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

Video system

Cameras

• Sony SN555/VSN700 camera - 768x494 resolution, 12V
• Sony SN777 - 752x582 resolution, 12V, can be noisy [2]

Transmitters

• Lawmate - Range of different models
• Airwave

Receivers

• EagleEyes FPV Station - Receiver with antenna diversity, antenna tracking
• Immersion RC Duo 2400 diversity receiver

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 [3]
• Fat Shard RCV922 Aviator - Video input, 640x480 resolution, Vin 6-12V [4]

Control system

Radios

The 35MHz radio will not be used, the PPM signal is feed to the long range transmitters.

• Futaba 6EXP PPM/PCM 1024 35MHz [5]
• Futaba 9CHP-PCM 36MHz [6]

Transmitters

• ImmersionRC EzUHF transmitter - Connects to any PPM radio via trainer-port, 433 MHz frequency, 200mW or 600mW power-mode, 9-12V prototype model
• Dragon Link transmitter - Transmits at 433MHz, 500mW [7]
• Thomas Scherrer OZ2CPU UHF system - Many hardware revisions, hard to keep track

Receivers

• ImmersionRC EzUHF receiver - 8-channel receivers, diversity signal/dual antenna
• Dragon Link receiver - 500mW

Other

• ImmersionRC EzAntennaTracker - Uses GPS-coordinates from EzOSD inserted in the right audio channel

Planes

• Ritewing Zephyr - Foam wing base, glass fiber rods, and winglets [8] [9]
• Multiplex Easystar - Simple glider-plane [10]
• ParkZone Radian PNP - Glider, prop in front, huge easy to spot [11]
• EasyStar - Cross between glider and sport plane, 3-channel, easy to modify [12]

Other

Motor

• Hacker A30-L [13]

Propeller

• Turnigy 10x6 folding blades

Servos

• Hitec HS-645MG [14]
• Gaupner Servo DES 708 BB MG [15]

Batteries

• Turnigy S3 2200 mAh
• Zippy S3 2200 mAH - Cheap Hobbyking packs

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 [16]

Glue

• 3M 90 adhesive - Spray adhesive for base to add laminate
• Zap-a-Gap CA glue - For sparing bars in wings
• Goop - Fasten winglets

Tape

• 3M Mailing & Storage tape - Mount elevons to the airframe, 1/3 on the elevon, UV resistant [17]

Shops

• readymaderc.com - Offer a range of products from the main manufacturers