INBOUND: SiFly Stellar X

SiFly have aimed for the stars with their new premium range of Stellar eFoils. And right at the tippity top sits the new Stellar X, which they’re particularly proud of, and by all accounts for good reason. We’ll have a test coming your way next issue, but for now, here’s what we gathered from team SiFly…

Firstly, please tell us where the Stellar range of eFoils sits in your line-up? What differentiates this range from the rest?

The Stellar range sits at the top of the Sifly eFoils range offering the highest performance, premium materials and stunning looks. The Stellar R and S models evolved from the successful first generation Sifly R and S composite boards, bringing a 25% weight reduction with their improved full carbon sandwich construction. The lighter boards with their reduced swing weight took the eFoiling experience to a whole new level, and the special metallic and pearl paint choices proved a hit with customers. Produced at what we consider to be the best surfboard factory in the world – Cobra – the Stellar series range of eFoil elevated Sifly to ‘premium brand’ level.

On the other end of the spectrum, we have the Rider series. It utilizes a soft-top construction from impact resistant closed-cell foam with an internal aluminum frame to support the mechanical stress from the hydrofoil. Apart from the affordable price tag, this board technology has many benefits for the everyday user. Being soft, it is much easier to transport and handle without the fear of cracking from hits. Additionally, the soft surface provides an extra layer of protection against injuries. 

Now, after a long season of development and testing, we are proud to announce the newest addition to the Sifly line-up: the high-performance Stellar X model. 

The Stellar X is pitched as the ultimate board for wave riding and aggressive carving. How have you achieved this, and what tech is involved?

The Stellar X builds upon the R and S models from the series, utilizing the same full carbon sandwich construction, providing the best strength to weight ratio and highest quality of premium materials used. The length of the board has been reduced to 4’6 to make it ideal for heavy leaning into aggressive turns. The weight has been further reduced to the 9kg range. The much smaller footprint and lowest swing weight in the range make the Stellar X ideal for sharp turns in waves or while racing in flat water. 

The Sifly team has put an immense amount of energy into shaping, simulating and on water testing in refining the shape of the Stellar X to reach perfection. It is important to mention that while we have strived to engineer the best performance of the X model to let the most athletic rides push their limits, we have not forgotten about the less professional users. The board shape has been optimized for easy acceleration and planing. Unlike many boards of similar size on the market, the Stellar X is incredibly easy to start on with a balanced behavior while accelerating. It is easy to get the board to planing speed without having to think too much about keeping the nose above the water level or having to push uncomfortably on your front foot to avoid being flipped backward. That ease of starting is useful both to the average user, as well as to professionals who sometimes need to get from zero to foiling before the next wave hits them hard. 

Talk to us about the boards’ “anti-dive architecture”…

The pure riding performance of boards and wings is often overlooked in the eFoil industry. A lot of newcomers in the surfing sports starting from the electrical end of the spectrum do not have the experience from different foiling disciplines and cannot adequately judge the performance of an eFoil. We however focus on the foiling characteristics before anything else and are particularly proud of the supreme “anti-dive” hull architecture of the Stellar X board. We have tried and refined multiple versions of the board’s shape with different rocker line, outline and 3D bottom to reach the final design of the board. The precise progressive rocker line in combination with a double concave in the front would save you from the hardest touchdowns with fear of a nosedive. The rebound is well controllable and predictable. Touching the rails of the board in turns are barely noticeable. Overall, the shape of the board allows you to have complete trust in your balance and control of the situation and focus purely on your racing or wave line.

For someone who doesn’t hold back and is looking to have a hard-carving session, what does the battery life look like?

The range of electric foils (similar to electric vehicles) depends heavily on the riding style and set up. While the lowest weight of the Stellar X SET in the product range helps increase the efficiency and range, the board is often pushed way above the speed limits. With a bigger wing, lower speed and no mistakes on the rider’s side, you could reach up to 120 minutes of riding time. At maximum power however you could finish the PowerCell Long Range 2.3kWh battery in about an hour. Most people would get roughly 90 minutes from a more demanding carving session. 

What’s the most effective way to minimize weight when designing an eFoil?

When designing a high performance eFoil, one of the key factors to consider is the weight and more importantly, the swing weight. The second is also known as moment of inertia and it is the equivalent of mass but for rotational movement. The lower the swing weight, the easier it is to turn the board around and engage in aggressive turns. The most important factor for reducing the swing weight of an eFoil is reducing the weight of the board. To do that, one must choose a proper construction that is both lightweight and rigid at the same time. The carbon sandwich construction provides the best strength to weight ratio and this is why we chose it for the Stellar series boards.

Your eFoils are all assembled and certified in the EU. What benefits can a customer expect from having these assurances?

Assembling and certifying SiFly eFoils in the EU ensures exceptional quality, strict safety standards, and adherence to sustainable production methods. Customers benefit from a reliable two-year warranty, faster post-purchase support, and ethical labor practices, providing peace of mind and a premium, eco-conscious eFoiling experience.

Where do you see the future of eFoil design going, and what do you feel are the main technological limitations currently?

In our opinion eFoils are currently limited by state of battery technology. The batteries and to some extent the motors are the heaviest components that make an eFoil bulkier than a lightweight surf foil. We are eagerly waiting for a new type of battery with much higher energy density, that will allow us to keep the same 120min ride time in a much smaller and lighter form-factor. 

If there were no budgetary considerations and using current tech available, what do you think an ultimate eFoil would look like, what materials and components would it use?

If we were to unleash our imagination and forget about budget constraints, we would take advantage of the latest innovations in the material sciences. We would utilize the incredible strength and weightlessness of graphene for the structure of the board and hydrofoil, while superconducting materials would allow us to make the powertrain that much more efficient. Jokes aside, we are already using some of the best carbons and aero-grade aluminum in our products and there is little that we would want to improve.