I have piloted the first successful flight of my experimental RC plane made from easily obtained parts.
Now I will share my creation so others may experiment with the design themselves.
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Finished Product
Video of short successful flight into tree. |
Control Demo Video
After crashing a balsa R/C airplane and contemplating the repair time, I decided I could make an entirely new airplane which would be much easier to repair in the event of unplanned ground contact.
There are quite a few resources out there for aspiring R/C builders:
The SPAD (Simple Plastic Airplane Design) Forum on rcgroups.com
http://www.rcgroups.com/spad-simple-plastic-airplane-designs-176/
SPAD to the Bone (their websites are a little scattered after they lost "spadtothebone.com")
http://spadtothebone.net/ or http://www.spadtothebone.org/ or http://spadworld.net/forum/
Ed's Experimental Airlines Youtube Channel - Dollar Tree Foamboard Planes
http://www.youtube.com/user/ExperimentalAirlines
A great source for cheap RC supplies
www.hobbyking.com
Design Constraints
- Wing made from one standard 18"x24" 4mm coroplast campaign sign.
- Tail attached using a standard 48" dowel, cut in half.
- Must work with my existing R/C setup (2 servos, ESC and LiPo Battery)
Having these constraints actually made the project a lot more fun for me and kept it from getting too expensive.
Supplies
Body
- One standard 18"x24" 4mm corrugated plastic campaign sign
- Two 48" long, 0.21" diameter wooden dowels. (this is just the common size, for this project you only really need two 24" and one 36" dowel)
OPTIONAL - Two 48" long carbon fiber tubes instead (much stronger)
OPTIONAL - Use arrow shafts, they are between 22 and 30" and you can sometimes find free ones
- One small plastic Odwalla bottle
- 4mm thick square piece of wood to fit in bottom of Odwalla bottle
- A bunch of zip ties
- Double sided foam tape
Electronics/Control/Prop
- ESC (Electronic Speed Controller) (20 Amp)
- Electric Motor (1400kv Brushless Outrunner)
- Plastic Prop (10x9)
- Three metal pushrods w/ threaded ends and clevises (18"x2mm diameter)
- Three nylon control horns with screws
- Three linkage stoppers (or you can just bend the pushrods into the holes)
- Two servo arms
- Two servos (Futuba)
- Receiver (Futuba)
- Transmitter (Futuba)
- LiPo Battery (Zippy 2200 30C 3S)
- LiPo Charger/Balancer (Thunder AC6)
You will need to figure out how to hook the LiPo, ESC, Motor, Receiver, and Servos together yourself. I soldered old molex connectors to the LiPo and used a lamp power switch.
Overview
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CAD diagram showing the main dimensions, structural components of the airplane, and proper orientation of corrugated fluting.
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Here is a link to a PDF of the above diagram:
https://www.dropbox.com/s/b6qhd1a3k055w8e/CampaignSignPlane4.pdf
Construction Directions
- Cut wings and tail from campaign sign (you may be able to use just one sign if you are careful)
- Cut two 24" dowels and one 36" dowel
- Cut along top flute approx 1.5" back from leading edge of main wings
- Bend leading edge up and back
- Fasten the main wing together using the 36" dowel and zip ties
- Fasten main wing back along centerline using zip ties, possibly adding a thin balsa rectangle for strength
- Make elevator and ailerons by cutting wedges out from the sides and making hinges as shown below
- Tuck the 24" dowels under the 36" dowel
- Fasten 24" dowels to wing and tail using zip ties
- Cut a hatch from the Odwalla bottle
- Place wood inside bottom of bottle
- Fasten motor to wood using 4 screws through outside bottom of bottle, making sure it spins easily (you may need a spacer of some sort, depending on your motor)
- Fasten bottle to main wing using zip ties
- Screw control horns on to ailerons and elevator
- Fasten the top wing elevator servo using zip ties
- Fasten the under wing aileron servo using zip ties
- Cut pushrods to appropriate sizes and attach clevises
- Attach pushrods to servos and control horns
- Fasten receiver and ESC using double stick tape/zip ties
- Switch main power off, connect all electronics
- Push LiPo battery into Odwalla bottle so that it will not come out in flight
- Perform prop test in a safe environment so as not to cause damage/injury in event of failure
- Calibrate servos
- Fly!
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| Detail of a wire I added across top to keep the wing rigid |
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| Detail of aileron and zip tie |
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| Detail of elevator control horn and clevis |
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| Vertical stabilizers added by cutting notches in tail and fins |
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| Detail of motor mount |
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| Odwalla bottle battery housing |
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| Under wing aileron servo with protective bottle |
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| Under wing aileron servo |
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| Detail of under wing aileron control horn and clevis |
Cutting Hinges into Corrugated Plastic
Because of the side to side orientation of the fluting I was able to create ailerons and an elevator without any additional hardware by carefully cutting the plastic along alternating flutes.
Use a knife or scissors to slice down the flutes, it is tricky at first, but goes smoothly once you get the hang of it.
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| CAD diagram of coro hinges |
