Your dream to get a pizza delivered by a drone or an Amazon drone knocking at the door will remain a dream as researchers have revealed that a drone delivery service is not realistic and may not be possible in densely-pulated areas.

The reason is simple: Demand for drone delivery in e-retail is high but the ability to meet that demand is very low.

For a city like New York, the optimal design for the test locations, based on all factors, is three drone facilities covering 75% of NYC area and 34% of the population.

Drone startup Wingcopter, working with partners Merck and the Frankfurt University of Applied Science, has completed a first flight of a new drone delivery trial designed to show the benefits of using drones instead of trucks or other road-faring vehicles for moving small cargo between two physically separate office facilities. This first flight covered around 25 km (roughly 15.5 miles), taking a sample of pigments from one Merck lab in Gernsheim to its headquarters in Darmstadt in Germany.

This trial is significant in more ways than one: The area it covered spanned a fairly dense metropolitan area, flying over power lines, trains, roadways and more. It also did all of this without continuous line-of-sight, something that’s been required of most drone delivery trials in a commercial setting to date. The partners involved are hoping this means it can stand as a blueprint to other similar pilot projects and trials being run all over the world.

Next up, the project will continue to fly additional deliveries and then summarize their findings in a report to be delivered in March. Already, using drones instead of trucks seems to provide advantages in terms of time (saving between an hour and even a full day in some cases) and emissions, and it can cut down on the amount of empty return trips made by large, heavy gas-guzzling vehicles, as well.

Researchers from Brown University have designed a new type of wing that could make small fixed-wing drones far more stable and efficient.

The new wing replaces the smooth contour found on the leading edges of most airplane wings with a thick flat plate and a sharp leading edge. Counterintuitive as it may seem, it turns out that the design has distinct aerodynamic advantages at the scale of small drones. In a paper published in Science Robotics, the researchers show that the new wing is far more stable than standard wings in the face of sudden wind gusts and other types of turbulence, which often wreak havoc on small aircraft. The wing also provides an aerodynamically efficient flight that translates into better battery life and longer flight times.

“Small drones can be really useful in many applications, including flights in populated areas as they are inherently safer for humans, but there are problems operating aircraft at those small scales,” said Kenny Breuer, a professor in Brown’s School of Engineering and the study’s senior author. “They tend to be inefficient, which limits the battery-powered flight times of most drones to around 30 minutes or so. They also tend to get blown around by puffs of wind and turbulent air coming from obstacles such as buildings and trees. So we’ve been thinking about a wing design that might combat those problems.”