Aeronautical engineering company Marenco Engineering Technologies Africa is developing a new helicopter in conjunction with its parent company Marenco Swisshelicopter.
The main advantage of the helicopter is that it is based on new-generation technology and materials. Most designs on the market are based on variations or derivatives of 40-year-old rotorcraft, says Marenco Engineering Technologies Africa engineer James Reeves.
“We have implemented new materials and methods from the start; therefore, this helicopter is lighter than other designs and will offer improved performance over its competitors. “This enables the helicopter to carry more weight and offers better performance in hot conditions and high altitudes.
“For example, Johannesburg is roughly 1 800 m above sea level and most aircraft struggle to carry maximum weight in such ambient conditions,” he explains.
The company is building a full-scale prototype of the helicopter in Switzerland, which is scheduled to fly this year.
“Marenco Africa is aiding in the development of the helicopter’s main and tail rotors, through the use of the FlightLab flight software and helicoper package, and computational fluid dynamics calculations. The team in South Africa has also worked on the engine integration, handling qualities and stability, and crash simulations,” he says.
Reeves explains that the helicopter has a maximum takeoff weight of around 2.6 t and is powered by a single turbine engine. The fuselage and vast majority of the structural components are made from carbon fibre.
“Another advantage of the helicopter’s design is that it uses a single 900 hp Honeywell HTS900 engine, while most competitors use twin engines. A single-engine rotorcraft reduces complexity. “It offers improved maintainability and reliability, which will ultimately reduce operating costs,” he says.
Reeves states that Marenco Engineering Technologies Africa is the first commercial design company to use the Honeywell HTS900 engine for this type of application and it hopes that the helicopter will reach a maximum speed of 300 km/h.
Reeves says the helicopter also has various commercial applications.
“The interior and configuration of the helicopter are customisable. There are eight seats in the general layout, which can be taken out and rearranged in ten minutes.
“Once the seats have been rearranged or removed, there is space for two stretchers and two medics,” he says, adding that, once the seats have been removed, the helicopter can also be used to ferry cargo. There are rails on the floor that can be used as attachment points for cargo, making the helicopter useful for military applications.
Marenco Engineering Tech- nologies Africa is investigating the handling and performance of the helicopter using a flight simulator that was designed and built by Reeves and the company’s team.
“We are constantly updating the features on the flight simulator to ensure that the software is current. The simulator is based on FlightLab software, which was also used in the design of the helicopter.
“The simulator enables us to model the helicopter in great detail, and obtain real-time feedback from a pilot. We can tweak the design of the helicopter and also model the engine, the controls and the tail rotor to provide feedback for Marenco Swisshelicopter on the design,” states Reeves.
“I wrote software that allows commands to be sent to the model using a joystick to mani- pulate the simulated model, instead of using text to command the model, which is what is typically done during analysis. We tweaked the model to make it run in real time, which has enabled us to develop a complete and accurate physical model that is flown by a pilot.
“Test pilots have provided us with positive feedback on the simulated model,” Reeves notes, adding that they record forces on the pitch links and blades, and many other quantities, while a test pilot in the simulator is flying the model.
“We can also perform auto- rotation analysis, which is difficult to conduct analytically. Auto-rotation analysis entails flying a helicopter, cutting the engine and getting a pilot to land it.” The controls are so compli- cated that it is nearly impossible to perform a proper analysis on the computer without a pilot in the loop, Reeves points out.
“This enables us to draw all the curves needed for the initial version of the flight manual. It also helps us to gauge our performance on various certification requirements,” he says.
Reeves highlights that Marenco Swisshelicopter is building a larger version of the flight simulator, with a moving base and projectors.
“It will eventually be certified as an instructor training-type simulator and it will be based on the same software as the original simulator,” he notes.
Marenco Engineering Tech-nologies Africa recently completed the construction of a wind tunnel on its premises, in which the helicopter’s aerodynamics are being evaluated.
“We built the wind tunnel because it provides greater flexibility and is more cost effective than renting one. Marenco Engineering Technologies Africa built the wind tunnel for the cost of about one-and-a-half days rental,” he says.
The company is also contracted by defence, security and aerospace systems developers such as BAE Systems to help develop land-mine-protection technologies.
“We design and test land-mine-protection technologies for the company, as well as others. We have experience in the design and testing of land-mine-protected vehicles and in simulating the impact of a mine on a vehicle” says Marenco Engineering Tech- nologies Africa design analyst Bertus Hechter, who adds that Marenco Engineering Technol- ogies Africa
also assists BAE in designing new armoured vehicles.