Tethered Power Solutions for Lightweight eVTOL Flight Testing

Kitefly Tethered Technical White Paper

Abstract

The rapid advancement of Urban Air Mobility (UAM) and the low-altitude economy has placed lightweight eVTOL aircraft at the center of global aviation innovation. Ensuring safe flight testing, long-duration hover capability, and propulsion-system validation remains a major challenge for developers. This white paper presents Kitefly Tethered’s high-voltage tethered power architecture—combining a ground high-power supply, high-strength HV cable, and onboard DC/DC regulation module—to enable controlled, continuous, and energy-stable eVTOL testing. Through a complete solution featuring the G40pro Ground Power System and WF24 Onboard Regulation Module, this document demonstrates how teams can perform extended hover tests, redundancy simulations, thrust verification, and flight-control tuning with enhanced safety and repeatability. The architecture offers high efficiency, reduced operating cost, and compatibility with next-generation lightweight eVTOL power platforms.

1. Background: UAM Development and eVTOL Testing Challenges

Lightweight eVTOL aircraft face multiple constraints during early-stage development:

l Limited endurance during hover

l Incomplete propulsion-system reliability verification

l Uncertain battery safety margins

l Risk of loss-of-control events

With test frequency increasing, R&D teams urgently need a solution that ensures:

l Safe fixed-area testing

l High-voltage, high-power endurance capability

l Repeatable aerodynamic and flight-control experiments

l Permission to conduct tests in urban or regulated airspace

Tethered power systems have therefore become a crucial tool for eVTOL developers.

2. Role of Tethered Systems in Lightweight eVTOL R&D

2.1 Reducing Flight Risk in Early Development

A tethered system restricts the aircraft’s altitude and radius, keeping it in a controlled test environment.
Even in cases of:

l Power interruption

l Thrust instability

l Flight-control anomalies

…the aircraft cannot drift or escape the designated zone—dramatically improving safety.

2.2 Enabling Long-Duration Hover & High-Power Tests

Traditional batteries limit test duration to just minutes.
This restricts:

l Motor efficiency curve mapping

l Thrust-stability measurements

l Redundant propulsion switching tests

l Long-duration vibration/noise evaluation

With tethered power providing tens of kilowatts of stable DC output, tests can run for hours, yielding far more reliable data.

2.3 Allowing Safe Testing in Urban or Restricted Areas

Free-flight testing often requires strict regulatory approval.

By contrast, tethered testing is more easily authorized, since altitude and flight envelope are constrained.
This enables testing in:

l Factory test halls

l Airport R&D zones

l Urban-edge industrial areas

l Enclosed eVTOL proving grounds

3. Typical Application Scenarios

1. Motor endurance and peak-output testing

2. Aerodynamic, blade, and vibration research

3. Flight-control algorithm tuning

4. Redundant propulsion system switching

5. Emergency-condition simulation

6. Controlled testing in regulated low-altitude airspace

Tethered systems ensure testing is safe, continuous, repeatable, and controlled.

4. Kitefly Tethered’s Lightweight eVTOL Testing Solution

A recent overseas lightweight eVTOL R&D project required:

l Extended hover testing

l High-voltage 1000 V DC input

l Secondary regulation to 14S (60V) onboard power bus

l Continuous, uninterrupted endurance tests

Kitefly Tethered supplied a dedicated test architecture.

4.1 Ground Power System — G40pro

Designed for High-Power eVTOL Testing

Input: 380 V AC (three-phase)
Output: 1000 V DC
Peak Power: 30 kW

Key Capabilities

l Stable HV output for direct-drive propulsion systems

l 30 kW peak for hover, pitch change, and acceleration loads

l Industrial-grade isolation for safety

l Compatible with high-voltage tether cables for long-duration tests

4.2 Onboard Regulation Module — WF24

High-Voltage → 14S Power Bus Conversion

Peak Power: 24 kW
Input: 800–1000 V DC
Output: 60 V (14S)

WF24 Enables

l High-efficiency voltage conversion

l Stable 24 kW output for heavy-load flight

l Continuous power for motors & avionics

l Zero voltage drop or fluctuation under high thrust

5. Advantages of Kitefly Tethered’s eVTOL Test Architecture

l High Safety
Eliminates risk of runaway flights.

l High-Power Capability
Supports long-duration, high-load propulsion tests.

l Lower Operational Cost
No battery swapping, no degradation cycles.

l Highly Repeatable Data
Enables controlled, repeatable test conditions.

l Roadmap Compatibility
Fully aligned with modern lightweight eVTOL power levels (800–1000V).

This architecture forms a foundation for large-scale future validation.

Keywords:
tethered eVTOL testing, 1000V DC ground power, G40pro, WF24, eVTOL hover endurance, Urban Air Mobility testing, lightweight eVTOL development, tethered power supply system

Request a Customized eVTOL Test Solution

Our engineering team can tailor a tethered-power architecture for your propulsion voltage, motor system, and testing roadmap.
Email: susy@tetheredsystem.com
Website: www.tetheredsystem.com