UAV EFI Integration Checklist: What to Prepare

An EFI integration starts with a defined engine, a clear operating requirement and an agreed set of interfaces. Before selecting an electronic fuel injection system for a UAV, prepare the engine details, fuel specification, electrical supply, mechanical measurements and the information you need from the ECU. That brief helps the supplier identify what can be reused, what needs adaptation and what must be tested.

This checklist is for engineers comparing configurations or preparing a technical enquiry. It is a planning document, not a wiring diagram or an engine installation procedure.

1. Define the job the engine must do

Start with the aircraft’s operating requirements rather than a target engine displacement alone. A fixed-wing cruise condition, a VTOL transition and a generator supplying an electrical load are different operating cases.

Record the required output, intended operating duration, altitude and ambient temperature range. Explain whether the engine will drive a propeller, a generator or another load. Include the installation space and cooling arrangement you expect to use.

Separate requirements from measurements. “We need this output during cruise” is a design requirement. “This engine produced that output in this configuration” is a test result. Keeping the two distinct prevents a proposed system from being treated as a validated aircraft installation.

2. Identify the exact engine and fuel

Provide the manufacturer, model and revision, along with displacement, cylinder arrangement and whether the engine is two-stroke or four-stroke. If it has been modified, describe the changes. Two engines sold under the same model name may not have identical intake hardware or accessories.

State the intended fuel and lubrication arrangement. Do not treat compatibility with gasoline as evidence of compatibility with another fuel. Likewise, a test on one engine and fuel combination does not establish suitability across a product range.

If you already have a calibrated engine package, record the ECU and calibration version as part of the engine configuration. If you are considering a conversion, explain what is currently fitted and which components you want to retain.

You can review Löweheiser’s EFI engine options or ask about adapting your existing engine.

3. Check the mechanical interface

Photograph the intake and measure the relevant mounting dimensions. Include the mounting-hole spacing, available clearance, intake orientation and the existing carburetor or throttle body reference.

A matching bolt pattern is useful information, but it does not establish that a complete installation is interchangeable. Clearance, fuel connections, throttle actuation and the surrounding installation also need to be checked.

A simple package of evidence is usually more useful than a long description:

• One photograph showing the complete engine and its installation.
• A close-up of the intake interface with a scale or dimensioned drawing.
• The part reference of the existing carburetor or throttle body.
• A sketch showing clearance around the proposed EFI components.

Use dimensions for the actual hardware you have, and identify estimates as estimates.

4. Document the electrical supply

List the supply available to the engine management system and the components it must power. Identify the intended ECU, fuel pump, sensors, servo and other relevant accessories with their part references.

Ask the supplier to confirm the supply requirements for the selected configuration, including start-up conditions and the connection arrangement. Do not copy a voltage from a different ECU revision or assume that an aircraft battery can power every component directly.

Include a preliminary connection diagram in the enquiry. It should identify the equipment and proposed connections without substituting for the supplier’s approved pinout and installation instructions.

5. Define telemetry and control separately

Receiving engine data and commanding an engine are different requirements. Specify which information you need to display or record, then list any control functions you expect the flight controller to perform.

ArduPilot documents multiple EFI backends and interfaces, with support depending on the controller and configuration. Its general EFI documentation is a useful starting point for identifying the appropriate integration route.

For the specific Löweheiser generator covered by ArduPilot’s documentation, the connection uses serial MAVLink and a dedicated backend. The documentation notes that this backend is not included in the default firmware builds and requires a suitable custom build. That is a detail to establish before an integration is scheduled; it is not a statement that every Löweheiser EFI kit uses the same interface. See the Löweheiser generator documentation.

Record your flight controller model, firmware version and required data fields. Ask for confirmation of the supported hardware, software and functions as one configuration.

6. Agree what will be measured

Before a test, define the question it is intended to answer. A video of an engine running can document an operating state, but it does not by itself establish fuel consumption, installed performance or suitability throughout an aircraft’s operating range.

For a useful test record, identify the engine configuration, fuel, calibration, load, ambient conditions and measurement method. Save the relevant logs and identify the instruments used. Record unexpected behaviour as well as successful runs.

When comparing configurations, state what changed and what stayed the same. If fuel consumption is compared at different outputs or operating conditions, explain those differences rather than presenting a single percentage as a general result.

Ask the engine and EFI suppliers to agree the test sequence and acceptance criteria for the intended installation.

7. Send a brief that can produce a useful answer

A technical enquiry becomes easier to assess when it answers the following questions:

It is fine to leave a value unknown. Marking a requirement as unresolved is more useful than filling the gap with a figure from another engine or installation.

Discuss your EFI configuration

If you are comparing an existing-engine conversion with a complete engine package, start with the information above. Löweheiser can use your application brief to discuss the relevant configuration and the details that need confirmation.

Explore our EFI systems for UAV engines or send an EFI integration enquiry with your engine model, application and available photographs.