Dec 12, 2018

F18 Cirrus R2 Convertible L foil explained










Renders by Cirrus / Boulogne Conception Marine. Photo by Cirrus from Salon Nautique Paris. Click pics for larger size & slideshow.

Cirrus R2 Convertible , L mainfoil: New photo published yesterday from the new R2 convertible L foil shows how they followed their initial design intent leaving the Z foil 4pt system for other builders to use it.

Bold move from Manu Boulogne, as that hard L foil will need some on the fly trim, in in our first from the distance guess. The L foil a la AC50
will provide much lift and the counter part will be control.

F20s & FPs use the original TNZ J 3pt system. Revisiting the concept we explained many times the J foil design has the ability to self trim in lift/fly height.

With an L that feature becomes a bit harder to achieve, but Cirrus has added a nice feature which is a canting setup for the convertible dagger case. The canting can set the L foil to become a slight V, thus it will take advantage of self trim feature of the TNZ J.

The AC50s did not had this active L foil trim problem as they were equipped with dedicated hydraulic systems controlled by simple push down buttons, a luxury you cannot have on board an F18 or small cats.
Still the A-Cats are developing and have implemented on the fly adjustment rudder and foil system but are not meant to be trimmed every 5 seconds as might be the case for ie with the mainsheet.
And surely the R2 has their own, the canting ones can be seen in case render above.

On rudders, their choice seems to be T winglets.

- Case & floating mode water filling issues
The Cirrus R2 dagger case solution is a clever one regarding the F18 floating mode, where is 'vox populi' now that the Infusion MK3 had issues on the big space assigned to their convertible cases filling up too much water (you need a quite ample body inside the case to allow Z foils a la N17), the R2 does not has this water (additional weight/drag)  problem, as the V shape dagger case will not fill while sailing in floating mode and also provides the space for the convertible L foil to cant.

On other Pro / Cons, L foils have to be inserted from below, thus my preference towards the insert over the top of Z foils (A-Cats / Nacra 17 / Phantom Essentiel)
But are details, current FP or F20 owners have no issues on launching their boats.

Congrats to Manu Boulogne and his team at Boulogne Conception Marine, builders of the Cirrus R2 F18. Hope to see this weapon flying soon enough, we'll keep you updated.-

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