a plane flying in the sky

The Tupolev Tu-404: Largest Aircraft Ever Designed

The world of aviation is littered with a number of dreams that rarely become reality. One such intriguing concept was the Tupolev Tu-404, a behemoth of a commercial aircraft proposed by the Russian aerospace company Tupolev in the early 1990s. 

Tuplev Tu-404 is the largest aircraft ever designed in the history of aviation. It wasn’t your average jumbo jet; it was a radical design with the potential to carry a whopping 1,214 passengers in a single-class configuration across vast distances of up to 13,500 Km.

This proposed behemoth from the Russian manufacturer promised to revolutionize passenger travel but ultimately remained grounded. 

a model airplane on a surface
Tu-404 Blended Wing Body Bonanza Design. Render: Found and Explained

A Cold War Dream

Born in the twilight of the Cold War, the Tu-404 emerged alongside another wide-body design, the Tu-304. The ambitious goal? Both projects aimed to establish Soviet dominance in the wide-body passenger aircraft market. The Tu-404, however, had a far more ambitious goal: transporting over 1,200 passengers, a figure that dwarfed even the Boeing 747.

This massive target necessitated a revolutionary approach, and the Tupolev design team wasn’t afraid to push boundaries. 

They explored two distinct configurations for the Tu-404:

  • The Double-Decker Dream: This concept resembled a giant, stretched version of the current double-decker airplane like the active Airbus A380. 
  • The Blended Wing Body Bonanza: Here’s where things get interesting. Tupolev proposed a radical “blended wing body” design. In layman’s terms, picture an aircraft where the fuselage seamlessly merges with the wings, creating a massive, tailless flying wing. This futuristic concept promised superior aerodynamics, potentially leading to lower fuel consumption and increased range.
a plane flying in the sky
Tu-404 Blended Wing Body Bonanza Variant. Render: Aero Por Trás da Aviação

The Double-Decker Design

One proposed configuration for the Tu-404 took a more conventional approach, a massive double-decker passenger aircraft. This design aimed to transport a staggering 1,200 people over long distances, up to 10,000 kilometers (6,200 miles).

The sheer scale of this passenger version necessitated some unique features:

Double-Decker Fuselage: Passengers would have been distributed across two full passenger decks, offering a significant increase in capacity compared to traditional wide-body jets. Even though, we know how it works after the launch of the A380, imagine the logistical challenges of such a massive aircraft at that time.

Multi-Section Cargo Hold: The lower level of the fuselage doubled as a multi-section cargo compartment, capable of holding standard aviation containers. This offered airlines the flexibility to configure the aircraft for either pure passenger transport or a mixed passenger-cargo configuration with an enlarged cargo section. A dedicated cargo model was also envisioned.

Imposing Wings: The low-level wing boasted a leading-edge sweep of 35 degrees and distinctive vertical wingtips. These massive wings housed equally impressive control surfaces, including multi-section leading-edge control surfaces, low-speed control areas, and multi-section flaps. Each half of the altitude control surface was further divided into two sections, further emphasizing the aircraft’s scale.

Engine Power: Four powerful Kuznetsov NK-44 turbofan engines or equivalent Rolls-Royce “Trent” engines were envisioned to propel this aircraft. These engines, mounted on underwing pylons, would have generated a significant amount of thrust to overcome the aircraft’s immense weight.

Reinforced Landing Gear: A robust undercarriage consisting of several carts with multiple wheels in each cart was designed to handle the weight of the Tu-404 during takeoff and landing. This undercarriage retracted into the central fuselage section for a streamlined profile in flight.

a blueprint of a plane
Tu-404 Double-Decker Design. Render: Found and Explained

General Specifications (Double-Decker Variant)

Length: 86.6 meters (284 ft)

Wing Span: 77 meters (253 ft)

Overall Height: 27.3 meters (89.6 ft)

Wing Leading Edge Sweep: 35 degrees

Max. Take-off Weight: 605,000 kg (1,333,760 lb)

Max. Payload: 126,000 kg (277,816 lb)

Max. Passenger Capacity: 1,200

Number of Engines: 4

Engine Type: Kuznetsov NK-44 turbofan or equivalent

Thrust on Take-off per Engine: 40,000 kgs (88,185 lb)

Fuel Consumption in Cruise Mode: 0.54 kg/kgf-h

Cruise Altitude: 11,000 metres

Practical Range with Payload: 13,500 Km (normal)/ 9,200 Km (With maximum payload)

Required Runway Type: Class “A”

Take-off Rum: 3,200 meters

The Blended Wing Body Bonanza: A Futuristic Vision

The other proposed configuration for the Tu-404 embraced a far more radical design, a blended wing body (BWB) concept. This futuristic design departed from the traditional fuselage-and-wing layout, with the fuselage seamlessly merging into the wings, creating a massive, tailless flying wing. This approach offered several potential advantages:

Improved Aerodynamics: The BWB design promised superior aerodynamic efficiency compared to the double-decker variant. The smooth, integrated design could have resulted in lower drag and potentially improved fuel consumption.

Unique Passenger Experience: The central fuselage housed six passenger compartments, offering a unique cabin layout compared to traditional airplanes. Imagine the panoramic views passengers might have enjoyed from windows integrated into the curved wing itself. 

a white airplane on a surface
Tu-404 Blended Wing Body Bonanza Design. Render: Found and Explained

Technical Specifications (Blended Wing Body Variant)

Length: 59.7 meters (196 ft) (Significantly shorter than the double-decker)

Wingspan: 110 meters (361 ft) (A massive increase compared to the double-decker)

Overall Height: 110 meters (361 ft) (A massive height due to the blended wing design)

Wing Leading Edge Sweep: 35 degrees

Max. Passenger Capacity: 1,214 (Similar to the double-decker)

Number of Engines: 6 (Two more engines compared to the double-decker)

Engine Type: Turboprop (A different choice compared to the turbofan engines of the double-decker)

Thrust on Take-off per Engine: 18,000 kg (39,683 lb) (A significant amount of thrust for each engine)

Fuel Consumption in Cruise Mode: 0.644 kg/kgf-h (Potentially more efficient than the double-decker)

Cruise Speed: 900 km/h (M=0.8) (A similar cruising speed to the double-decker)

Cruise Altitude: 11,000 meters (36,089 ft) (Similar cruising altitude to the double-decker)

Practical Range:

  • Normal Payload: 13,500 kilometers (8,389 miles) (Similar range to the double-decker)
  • Maximum Payload: 9,200 kilometers (5,716 miles) (Similar range to the double-decker)

Required Runway Type: Class “A” (Same requirement as the double-decker)

Take-off Run: 3,200 meters (10,500 ft) (Similar requirement as the double-decker)

The BWB Tu-404 offered a glimpse into the future of aviation, but it also presented significant challenges. The technological hurdles of building such a massive, structurally sound BWB aircraft were significant. Additionally, the noise pollution from six turboprop engines could have been a major concern.

a plane wing with propellers
Tu-404 Blended Wing Body Bonanza Turboprop Engine Designs. Render: Aero Por Trás da Aviação

Airlines and Customer Response: A Dream Too Big?

Despite the audacious design and impressive performance targets, the Tu-404 never left the drawing board. The fall of the Soviet Union and the resulting economic turmoil in Russia severely hampered the project. 

Additionally, the technological challenges of building such a massive aircraft with the desired efficiency were significant.

The Tu-404’s sheer scale and ambitious performance targets undoubtedly captured the imagination of airlines and aviation enthusiasts alike. However, significant challenges loomed:

  • Infrastructure Concerns: Existing airport infrastructure simply wasn’t designed to handle such a behemoth. Imagine the need for reinforced runways, wider taxiways, and specialized boarding gates. Even the introduction of the Airbus A380 necessitated a number of upliftments of the existing facilities.
  • Market Uncertainty: Airlines weren’t entirely convinced of the need for an aircraft carrying over 1200 passengers. Filling such a massive plane consistently on specific routes seemed challenging.
  • Economic Turmoil: The fall of the Soviet Union in 1991 significantly impacted the entire project’s funding and development.
  • The Environmental Impact: A giant aircraft like the Tu-404, even with advanced engines, would have undoubtedly had a significant environmental footprint. The sheer amount of fuel required for operation and the potential for noise pollution resulted as the major drawbacks.
  • The Passenger Experience: Imagine being one of 1200+ passengers on a single flight. Boarding times, potential delays, and in-flight amenities would have required significant planning and innovation to ensure a comfortable journey for everyone.

Building such a massive aircraft wouldn’t come cheap. Estimates suggest the development costs could have reached tens of billions of dollars, making it one of the most expensive aircraft projects ever conceived.

a diagram of a plane
Tu-404 Blended Wing Body Bonanza Interior Design. Render: Found and Explained

Legacy of a Giant

The Tu-404 may not have graced the skies, but its legacy lives on. The concept served as a testbed for advanced aerodynamic designs and continues to inspire aviation enthusiasts. Some believe elements of the Tu-404 project influenced the development of Russia’s next-generation military transport aircraft.

The Tu-404’s story is a fascinating glimpse into the “what if” of aviation history. It serves as a reminder of the audacity and ambition that can drive innovation, even if the challenges sometimes prove insurmountable.

Sources: Aerotime, Found and Explained, Secret Project Forum (Donald McKelvy), Aero Por Trás da Aviação