Inflatable Balloons to Enhance Drone Flight Time

Quadcopters are among the most advanced drones on the market. In a new experiment, two authors try to enhance the flight time of these drones – endowing them with special features such as controllable and inflatable airbags filled with helium and stored in replaceable cartridges.

The new paper is submitted at the Universitat Politecnica De Catalunya (BarcelonaTech) in which Arias Montenegro and Francisco Javier (the authors) are aiming to enhance the flight time of drones through an experiment that involves the use of these airbags.

“To begin with, let us assume a simple quadcopter as depicted in Fig.1, which in addition, it has been endowed with a controllable inflatable airbag which, as aforementioned, can be inflated when is desired by just opening a control valve and can be equally deflated by using another simple relief valve and evacuating the helium into the atmosphere. The helium cartridge can be replaced or refilled after landing,” as noted in the paper.

Flight-time enhancement as function of the mass ratio between the airbag and the quadcopter.

Quadcopters: How Can they Benefit from this Inflatable Cartridge-Based System?

According to the authors, the drones and specially quadcopters are on the rise right now, which is why they need continuous improvement and development – especially in the battery field. Their experiment is similar as the one where air is used to inflate a bike tire – in which the drones can benefit from increased flight times.

The authors begin by explaining the idea of a simple quadcopter packed with an inflatable airbag, which can be inflated by opening a control valve and evacuated in the atmosphere. The helium cartridge, according to the authors, can be replaced or refilled after landing.

As the authors note in the paper:

“If one uses a cartridge as used to inflate tires, the maximum pressure is just around 10 bars. So, assuming a practical cylindrical cartridge with a diameter, say, 3 cm and length 15 cm (easily transportable by a small drone) we will have a volume of the cartridge around 106 cm3. The density at 1 bar and normal conditions of helium is around ≈ 0.18 gr/cm3 or thereabouts, and thus we have in our cartridge with 10 bar a density of ≈ 1.8 gr/cm3 or thereabouts. That give us a mass of helium contained inside the cartridge around 190 grams of helium.
Therefore, if our drone weight around 5 times the weight of helium., i.e.., 950 grams, we have from Fig. 1 a magnification of its flight time a ten-fold.”

The Extension of Flight Time Through Different Formulas

Both Montenegro and Javier know that the mass of the drone and the helium filling it are the two most important factors in this experiment. Knowing that helium helps objects to fly in the sky, their theory uses the exhaust velocity from the engine (using the helium) and therefore extending the inflatable airbag within the drone.

With the experiment, the authors believe that the battery in quadcopter drones would not suffer from its maximum usage – and would benefit from the helium-packed cartridges which in total will weigh no less than 200 grams. The total weight with the drone, on average, will sum up to around 1 kilogram, including both the drone’s original weight and the added cartridge.

Obviously, an idea like this seems very exciting especially for drones that weigh less than 1 kilogram and the ones that are using small helium replaceable cartridges in a similar fashion as ‘inflatable bike tires’.

The project has been supported by the Spanish Ministry of Economy and Competitiveness under a fellowship grant.

Citation: On inflatable drones for flight time enhancement with particular reference to spectator aerostation, Arias Montenegro, Francisco Javier, Department of Fluid Mechanics, University of Catalonia, http://hdl.handle.net/2117/122010