Mother Nature's wind is a phenomenon whose energy and power should never be underestimated. To survive stormy winds is to experience one of the nature's most brutal forces. Wind is also the force that provided wings for humankind to explore the world, we would never have flown, nor understood the importance of construction efficiency and mobility. Without understanding and respecting the wind, its energy would forever have remained a threat to us. Mankind has learned to capture the air currents of wind and channel them as they pleased, turning it from an enemy to an ally.
Aerodynamics is the study of forces and the resulting motion of objects through the air. Now Adria is pioneering this science with caravans. Starting with Astella, which uses aviation efficiency, channelling air currents to make towing safer and more efficient. An integrated aerodynamic design supported by high-tech electronic tests and analyses conducted in a virtual wind tunnel of the world-famous Slovenian aircraft manufacturer Pipistrel Aircraft, took the airflow effects in towing Astella, to the next level. This science has now been applied to Adria's new generation caravans - first to Adora and now the new Alpina. Never before has towing a caravan been so directionally stable and energy efficient when it comes to such large, comfortable and spacious homes on wheels. These caravans do not defy the wind when in driving, they work with it. Long-distance travel is now easier on the wallet, as the efficient aerodynamics reduces towing average fuel consumption. These caravans have a characteristic design, beautiful new silhouettes with perfect proportions and elegant, clean lines with softly rounded edges. Quiet and stable on the road, these new caravans retain their stability even in a storm.
Nature has always been a source of inspiration for Adria products. Adria's home, Slovenia, is a green country whose people value contact with nature. It is one of the European countries with the highest of biodiversities and the cleanest of environments. Just as a view from the mountain tops or the colours of a forest bring a sense of calm, so do the light and scenic views make a stay in Adria's vehicles worthwhile. Even the mildest of winds provides natural ventilation, while the excellent insulation helps you stay cool during the summer even without air conditioning. When designing aerodynamic solutions, Adria's first thought was to seek inspiration from nature. Imagine how the wind shapes a drop of rain that is falling high from the sky towards the ground or the exceptional stability control at high-speed vertical descent of a peregrine falcon. The Adria development team combined the aesthetic design with the wind principles in a very natural way.
Adria and their design partner, Gigodesign studio, embraced bold ideas and innovative thinking, combining the best solutions from experts in the science of wind – Pipistrel's aeronautical engineers. Slovenian aircraft manufacturer Pipistrel, the first company in the world to certify an electric aircraft, a leader in the aviation industry in terms of alternative propulsion development. Astella represents a technological breakthrough, a pool of combined knowledge and ideas, and the collaboration of very different, seemingly incompatible fields and professions. Inspired by nature, Adria combined the best and most advanced science solutions to create state-of-the-art caravans that cleave the air according to the principle of aviation laws. Pipistrel's expert in aeronautical physics and aero simulations, Matej Andrejašič, explains the key purpose of aerodynamic solutions:
“The main purpose of improving, firstly, Astella’s aerodynamics was less drag and, as a result, also the lower fuel consumption. A strict condition, of course, was that
the solution should not affect the quality of driving, i.e. it had to retain directional stability and therefore the balance at the front and rear of the caravan.”
Designer Matic Vihtelič explains that a caravan must, first and foremost, come as close to its key mission as possible, which is to provide a living space. The relationship between housing efficiency and mobility is therefore very important: "In designing the Astella, at Gigodesign we wanted to take a step further and come closer to the basic purpose of the caravan. Any caravan is used more time as an accommodation than as an object in transport. With this in mind, the basic concept was to increase the internal volume, so we wanted to give up the wedge-like shape in the front wall and make a caravan with a flat front wall. We wanted to achieve the spaciousness of the interior and add panoramic windows on both, the front and rear side, which would open up the space visually." Adria's understanding of living with the travelled landscape prompted the development of a new architecture approach that is now part of the Adria design DNA. The installation of panoramic window and door solutions has become part of the added living value in all Adria's premium products, especially in Astella. Adria's construction expert Uroš Dvornik went a step further. Aware that true modern nomads do not need as much space for themselves as they need it around themselves, even when the caravan is parked, he found a solution that literally opened up the living space to nature, with a unique new panoramic door. This door fitted Astella with a "natural" terrace modelled after the modern building architecture. The panoramic door adds a domestic feel, with the caravan's own terrace providing pleasant memories for the later time, when one is soaking in thousands of different views. This learning is applied to the new Alpina layout 663 PT, which has its own panoramic door. However, the requirements of safe towing and low fuel consumption had to be considered with this design. "In proposing a flat wall, we proceeded from the fact that caravans of this size are towed by fairly large cars, i.e. often SUVs, which displace extensive quantities of air, so we assumed that the angle at the front wall was irrelevant. Instead of dealing with the aerodynamics of the caravan on its own, it was necessary to analyse the entire convoy, that is the both car and the trailer. This concept is similar to a train composition, where the wagons are completely cut off and the locomotive is the one that displaces the air.” Gigodesign started to study the effectiveness of a holiday convoy in collaboration with Adria Mobil and Pipistrel. It was crucial to find the most effective solution in how to stream the strong airflow that creates the drag and the vortex between the towing vehicle and the caravan. "This phenomenon is typical of all caravans. Due to the flat roof, it was slightly difficult to position the air exhaust, yet it was extremely important for the use of interior space, which was why we opted to place the exhaust on the sides”, explains designer Matic Vihtelič.
Pipistrel were eager to collaborate with this ambitious Adria project, tailoring excellent aerodynamics to safe and energy-efficient driving without compromising on living comfort. Aviators from the land of the strong wind called bora, or Burja in Slovenian, have indispensable knowledge about the lift and drag, knowing how to work with both. In airplane design, providing a lift at the lowest possible drag is essential. However, when it comes to road travelling, the situation is quite different. While in travel, both the car and the caravan must be surrounded by air currents providing optimal stability. Aerodynamics expert Matej Andrejašič from Pipistrel explains: “It is true that, in an aircraft, the lift and drag are both important. But when it come to caravans, the lift should be avoided, as should the lateral forces. It is necessary to stream the air flow in a way that will primarily affect that component of the force active in the direction of travel, i.e. the drag. The lift could drastically affect the safety of the vehicle by reducing the grip of the tires.”
Designers and aviation experts faced a demanding task to upgrade the 'modern cube on wheels' so that gusts of wind at what were practically perpendicular surface edges would not cause a safety hazard and consume energy. Matej Andrejašič admits that the basic design was a great aerodynamic challenge. We had to give Astella some discreet efficiency. “Of course, the basic shape of the caravan was very close to that of a square due to the optimization of usable space. In the field of aviation, such body shape is rarely encountered as it causes the greatest air drag, which is one of the worst inhibitors of aerodynamics. So one of the most notable innovations in the world of caravans essentially emerged from the world of trucks rather than aircraft. These are air flow guiding vanes on the front vertical edge of the caravan between the front and side surfaces, which drastically reduce the area of increased air pressure between the towing vehicle and the caravan while ensuring that the air flow on the side surfaces does not get detached. As with the aerodynamic optimization in trucks, the original goal with Astella was to reduce the maximum contribution of the drag resulting from the air flow that gets detached from the surface. If an airflow travelling around the body encounters an obstacle and has insufficient energy to bypass it, it can detach itself from the surface. One of such examples can often be seen on the edge between the front and the side of the caravan. Such a detached air flow is most easily detected by a series of woollen strips glued to the surface. The comparison of patterns in woollen strips created during the ride and the calculation simulations showed a positive match, which confirmed the effectiveness of the solutions used.”
Once aeronautical experts used their measurements to pinpoint the exact position and surface of the airflow rectifying elements, the designers had to add the aesthetics. A newly-emerged and very important challenge was how to achieve the typical Adria design with guiding vanes. Designer Matic Vihtelič explains how they tried to find elements that would be sufficiently integrated and at the same time become part of the new design with other Adria products: “Together with Adria's engineer Uroš Dvornik, we managed to integrate the guiding vanes into the multifunctional element of the caravan's rim, which also provided a unique silhouette and enhanced the quality of living in the Astella. With the design, we wanted to place greater emphasis on the side wall rather than the front one. The competition is dedicating extensive efforts to the front and rear walls to make the shape as similar to that of a car as possible. We wanted to move away from that approach and make the walls more discrete. Instead of producing a house that pretends to be a car, we wanted our product to offer the best possible living experience.”
Once you experience stormy weather and strong winds sweeping the camp ground, you become aware of the significance of efficient aerodynamics. The question here is whether an aerodynamically advanced design can also improve the safety of living in open plots when a caravan is exposed to a downpour. Pipistrel's expert in aerodynamics, Matej Andrejašič, confirms: “Of course it can. However, the problem is that the raindrop shape, which is the most wind-resistant shape, is far from optimal in terms of interior space usability. One of the worst and potentially most destructive events is a gust of wind coming around the sharp edge of a building. Here, air flow accelerates even at a greater speed and, due to the emergence of a very low air pressure area, it can tear off even a well-attached part of the building. With its rounded edges, Astella is more resistant to strong winds, which certainly shows when you drive with it.” Adria has tamed the wind, formed an alliance with the enemy and applied this learning to Adria's new generation caravans.
BURJA
The wind is so deeply embedded in human lives that people from all over the world have given it names according to its power, effect and direction. Slovenia is well familiar with the power of "Burja", the country's strongest wind that blows from its mountain barriers towards the sea. The strength of Burja serves as a safety reminder, as its gusts can reach hurricane levels and even stop traffic. On the other hand, Burja is also a noble wind, as it always brings sun, stable weather, and the harmony of taste exemplified in the Slovenian kraški pršut, a type of air-dried prosciutto produced in the Burja-swept region of Kras.
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