A figure from Amazon's patent application shows how a delivery drone's rotors would be encased in a protective shroud. (Credit: Amazon via USPTO)
A figure from Amazon’s patent application shows how a delivery drone’s rotors would be encased in a protective shroud. (Credit: Amazon via USPTO)

A newly published patent application almost literally delves into the nuts and bolts of the package-delivering drones that Amazon is developing – but it also makes clear that the look of the drones could vary, depending on where and how they’re being used.

The proposed designs include quadcopters and octocopters, drones with motors as wide as 18 inches that are mounted vertically to push the craft and its cargo through the air, and drones with fixed wings that extend well beyond the craft’s protective shroud.

That safety shroud is the common thread in all of the described designs.

The application was filed in December 2014 by Gur Kimchi and Rick Welsh, two of the lead engineers for Amazon Prime Air, but published by the U.S. Patent and Trademark Office only last week.

Amazon’s plans have moved much further forward over the past year and a half, as illustrated by last November’s revelations about one of the company’s drone prototypes. Nevertheless, the latest publication adds to the store of publicly available information about Amazon’s plans.

Amazon declined to comment on the application.

Previously released applications have described how Amazon’s drones could recharge themselves on docking stations that would be installed on streetlights, power poles and other potential perches, and how the drones could home in on the GPS coordinates sent from a customer’s smartphone.

The newly released filing focuses on the drones themselves: The craft’s vertical propellers are shrouded in a molded structure that’s designed to keep them from doing harm or sustaining serious damage, even if the drone were to crash into something. The structure could incorporate an antenna that receives and transmits data via wi-fi, near field communication, cellular networks or satellite links.

The navigation system could take its cues from GPS, an indoor positioning system or an inertial measurement unit. There’d be a motorized system to pick up and drop off payloads, but the application doesn’t describe that system in depth.

Amazon drone with fixed wing
This configuration for a delivery drone shows a wide fixed wing as well as two “pushing” motors mounted on the sides of the drone’s shroud. (Credit: Amazon via USPTO)

Like the design shown in last November’s reveal, the drones described in the patent application have vertically mounted “pushing” motors as well as the horizontally mounted “lifting motors.” The filing also covers a configuration with a fixed wing for aerodynamic lift.

Amazon has been working on its drone delivery system for years, with the aim of setting up the infrastructure to deliver packages weighing 5 pounds or less to customers by air in a half-hour or less.

In the United States, such a system would require the regulatory go-ahead from the Federal Aviation Administration – a go-ahead that would have to go beyond the limits laid out in the FAA’s recently issued rules for commercial drones.

In the meantime, Amazon has been testing its drones on privately owned U.S. land, as well as in Canada, Britain, the Netherlands and potentially other undisclosed locales. Last month, Amazon said it was partnering with authorities in Britain to expand its drone development effort there.

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