Wednesday, May 28, 2014

Rogla race report

The past weekend i was in charge to organize the third stage of the nationalchampionship series in the F5g sailboat class.
Earlier this year i made sure that we were allowed to use a small lake on top of Pohorje, a mountain nearby.
This lake is right next to a hotel resort and ski slopes. The location is at about 1520m above sea level, the water is clean, cold. It is often windy there.
This saturday was sunny, the wind was not exactly what i hoped for, but was good for sailing, gusty from3-above10 knots.
With help from a friend we set up the course, it was a classic "stick" and not the usually sailed triangle.
Luka, an experienced sailor and sailing judge did not manage to finish his new boat until the race and offered to judge the regatta and take care of the results.
Only 9 competitors entered the race, i was hoping for more, but for a first time on this location it is ok.
We started racing at about 12.20.

The starting line was set quite well, the left side was a little bit favoraised, but it lead ashore, where there was less wind. It was well possible to "win" an upwind leg by starting on either side which i proved along the day.
The boat with no number is my fathers old bot, similar to #165, it has a Fila b-rigg and is sailed by another friend who has decided that he will also compete in the naional championship series

there was no wave and fila is very fast in such conditions

A  strong left shift gave me the lead to the first mark in this race

Father brought his hobbyking wind tunnel, we had to remove one section of the wood fence, there is no gate to the lake

father was sailing evolution, having all sorts of problems i never encountered before

alinghi #68 was aiming for a spot in the top three

there were some borin luls

in this race the right side of the course was more promising

The friend who sailed the boat with no numbers was doing really well, aspecially considering that his boat was made mostly of spare parts! He was was always in the top 3-4 upwind, but dobnwind he was lacking sail area.
some people also came to watch
me, giving the jib more twist, the friend is watching closely
This beautiful colin archer was present, it can move under its own sail power, but has a propeler for help
leading the way around the bottom mark.

Left shift gain, a quick tack to make sure i am above everyone
after all 8 races were completed a navigational race was sailed, 4 started ,two finished
I really did not want to go somewhere and buy medals for the race, yes they would be metal, but also they would be small and the budget did not alow spending much money

i got around to designing my own medals in solidworks and printing them out in two parts
They are also bigger than bought ones, and are special!
Overall the race went well, the max number of races was sailed(8) + navigation, Everyone seemed happy.
The stick course was IMO much beter than the triangle, making upwind and downwind tactics possible.
The starting procedures were flawless, with the help of Nikos megafone.
The presence of a judge made the races even a bit more interesting.
A traditional pohorje plate menu was served at a local restaurant.

The results:
red are the discards
For the next time i wish we could get more competitors, i know that there are about 20 competitive and active F5g sailors in Sloveina, it would be nice to see all of them present at races.

Again Fila dominated the race.
A sharp start in all of the races gave me an early advantage.
My speed was very good again, and so was the angle, as a result i was first to turn the windward mark.
Downwind it was just a matter of spotting the incoming gusts and moving slightly to the side from which the gust came.

The reason for a sixth place finish is that the jib twist line caught the spreader and i could not manouver for about 30sec.
More photos sholud emerge shortly.

Videos at:

Friday, May 23, 2014

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

Thursday, May 15, 2014

more 3d printed stuff

More 3d printed stuff

this artistic piece was printed at 0.1mm layer thicknes

it took 21hours to print, the detail is good

support from beneath

mini quad frame, left are motor mounts with legs, mainplate, booms

minecraft figures in transparent pla



more of something

LED holders

new F5g b-rigg

Above is the new b-rigg to be used with wide F5g class boats, it has 3900cm2 of sail, the man/jib ratio is 60/40.
This is the second generation of b rigg, the jib is borrowed from mk1 b rigg. On later riggs the boom will be replaced with a telescopic one.
The main has a shorter foot(5cm), and is 5 cm higher. The area is the same as mk1.
The shorter foot brings the force resultant closer to the centerline. Meaning that the main doesn't put so much strain on the rudder when running.(better directional stability) The shorter sail also makes the boat more agile(force resultants of main and jib are closer together), making it easier to bareaway, and sail the boat downwind with the waves.
The mainsail is higher, to keep the heel angle and speed up throught the luls.
The 3d printed kicker and the stainless spreader make setting the rigg up easier.
Mast bend, when Fila si supported at hull and held horizontally by the tip of the mast(biggest possible moment) is about 4mm   ~ 0   :)
I am very happy with that.
the basic mast curve, depending on the conditions it can be trimmed
Yesterday was the first day of testing.
The winds here in north-east Slovenia are fourious, yesterday the average was 17 knot on the airport(500mm away from the industrial lake sailed), gusting to 25knots
the conditions were abit to fierce for b rigg, sadly the c-rigg is still a work in progress
i bent the mast real good, trimming the sails for speed with a really lose luff
upwind is ok,tacking good, speed is ok, angle not so much
Downwind is a blast
Gusts above 20knts were unresistable, submarining was unavoidable
overall i am happy with the rigg, however i know i have to get more days sailing it
the only really disturbing thing was the main boom dragging through water..
2.nd day of testing.
For this day the forecast was 30+knots with gusts up to 40 knots..     ..this is not very likely, because if a 40 knot gust was to hit the city park, half of the old trees would go down..     ..none of the trees in the park went down and the day is past..
..anyway the wind was to strong to go to the industrial lake, the pond in the city park seemed a good alternative.
The foot of the mainsail was cut and the boom was raised for about 4cm = problem solved
conditions were gusty, there was almost no wave, i could trimm the rigg to deafult settings 
speed dropped compared to the day before, but lots of angle was gained, tacking is spotless
downwind is good, catching the boat going into irons is much easier now
Today the mast prooved to be abit to stiff, it doesn't want to bend in a gust, this is desired to loosen the luff and gain the all important speed.
I have to try with less pre-bend in the mast when the rigg is set.
I recon 10 more hours of sailing with the b rigg in b rigg conditions to sort out the little things are needed.
After that the boat is competition ready.

The little things:
-Mast pre-bend
-Match the luff curves perfectlly
-find ideal main foot depth
-fix spreader and wang rings with super glue

Some clips of todays sailing:

Fila is beating upwind, the speed is good(note the flowers and branches) although it is hard to judge as i am walking with the boat.
In the strong gusts leeway increases and speed is lost..    ..this is predicted, and can not be tammed, yet.
Downwind, the main luff is too loose. I have walk quickly or lightly run in order to keep up with the boat.
The bow is pressed into the water. That is horrible for speed as we know. In the future inverse foiled rudders and forward foils should take care of that.
But for now i am confident that if such conditions appear on the race course Fila will be in the foreground if not even dominant.

Here you can see that the strong gusts are barelly survived. It is also obvious that i have to sheet out after a tack to gain speed. Lighter sails should reduce the speed loss after tacks.
Downwind...      ...ehh, ..    
In such conditions i would always choose the b rigg, to the C, just to get through the luls.

C-rigg comming soon.
That's it for now.

Sunday, May 11, 2014

Koseze F5g race report

This past saturday(10.5.2014) me and my father headed to Koseze, to take part in the second round of the national championship.
Koseze is the pond whith no wind, at least in my eyes. Out of seven races sailed there i only saw wind twice, this year and two years ago.
The wind was ok, about 10knots if the pond would lay on a field, but since the pond is surrounded by trees and houses the effective wind speed was probably around 5 to 6 knots and gusting.
The course sailed was a triangle, due to shifty conditions there were mostly upwind and reaching streches, no real downwind sailing.
The organisation was good, we had two judges for a change.
The conditions were shifty and gusty but very sailable the whole event.
8 races were sailed.
11 competitors were present. Only one of them a junior(below 18yrs)
Below, the pictures tell some more stories, sadly they are of bad quality, taken with my phone by me during the races.
the weather was nice, lots of spectators came to watch, n141 is a  dragonforce rg65 with a bigger rigg

This is alinghi the boat with the most draft in the fleet

the lonely junior, i ended up lending him my fathers backup controller, his died.

Niko made a footy.

Inspired by karo, but rounded, it was its first outing, the mast broke, but the boat will be back!

more Nikos boat, last year he introduced a new sailor to the fleet here he is working on his boat

alinghi on the water, it carries alot of sail, and is fast! i admire it 

nr.93 during a gybe, it is a very fast boat, but not dominating when the wind picks up

Dad was going strong, checking his cunningham tension, two mistakes in the last two races made him two dnf's and worsened his score.

66, with a new paint job this year

Niko's personal boat, the most balanced allrounder in the fleet, it can cope with any conditions

Starting procedure machine

in the end there was some time to release the footys, duck and karo

duck is light and fast.

Missing from the action were the winged prototypes, and all the new guys seen at Bled.

below is the thread on our national forum(with results):


The prevailing reaching and upwind conditions gave my boat, Fila a good advantage over the rest of the fleet.
I knew the boat can carry sails, and survive the gusts(above the a-rigg range), also i trimmed the boat for speed.
Sailing with less angle than the rest of the fleet, when a gust hit my boat just pulled away, a meter of height(they gained in respect to me) was nothing compared with three meters of lead(distance in front, i gained in respect to the fleet).
This speed made my work easy, the moment i reached a bouy in first place the race was mine.
My father sailing Evoution, which is getting faster and faster, was the only one with the same speed as Fila, but he got stuck in the fleet again and again.

some clips here:

Fila took first place again, putting me in the hotseat, as a championship leader in this early stages of the season.

We will see what happens on Rogla. This will be the third race of the championships.
It will be the first ever rc regatta i've organized. We will see how it goes!