A wide-body passenger jet with an elliptical fuselage cross-section, the Fregat Ecojet was a proposed Russian commercial aircraft project that was intended for medium-haul routes.
The Fregat Ecojet’s narrative began more than thirty years ago. In 1991, Russian aircraft designer Valentin Tikhonovich Klimov initiated the development of the Tu-304, a mid-range, wide-body aircraft.
The aircraft was initially intended to be powered by two engines with a thrust of about 20 tons each, as the aviation industry was already transitioning to this configuration. Various powerplants were being considered, including Russian engines such as the PD-18R and PS-90A20, as well as foreign engines like the Rolls-Royce Trent-500.
Nevertheless, the project leaders adopted a four-engine design, which they dubbed “Freejet,” in defiance of this trend. The Perm-made PD-14 engine, which was also under consideration for the Irkut MC-21 project, was expected to power the aircraft.
Waiting for the development of a new engine would not be necessary if this course of action is pursued. Additionally, the aircraft’s systems are designed to be entirely powered by a new configuration, which would have converted the excess energy from the engines. It was anticipated that the four engines would collectively produce approximately 1,000 kilowatts.
Here I want to add that this is a comparatively low power output for an aircraft. It is more akin to a turboprop or small private plane than a commercial airliner. Tens of thousands of kilowatts and several tons of thrust are the typical outputs of modern commercial aircraft engines. For example, a single engine on a Boeing 737 generates approximately 20,000 pounds of propulsion, which is equivalent to approximately 89 kilonewtons or approximately 9 metric tons of thrust.
Valentin Klimov provided an explanation for the increase in the number of engines in a 2017 interview with Russian Aviation Insider. He said that while twin-engine aircraft had recently matched the performance of four-engine aircraft, the four-engine configuration would more effectively achieve the aircraft’s objectives.
He acknowledged that four engines are inherently inferior to two unless they provide substantial advantages. This was the case with the four-engined A340, which was discontinued due to its failure to provide benefits, whereas the A330 and A330neo continued to be successful.
Klimov further stated that his team intended to electrify all of the aircraft’s processes. This would mean the installation of an electric taxiing system, an electric anti-icing system, and air conditioning, in addition to electromechanical and electrohydraulic actuators. The bleed air system would be rendered obsolete by these innovations.
Please note that the bleed air system is responsible for supplying pneumatic power to various aircraft systems by extracting air from the turbines. This air is used for deicing surfaces, pressurizing the cabin, and providing air conditioning.
Klimov’s team predicted that the electrification of all onboard processes would result in a 12 percent reduction in fuel consumption, a 5-10 percent reduction in operational costs, and a weight reduction of up to 10 percent for the aircraft.
The aircraft, equipped with fuel containers only in its wings, could transport 250 to 350 passengers and travel a maximum distance of 4,500 km. Nevertheless, a variant with a central tank was also taken into account, which would have extended the range to 8,000 km.
The oval-shaped fuselage, which is intended to accommodate three aisles in the interior, was identified as one of the main innovations by TsAGI (the Central Aerohydrodynamic Institute). The designers anticipated that this would improve the convenience of passengers. It is anticipated that the aircraft will maintain a cruising speed of 850 km/h.
Klimov emphasized three critical components of the project: the aircraft should be “digital,” eco-friendly, and low-noise. Furthermore, he underscored the necessity of maintaining low flight costs to realize the objective of global mobility.
The Fregat Ecojet was the subject of much discussion, as it was intended to bridge the divide between narrow-body and wide-body aircraft. Presentations were made at exhibitions, and a series of theoretical calculations were completed. Tests were planned using scale models. The Central Aerohydrodynamic Institute (TsAGI) released a press statement indicating that a model has been tested in a wind tunnel. S7 Airlines and UTair representatives were brought in as consultants.
The “Fregat Ecojet” was a niche product in terms of the modern passenger airline market. It is focused on the segment of routes with distances of 3,000–4,000 km, where wide-body aircraft could be effectively used, placing it in the market niche of the Il-86. Today, more than 56% of all wide-body long-haul aircraft flights globally cover distances of less than 3,000 km, with this share being significantly higher in some regions.
“Now, will the Frigate Ecojet project be revived in Russia
The question doesn’t have a simple answer. Still, there is hope. Russia has not officially announced the closure of this project. As of May 2024, TsAGI shared the findings of a study that looked at how well non-traditional aerodynamic configurations of long-haul airplanes work when using new technologies and fuels other than jet fuel. The institute tried different aerodynamic configurations of long-haul planes that could carry 220 to 250 people over 8,000 to 9,000 km.
Scientists at the institute are looking into different choices for future mainline aircraft, including both classical and integral designs, in three possible layouts: The MS-1 has a classical layout and a body in the shape of a circle. The MS-2 and MS-3, on the other hand, have oval fuselages and different arrangements of the wings. To keep things clear, MS stands for “long-haul airplane” during the study.
The MS-3 layout has an overlap between the wing consoles and the body that makes the plane more aerodynamic and better at carrying weight at low speeds, which means that the runway doesn’t have to be as long. The oval shape of the MS-2 and MS-3’s body also saves fuel and makes more room for passengers, giving them more comfort and space. The bottom deck of the plane will also be bigger so that more cargo can be put on it.
A comparison test showed that the MS-3 variant had better load-bearing and moment parameters than the classic scheme, even though there were no major changes in aerodynamics at low speeds. To move on to the next step, TsAGI experts will test the combined model in a transonic wind tunnel while it is in cruising flight.
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