Fila 89 - technical details

Fila 89 is the second fila boat i built.
The goal was to improve the sailcarryingability while maintaining the excellent handling of the boat.

The the original fila handles as good as any of the rc sailboats i have sailed, and still sets the standard for comparison for me.

The new boat has the mast and the keel box set further backwards to compensate for the expected bigger rigg, and longer keel.
The goal was also to sink the stern at heel angles bove 25deg(with the weight further aft and the big luff), lifting the bow. Giving it the ability to jump waves, reducing the entrance angle and improving agility.

It is not finished yet. It has a rigg and keel borrowed from evolution. Later it will recive a rigg identical to evolutions.

But the keel will be different.

The rudder is the same as evolutions.

The keel is 58cm long from the bottom of the hull to the bottom of the bulb, the bulb is 700g the keel 140(too much, but hey its aluminium)

Some diy stuff, 2.5mm allen key makes sure the backstay clears the sail and the boom

Why plastic sucks, the wang is loosing colour, and the right-most piece is bending despite 100% infill

the jib pivot is set further furward on this boat. The idea is to get the sails more paralel. This way the jib should depower later while keeping the desired gap at the back of it. And the ce doesn't move as far back when reaching(a better explanation would be that the jib remains more sheeted in, but the gap to main is still the same, the jib is more parallel ti the center line).
This is the best change compared to other boats. It makes bearing away much easier!, and smoother, there is no need to depower the sails all the way to the top of the riggs wind range.

This ,aom/sheet-servo position is a first for me. and it will stay this way for boats to come.
There is much more "hand space" inside, but it is a pain to change servos...  
note: 3d printed servo arm(seems to hold the 17.7kg@1cm@6V for now, it is 8.5cm long) and mount

3d printed mastbox and rudder servo. Positioning of the servo is not ideal, but the woodden support was to narrow for longitudinal mounting. The link is just temporary.
Note: this boat uses only stainless steel fittings and screws, the hooks for the stays are 1mm tig welding wire, the screws m3 stainless, whatever lenght is required.

I managed to loose the little 10mm tube that slides over the mast crane to extend it. Recently someone said that zipties are a temporary lifesaver. But all life is temporary they say..   ..mening this should break soon.

When i recieved the hull there was a big hole where my jib sheet outlet/hook would be. This flying hook/outlet the idea came from some beach cats and fireball dinghies, it is accompanied by the "standard" jib pivot tensioner.

Sailing tests concluded that the boat is floating on her desired static waterline(probably with a dispalcement of 1600-1700mm3), i have yet to weight her.
It also needs a keel with more surface, or more lift. since it sometimes goes sideways when not at ful sailing speed and it drifts quite alot when standing still.

I have a special keel planned for this boat, one with area concentrated just below the hull, and a strut hanging from it deep in the water. Similar to mal smiths boat here:http://www.users.on.net/~malcolmandjane/750.html

A post with sailing photos follows.

The sea and the salt featuring evolution

At the moment i am in Premantura, Croatia near Pula.
Evolution passed it's first hours sailing in saltwater with no problems.
Today the wind was up at 11am gusting just above 15 knots with about 20cm waves.
Perfect conditions for f5g b-rigg.
I was sailing evolution, with a b-rig borrowed from Fila, and a new slightly bigger rudder with a foil.
The boat is very fast and ready for racing in such conditions.

 

upwind is the usual; hit hullspeed, point high, work the waves..

Here are some pictures:

downwind is a blast, the boat actually starts planing(yes it doubles its hull speed which is offically considered planning)

in hectic conditions the foil keeps the stern planted, so far i haven't ever stalled the rudder or lost control downwind!

picasa is shit software for editing photos..

main sail trimm for downwind is something to improove, the spreader is in the way of the sail, and i have no clue how to solve that problem, yet

this is still happening when bearing away..
no big deal though.

this is the new rudder, it is larger than standard, the foil attached is a hq3.5_10% thickness low renolds airfoil originally for model gliders 

previous experimets showed that an angle of attack of 1-2 deg is enough to keep the stern planted, so this 100x60mm foil is tilted 1.5deg downward.

So far so fun, thw boat is showing some cracks around the mast ram, these will have to be fixed before painting.
I am happy with the boat.
I will keep collecting speed and course measurments with the mobile phone inside the boat for the next week or so and come back with another post with a more numerical approach to the evolution of F5g sailing yachts.

Eolution's evolution

Putting evolution through different setups has been very rewarding so far

sporting a 50cm long keel, the deepest in the fleet, made of hi tensile aluminum

the cg is now 10% aft of midboat, the bow is light, the boat is light nad lively

but also destructive

Two new principles for F5g class.
-More is more

-Keep the stern planted

These two will take my design dimensions up.
Aspecially the sailarea, the mast will also move back, as the rudder foil neutralises the helm.
Keeping the CG far back gives the boat skiff-style livelyness.

Another unfinished boat found!

The other day i was digging through some stuff laying around the atic.
To find this:

A nearly finished hull, the fifth and final boat from the afterlife project.
more: http://footyslo.blogspot.com/search/label/afterlife%20project

This is the first f5g boat i designed completely by myself.
It is a lightair boat. 4years ago when designing it a prismatic coefficient of 0.42 seemed good for light air, the reason for such a low CP is that the front 8cm of waterline are concave! i tried to keep the boundary layer flow laminar as far back as possible.
The goal for the project was to test unariggs on f5g boats:

And to get good results at Koseze, the pond with no wind.

I never won a Koseze race with such a boat, but i learned a great deal about una-riggs!
more on that soon.


The above hull is identical to Blulife, the deck and layout are also very similar. The differene is that this hull has a badly alligned keelbox, so that will need fixing. Mast hole and rudder post are already in place.

At the moment it weighs 240g, once the deck is trimmed, masking tape removed and hooks are added i expect the hull to weigh less than 250g
This is a light hull considering it is all fiberglass.

The boat will be build with a 4500cm2 rigg, true to the blulife rigg, Fila spec. rudder and a bullb that will be shifted slightly further aft than on Blulife.

The boats name will be Life Afterlife.

Fila raw sailing clips

Here is fila sailing with flaps, this are clips from friday, when i went for a session to tune the rigg in detail.

I really love this boat now that it is finalized, handling perfectly and sailing close to the hull speed at all times.

New rigg for Fila

After the parts for the rigg were sanded with 600grid paper they were polished

the rigg:

10 grams of weight was added to the mast with new parts, too much, would be better of with a carbon spreader, the main benefit is the reduction in bend.

the mast bends sideways only 2-3 cm when heeled 90 deg wich is alot les compared to previous 7-8cm without the spreader

Triming the main is much easier now that the twist of the sail doesnt increase that much when in a gust

Today i checked all the sistems and marked the basic setup

The telescopic bum enables fast changes to the depth of teh jib

reaching and downwind nothing has changed, the travel of the jib was bang on for butterflies, the jib weight is missing

The 3 points of improvement on this rigg are; easier trimming of the sails, less mast bend sideways(the boat accellerates better upwind), and the looks of the clean design which is to be refined with the mast head improvement and a new main boom, comming in a months time.

Weight of the mast is to be improved, by using a carbon spreader. The lower part of shrouds will be replaced with wire(now 50kg dyneema) because the rostfrei tensioners tend to cut the rope..

The upper seam of the next jib will get some camber(now all seams are flat) to keep the jibs luff abit tighter, now it opens too much under gusts.

I am looking forward to the race on saturday, it is the last race of the season, in case of a win i can win the naitional series, but the number of competitors will play a big role due to the new scoring method.

Goooodiess

Today the first gen of lasercut parts arrived:

the parts will be sanded around the edges, and polished

Building riggs will be much easier and faster now+ i have something to offer the guys at the races

And its nice to have something go from a Solidworks part file, to a product!
These parts are rostfrei(2mm) , ment for all riggs, aspecially C and B.
The next generation will probably be out of aluminium and somewhat refined.

Flaps on KARO footy and over-powering the a rigg

We had a few days of good wind here in Maribor, SLO.
The wind on the pond in the city park was gusting up to some 10-12knots and shifty.
the trimm, the pivot point of the jib was set 4cm forward.

a crappy clip:

It seems like the vertical down force created by the sails is quite big in relation to the available volume in the hull. The boat gets pushed down upwind.
Obviously a solution for the next evolution of the karo is more volume, but i have also tried flaps below:

The flaps are at an angle which would be considered stupid with normal boats but at footy speed, or at such low renolds numbers it seems to be the most effective, and by eye it doesnt hurt the speed at all!

The flaps help to keep the bow up when over-powered upwind and reduce submarining downwind.
I noticed that leeway was increased with flaps. That was because the flow separated of the flaps and the hull, and then reatached at the end of the first half of the hull.
The midle third of the hull is the part where the chine provides the most "grip" upwind, so i cut the last 3 cms of the flaps, so the flow would separate earlier(from the flaps), and reattach on the hull after the first third so the whole middle third is immersed.

the cut flaps

Below is the clip of sailing with flaps, if the flaps do any good will be confirmed when i get another chance to put both KAROs in the water.

Fila, b-rigg

Back in hometown. It is time to get back online after 12 days of sailing in Premantura, Croatia.
With me was my laser and Fila.
There were good 8 days of wind 6of them with b-rigg conditions. Sadly with no comparison i tried differend settings, ending up with a seemingly good setup nevertheless. The boat is pointing high, and sailing superbly balanced, nearly planning downwind, sailing at about 1.5 to 1.8 times of hull speed.
So now i am really ready to sail well in case of more wind on some of our national class races.

But better than the settings are speed measurments i collected putting my phone into fila, i will speak abou those in another post.
Also an idea for the next generation f5g(national class)boat is slowly taking shape.

Upwind, this is the basic setting i found, from here i give the sails more twist if the wind is in the upper range of the rigg

Sailing heeled, near the hullspeed(according to measurements) nothing special happens, with the future canting keel i hope to exceed the hullspeed upwind

The downwind, where much boat speed is to be gained, above just "shaking" the rudder to get the jib to the other side

Surfing the waves downwind

 

And jibing to get back upwind

The shots below show the boat sailing downwind, in upper wind range of the rigg, with a good setting, and lots of tension on the rigg even in waves nosedives were rare, but inbetween the waves the boat lacks lifting force.
It sails sort of low in the water, increasing wave an wetted surface drag like here:

Obviously a jib providing more lift is needed, in the future i will try something like on a footy.

The second thing is a forward t-foil rudder, the third is a canting keel wich will move, not only move side to side, but also tilt backwards.

That's all for now, i am happy with Fila,

the autum races are getting closer, and i am confident to continue the streak of wins on national regattas, and having lots of fun putting this boat into water wherever there is wind.

KARO, the big rigg

The biggest rigg since my footy affair was tested, it is a 2000sqcm rigg, the mast height is 75 cm, the AR of the main sail is somewhere around 2.6 and jib AR is 3.

the vang is simplified as much as possible, 4 hole tensioners were made because three hole ones(both made of 2mm plexi glass) were releasing tension

The problem to solve is the mast crane, it is preventing the upper 3-4cms of sail to open properly

Today i was sailing on the pond in the park, where shifty conditions prevail. Acceleretaion of the boat is nearly instant, upwind there is a bit of weatherhelm, maybe too much for my taste but totaly sailable.The mast has to be bend forward as the luff pocket on the main has no curve. Heeling is logically increased with the sailarea, but the boat handles it well, the problem is the vertical downforce sinking the boat alot, thats about 4cm at bow, sort of increasing the displacement drastically, i will write more about that in the upcoming hull design post. Nosediving, today some 10+ knot gusts were present and it seems that the classic rigg only sinks the bow to a certain degree and no more, and thats superb! it means that i can easily sail a heavily overpowered footy.

Below is a crappy clip, the white sails and the bright sun make the phone to over-expose the boat...

Clip

The plan for the weekend is to make a new main with a shorter foot, reducing the weather helm.
And testing the big rigg in real(not so pondy, shifty and unfair)conditions to se the real performance.