Voting Result: 2.2090701777
Overview for X-Ray Inflatable Cargo Drone
This concept aims to provide an inexpensive (cf. 3rd paragraph), low operating cost, versatile, easy to operate & maintain and safe drone solution for cargo transport and other missions such as surveillance, observation, data transmission, telecommunications, ...
The use of an inflatable structure aims to provide a solution for potential scaling-up, as the air used to pressurize the structure for the low-weight drone considered here could be replaced by helium or hydrogen in larger model and provide buoyancy in addition to the aerodynamic lift. Such hybrid aircraft are interesting to simplify the structure and reduce required engine power, and hence to reduce buying prices, operating costs (through lower fuel consumption) and maintenance costs (less mechanical parts to maintain).
The Excel Frame Sheet provided in the ignition kit is uploaded in the additional files to support the geometrical sizing and the aerodynamic & mass calculations. These details ensure the coherence of the overall concept between different aspects, with or without the integration of solar cells for extended range / long endurance missions. Another Excel file presents an estimation of the different costs to produce one X-Ray drone, which is evaluated to be around $6000 for the complete structure with its motorisation, including manufacturing and assembly costs (the costs of the systems presented in the ignition kit are not included however), as well as the estimated cost of the complete development program. A Word document provides a description and details of the advantages and specifities of this inflatable concept. The locations of the different systems & structures are presented in the uploaded pictures and are taken into account in the CoG evaluation included in the filled Frame Sheet.
Regarding the internal structure, 2 longitudinal and 2 transverse metallic beams are envisaged to provide the necessary stiffness & support for the engines / systems / payload. These beams are harnessed to the envelope through wires and laces, in a similar fashion to blimps (as visible in the last uploaded figure, only presented here as a sketch). Further studies are necessary however on the full sizing of these beams and attachments. The envelope is made out of thermoplastic material to give the outside shape when inflated. This solution is well adapted for ‘small’ size airship, which should preserve their shape with internal pressurizing under aero loads.
The access to the interior of the deflated structure is envisaged through an airtight zip being located right behind the payload bay (represented by the purple box in the internal views). This access would allow to crawl inside the envelope and to disconnect the structural beams (each independent beam being highlighted in a different color in the internal views) in order to provide a solution for compacting the drone into a box inferior to 2 m long for shipping. Concening the batteries, for ease of access and changeability between flights, it is possible to integrate an access panel on the upper surface of the envelope, right in front of the duct for the rear lift propeller.
Regarding security aspects, combined actions of the remaining operating vertical rotors can deviate the drone in a glide to a safe landing area. A parachute is also integrated. In case of crash, the inflatable concept reduces the damages on impact since the deformation of the envelope absorbs part of the energy. Moreover, this specific design places the systems, batteries and engines masses at the rear of the aircraft, with only the payload being at the front to provide the balance, which further reduces the impact energy in case of frontal collision.
Another important point is the psychological acceptance of the drone by people, which can be achieved by this design thanks to several characteristics : there are no apparent propellers outside of the airframe, as opposed to conventional quadcopters (N.B. : the pusher propeller can be ducted for protection), and the sleek, beautiful, natural-like appearance of this drone could bring a feeling of confidence and security. Overall, this might tend to reassure populations and lead to their acceptance of drones flying over their heads.