Evolution progress

Slooowly evolution is taking it's final shape.
Today the forward rudder was added.
The result is awesome!
The boat is designed so that the ce(centre of effort, aerial)  is far forward this enables it to carry the same rigg through a broad wind range.

The boat has a wide stern, a nose down tendecy is expected when sailing upwind. In addition the Rc components are placed far forward in the bow. These are the reasons why cg of the boat is set far aft(12% aft of midship), the result is a "light bow" (the boat is happy to change direction, and does not digg into waves)

With the second rudder, the ce of foils(center of effort, hydrodynamic) is moved forward and the boat should gain weather helm at first glance.
But it becomes more neutral!
Normally in order to have weather helm a boat must rotate around a certain point.
The forward rudder is added in front of this point so it stops rotation, because the boat would have to move it sideways throught the water in order to rotate.
In addition this added surface(the fore rudder) is controlable.

Sailing bluelife with twin rudders i could eliminate leeway by moving both rudders so that they pulled the boat into the wind.
With evoulution i can, not only eliminate leeway, but make the boat go to the wind.
Later i measured thatgood angles off the centerline for the rudders were up to 5deg.
More than 5 and boat speed would drop.
When pushing the boat to windward the speed is offcourse lower than sailing in a straight line, but the height gained is excellent(compared to speed loss).
Once the aluminum keel finn is replaced with a carbon strut, the boat will be able to sail even higher.
Many clips sailing with Fila will be shot, to show the difference between the two.

The above are the reasons why canting keel twin rudder boats will be able to have the mast far forward and still sail almost neutrally.

This is the only clip i got yesterday, because this boat requires both hands to be sailed properly.

There are two more positive effects gained with the fore rudder.
Firstly, control is not lost a very very high heel angles.
Yesterday was gusty and i managed to sail the boat at heel angles above 50deg, i don't know many boats that can sail at such an angle, maintain speed and tack!!, the forward rudder stayed in the water the whole time, providing enough control to sail the boat confortably. Speed was not ideal but it survived the strongest gusts well above 15 knots, at times sailing so heeled that the aft rudder would go completely out of the water.
Even at that state the fore rudder could iniciate a tack!

Secondly, the fore rudder adds directional stability. As a result this boat does not fall to the side when it nosedives sailing downwind. It just diggs deeper and deeper and eventually stops when the drag is really big.
Then it just surfaces and sails on.

the cg of the bulb/finn is marked green, black is boat cg, bulb/finn cg will be moved further aft with the carbon strut
the deck is 2x80g/2 cloth, some of it died today

forward rudder setup, the aluminmum rod to the right is a quick relese sistem for the servo plate(it is pushed into the bow, and easily removable.

In the near future evolution will get a 50cm long carbon strut finn, instead of the aluminum finn. With the strut bulb cg will be moved 4cm to the back.
Paintjob also follows.

a B-rigg will be introduced in a month or two.

At the moment i still would not choose Evolution over Fila at a race.
Since i know everything about #87, it is damn fast up and down wind.
But Fila does make alot more leeway and Evolution beeing almost 300g lighter than Fila, it gets up speed quicker out of turns.

Evolution will serve as a foil testing platform,

hq3.5, 60mm chord low Re. profile foil

The original reason for starting the evolution project was to get a pre-canting keel test platform for foils.
Quote: "in the future they will all fly" says the father of Hydroptere the true fastest sailiboat in the world(not the fastest water skimming UFO)

So i've been messing around with some numbers. They tell me that a boat such as evolution can fly. But they did not tell me anything about drag, meaning that i do not now how much power is required to get the thing foilborne.

To start with i will fit this foil to evolutions forward rudder, and make it adjustable in angle. Then i will tow the boat(with no rigg) behind a model powerboat.
I know aproximately how fast i have to walk to match the boats speed sailing in different conditions.
Assisting me will be a stepcounter and a runtastic app.

The foil above is a 180cm2 foil, it has a 15-15(deg) V form.
Theprofile is a hq3.5, designed for model planes. It works best with renolds up to 130isk thousand.(i wont reach that probably)
The thickness is just above 10%
It is 3d printed in black Pla, and will get painted and wet sanded.

The goal for now is to try different foils and get the boat to raise its bow. The bow has to be raised just 1-2cm from the static wl, in order to reduce the wetted surface area greatly.
Under sailpower this should already mean a great increase in speed.

After that a foil will be added to the back rudder.
At that point the boat will get very ustable and stability calculations will have to be performed for future foils.


There is a problem to the "moth style" concept, such foils are unwanted upwind, they have to be manipulated somehow in order to make profit sailng in all directions.
But this is some brainfood for the future at the moment

Fila #87 ready for sailing season

Today i took some time to check and update Fila for 2014 F5g season.
No major changes, just a wash, polish and cosmetics

The old rudder had a gap and a steel shaft

leaving rust behind

This was the prototype rudder, but it stayed with the boat for the whole season.

The 3d printed rudder(which has a refined shape) will be used on fila

The paint match is not good at all, but makes me think about doing a blue-white boat one day

The kicker

3mm thick 3d printed tensioners are used on all lines
a new hook design holds them in place

the hooks are 2mm aluminum bicycle spokes

new jib weight, 20g lighter, hopefully i won't catch something on it

The super simple telescopic boom is making adjustments easy

The rudder looks bigger, and does not fit in the red-white-black color scheme, but it's functional.

I am not sure what boat i will sail this year. Maybe Fila or evolution. But hopefully a canting keel boat.
The goal for this year is to experiment with different boats, incorporating movable ballasts. Offcourse the competition spirit remains and winning another national championship would be nice.

3D printed rudder for f5g

Last year i designed a rudder to suit Fila, some points had to be taken into account when designing it.

-fila is a wide boat, meaning that the rudder will go out of the water under heel, so the rudder has to be long(17cm)
-it is relatively light(little momentum), so the overhang behing the rudder shaft has to be great, to swing the boat into tacks
-it has lots of sails(sa/weight is high) same as above

-it was to be a race boat, control was key, avoiding stall= fat naca 0010 profile(no laminar separation bubbles luckily)

So the rudder for fila was designed and build in glassfibre with a wood core. It gave great results, the boat tacked well, the bow could go down and control wasn't lost, queueuing was good etc.

So with the 3d printer i decided to build another one for the evolution boat.
I was printed at a high resolution in 7 hours(still less than waiting for epoxy to cure)
2 more hours went into sanding and gluing it together.
It is printed of pla plastic, glued together with super glue. The shaft is 3mm brass tube.
Weight is 35g, not light but for a " prototype" it is ok.
It is finished with 5 coats of spray paint. In the future car paint will be used.

Printing is on!

My ultimaker is on an endurance test, it is running for 16h nonstop.
I was waiting for quite some time for the printer, so i had plenty of things to print.

this are two hlafs of a rudder

it is basically the same as the one on fila, two or three thick layers of 2k paint will be needed to cover the steps from printing

this print will be used as a rudder on fila, the next print will serve as a positive for moulds

For future F5g boats such as evolution, cardio etc. a new bulb will be introduced

this is the printed positive, painting is required before a mould can be made, it took the printer 4h to print this

the expected weight is 700g, it is 22cm long and has a max thickness of 12% at 40% of chord

this is the first sold print, it is a gimbal mounting plate, for my friends hexacopter

The last print for today is a keychain for my girlfriend, after that the printer will get a well deserved rest. :)

If anyone is interested in prints: http://www.3dhubs.com/maribor/hubs/erik

IMO the prices are fair, much cheaper than other guys..  

Evolution slooowly coming along

Snow white paint should be on the boat by the end of this week, The rudder mechanism is done,
Carbon-fiber sandwitch for the sheeting arm is in the press.
A symbolic keel(alu) is in the boat, a bulb and final touches to the rigg are missing.

Later, a carbon strut(about 2.5cm chord) will replace the keel, a bow rudder will be fitted, similar to this.

IOM bits arrived

A month ago i ordered some IOM bits from chrissails.
These are a Dave Creed build keel fin, rudder, mast-finn box and a plain bulb.

Everything was nicely packed and arrived undamaged.
details:

The bulb needs to be sanded, filled and painted, mounting holes have to be drilled.
There seems to be a stainless steel rod through the midle of the casting to prevent bending, it also gives a sharp end to the bulb, Clever :)

The keel's core is foam, in the middle there is a fullcarbon strtut approx. 12x4 mm giving the strenght, the skin seem sto be two layers of carbon on each side, 4 in total.
Thicknes is about 7% of the chord

The rudder is stiff, there are some moulding faults in the lower part, but not a big deal, i dont realy like the shape, because the lover edge, which is a v, does not align with the waterline if the strut is positioned vertically.

Mast-fin box is stiff, weighs 28g

I am happy with the investment, these parts will go into my first IOM boat.
And will be definately used as a reference when designing my own foils.

Making KAROs look good

The le Havre GOLD CUP is only days away, final preparations are underway.
Today boat 04 got it's final paint.

I found some super cheap acrylic paint sprays in baumax, a big market selling building and gardening supplies.
With all the pinholes fixed the paint turned out really nice, smooth and shiny.
It's a low quality paintjob but it is lightweight and generally good enough for footys.
The name of  boat 04 will be Jaundice, just because every other yellow boat is called
banana-something ;)
Boat 03 also got the first of the two coats of black paint.

today the temperature here in Maribor droped to 23degrees C and the cheap paint takes the whole day to dry, in comparison to the more expensive sprays which take about 1h to dry at this temperature, but for 1/3rd of the price the cheap one works superbly.

Bow rudder

Here is a photo of  "Blulife". my own design, 1260g, light air boat, competing in our national class, skippered by my father. Carrying its 4500sqcms of sail make it very competitive, but since i am working on a catnig keel twin rudder boat is this the first boat i have sailed with two rudders, just to get a feel for such a configuration.

Since i had a chance i had to try out the forward rudder only option:

Here is a quick clip:
http://i1186.photobucket.com/albums/z368/spadefooty/9AFFB674-C0C1-4359-80B4-493E496CD2E3-12284-00000CB9BC4A9660_zpsb057ecce.mp4

In this cofiguration the boat sails well, turns and changes direction sharply.
But for regata use the clr should be recesed further aft becouse it doesn't accelerate as easily as one would want and that would lead to problems on the line and in the chop.