Maybe not snakes on a plane, but ... sharks?

 

Well, the synthetic variety, anyway - and on the outside of the plane, not the inside!

Lufthansa Cargo next year will cover its fleet of Boeing 777 freighters with a high-tech coating that mimics the structure of a shark’s skin to reduce aerodynamic drag and fuel consumption, the company said Monday.

The low-friction film consists of riblets measuring about 50 micrometers that imitate the properties of sharkskin and allow air to flow more smoothly over the aircraft during flight. Sister company Lufthansa Technik developed the new AeroShark technology with German chemical manufacturer BASF to meet aviation needs and estimates it can reduce drag more than 1%.

Lufthansa said the special coating on its 10 777s in 2022 will provide annual savings of about 3,700 tons of jet fuel and nearly 11,700 tons of carbon dioxide emissions — the equivalent of 48 individual freighter flights from Frankfurt, Germany, to Shanghai. Lufthansa Cargo currently operates nine 777s, but is adding another one later this year.

Aircraft surfaces are exposed to UV radiation, temperature and pressure fluctuations at high altitudes that can alter smoothness. The BASF coating is designed to be weather resistant and simple to apply.

. . .

The aviation industry has been researching the use of sharkskin for aircraft for many years. In late 2019, Lufthansa Technik and BASF fitted almost the entire lower half of a Boeing 747-400 fuselage with 500 square meters of jointly developed sharkskin surface and had the modification certified by EASA. The aircraft subsequently validated the savings potential of the technology on long-haul services during 1,500 hours of flight, according to BASF.

The sharkskin modification reduced emissions on the flights by about 0.8%, but BASF said the savings for the 777 freighters are estimated to be higher because film will be applied to an even greater area because of the absence of windows.

There's more at the link.

It's always interested me how fluid dynamics - incorporating the sub-disciplines of both aerodynamics and hydrodynamics - can affect both aircraft and ship design, using the same principles.  There are innumerable examples, including;

• The multihull yachts that compete for the America's Cup, using both hydrofoils and wingsails to achieve previously unimaginable speeds;

• Scimitar propeller technology, used in both aircraft and ships (particularly high-performance submarines);

• Hull design of both ships and aircraft, shaping them to achieve the most efficient flow of water or air over their surfaces.  In particular, high-speed vessels are now incorporating lessons learned from aerodynamics in their shape.

The use of a sharkskin-like coating is just the latest in a long line of technological developments.  I wonder if the same coating could be applied to ships?  Something similar may already have been tried, particularly for submarines.  Navies are notoriously close-mouthed about such things, for obvious reasons.

Peter