In the buildup to the Moth Worlds, we’re diving into the cutting-edge innovations that make up the Mackay Bieker BM-V3 Moth, starting with its foils.
Foil Power
Foils are a huge part of the Moth’s performance, with the accuracy and quality of the foil’s finish being exceptionally important.
The Mackay Bieker foils are built in-house at Mackay Boats, designed by Paul Bieker, modeled by Riley Dean, engineered by Frederick Leopold, and overseen by in-house engineer Andre Terzaghi.
Let's take closer look into the technology involved in the horizontal and vertical foil -
The Horizontal
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A range of main and rudder horizontal foils are built as each foil produces a different lift/drag profile to suit different conditions, sailor weights, and sailor preferences. The lift/drag profile changes with shape profile and sectional shape.
The Mackay Bieker horizontal foils are made with up to 100 individually cut layers of pre-preg High Modulus Carbon Fibre. These are carefully laid into an exact position in an aluminum mould and cooked under 30 tonnes of pressure.
In general, heavy-air foils are smaller while lighter-air foils are larger. However, we are experimenting with the sectional shape within this envelope and have seen subtle changes affecting performance.
The Vertical
Vertical foils are all about minimizing drag while retaining maximum strength and stiffness.
Vertical foils are made the same way as horizontal foils, with up to 70 individually cut layers of pre-preg High Modulus Carbon Fibre carefully laid into an exact position in an aluminum mould and cooked under 30 tonnes of pressure.
Vertical foils are made from a combination of metals like titanium and high-strength Stainless Steel spliced into High Modulus Carbon fibre.
The latest foils feature longer metal segments at the bottom to reduce drag then spliced into carbon heads to try and keep the weight as low as possible.
When developing a horizontal or vertical there are always tradeoffs; the trade-off on the Horizontal foils is lift v’s drag (more lift comes with more drag), while for the Vertical foil the trade-off is drag v’s stiffness and weight.