The US Army is working on a drone that can transform mid-air from "hovering like a helicopter to speeding along like a sleek aeroplane" to aid soldiers on the ground.

According to a report published by the Department of Defence's (DoD) Army Research Laboratory, the half pound drone, or unmanned aerial vehicle (UAV) will be able to move its rotors from a hovering stance that has the blades horizontal, to a forward facing, aeroplane-like, vertical stance. This will give the drone added speed, agility, flexibility and precision.

Such a design has a number of advantages over the traditional quad copter-styled drones that are used now, but there are several challenges as well.

"In an aircraft, weight is everything," said Steve Nogar, a postdoctoral researcher with the lab's Vehicle Technology Directorate.

He added: "There are a lot of vehicles out there where designers take a quad-rotor and staple it to a fixed-wing aircraft. It may have extra propellers and actuators and it's not very efficient. You have a lot of wasted weight."

The final working model, should it be developed, will be around 10 inches long. Testing of the drone involves attaching a semi circular paper sail that adds drag and weight. Future tests could involve landing, or perching the craft "on something in the environment", researchers said.

The researchers want to build a UAV that can sense its surroundings, perceive environment, and be able to detect obstacles like walls.

If the drone is flying like a plane, it will also need to read landing spots quickly. This might require a level of machine learning from the drone and it is also being developed, according to the report.

According to Nogar, in the near future, "soldiers are going to have to be able to interact with these vehicles all the time and they're going to have to work as a team to achieve their objectives."

The drone by itself will first be developed as a simple spying machine. It will not be outfitted with an array of sensors or equipment and it is an exercise on what can be done "with just one camera", said Nogar. The aim right now is to "control and study the dynamics of this vehicle", he said.

The Osprey V-22 is widely used by the US government SAUL LOEB/AFP/Getty Images

The US Army is already in possession of a hybrid VTOL craft called the V-22 Osprey. It has a tilt-rotor design that allows it to take off and land vertically like a helicopter and transform itself into an aeroplane mid-flight. Osprey is 57 feet long and capable of carrying 24 fully loaded troops over 1,000 miles.