Dario's Lab

Development of a 10Kg High-Efficiency Surveying Drone

A project that cemented the growth trajectory of Carbonix. After a couple of years of marine product development and aerospace consultancy work, the opportunity arose to participate in a tender with D3 Applied Technologies to create a new airframe for a Spanish/EU programme with military and civilian applications.

The requirements called for extended flight time with a strict size limit on the transport box. Channelling the America’s Cup background of the teams at D3 and Carbonix, we looked at how to meet these requirements in the most creative and effective way possible.

This drove the concept of a twin-boom configuration with the wing connection is as far outboard as possible. Thanks to the wing junction being shifted outboard, the carry case could to be closer to 1/3 wingspan than 1/2. Meaning we could fit a bigger aircraft in the given box. Thus having more wing area and carrying capacity.

The twin-boom layout also allowed for an inverted U empennage with twin (redundant) rudders.

Once the basic layout was selected, D3 generated the aerodynamic surfaces and performed their uniquely advanced specialised CFD (developed out of America’s Cup technology). The teams collaborated in optimising the structure and aerodynamics together.

Unusually, wing sweep was adopted to enhance stability and provide positive aeroelastic behaviour (since the tips are aft of the roots, washout tends to increase under increasing aero load).

Box size also drove features like wingtip fences (winglets) and the removable nose payload fairing cone.

This successful collaboration was a great example of truly integrated design. The aerodynamics and structure developed together and complemented each-other.

Carbonix then developed tooling, composites details, fittings, and construction techniques.

Much experimentation was involved with materials and assembly methodology. For example, the main spar went through maybe a dozen iterations, evaluating foam-filled rectangular boxes, carbon H sections, Z sections and C sections. All with different fibre layouts.

As I’ve often found, a practical approach – building full size specimens and physically loading them on a test jig – paid dividends. Though some coupled CFD/FEA was involved, using real-world measurements to calibrate the models was absolutely key.

This project represented the definite pivot to aerospace for Carbonix, and the beginning of a long period of developing methodologies and capabilities ot push the boundaries of long-range drones. It was also the first of many happy collaborations with D3.