The delivery drone space is getting more and more crowded, but we tend to see slightly different flavors of the same basic designs and modes of operation. There are point-to-point multirotors, hybrid point-to-point systems (like tailsitters), and fixed-wing drones that require launch and landing infrastructure. One thing that all of these drone platforms have in common is scale—the current generation of autonomous commercial delivery drones are optimized for payloads of a few kilograms, delivering high-value, time-sensitive payloads in low-infrastructure areas.
There are plenty of use cases where small drones work just fine, but once you need more than a handful of kilograms at once, commercial options are few. The military has been experimenting with glider drones and parafoil systems that can handle hundreds of kilograms and uncrewed helicopters that can manage over a thousand kilograms at once. But in most cases, aerial cargo delivery for commercial or (even emergency) purposes means using a a small cargo aircraft like a Cessna Caravan (if there’s somewhere for it to land), or a helicopter. And that can be a challenge in cost, platform, and pilot availability.
ThereCraft, a delivery-drone startup based in Los Angeles that came (mostly) out of stealth earlier this year, has been working on a novel design for a drone that can scale from delivering a few kilograms to 1,300 kg. It uses a design that originated back in the 1960s, along with a uniquely acrobatic delivery system that promises precision delivery without landing, hovering, or parachutes.
The folks behind ThereCraft aren’t yet ready to share all of their secrets, but this brief video clip should provide a reasonably complete picture of how their drone delivery strategy works:
This acrobatic cargo-delivery maneuver is obviously not something that you’d want a human to be doing over and over, but for an autonomous drone, it’s both effective and repeatable. It’s a bit hard to see, but the drone’s wheels aren’t actually touching the ground at its closest approach—it’s skimming just above the runway at bicycle speed. “We place things on the ground, rather than drop anything,” ThereCraft’s founder Star Simpson explained to us. The essential concept is to provide an aircraft that can deliver a substantial amount of cargo precisely without using a parachute, eventually scaling up to take over from aircraft like the Cessna Caravan except with the pinpoint delivery capability of a helicopter.
ThereCraft uses a lifting-body design, something that we haven’t seen all that much of since NASA did a bunch of research on the concept in the 1960s and ’70s. If you look closely, you’ll notice that ThereCraft’s drone doesn’t actually have any wings, really, just a streamlined body that kind of flares out toward the back, with a couple of vertical fins plus what looks like a rear control surface. You can think of a lifting-body aircraft as the opposite of a flying wing like the B-2—where the B-2 takes a conventional aircraft and replaces the fuselage with more wing, a lifting-body aircraft is all fuselage, foregoing the wing altogether.
The reason that NASA was interested in lifting bodies was as a way of making reentry from orbit a little more versatile. The capsules of the Apollo program were reliable, but you needed a huge landing area plus a lot of support because they weren’t steerable, you just pointed them in the right direction and rode them down into the ocean. Having a steerable reentry vehicle would simplify things, but the conventional way to do that was by adding wings, which are great during a glide and landing phase but the opposite of what you want during reentry itself where they’d have to somehow not rip off or melt. NASA’s solution was to just lop the wings off completely and redesign the body of the craft to generate enough lift to enable controlled gliding, which led to chubby looking prototypes like these:
NASA’s experimental wingless lifting-body aircraft.Photo: NASA
The overall chubosity and rounditude decreased over time until NASA ended up with the X-24B, which looked like this:
NASA’s X-24B lifting body aircraft.Photo: NASA
For NASA, it turned out that lifting bodies didn’t offer the kind of flight envelope the agency thought would be necessary and it went with something much more traditional (the space shuttle). In general, lifting bodies weren’t especially efficient at low altitudes and were at times challenging to control. But the lifting-body design is still perfectly viable for reentry from orbit, and Sierra Nevada Corp.’s Dream Chaser is scheduled to prove the concept within the next year or two.
Meanwhile, back on Earth, the lifting-body concept stuck around. In the 1990s, an aerospace engineer at Northrop Grumman named Barnaby Wainfan designed, built, and flew an experimental lifting-body light aircraft called the Facetmobile which (according to this feasibility study that Wainfan coauthored for NASA in 2004) offered a bunch of advantages over similarly sized light aircraft. A smaller, uncrewed version called the High Altitude Shuttle System (HASS) was used by Near Space Corp. to experiment with payload recovery from high-altitude uncrewed balloons about a decade ago. Wainfan is the chief technical officer of ThereCraft, which pretty much brings us up to date on where its design came from.
Talon Topper was originally developed as a demonstrator for the U.S. Army (top). More recently, it has been operated for NASA as a research aircraft and called the High Altitude Shuttle System (HASS) (bottom).Images: Barnaby Wainfan
ThereCraft’s drone, which we’re guessing looks a lot like NSC’s HASS pictured above, offers a large internal payload volume, simple design and construction, and the ability to fly precisely and at low airspeeds. This is what enables the novel delivery capability, which ThereCraft says can put a payload into a 3-meter circle on the ground, although it’s working to shrink that down to a meter and a half. Admittedly, the payload isn’t delivered quite as gently as it can be by a helicopter, and it’ll likely need some robust packaging if it’s at all fragile, but you can just think of it like a parachute delivery except you don’t have to deal with the parachute and all of the complications that come with it.
The video demonstration that ThereCraft has made public is of course just a proof-of-concept demonstrator, but the company has already built a 330-kg version that can carry half of its own weight as payload, and the design scales up well beyond that. Simpson says that the aircraft has undergone significant engineering testing and is ready for demonstration and operations.
[ ThereCraft ]
Evan Ackerman is a senior editor at IEEE Spectrum. Since 2007, he has written over 6,000 articles on robotics and technology. He has a degree in Martian geology and is excellent at playing bagpipes.