FPV
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Flying electronic RC planes from the ground is fun. Piloting a FPV plane from First Person View is really cool. With the arrival of light and powerful video stream transmitters and long range remote RC transmitter modules , the range of flight has increased from line-of-sight to an order-of-magnitude wider.
Research
To build a reliable platform I want to begin with the fundamental basics and then extrapolate more specific products.
Electronics
- Lower frequency will allow greater range, longer wavelength requires larger antenna
- Higher frequencies, 2.4GHz or 5.8GHz, will quickly get attenuated by the atmosphere
- One energy-source, single set of batteries for motor, camera, OSD, VTx, Rx, servos
- Minimized weight, as batteries contribute as the heaviest component
- Receiver antenna diversity for maximum flexibility of the airplane, each antenna 90 degrees perpendicular
- Omni-directional antennas will have a radiation pattern much like a form of a doughnut, with dead-spots center, above and below
- Same radiation polarization on ground station and airplane where possible, alternatively circular polarized ground antenna
- Signal quality of same polarized electric fields can be many tens of dB different [1]
- Parallel 3S 11.1V Lithium-ion Polymer batteries, both on plane and ground station
- Prevents voltage drop if one cell is bad, might add reverse current protection (diode) to avoid 3S "charging" the then 2S battery
- Power- and signal-wiring separated as much as possible
- Noise from motor can degrade digital signals if coupled with signal-wires
- Shielded components and twisted wires to eliminate noise and oscillation, PCB ground plate facing interference source
- Minimize both ambient noise and interference from nearby components, think of a long wire as an antenna that picks up anything
- Video-transmitter on a higher frequency band than RC-transmitter, 1.3GHz VTx and 433MHz RCTx
- Having the same frequency/band on VTx and RCRx will cause signal degradation
- Video-transmitter, as well as RC-receiver, powered by 5V voltage from main Lipo-batteries
- When the main engine batteries are drained, for 3S the low voltage limit is 9.6V, the rest of the system can still function
- Clone aileron servo signal to use two servos per wing
- Prevent loss of control on servo failure, must be mounted close together to drive force-drive the dead servo, might drop this
- Proper cooling of video-transmitter using an appropriate heat-sink and thermal-adhesive
Plane
- A wing for speed and stability
- Makes it possible to fly in windy condition and greater distances, less drag
- Batteries in front and electronics behind the batteries, suitable motor to create enough lift
- Front heavy for stable dives when motor is inactive and in up- or down-drift
- Find the center of gravity by temporarily putting everything where they're supposed to go
- Makes it easier to find where the sparing bars between the wings will go and position of the motor mount
- Motor mount on or close to the center of gravity
- Easier to handle during acceleration and less wobbly when the force is pushing the center instead of the back end, imagine a horizontal axis over the wings as center of gravity
- Antenna for VTx mounted at the end and center of the left-wing, while the two RC-receiver antennas on the other right-wing, shifted 90 degree
- Minimize interference between the two radio systems, 90 degree angled to allow cross-polarization, both vertical and horizontal for better signal quality at different plane orientations
Gear
Use this as a guide to ballpark what is needed and then just pick whatever falls inside your needs and specifications.
Video system
Cameras
- Sony SN555/VSN700 camera - 555 lines resolution, 12V
- Sony SN777 - 555 lines resolution, 12V, can be noisy [2]
- Black Widow KX131 Color Camera - 380 horizontal lines of resolution, 5V [3]
- FPVCAM-480 OSD - Resolution 480 lines, 12V [4]
- GoPro HD Hero - On-board recording
Transmitters
- Lawmate 500mW 2.4Ghz TX [5]
- Airwave
Receivers
- EagleEyes FPV Station - Receiver with antenna diversity, antenna tracking
- Immersion RC Duo 2400 diversity receiver
Antennas
- Active Robots 433 MHz Straight and Angled
On-Screen Display
- ImmersionRC EzOSD - Uncluttered display, GPS on-board, signal strength indicator via I2C, current/voltage sensor with Deans
- Eagle Tree OSD Pro
- DOSD
Goggles
- Fat Shark RCV230T/922T Teleporter - All-in-one, limited 320x240 resolution and range [6]
- Fat Shard RCV922 Aviator - Video input, 640x480 resolution, Vin 6-12V [7]
Control system
Radios
The 35/72MHz radio will not be used, the PPM signal is feed to the long range transmitters.
Transmitters
Connects to any PPM radio via trainer-port.
- ImmersionRC EzUHF transmitter - 433 MHz frequency band, 200mW or 600mW power-mode, 9-12V prototype model
- Dragon Link transmitter - Transmits at 433MHz, 500mW [10]
- Thomas Scherrer OZ2CPU UHF system - Many hardware revisions, hard to keep track
Receivers
- ImmersionRC EzUHF receiver - 8-channel receiver, signal diversity, 50A current-sensor, 10 Hz GPS
- Dragon Link receiver
Other
- ImmersionRC EzAntennaTracker - Uses GPS-coordinates from EzOSD inserted in the right audio channel
Plane
Airplanes
- Ritewing Zephyr - Foam wing base, glass fiber rods, and winglets [11] [12]
- Multiplex Easystar - Simple glider-plane [13]
- ParkZone Radian PNP - Glider, prop in front, huge easy to spot [14]
- EasyStar - Cross between glider and sport plane, 3-channel, easy to modify [15]
Motor
ESC
- Hacker X-55 SB Pro Brushless Motor Speed Controller ESC 55A
- Turnigy Plush 60A ESC [18]
Propeller
- Turnigy 10x6 folding blades
- Aero-Naut CAM foldering carbon propellers
Servos
Batteries
- Turnigy S3 2200 mAh
- Zippy S3 2200 mAH - Cheap Hobbyking packs
- Flightmax S3 2200 mAh [22]
Charger
- Bantam BC-6 - Korean, high quality
Materials
- Laminate - Apply to foam wing to give it a outer strength and cover for paint
- Riteweave - Flass fiber mesh to add strength over open cuts in the foam [23]
Glue
- 3M 90 adhesive - Spray adhesive for base to add laminate
- Zap-a-Gap CA glue - For sparing bars in wings
- Goop - Fasten winglets
- Epoxy adhesive - Properly fasten the motor mount plate to the surrounding foam
Tape
- 3M Mailing & Storage tape - Mount elevons to the airframe, 1/3 on the elevon, UV resistant [24]
Shops
- readymaderc.com - Offer a range of products from the main manufacturers
- [25] hobbyking.com] - All-around-supplier of batteries, servos, motors, cables, wires, rods
- hobbywireless.com - Everything cameras and transmitters
