RC Aircraft

Cheetah RC Conversion

Conversion Steps

Decided to try using pitcherons/wingerons instead of elevators and ailerons. From the videos I watched, it allowed the glider to do tight rolls. I used this video as the main reference. This video was helpful when figuring out the tranmitter mix for the pitcherons, and this video was as well when it came to the idea of using a quadcopter ESC and a mini DC-DC voltage buck converter for the BEC.

First step was to figure out how to do the wingerons. I marked the CG points under the wing with the glider all put together before doing anything else. I used a 3mm carbon rod instead of the 4mm one mentioned in the reference video. I created some half-tubes in Blender that I could just glue together, and then hot glue in place on the wings, which I figured was much easier than sourcing the right size carbon fiber tube, and also created and printed some endcaps. After gluing the two-halves of the four small tubes together, I put them on the carbon fiber rod and glued on the endcaps. I created a channel on the wings for the rod, and taped the wings together so they wouldn't move when gluing down the four tubes into the wings, as well as the carbon rod itself to the middle section.

Created and printed out some small square tubes that would hold the 1mm wire control linkages on the wings in place when installed on the servos. These were glued in after cutting out channels for them on the underside and inside front of both wings. This was easier than drilling into the wings as shown in the reference videos. Made some z-shaped control rods that would first slide into the square tubes on the wings, and then could be slightly bent outwards to place the other end of the wire in the servo control horn hole to spring back and lock into place.

Wings being marked, cut, and glued for pitcherons

I used a coat-hanger thick wire heated with a propane torch to melt channels from the fuselage to the motor, as well as from the fuselage to the servo cutouts for all the wiring. The completed wings with the glued rods was placed into the fuselage. The control rods were connected from the wings to the servos.

For wingeron/pitcherons, pulling down on the right stick should result in the leading edge of both wings going up, trailing edge going down. Pushing up on the right stick does the opposite, leading edge of both wings should go down. When pushing the right stick to the right, the leading edge of the right wing should go down, and the leading edge of the left wing should go up. Pushing the stick left should do the opposite. View the reference video for details.

Servos and linkages

I didn't like the old-wooden-stick-found-in-the-woods as a motor mount as was used in the reference video, so I decided to create one myself in Blender to 3D print.

Custom motor mount

Cut some space on the left of the cockpit for the ESC, and in the back and straight down for the receiver. Then cut space at the front for the battery and down under the rectangular foam piece that holds the canopy, making sure to keep the CG in balance. The two ball bearings were removed from the canopy, and parts of foam at the front and back were also cut out to allow room for the wires and connectors.

Cockpit cutout for components

The original 12 amp ESC that came bundled with the motor was basically useless. The motor would stutter quite badly at low throttle, even after calibration. Some forum threads stated this was normal, however, this is the first time I've encountered such an issue. The bigger problem was that after a few minutes of flying, the motor would just shut off, and it seemed be after trying a higher throttle maneuver. I tried another 10 amp one, and the issue was the same, motor would stutter at low throttle and die after high throttle from the ESC resetting. Not quite sure why considering the reference video showed he was using only an 8 amp ESC. It could also just be a problem with my particular motor, it could be slightly defective and drawing too many amps. My guess was that it needed at least a 20 amp ESC so to save space instead of using the standard bulky RC plane type, I used a 20 amp ESC for quads as well as with a mini DC voltage buck converter, as was shown in this video. I put an extra 20v 220uf capacitor across the power input leads just to be safe, even though there's a SMD one on the ESC board.

Completed Model

After getting the mix into a better state (about 60% for ailerons compared to elevator), I created a mount for the Hawkeye thumb camera, and ran another wire through the fuselage to connect it to the battery charge lead.

Morning Glide

Parts List

Cheetah STL Files: Left and Right base parts of the motor mount need to be printed with supports, then glued together afterwards. Top part of motor mount can then be attached with two M2x5 screws, as well as the motor itself with four M2x5 screws.