News / Cargo-carrying gliders could save 65% of aviation fuel costs, says US developer

A company called Aerolane believes some 65% of aviation fuel costs could be reduced using ‘cargo gliders’ towed behind a lead aircraft like an HGV trailer.

With designs undergoing tests at an ex-USAF airfield in Texas, Aerolane plans to begin making the gliders commercially available next year, contingent on FAA approval.

The company has so far raised around $11.5m in seed funding for a three-ton capacity autonomously piloted Aerocart glider, and aims to follow this up with a 10-ton capacity unit.

Aerolane said the idea would help carriers flex capacity more easily, and with less capital outlay, adding: “Like trailers in trucking or rail, Aerocart is designed to be an affordable capacity-adding accessory to engine units.”

Gliders can also be more efficient than planes, thanks to their wide wingspan. Glide ratio, a measure of aircraft efficiency, is used to express the unpowered distance it can travel, in miles. At a vertical height of one mile, a modern glider can travel 60 miles while descending – expressed as 60:1 – while conventional cargo aircraft have glide ratios of less than 18:1.

The configuration could be afforded greater wing area without the same increase in the drag normally associated with bi- and tri-planes.

The extra lift provided by the glider’s wings would cancel out the additional weight, and slipstreaming behind a lead-aircraft would reduce drag, a principle observed in the formation flying of migrating birds.

Although this approach increases the tow plane’s fuel burn, Aerolane says substantial gains in cargo capacity would be available for the relatively modest increase. And, theoretically, the glider’s greater wing area could allow for heavier cargo to be hauled by aircraft at slower speeds without stalling, impossible in a large cargo plane. This could allow air cargo to practise a similar principle to that of slow-steaming in shipping, where a small decrease in speed leads to a greater decrease in fuel consumption.

“Aerocart is competitive in emissions reduction to hydrogen or battery-electric aircraft, but is far closer to market,” it said.

Aerolane even suggested that multiple Aerocarts could be towed by a single plane.

The idea is proven in principle, thanks to military operations during WW2, when gliders carrying paratroopers, materials and, in some cases, 7- to 8-ton battle tanks were dropped into France and Belgium.

“We’re just dusting off some of the most proven concepts in aviation history and modernising them with today’s technology,” Aerolane’s co-founder, Todd Graetz told Bloomberg. “It’s far less radical than anyone thinks.”

You can watch a promotional video here