Markla has been debating with himself the merits of a set of standard sockets for foil components. In particular all the bits that require re-work on other carbon components:
- main strut head (to hull)
- rudder head (to gantry and/or rudder stock)
- main strut base (to main foil)
- rudder strut base (to rudder foil)
The main strut head is the biggy since it appears as though to install new foils you either need to buy from the boat/foil manufacturer that the last lot of gear came from, or cut a gaping hole in your hull to install a new cb case.
Although the details haven't been worked out yet, above is an example of a possible main strut head socket that could be exploited.
Some things to consider are:
- should be slightly larger at the hull than currently built foils
- hull opening needs to be a fixed size no matter which hull
- tapering is easier to ensure fit, plus it is easier to plug in.
- taper is to be at a fixed angle rather than top and bottom fixed shapes due to reason below
- cb case depth would need to be standardised, maybe a range of say 200, 250 and 300. (advice requested here)
- construction could be a two step or single step process, depending on tooling.
- could usher in a whole new era for foil construction and experimentation
- structural continuity needs to be considered. large kinks in laminates are to be avoided at this high load area. this could be very easily achieved but I'll let you come up with your own methods.
- weight increase would be minimal. it would be negligible when considering the extra weight from cb case re-work with wet laminate.
- a tapered shape like this could easily be ordered from a builder and fit perfectly as opposed to quoting NACA or custom foil shapes and pin positions
- pin position and size would also need to be incorporated.
- trailing edge of socket would most likely need to be colinear with trailing edge of blade to facilitate push rod installation.
- wheels (eg. fork widths and axle diameters)
- tyres (diameter and width)
- brakes
- seat posts
- handle bars
The only problem is different freeboard depths which would mean the taper would have to be altered for each boat. However, a great idea and I think eventually all boats will develop similar systems very much like in windsurfing with the different types of fin boxes.
ReplyDeleteThe freeboard and taper issue can be dealt with this way, have a base length and the taper can extend beyond this for deeper freeboard/case depths. So the angle doesn't change, just the extension.
ReplyDeleteNarkla the whole idea of molding a profile of any shape into a hull is silly. The trunks should be proper square trunks into which can be fit any foil deemed suitable using a cassette. There are a few moths sailing with this system already.
ReplyDeleteMy whole daggerboard tilts so that would be incompatible with your setup also.
I like the rudder gudgeon spacing idea though.
I like the idea of tapered cases because they are practically as easy to build as a square case, have built in release angle for construction purposes, are lighter than a square case and the force is taken by the case rather than the pin.
ReplyDeleteYou're comments are valid. M4rkla has also installed a square case in the SLINO and Stress Less had a square case. The tapered case proposal is just an evolution of the square case based on those previous two builds.
Modification of any existing foil to a tapered socket is relatively simple if the owner desires it. Make an MDF female mould of the socket, trim the foil to fit (chamfer top of leading edge), jig to align cb in mould, fill mould with bog and clamp mould around foil top. A bit of finishing and it is done. Structural strength shouldn't be compromised, only the top of the strut inside the hull is being modified at all, the first third of the strut inside the hull should not be altered.
A tilting cb could easily be incorporated into the tapered case, depending on how much you want the board to tilt.
Yes, the gudgeon spacing is next priority I believe.
ReplyDeleteGood idea.
ReplyDeleteFor WS fins the Tuttle box seems to work well, it has taper on the LE and TE but the sides are parallel. I think that would be easier for the home builder to tool up than tapers in both directions. Plus, if you want to shim the LE or TE to change the AOA of the main foil it only be possible with parallel sides.
Kirk
Sorry, I didn't explicitly state that there are parallel sides, but it is true. Only leading edge is "tapered".
ReplyDeleteYes, very similar concept to Tuttle box, except trailing edge of socket should be collinear with trailing edge of blade to easy push-rod installation.
It's a great idea but entirely up to the builders to do it or not. I don't think they have an interest at the moment. And I don't think the open class ethos supports writing it into the rules.
ReplyDeleteI agree entirely, it can only be adopted by the builders, home and professional, and shouldn't be part of the rules.
ReplyDelete