Engines are the heart of an aircraft, driving the platform farther, faster and for longer. “You want everything critical to mission capability out of an engine,” declared Bob Muse, Instructor Pilot and Safety Course Instructor at Robinson Helicopter Company, a view that is echoed by Bell Flight’s Vice President Commercial Programs, Linda Deslatte.

The big three: performance, efficiency, and reliability

“Robinson helicopters have everything needed in terms of performance, efficiency, and reliability, especially the Rolls-Royce RR300 turbine, which has 1.9 million total hours recorded with zero engine failure,” reported Muse, a former law enforcement pilot who has been teaching the flight safety course at Robinson for several years.

Designed as a replacement for piston engines in light helicopters and general aviation aircraft, the RR300 turbine is optimized for performance in the 240–300shp power range. Robinson’s R66 Turbine Police Helicopter uses a single RR300 as its power plant to provide an economical and easy to maintain aerial law enforcement platform. The R66 is used by multiple law enforcement agencies, including Fontana Police in San Bernardino County, California, and the Polk County Sheriff’s Office in Polk County, Florida. Robinson’s Lycoming IO-540-powered R44 Raven II police helicopter is operated by the South African Police Service (SAPS) Air Wing and Philippine National Police Special Action Force, among others.

Deslatte explained her company’s vision: “At Bell, we require an engine that delivers high power output, ensuring optimal flight performance under a variety of conditions. This includes maintaining stable flight at different altitudes, in diverse weather conditions, and during critical phases such as takeoff and landing.”

An efficient engine reduces operating costs and increases the range and endurance of the helicopter

Bell helicopters are operated by police forces and emergency medical services (EMS) across the world, from the USA to Sweden and New Zealand, using the 407, 429 and 505 platforms. Power plants include the Rolls-Royce Model 250-C47E/4 (Bell 407), dual Pratt & Whitney Canada PW207D1/D2 (Bell 429), and Safran Arrius 2R (Bell 505).

Deslatte continued: “Efficiency is equally important, as an efficient engine reduces operating costs and increases the range and endurance of the helicopter. It’s not just about consuming less fuel, but also about maximizing the power derived from the fuel consumed.”

Mechanical reliability is also a crucial factor. “An engine must have everything we’ve already listed – performance, efficiency, and reliability – to safely execute any mission,” commented Muse. It’s a truism that reliable engines equate to fewer breakdowns, more straightforward maintenance, and therefore lower running costs.

“More importantly, a reliable engine enhances safety, which is of utmost importance to every single aircraft that we design and manufacture at Bell,” added Deslatte.

Special performance characteristics

Specific special operations roles require distinct performance characteristics, explained Deslatte: “For search and rescue (SAR) missions, the engine needs to provide sufficient power and thrust to operate in various weather conditions and altitudes, particularly during hoisting operations and while carrying heavy loads. Engine reliability is equally critical for ensuring safety, given that SAR missions often occur in remote or hostile environments. Long-range endurance is essential, so engines need to be fuel-efficient to maximize search time and minimize refueling needs. Additionally, engines should be adaptable to different aircraft configurations and mission profiles, allowing for versatility in SAR operations, across all different environments and conditions,” she remarked.

Engines should be designed for easy maintenance and rapid replacement of components to minimize downtime during critical firefighting periods

In the context of helicopter emergency medical services (HEMS), engines must be capable of rapid response time to enable quick deployment for medical emergencies. “Smooth power delivery is crucial for maintaining stability and patient comfort during medical evacuations,” asserted Deslatte. “Reduced noise levels are also essential for minimizing disturbance to patients and medical personnel during flight.”

Given that HEMS missions can involve frequent takeoffs and landings, engines should be durable enough to withstand repeated cycles without compromising performance or safety.

When it comes to firefighting missions, these often require prolonged flight times, which makes fuel efficiency an important factor for extending operational range and reducing refueling frequency. “Furthermore, engines should be designed for easy maintenance and rapid replacement of components to minimize downtime during critical firefighting periods,” observed Deslatte.

In summary, engines used in SAR, HEMS, and aerial firefighting roles need to balance power, reliability, fuel efficiency, and adaptability to meet the unique demands of each mission type effectively. These performance characteristics are crucial in ensuring that each mission is carried out safely, efficiently, and successfully.

Power plant performance and limitations

Muse summed up the essentials: “Understanding limitations, such as environmental factors and higher-density altitudes, can help you get the most out of the power plant,” he remarked.

Maximizing the performance of a power plant within its limitations is a complex process that requires a comprehensive approach. “Regular and meticulous maintenance is crucial to ensure the power plant operates at its peak performance,” affirmed Deslatte. “This includes routine inspections, timely replacement of worn-out parts, and adherence to the manufacturer’s recommended service intervals. Servicing should be carried out by trained professionals who can accurately diagnose and rectify any issues, preventing minor problems from escalating into major ones.”

Flying technique affects performance

The impact of a pilot’s flying technique towards optimal performance is substantial. “Having the knowledge and skill level necessary to complete missions, as well as understanding the limitations of an aircraft’s design and power plant, contributes to a pilot’s performance,” commented Muse.

Understanding limitations, such as environmental factors and higher-density altitudes, can help you get the most out of the power plant

“Moreover, a pilot’s adept use of energy management can extract maximum performance from the power plant without breaching its limitations,” affirmed Deslatte. “This is why Bell relies on our Bell Training Academy (BTA) located in Fort Worth, Texas, to train global operators in flight maneuvers, maintenance and product knowledge. The BTA also leverages a satellite location in Valencia, Spain, with a Level D simulator for the Bell 429 to give regional pilots training to understand the power plant’s capabilities and limitations.”

This includes knowledge of the power plant’s operating parameters, such as maximum and optimum RPM, temperature limits, and fuel consumption rates. Through smooth control inputs, proper management of power settings, and avoiding abrupt maneuvers, a pilot can help prevent unnecessary strain on the power plant.

Pilot training in engine handling and management

Muse also emphasized the importance of pilot training: “It is very critical in engine handling and management techniques. Robinson Helicopter Company’s new instructor pilot courses set a high standard of training to understand how all aspects play a role in safety,” he said.  

Comprehensive training equips pilots with the necessary knowledge and skills to operate an engine within its optimal parameters, thereby ensuring maximum performance and fuel efficiency. Good training also encompasses emergency procedures, enabling pilots to respond effectively in crucial situations.

Deslatte highlighted the importance of the pilot–power plant interface: “Pilot training is not just a component, but a cornerstone in engine management, contributing significantly to the overall performance and safety of flight operations,” she concluded.