“Having the carbon designation alone is not enough to make a foil faster compared to an aluminum foil.”
Carbon foil and aluminum foil, what are the differences?
| Criteria | Aluminum foil | Carbon foil |
|---|---|---|
| Price | Less expensive | More expensive |
| Resistance | More solid and impact-resistant | Does not like impacts |
| Ease of use | Easy to assemble and adjust | Faster, therefore finer adjustment. |
| Scalability | Adaptable to desires and conditions | Also adaptable, but each part costs more |
| Durability | Robust but susceptible to corrosion, 100% recyclable | Durable and resistant if well maintained but sensitive to impacts, not recyclable. |
| Weight | 4.7 kg | 3.5 kg |
| Maintenance | Needs to be disassembled and rinsed as often as possible | Does not require special maintenance (occasional check of all parts) |
First, let's look at the characteristics of aluminum foils:
- Price: an aluminum foil is cheaper because it is mass-produced. The mast and fuselage are aluminum, and the wings are fiberglass or carbon.
- Resistance: Aluminum foils are robust and withstand impacts. A dented aluminum mast remains usable.
- Easy to use: Aluminum foils are generally easier to use because they are better suited for beginners with larger wings.
- Scalable: You can easily change the length of the mast and fuselage at a lower cost depending on the program you want to do.
- When combined with small wings, they can be very high-performing and sometimes even faster than some carbon foils.
- Durability: an aluminum foil is perfectly recyclable (all aluminum parts).
However
- It requires a little maintenance; you need to rinse and disassemble it after each session (this takes 2 minutes).
- It is generally heavier compared to a carbon foil.
- Even if the mast is stiff, it is a little less responsive than a carbon mast.
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Characteristics of carbon foils:
- Price: a carbon foil can be more expensive, even much more expensive, compared to an aluminum foil. An aluminum mast is mass-produced, and it is possible to produce many at a lower cost. A carbon mast is handmade; there can be up to 160 layers of carbon in a mast, which automatically leads to an explosion in manufacturing costs.
- Stability: if the carbon foil is well designed, it will be more rigid and provide more stability at high speed. If the technical development of the mast is not done optimally, no performance gain will be observed; it may even be less efficient, less rigid than a well-developed aluminum foil.
- Performance: a carbon foil will be more efficient if and only if it is more rigid with less chord and less thickness, which reduces the drag generated by the mast and thus increases performance.
- Durability: a carbon foil requires more care because it is more fragile. It does not resist impacts well (even if all carbon parts are repairable) but can last a long time if you protect it. However, it is not recyclable, so choose it carefully.
As we have seen, an aluminum foil has advantages and disadvantages, just like a carbon foil, however
Is an aluminum foil really less efficient than a carbon foil?
We will explain why this is not always true, and if you opt for a carbon foil, make sure you are well-informed to avoid disappointment.
First, let's establish some postulates so that everyone can understand our reasoning.
First, we will imagine that we are using the same airplane (front wing, rear wing, and fuselage). We will focus on the mast because it generates significant drag due to its length, thickness, profile, and chord.
There is 800 times more drag in water than in air. Consequently, the more contact surface there is, the greater the drag.
The contact surface is defined by the mast's thickness, chord, profile, and length.
For example:
- If two masts are identical except for the construction (one in carbon and the other in aluminum): the performance will be the same because the drag will be identical.
- If a carbon mast has a longer chord (distance from leading edge to trailing edge) than an aluminum mast with an identical profile, identical size, and identical thickness: it will be slower than an aluminum mast because a longer chord equals more drag.
- A carbon mast with a less fast profile (with more thickness near the leading edge, and there are an infinite number of such profiles) will be slower than an aluminum mast with the same characteristics (chord, thickness, height) but with a faster and more efficient profile.
- A less rigid carbon mast (in torsion and flexion) will be less stable and therefore potentially slower than a stiffer aluminum mast. In this example, it is entirely possible for an aluminum mast to be more rigid than a carbon mast, especially if the carbon used is standard (not good quality).
In summary, claiming that a carbon mast is faster than an aluminum mast is completely false because many parameters influence the rigidity and performance of a mast. Test and observe carbon foils carefully before buying one.
So how can a carbon mast, and therefore a carbon foil, be more efficient?
To be more efficient, it must be more rigid, thinner, have less chord, and have a more effective and efficient profile.
How is this possible?
To go fast, you need to reduce the mast's chord (on the submerged part). Our aluminum mast has a chord of 121mm, our carbon mast has a chord of 108mm. This means a reduction of more than 10% in chord and also a 10% reduction in chord-related drag.
To go fast, you need to streamline the mast as much as possible and thus reduce its thickness. To give you an example, our aluminum mast is 18.5mm thick, and our carbon mast at the bottom (where there is maximum drag) is less than 14mm thick. In this example, we have reduced the thickness of the carbon mast by more than 25% and consequently reduced the mast's drag by more than 25%.
The profile applied to a carbon mast must be the most slippery and fastest. Our profile used on our carbon mast reduces drag by 10% compared to our aluminum mast.
Finally, the mast must be as rigid as possible in torsion and flexion. This is the most complicated part because to be rigid, you need:
- A perfectly designed lay-up plan to reduce torsion and flexion. (And this is not so easy to do; some brands fail at it.) A mast with too much torsion cannot be used with large wings like a 1.40 m wing. It will not withstand lateral forces and will cause parasitic movements and uncontrolled movements that will make your navigation uncontrollable at times.
- Increase the amount of carbon to maximize stiffness. At SROKA, our carbon mast is a mast with over 140 layers of carbon. In the lower part, the mast is completely solid. There is no foam, which optimizes rigidity and torsion.
- High modulus carbon fibers. Following all these surface reductions to reduce drag, our mast is made of 100% high modulus M40 J fibers, which guarantee less elasticity and better rigidity. Most of the time, this type of carbon is used in F1, aerospace, or aviation. However, it should be noted that this carbon costs much more and therefore increases the overall cost of a mast. A high-performance carbon mast will therefore be an expensive mast. Few foil brands make 100% carbon masts with high modulus fibers.
In summary
In summary, for a carbon mast to be more effective and allow for greater speed, its thickness and chord must be reduced, it must have a fast profile, the amount of carbon in the mast must be increased (because by reducing the chord and thickness, the mast becomes more flexible), and finally, high modulus fibers must be used to optimize rigidity for a responsive and fast foil.
In this case, and only in this case, a carbon foil is faster than an aluminum foil.
“Having the carbon designation alone is not enough to make a foil faster compared to an aluminum foil.”
At SROKA, we truly want to push the boundaries of carbon foils and create a real difference compared to aluminum masts.
Therefore, we offer a 100% carbon mast with high modulus fibers, which is thin and stiffer than our aluminum mast, which is already a benchmark.
Increase your performance by opting for our Elite HA 14mm carbon mast. You will gain more than 25% performance compared to an SROKA aluminum foil and nearly 40% additional performance compared to other competitor foils.
If you have any further questions on this topic, or for any other request, do not hesitate to contact us!
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