsicle sticks. For those questioning why I mounted the ESCs the way I did, the reason was simple: No room. The upshot? I know for certain that overheated ESCs will not likely be an issue.
Post Flight Notes
16 April 2014 – The maiden flight of the twin engine EDF went as well as could be expected. As you can see in the video, the aircraft’s center of gravity (CG) needs further testing. Additionally, I’m not sure if the issues is 1) too little power from the motors or, 2) severe drag from the gliders design but, at full throttle I was simply staying afloat. My plan is to adjust the wings leading edge (LE) to create a more streamlined wing geometry thus, hoping to increase lift. I’m hoping this design adjustment will also allow for a heavier payload (e.g., larger batteries) which, would equal longer flights.
After a few more test flights, I began to wonder how much of this EDFs flight issues were related to the wings leading edge. Compared to the Air Hogs wing, this models leading edge was far more rudimentary. I decided to re-shape the leading edge, reaffix the wing, and give it another try. The flight with the new reshaped wing performed far better then any flights to date. Unfortunately, the EDFs that I’m using still don’t make the cut. Regardless, this plane is still fun to fly, albeit a bit slower then I had anticipated.