For all the time I spend on the internet and practicing my fiddle (electric, in headphones so the neighbors don’t have to listen) I still manage to make progress on my footy. This is harder than it looks since all I’ve ever seen is pictures and I have only a hazy idea about how to actually rig one.
Still, as you add pieces the next piece becomes easier to find a logical place for and like the final note of a piece of music I expect the final piece of the footy to have the same feeling of inevitability.
There is one bulkhead that is the mounting place for the structure of the fin keel and the servo tray. The mast step (three tubes) braces itself between the bow and the fin. The fin is two pieces of 5 mm square CF tubing to which I will glue balsa to form the fin out of, which will then be glassed.
No rudder yet, but that will be a tube inside the hull with a bicycle spoke rod to connect to the actual rudder. I will probably use a piece of helicopter blade from my Blade 400. I seem to acquire a lot of single blades. I’d go to CF blades but I will wait until I am in a less destructive phase of my learning cycle.
BTW, notice that the rig pivot is raked. I hope that will help to keep the boom out of the water on runs. Works on schooners and New England cat boats, and was a problem in Finn’s with their more or less vertical mast. It’s hard to steer with the boom in the water.
I suspect you are in for a tough time downwind in breeze with your mast so far forward.
I also suspect…well not suspect, know from experience that raking the mast tube creates a problem in light airs as it takes more wind to blow the boom out since it has to travel “uphill”
My solution is to have a very high slope to the boom so it clears the water whilst maintaining a vertical pivot.
Finnish the boat,get it wet and I am sure it will provide fun and learning!
Thanks for the analysis. I am also aware that the structure that I am sticking the fin on is a bit far forward compared to most boats I have looked at. I just keep asking for trouble.
There are three pivots for the mast but the total range of position is probably a bit over a half an inch.
The bows are very full, with a lot of volume forward so I am hoping the forward position of the sail won’t be that bad. If it is I can always make a new rig with a shorter forward section. (Which in turn will be less counterbalanced exacerbating the downwind problem you describe.)
My next hull will be molded so maybe I can make a few versions. I was thinking of a daggerboard type fin that can be adjusted fore and aft. Problem is I am lazy and want to “git 'er done.”
The Footy is a development class and half the fun of making one is allowing yourself to experiment. The molded hull will enable easier experimentation, but I am going to be trying something a bit different as far as hull shape, so maybe I won’t get to make that many before I have to make a new mold.
I have to leave time for airplanes and fiddles too.
Anyway, it’s getting close to finished and almost time to start figuring out the details of rigging the radio gear.
BTW Brett, I read the entire thread about your very small boats on RC Groups. Learned a lot there and was almost tempted to start working on two boats at once, but sanity prevailed. (temporarily, at least)
Not to disagree in an area I admittedly know only from full scale boats sailing in open water as opposed to tiny boats sailing under conditions I know nothing about. I came up with an alternate idea of what might be taking place when light airs can’t pivot the rig in the expected direction.
In picture one the pivot is vertical and divides the sail into a large and small areas A and B.
In picture two the pivot is raked and the sail is divided a lot closer to fifty-fifty creating a situation where there is not enough force on one side of the sail to cleanly swing it to where you expect. A and B are very close in size and it is conceivable that you could even have B larger than A if the pivot is raked a lot and the mast is close to vertical.
There are two solutions for the raked pivot: One is to move the pivot much closer to the front of the sail, and the other is to rake the mast much more than normal, and definitely more than the pivot, so it looks almost like a lateen rig. Both methods will reduce area B and hopefully allow the sail to pivot as expected.
My sail area is probably divided about one third in front of the pivot. The sail plan is not fixed, but you have given me a lot to think about.
The very raked mast solution (if my current setup doesn’t work) will also move the sail area back, solving two problems. (Maybe)
Once again, I have zero experience, I am not disagreeing, I am just visualizing an alternate explanation and possible solutions to getting a raked pivot to work.
To me half the fun of this is that I am not following someone’s recipe, but cooking something up myself and seeing what happens. As already said, the mold for my rounded hull will not be conventional but I will try it and see what happens.
Sorry the drawings are so crude, but they were done in Photoshop rather than a technical drawing program.
Just as a point of reference I have several MacRigs that pivot okay at up to about 61% aft and 39% forward of the pivot line extended. As per your second attachment you may be able to cut a profile that will move your sailplan back a good bit should you find you need it to provide a little weather helm. My mast pivot is vertical and so far no issue with the boom dragging in the water but my clew may be high compared to yours.
I want to play around with the relative areas for and aft of the pivot to see how close I can get to 50/50 before the sail stops pivoting reliably.
For the time being, most of my “experiments” are done in my head, in anticipation of when the boat will be ready.
I expect to have my eyes opened a bit when I see the thing in the water and can come to grips with these imagined problems and imagined solutions in real life.
I can appreciate the weather helm idea after reading about your difficulties in your first race. I don’t know how much time I am going to get with the boat in the water, but at least Central Park is a short subway ride and I’ll be using 2.4 gHz so I hope none of the local racers will get annoyed. They often drain the conservatory pond in the winter so I will have to see when the place is available.
No big rush, I still have to stick all the pieces together, melt some lead and make a sail or two.