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Posted by Akerman | Oct 04, 2015 @ 09:01 AM | 1,770 Views
The new rig is based on a 5 mm carbon tube mast. The original aluminum mast is too flexible IMHO. All fittings etc. were fixed to the mast with CA and additional wraps of carbon roving, soaked in CA (keep your nose and eyes away!). The spreaders are removable, fitted around a 2 mm carbon rod. Yes, I drilled a hole through the mast for this rod. I hope to get away with it as I wrapped it with CF tow afterwards.

The 0.8 mm wire for the gooseneck rotates in plastic tubing typically used for bowden pushrods. Very low friction. I think I should switch positions of vang and boom though to get the sail a bit lower.

The 3 mm CF tube for the jib uses silicon tube for defining the position of the several wire fittings. The counterweight is removable....Continue Reading
Posted by Akerman | Oct 02, 2015 @ 09:41 AM | 2,091 Views
since the last post. Got a bit busy.
The new sails proved to be good, but not quite good enough. In light winds, even this thin mylar is too stiff when glued with double sided tape at the seams. So I switched to a new method for another new set of sails.
No overlap and no double sided tape anymore, just clear tape on one side only to cover the seam. This results in much more flexible sails.

The first race with the new sails proves the point: Won the first two rounds, then ran out of luck and finally got the maximum DNF penalty in the fourth and last round for not finishing within three minutes because the wind had died down...

anyway, it was great fun and astonishing to see that the Fortune with a new rig was one of the quickest boats in the light conditions, faster than the DF 65, CR 610, MicroMagic and many others. This video shows the starts only. My boat is the one with the all white sails and very small sail number.

27 9 27SaikoRCyacht ミニクラス スタート集 (8 min 31 sec)

Posted by Akerman | Aug 27, 2015 @ 10:35 AM | 1,206 Views
Time for a new mainsail. The fantastic white non-stretch plastic film that I used for the A-rig of my IOM will be just right for the Fortune. Very light and thin, around 0.04 mm. Before you ask: I don't remember at all where I got that stuff from. Must have been some specialist in Germany. I bought it about 15 years ago...
And I was happy that the special "pekabe" 6 mm double sided tape still is sticky
Yes, I will be trying to get some profile into these sails. Out comes the plywood template. I am using the method of this most excellent tutorial:

(sorry for the german...)
Posted by Akerman | Aug 25, 2015 @ 09:38 AM | 1,835 Views
The new servo arm is made of 1 mm fiberglass. Uses all available space. Almost hits the keel tube in the front and passes over the rudder servo arm in the back. But works great
I wrapped clear tape around the corners of the servo arm because the edges of glass fiber are always a bit rough and tend to mess with the sheet.

I had two Turnigy round cell 1200 mAh LiPos lying around, so these were elected to replace the bulky battery box. First I did some testing if the servos and Rx survive unregulated 2S, and yes, they did phew...
so now we also have some extra torque in the sail servo. Will come in handy. And the weight: Battery box 115 g, LiPos 53 g Lets see what this does to the weight distribution...

And some carbon tubes arrived for a new rig. Tomorrow I'll get the sail material
Posted by Akerman | Aug 24, 2015 @ 10:31 AM | 1,064 Views
With a direct sheet arrangement, the sails did not open wide enough yet. So the only option is to make the servo arm longer, which required relocating the servo to starboard side.
The servo mount post got dremeled off and glued back in with rubberized CA. This shifted the servo by almost 2 cm, allowing a 2 cm longer arm.
The second picture illustrates how much longer the arm can get. I actually bolted the arm to the servo horn like this to find out how long the new arm can be.
Posted by Akerman | Aug 24, 2015 @ 10:30 AM | 1,042 Views
Next was the leading edge of fin and rudder. It makes sense if you can cut your finger with the trailing edge, but not with the leading edge. Sanded it round with 320 grit paper.
Posted by Akerman | Aug 24, 2015 @ 10:29 AM | 970 Views
One thing that I did not like at all was that the rudder had a lot of play in its bushing. The 3 mm shaft was guided by a tube with 3.2 or more inner diameter. So out came the soldering gun, carefully heating up the tube until it came out. I replaced it with a brass tube of 3.05 mm inner diameter, for a much better fit.
Posted by Akerman | Aug 24, 2015 @ 10:28 AM | 953 Views
First outing was much better than expected. Wind was at or over the upper limit for the rig most of the time, but the Fortune behaved surprisingly well. No problem at all to tack despite the rough water, but much more difficult to do the opposite because the booms would drag through the water, rendering the rudder rather useless. Speed was good, I could keep up with most of the other boats.

Update: T川-san uploaded a video, thanks a lot!

Fさんの京商フォーチューン (1 min 2 sec)

Posted by Akerman | Aug 24, 2015 @ 10:01 AM | 953 Views
Recently the members of my local glider club got into R/C sailboats, most of them with small boats around 60 cm. Several MicroMagics, a CR612 and others. I had been sailing several R/C yachts including an IOM "Woodpecker" in Germany, so it did not take much to get me started...

So it was Wednesday, and the plan was to go sailing on the weekend. What to order. Decision fell quickly to a Kyosho Fortune 612 III ready set with 2.4 GHz system. A surprisingly big box arrived on Saturday, and the "build" started in the evening after work.
Overall impression of the kit was good, astonishing what you get for your money. Of course it does look a bit like a toy, and some details also did not find my approval.
So it was a long night. Changed the way the servo arm actuates the sails to a direct arrangement, no need for so double travel on the first outing. Rather have something that works reliably.
The jib boom is way too soft and was quickly replaced by a 3 mm carbon rod. The main boom did not rotate freely in the fitting, a lot of "sanding it round" helped a bit.
With some small mods, the stock sails could be trimmed to a sort of decent shape. Not too bad.