The USA eyes ekranoplan innovation to boost global reach

The USA, as a superpower, has interests worldwide, including in the security sphere, with American garrisons stationed in multiple countries. Notably, in Europe, there are bases in Poland, Germany, Italy, and the United Kingdom. In Asia, there are bases in the Republic of Korea and Japan, and in Africa, in Morocco. This list is far from exhaustive. These deployments result from the Pentagon's need to address various threats, including those from China, North Korea, Iran, Russia, and Islamist entities.

Having large forces dispersed globally necessitates their supply and potentially their local expansion, such as the increase of forces in Poland following Russia's invasion of Ukraine. However, the USA's transport capabilities are limited: while fast air transport can carry a relatively small amount of cargo, large transport ships and chartered vessels are slow. The intermediate solution proposed is the ekranoplan.

At the end of April, Aurora Flight Sciences, which has been working on the project since last year, reported progress on the ekranoplan transport program under the Liberty Lifter X-plane initiative, commissioned by DARPA.

The project's goal is to build a technology demonstrator of the ekranoplan to facilitate research and data collection. This could eventually lead to the development of a full-sized transport vehicle that would complement existing aircraft like the C-130, C-17, and C-5 and various types of transport ships.

Information from The War Zone indicates that the technology demonstrator is intended to lead to a very large design. The conceptual graphic shows a large flying boat with floats at the wingtips, powered by eight turboprop engines. For comparison, the relatively large Hercules is powered by only four engines. The ekranoplan features a double vertical tail connected by a horizontal stabilizer. The fuselage is traditionally configured for transport aircraft, with the cockpit positioned slightly forward on top and a loading ramp at the rear. It is not yet known how large the final model will be, but it will certainly be larger than the C-130 Hercules.

Today, it is known that the wingspan of the technology demonstrator is expected to be 216 feet (65.8 meters), which is about 80 percent of the final model's expected wingspan, suggesting a span of over 270 feet for the actual ekranoplan. For comparison, the huge C-5 has a wingspan of just under 223 feet. The payload of the demonstrator is anticipated to be similar to the C-130, around 55 tons, but the final model, according to DARPA, should carry roughly the same load as the C-17A, about 176 tons. The target ekranoplan should be capable of taking off and landing at sea state 4 or lower and be able to fly in sea state 5 conditions (wave height up to approximately 8 feet). This presents a significant engineering challenge because the surface over which an ekranoplan flies greatly affects its flight.

The demonstrator will not have a pressurized cabin as it is unnecessary, which will also be the case for the final model. Ekranoplans naturally fly low, so there is no need for pressure equalization. The American model is designed to fly at altitudes of up to several hundred meters. The speed is unspecified, but engineers are likely aiming for several hundred kilometers per hour, which would be much faster than any ship. Additionally, the transport cost will be lower than traditional aircraft due to reduced fuel consumption.

An ekranoplan is an aircraft designed to fly at low altitudes, taking advantage of the so-called ground effect, which occurs when wings generate greater lift during low-altitude flights above a surface. Typically, they are flying boats with relatively short wings, usually small, intended for flights over calm coastal waters.

This design allows for a good payload and relatively high speed (usually below 373 miles per hour) with relatively low engine power requirements (and low fuel consumption). These aircraft must consider factors like wave impact during takeoff and landing or the effects of prolonged flight in high salinity and high humidity conditions, which engines find challenging. The typical flight altitude of an ekranoplan using the ground effect does not exceed half the wingspan and is usually even lower (generally up to just about 33 feet). The maximum flight altitude is also low, usually 1.2 to 1.9 miles, after which the ekranoplan becomes less efficient.

Ekranoplans were designed in various countries, including Canada, the USA, Germany, and Italy. However, Soviet engineers were the true specialists. The Soviet Navy operated mainly in relatively small water bodies such as the Caspian, Black, and Baltic Seas. Thus, an inexpensive, fast aircraft with a large payload and low detectability (due to low flight altitude) was highly appealing.

In the USSR, many ekranoplans were funded, including some of the largest ever built. However, mass production never reached a large scale due to costs, even in Soviet conditions. For example, the successful A-90 Orlyonok project, with a wingspan of 103 feet and a length of 191 feet, was produced in only five units in the 1970s, used for transport until the 2000s.

The KM, known as the "Caspian Monster," was an experimental machine built in the 1960s, powered by ten jet engines. It became famous but was lost in an accident in 1980. The Soviets also attempted to build a "semi-missile boat," an ekranoplan armed like missile boats with anti-ship guided missiles.

This led to the creation of the large, heavy ekranoplan project 903 Lun. It had a 144-foot wingspan, a 239-foot length, and a maximum take-off weight of 837,756 pounds, capable of reaching speeds up to 311 miles per hour. The ten-person crew was equipped with naval armaments: three twin launchers of 3M-80 Moskit anti-ship guided missiles and two quadruple sets of 23 mm anti-aircraft guns for self-defense.

After tests concluded in 1991, it was used for several years by the Caspian Flotilla and then withdrawn from service. The unusual machine was vulnerable to enemy fire, not as undetectable as initially thought, and it likely remained expensive to operate, making it redundant for the Russian Federation in crisis. Attempts were made to build a second unit as a search and rescue vehicle, but the "Rescuer" ekranoplan was abandoned with progress at 75 percent due to a lack of funds. Allegedly, work resumed in 2019, but no updates have emerged since.