Flight Level Engineering Application Story

Have you ever wondered how flight test professionals truly understand the complex flight control laws of a modern aircraft? Flight Level Engineering (FLE) Navion Variable Stability System (VSS) In-Flight Simulator sets a new standard in aviation testing and training. This innovative platform allows students to directly experience how High-Order Flight Control Systems translate pilot inputs into flight. It’s more than just theory, a VSS can mimic everything from agile fighters to large transport aircraft, letting flight test engineers, and aspiring test pilots feel the subtle yet critical differences in control laws, handling, and flying qualities. This builds invaluable skill for evaluating and troubleshooting advanced aircraft.

FLE is a leading innovator in variable stability flight simulation, one of only two commercial organizations in the world focused on VSS In-Flight Simulators. In a recent project, they integrated Iris Dynamics’ ORCA-6-24V smart linear actuator into an experimentally modified Ryan Navion airframe, enabling a fully controllable throttle input within a custom fly-by-wire system. In this application, the ORCA actuator functions as an actively controlled throttle, designed to simulate the physical resistance a pilot would feel in an aircraft. Unlike passive throttle setups that rely on fixed friction mechanisms, the ORCA enables software-defined control loading. Engineers can precisely adjust how much force is required to move the throttle and how it responds to pilot input. This tunable feedback helps prevent overcorrection or unintended inputs, especially during high-workload situations, and plays a critical role in creating high-fidelity in-flight simulations. For all pilots, engineers, and trainees, this realism improves muscle memory, enhances control accuracy, and supports more reliable system validation.

For these simulations to feel authentic, accurate tactile feedback is essential. The sense of resistance and motion in cockpit controls helps pilots interpret aircraft behaviour, develop muscle memory, and maintain fine control under varying conditions. Without this feedback, pilot inputs can become less precise, reducing the value of the simulation. Until now, their fly-by-wire setup lacked an active throttle system with adjustable friction, which had been a key missing component for replicating realistic throttle response.

The Challenge: Simulating Realistic Throttle Friction in a Compact Package 

One of the key challenges was simulating the adjustable friction found in real aircraft throttles using a compact, all-electric actuator. Traditional throttle controls rely on mechanical linkages and passive detents to create resistance. To create a realistic simulation environment, the team needed a system that could provide software-controlled friction, respond dynamically to pilot input, and physically fit within a constrained cockpit layout. Just as importantly, it had to meet strict safety requirements, including the ability to enter a compliant state when unpowered. In this context, compliance means the actuator allows the shaft to move freely without applying force which provides a mechanical fallback in case of power or control failure. The ORCA motor delivered all of this in a single integrated unit, eliminating the need for custom mechanical systems, external sensors, or dedicated fail-safe hardware.

Traditionally, achieving realistic throttle response in a simulator requires building a custom closed-loop force control system. This involves installing load cells or position sensors to measure pilot input, designing mechanical linkages to handle force transmission, and writing software to interpret those signals and command actuator response in real time. While Flight Level Engineering had the in-house expertise to do this, developing the mechanical design, integrating sensors, tuning the control loop, and validating the software would have consumed significant engineering time and development costs.

Instead, the team selected an actuator that simplifies this process by handling force control natively. The ORCA-6-24V combines internal sensing, control logic, and a linear motor in one compact, self-contained unit. It eliminates the need for external load cells, linear encoders, separate motor drivers, and complex cabling. With a single command interface and open protocol, the ORCA was able to integrate cleanly into their existing control system without the need for custom hardware.

The actuator runs internal control loops at up to 3 kHz, with external command and update rates up to 1 kHz. It uses both feedback and feedforward control to produce stable, real-time force output that can be adjusted in software. This allows for precise simulation of friction, compliance, or dynamic resistance based on pilot input and aircraft model behaviour.

Unlike traditional actuators, the ORCA is fully backdrivable and operates with smooth, cogless motion and no torque ripple. When unpowered, it becomes fully compliant, which is essential for safety-critical environments that require a mechanical fallback. Engineers can also define tactile features in software, such as resistance ramps, detents, or hard limits. These software-defined dead stops and force profiles make it possible to match the feel of a wide range of aircraft configurations without additional mechanical components.

ORCA-6-24V Linear Actuator as an Ideal Solution

For Flight Level Engineering’s variable stability test platform, the ORCA-6-24V smart linear actuator was a strong match. Its compact, direct-drive design eliminated backlash and reduced mechanical complexity, allowing for straightforward installation into the aircraft’s cockpit without the need for gearboxes, dampers, or custom linkages. Just as importantly, it delivered native closed-loop force control in a fully integrated package.

The actuator is designed to run directly on low-voltage DC power with a wide input range  of 12 V to 60 V. This makes them suitable to be powered directly from a vehicle’s primary or secondary electrical system, typically a battery charged by a generator, without requiring any additional power conversion equipment like inverters or regulators. The ORCA’s internal control system continuously normalizes force output across the full range of input voltages, ensuring consistent performance even if bus voltage fluctuates.

By selecting a commercial off-the-shelf actuator with built-in sensing and control logic, the team avoided well over an additional $3,000 in component costs. More significantly, they eliminated an estimated six weeks of engineering effort that would have gone into mechanical design, sensor integration, control loop development, and software validation. This not only reduced internal resource strain, it helped the team meet aggressive project timelines and accelerate overall system readiness.

Performance & Safety Benefits

• Friction Modeling Integration: Enabled by porting a Simulink-based throttle model into C++, allowing the ORCA actuator to apply dynamic, real-time resistance that accurately followed pilot input.
• Force As Data: The ORCA provides calibrated force output in milliNewtons, enabling friction and feedback profiles to be defined in absolute physical terms instead of percentages.
• Smooth, Stiction-Free Motion: Essential for capturing fine input behaviour. The ORCA’s linear, cogless architecture delivered consistent, high-fidelity feedback without added mechanical dampers, gears, or springs.
• Tactile Feel Customization: Handled entirely in software allowing engineers to define detents, resistance ramps, or software-defined end stops to match the behaviour of different aircraft without changing hardware.
• Bi-Directional Function: The actuator functions not just as a control surface but also as a sensing device. It simultaneously acted as both a muscle and a measurement tool, reporting force values while applying them.
• Passive Fail-Safe Compliance: Provided peace of mind in safety-critical environments as the ORCA’s backdrivable shaft moves freely when unpowered, offering mechanical fallback without external clutches or override systems.
• Low Voltage-Tolerant Design: The actuator can run directly from the aircraft’s 12 to 60 volt DC power system without requiring inverters or converters. The system continued to deliver accurate, calibrated force even as the bus voltage varied.
• Low-Latency Integration: With internal control loops running at 3 kHz and external command updates up to 1 kHz, the actuator responded instantly to friction model changes and pilot interaction allowing for seamless low-latency integration.
• Long-Term Durability: Was ensured through the use of non-contact sensors and solid-state components. With no internal gears or mechanical wear points, the actuator maintained precision even in demanding conditions.

Ease of Integration & Cost Savings

• Minimal Installation Overhead: The ORCA’s all-in-one design eliminates the need for external sensors, controllers, and custom cabling, saving the team both time and engineering complexity.
• Customer Support: Iris Dynamics' free customer support throughout the project played a key role. Iris Dynamics provided hands-on integration support that ensured seamless compatibility with Flight Level Engineering’s variable stability system. “The team support received by Iris Dynamics was critical,” noted Dr. Borja Martos, President of Flight Level Engineering.

Technical Specifications

Integration

The ORCA-6-24V actuator is installed in the left-hand seat of the cockpit, replacing a passive throttle in the standard Pilot in Command (PIC) position. This mirrors typical fixed-wing control layouts, supporting realistic ergonomics for simulation, testing, and training use.

The actuator is cantilever-mounted to a structural plate with a direct connection to the throttle shaft, eliminating the need for mechanical linkages or gearboxes. This simplifies installation and reduces mechanical complexity.

On the software side, Flight Level Engineering is implementing a C++ friction model adapted from their Simulink framework. The ORCA’s open protocol integrates seamlessly into their control architecture, which uses C++, Simulink, and autocode to manage flight dynamics and feedback loops.

Because the ORCA is fully backdrivable, the shaft becomes compliant when unpowered, supporting mechanical fallback in safety-critical systems. While the immediate goal is throttle simulation, the team is also considering its use in flight control surfaces thanks to its compact form factor and programmable force control.

Final Thoughts: Redefining Control Interfaces

Integrating the ORCA-6-24V actuator into Flight Level Engineering’s fly-by-wire platform highlights how compact, force-controlled hardware can address real gaps in system development and testing. With real-time control, programmable friction, and fail-safe behaviour, the actuator enables precise, repeatable interaction between human operators and mechanical systems, without the need for complex support infrastructure.

While this project focused on throttle simulation, the same technology is well suited to a wide range of applications. From flight control prototyping to robotics, motion control, haptics, industrial automation, and research instrumentation, ORCA actuators provide both high-fidelity force output and integrated sensing in a compact, configurable package. For design teams building test rigs, pilot-in-the-loop systems, or early-stage product prototypes, the ability to treat force as both an input and output opens up new possibilities for interface design, control systems development, and responsive hardware integration. Because it combines precise motion, force sensing, and software-defined behaviour, the same actuator platform can accelerate testing and interface design across aviation, mobility, robotics, medical, and industrial sectors.