Air Hogs Foam Glider Conversion
You could say that this is yet another foam glider conversion to rc, and like many rc enthusiasts before me, and you’d be right. But rather then show you the end result, I want to share exactly how I built this creation. While this may not be the best airplane for a first time pilot, an experienced hobbyist looking to try something new will surely enjoy the easy build and its stable flight characteristics.
I’ve provided some in-depth image galleries of the construction techniques I used when converting an Air Hogs Titan foam glider to rc. Materials I used were:
- (1) Air Hogs Titan foam glider
- (1) E-flite Brushless Park 450 motor
- (1) Castle Creations Phoenix 25amp electronic speed control (ESC)
- (3) Hitech micro servos
- (1) 9×7.5 SF Slo Flyer APC propeller
- 1300 mAh 11.1v LiPo Battery (any brand)
- Scotch® Heavy-Duty Strapping Tape
- A hot glue gun
- 5-minute epoxy (hobby grade)
Electronics and the glue gun aside, this build was purposely created on a tight budget. The goal was to use only the electronics I owned and focus on a build that can be done by even the most novice of builders. The total cost of materials, Air Hogs glider included, was approximately $25. I hope you find my how-to build useful when venturing to create your own foam-to-rc conversion. ‘Njoy!
Wing Construction Gallery
The wing was where I spent most of my time for the build. A majority of this time was spent planning how to assemble a strong wing with simple and affordable basswood spars, not carbon fiber. I removed the wing dihedral but, kept the swept back design of the wings the same.
5 September 2013 Build Note
After further flight testing, I found the best location for the Center of Gravity (CG) was approximately 75-80mm from the tip of the leading edge of the wing (measured from the center of the wing).
Fuselage Construction Gallery
To add more stability to the aircraft design I shifted the wing mount to the top of the fuselage (not the middle, it’s original location). This also created a stronger wing mount design using wing dowels and rubber bands.
Elevator Construction Images
Through experience and test flying I learned one should not use packing tape to adhere the wood elevator. My construction came apart mid-flight and almost caused catastrophic failure. I changed my design to instead use CA Hinge’s and epoxied them to the foam. Don’t use CA glue on this type of foam as it will melt the foam when applied.
Modifications v.1 & 2
After the preliminary test flights, I found a few structural items that needed to be addressed. The biggest issue was the amount of flex the elevator was showing when achieving higher speed flight. To remedy this, like the wing, I installed some basswood spars with epoxy. Also, I filled in the wing holes (from the original design) using the foam I had cut off during the wing construction.
The focus of this modification was to create a larger battery bay. At the time I was using 3-cell 1350mAh lipo’s for flights, however, I had several 2250mAh and 3200mAh batteries available for use. Keeping the structural integrity of the fuselage was my greatest concern since the size of the bay was going to be triple the size I currently had. Also, the need to shift the batteries forward or aft (in the bay) to keep the center of gravity the same was going to be a requirement. The test video shows how well the plane performs with the weight of a 2250mAh 3-cell lipo in the battery bay. This gave me a comfortable 22 minute flight at approximately 60% throttle. Later tests proved the weight of the 3200mAh was negligible and provided over 35 minutes of flight time. The weights of the batteries are as follows:
- ThunderPower 3-cell 1350mAh 11.1v, 89g
- Pulse 3-cell 2250mAh 11.v, 205g
- E-flite 3-cell 3200mAh 11.1v, 248g
Modification 3 Test Flight Video
Modification 3 Image Gallery
Modification v.4 Leading Edge of Wing
After having flown the Air Hog all summer long, the leading edge of the wing started to show significant damage where the rubber bands held it in place. Repairs were clearly required but, only to a small portion of the wing so I decided to cut out the damaged areas and replace the foam with a hard balsa wood triangle. I decided to use a balsa wood triangle rather then a symmetrical leading edge because I needed to hand sand the balsa to match the shape of the Air Hog leading edge. I cut out a 2 inch slot for each of the leading edges, hot glued the balsa pieces in place, and sanded to match the wing shape.
Modification v.5 Adding Winglets
Using the left over parts from when I trimmed the elevator (see Elevator Construction Images above) I decided to experiment with winglets to see if there would be any significant change in flight characteristics. My assumption was that the winglets would make the aircraft more stable and increase efficiencies (i.e., less drag). The reality was that the winglets created more drag when I recorded increased times during high speed test runs. While a novel idea in concept, the winglets served no benefit to this prototype other then to make it look cool.
Several people have asked to see more video of this build in flight. Below is a video short showing some of its characteristics in low level flight.