FPV

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

1. 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
2. One energy-source, single set of batteries for motor, camera, OSD, VTx, Rx, servos
   • Minimized weight, as batteries contribute as the heaviest component
3. 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
4. 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]
5. 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
6. Power- and signal-wiring separated as much as possible
   • Noise from motor can degrade digital signals if coupled with signal-wires
7. 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
8. 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
9. 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
10. 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
11. Proper cooling of video-transmitter using an appropriate heat-sink and thermal-adhesive

Plane

1. A wing for speed and stability
   • Makes it possible to fly in windy condition and greater distances, less drag
2. 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
3. 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
4. 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
5. 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.

• Futaba 6EXP PPM/PCM 1024 35MHz [8]
• Futaba 9CHP-PCM 36MHz [9]

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

• Hacker A30-10L V2 [16]
• Turnigy 35-36B 1300Kv Outrunner [17]

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

• Hitec HS-645MG [19]
• Gaupner Servo DES 708 BB MG [20]
• Turnigy 380MAX Micro Servo [21]

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

Build logs

• Ultimate Ritewing Zephyr - Trappy
• Trappy Maxi Swift
• Project transportable / Bandarra's 54-inch Zephyr