The Aero-Grid is a tethered, high-altitude (sub-150ft for testing, up to 500ft for deployment) platform designed for autonomous power generation and long-range communication. It utilizes a stabilized tri-balloon array, Archimedes screw turbines, and PCB axial flux generators to provide a self-sustaining energy source for onboard systems and a ground-based load.
- Configuration: Three balloons arranged in an equilateral triangle (120° separation).
- Thermal Lift: Each balloon contains a dedicated Nichrome heating element controlled via PWM from the central ESP32.
- Differential Buoyancy: By varying the heat in each balloon, the system can actively control pitch, roll, and altitude, counteracting "blow-down" from wind gusts.
- Materials: Biaxially-oriented PET (Mylar) or TPU to withstand internal heating without melting.
- Structural Frame: Constructed from 6061-T6 Aluminum, acting as both a rigid chassis and a heatsink for power electronics.
- Decoupled Drive Train:
- Horizontal mirrored shafts supported by Ceramic Hybrid Bearings.
- Thrust Bearings to handle lateral wind pressure.
- Flexible Jaw Couplings between the turbine and the generator to absorb vibration.
- Type: Twin Archimedes Screw Turbines (Horizontal axis).
- Dimensions (Optimized): 0.8m diameter x 1.5m length per turbine.
- Scaling: Designed for high-torque, low-starting wind speeds to ensure rotation in ground-level boundary layers.
- Design: Dual Axial Flux Generators using multi-layer PCBs as stators and N52 Neodymium rotors.
- Configuration: Mirrored on the horizontal shaft to cancel torque-twist on the tether.
- Independent MPPT: Each generator has its own Maximum Power Point Tracking (MPPT) controller to optimize energy extraction from independent wind eddies.
- Storage: Central Supercapacitor bank (for high-current radio bursts) and a LiFePO4 battery bank (for thermal and base load endurance).
- Onboard Inverter: High-frequency, transformerless inverter converting DC buffer power to 120V/240V AC for:
- Balloon Heaters.
- Ground-based load via the tether.
- Rectification: AC from PCB generators → DC via Bridge Rectifiers.
- Regulation: MPPT optimizes DC voltage for the Battery Room.
- Step-Down: DC-DC Buck converters provide clean 5V/3.3V rails for the ESP32 and Ham Radio.
- Priority Tree: Buoyancy (Heaters) > Logic (ESP32) > Transmission (Radio) > Ground Export.
- Protocol: LoRa APRS (433.775 MHz) or high-power 70cm/2m FM relay.
- Power: Onboard power allows for 10W - 50W RF output, significantly increasing regional footprint.
- Antenna: Omnidirectional vertical whip or stabilized directional Yagi (enabled by the stable tri-balloon platform).
- Platform Brain: ESP32-S3 managing the PID loop for altitude and the telemetry stream (Battery SoC, Wind Speed, Temperature, GPS).
- Startup: Ground-based AC power is sent up the tether to initiate the heaters.
- Ascent: As lift increases, the platform rises to the "Wind Sweet Spot" (>100ft).
- Hand-off: Once the Archimedes turbines reach operating RPM, the ground power is disconnected, and the platform becomes a net-exporter of energy.
- Aviation Compliance: Below 150ft for testing to minimize FAA oversight.
- Visual Warning: Aviation Orange blades, navigation strobes, and tether streamers.
- Emergency: "Burn-wire" rapid deflation system triggered by the ESP32 if the tether tension is lost or the platform enters restricted airspace.
- Distance to Horizon (d): d \approx 1.22 \times \sqrt
- Wind Power (P): P=21ρAv3Cp
- Buoyancy Gain: ~0.3% lift increase per 1°C temperature rise.