wingtips

Ok so i have been slack. I still dont even have a mould for the new hull or even a block or foam. absolutely no progress there. the 3d file is router-ready but thats about it. Had a few projects that took over and now that theyre done im back at uni and so progress i fear will be slow. 

anyway ive been still tinkering with the blue boat - broke the gantry and it was off the water for a while and now its fixed back up again, a truly crap repair job later. one of the things i did was redistribute some area between the foils, just for the sake of an experiment. so i cut 100mm off the rudder span and added that to the centreboard, in the form of these wingtips. 

 Everyone i talk to says "wingtips are tricky, you need to do 3d analysis and work out the nature of the vortex at the design speeds etc." Anyway i pretty much ignored the advice of everone who knew what they were talking about and just designed some in rhino that looked good, cut them out, took a mould etc. I think they came up pretty good, the foil sections are pretty accurate at least. and they seem to work too, subject to a bit more testing, two things have happened; the boat launches much better and at lower speeds, and the hum that i used to have is gone. also there is no noticeable loss in stability from a smaller rudder (550 span i think) and it all feels smoother, and the boat want to go straighter. i could be kidding myself about that last bit. foiling manoeuvres were easier. also i have a new wand which i reckon is my best one so far, with a paddle about 200mm from a very flexy tip. If i do anything else i may want to extend the flap onto the wingtip, i dont seem to have quite as much response.

anyway heres a pic of my wingtip, if anyone wants one for their old and shit square foil let me know and ill make you a pair of blanks, im keen for another opinion. chord is like 115mm or so.

done

So the aussie flasheart design is done... sort of. feel free to email me if you would like the rhino file. note the bridle attachment point. i think its cool. wand mechnism: grearing is adjustable by a thumb screw. the front bung goes in above the pushrod exit point, under the cover.I thought of a neat way of adjusting the rake of the centreboard too, which is basically a stevo top rudder gudgeon for the centreboard, that the retainer pin goes through. a thumb screw at the front of the centreboard, just above the deck, pushes a rod back and forth inside the top of the foil and the pin goes through that. the rod would be like 50mm long and is held in there pretty well so the hole in the carbon can be elongated. it means your centreboard case needs to taper slightly, but the range of adjustment is no more than 1 or 2 degrees to accommodate all wind conditions.. just a thought. i think ill be doing that if i build another foil.

also had a glamour sail in 12-15 kts and pretty flat water at RQ, took my iphone with recently updated gps software and for the first time i could download my track. the data was pretty noisy, but i used excel to average it out and im pretty sure i hit about 20.5kts, my best average over 100m was 18.1. i was doing about 12.5 - 13 upwind, but not pointing very high at all. I might try again one day with a real gps. it really didnt feel that fast, and i think the boat has gone faster so ill keep pushing it.

^ i entered the seabreeze.com.au competition. i couldnt help myslef, the prize is pretty amazing. i reckon the dude with his hair on fire is a definite winner but.

fixed the mast, sort of. have been sailing without using too much vang or cunningham, and because it has two sleeves in it now its pretty much the stiffest topmast ever. so i dont really get a good leach anymore and hence the no pointing. im getting a new one.. just as soon as i go to work, earn some money and get paid, subtract bills and living expenses. i think i logged 6 hours this week so im not looking good.

finacial situation doesnt look good for a speedy build either, i might have to find a sponsor. though i am in brisbane, going to uni full time, its all a bit hard. anyway at least that gives me time to go over in my head the procedures and simplify it right down.

anyway thats about all, best of luck everyone at the nationals, hope you dont break anything, forget what hole it was in etc, hope your knots all stay tied up, and that the breeze is between 8 and 20kts the whole time and that the chop is less than 2 foot!

hand luggage

heres a concept, maybe for the mach 3: a moth that fits in a suitcase! or better still hand luggage. they have fishing rods that do it.

step 1: cut your mast/hull/wings up into little pieces
step 2: place in luggage
step 3: reassemble at desired glabal destination.*

*nick flutter takes no responsibility for any complications arrising from above process

Just a few more images of the specific failures. you can see that the pocket was clean, no sand, dirt or grit. the sail has been rigged up pretty much exclusively on this lawn the last 10 times. and the condition of the mast is, well, brand new.

1 hour sailing, 3 hours commuting, 2 masts and 1 drunk dude with a broken spirit.

The photos say it all really. 2 out of 3 attempts to go for a sail have had me in my gear, getting ready to lift the boat in the water and this. First my old mast, below the hounds, so i put it down to age or cracks or something. Today's victim was a bladerider mast that had been used twice. im not sure why its happening - maybe i had too much vang on or something when the boat was leaning over. but it was well and truly eased from where id have it sailing, like at 30%. same with cunningham, at say 40%. maybe my spreaders are keeping the bottom section too straight. but how do you tell that? there was about 50mm of 'kink' in the forestay after the mast broke, no idea what it had before. maybe my rig tension was too much, but i doubt it. maybe i crushed it last time i sailed in like 20 - 25kts, maybe a manufacturing flaw (but the new one broke in 2 places) maybe i broke it when i cranked the cunningham while rigging , boat upright, to see how flat i could get the sail for the windy day. but i have 2 less purchases on that than lots of people, and i didnt go past the red line on the mast. maybe its because this mast was different to the standard ones, apparently having a stiffer top section, and that stiff section couldnt take the bend that i put on it with the long front prodder. but then why did the last one break that the spreaders were designed for? surely there is more load when your out sailing...

anyway id be interested to know if anyone has seen this before, and whether, when you rest the boat on the mast, there is a common law that you let the control lines completely go.

to top it off i got yelled at (and told to fuck off) by some RQYS voulenteer with 3 missing teeth, who was at me to move my car when i was packing away the broken bits in despair. a great day in sunny queensland.

the next iteration:

bow higher, aft deck convex, aft wing struts... strutting, gantry (not fully thought through) more kingpost rake to resist max loads (12 deg), decision made not to slope the transom because i couldnt get it to look cool (tiny transom anyway, might revisit this) tramp not updated re. filling holes slightly.

Still not sure about the volume / freeboard, im inclined to thing there is too much at the mast, (450mm to top of deck) yet to measure a bladerider for comparision.

the rest of that foil article

Heres the rest of that article. 80s gold.

Aso i just want to put it out there.. i have hinge damage...

Though i have yet to lose the whole thing on foreign soil, this moderately irreparable cracked hinge may be something that we will be seeing more often.

foil article

heres something i just stumbled apon when flicking through a 1983 issue of Australain Sailing. may explain why some people have massive rudder ventillation issues and I dont seem to. my rudder is a 66012 as opposed to a 0012. bring back decent sailing journalism!

new stuf (hull, wings etc.)

so ive been neglecting this for a while, mainly due to another architecure folio.
been sailing a few times, but mainly been in front of the computer evolving into one of those hunched, pale, widescreen-format-eyed little creatures (from the future).


anyway the whole time i was studying i was sidetracked with a stack of new ideas for a moth, and im pretty sure ill be building something over the summer "break". The lines are from Doug Culnane's Lord Flasheart, designed in collaboration with Adam May. (cheers doug, looks great)


Flasheart is available for home builders like myself to have a crack at, so in the interests of total tansparency ill be chucking everything up here form design to eventual completion. that puts the pressure on to not fuck it up i suppose.


construction will hopefully be by female mould, cut from high density foam using a 3d router. dont know how much that will cost yet, but the plan B is a hot wire and ply plug. the boat will be built in 2 halves, vacuum moulded etc etc. the aim is to keep construction extra simple and quick so that the thing isnt still half finished in a year or 2. kinda defeats the purpose. 10kg for the hull will be acceptable, but i will of course be going for lighter. as this is my first go i want to make sure it holds together.

what the wind 'sees'

there are a couple of odd ideas in this. this is only the first iteration, i might do a few versions with different configurations to get a feel for what will work best, be lightest and cheapest. I'd love some feedback on what you think will work and what wont. at this stage i think its better to get a bit of consensus on things. The main decisions i've made with this one:

• Foredeck, wavepiercing bow - The stem is even shorter than Flasheart, which is on the short side as it is. im hoping that the bow in this configuration will go further underwater without digging in, and use the buoyancy around the mast base to pop back up. i find that most of my stacks at the moment are due to the drag of the foredeck, tramps and ropes stopping the boat, rather than the pitch.
• Kingpost, Recessed foil wingbars - The foil shapes are mainly there to reduce fricion when the hull does go under a wave, though they should reduce windage a bit too. circles are terrible in terms of drag and im avoiding them as much as i can. The kingpost is cantillevered from the keel, so there is no need for a forward support, that adds areodynamic and hydrodynamic drag. ill make a bladder mould for the kingpost, so i can cantrol the fibre orientation and reinforcement.
• Wings - Raised up and out of the way of everything. the freeboard is slightly lower than flasheart aft, (50mm) the wings are slightly higher. They are airfol shaped, only because i think it would actually reduce drag a bit. it opens up a big gap between the tramp and hull which will reduce windage.
• Flare - I altered the bow of Flasheart a bit to include a 10 - 15mm deep step. for lift.
• Centreboard is 100mm further forward that Doug had it - his was in the same place as my current boat, on which mast is 200mm further aft. what is a standard dimension these days from transom to front of centreboard case? assuming 8 degree strut rake.
• the outside wing bar continues aft of the back wing bar. the joint is easier, and you reduce tramp area, while still having somewhere to sit. and if i find the back bar is too far forward, i dont have to buy new outer bars.
• There is only one internal bulkhead at the centreboard case, which is pretty small. (divides in 2 as per rules) some diagonal reinforcing will be built into the hull laminate.

anyway the only things i am sure about at this stage are the general freeboard, and the step in the chine.. foredeck could come up, aft deck could be convex (better for 3d router). wings could atach to the hull (i feel it may be better to have something solid to stand on, rather than just tramp, though this means reinforcing the deck a bit?)

anyway ill keep plugging away, please email me if you have any ideas

been out sailing a couple of times since the lake

the boat is getting better and better. the foil mods were aimed at reducing induced drag when the flap is fully deflected, and do seem to give a smoother accelleration at takeoff. the wand system is getting better fast, with my bendy bit of aluminium allowing for the whole thing to be mangled on the water. ive taken all the slack out of it and i now get that bumpy feeling when the boat is going quick upwind, and have a greater range of where i can sit.

my dodgey skin fitting rudder adjuster works a treat as well, after a bit of WD40! ive also managed to reduce a bit of friction everywhere (hello wd40 again!) and im now almost at bladerider standard in this department.

the flap hinge incorporated into the laminate has started to crack and distort, and im not sure ill do it agian. if i do, ill use something different. the problem is you cant replace it when it gets a bit shit (if this one gets worse, ill cut it off and do a sikaflex hinge)

its now obvious that the boat is too heavy, too leaky, and the foils are too square. time, it seems, for a new boat!

allboats

lake cootharaba is getting a bit too shallow. the long walk out to the middle to get on is getting too long. and then you get the boat up and get on and you're sitting on the foils on the bottom, i ended up just sitting  back dragging them through the mud until i was up and going, then trying pretty hard no to crash. and repeating this procedure after every tack.

aside from that the boat went well, and improved over the weekend. in 10 - 12 or more it goes fine around the course. in less than that i can foil on reaches and sometimes upwind but not really downwind, and i cant point. since the setup is getting close to good, i'm starting to blame weight, 'square foil drag' and 'fat ass hull drag'. these are things that wont be fixed with tuning, though i plan to make a few changes to minimise 'odd shaped gantry drag' and 'poor sailor finesse drag'. also im getting the pocket in the sail adjusted to my mast, which may hopefully pull some draught back in the sail to line up with my aft centreboard case. i think that may give me some more height upwind. 

anyway that said i had moments of glory; like picking through a fleet of A calss and nacra 5.8 cats on a reach in 10 kts. or beating sharpies and MGs around the track in breeze, despite my shit upwinds.

on the way home some tired dude ran up the back of the trailer in traffic on the highway, doing about 20ks and we were stopped. missed the gantry (that hangs 600mm over the back of the trailer) by centimetres, broke some lights and stuf on the trailer and sheered the bolts connecting the hitch on. so while his car got put on a tow truck with some pretty severe facial modification we sat on the side of the highway wondering how we were going to get 3 M12s to get the trailer back together and get home. anyway long story short his dad rolled up to take him home, turned out he worked with my dad, (brisbane is small) so they went off on a mission to get bolts leaving me and the tired dude who'd just nearly written off my boat to make small talk for an hour on the side of the highway. fun times.

sailing

went out for a sail in gusty 15 kts with Rod from the gold coast. the boat went ok, though the flap response is still not adequate despite all the improvments. i need another change of wand to a bladerider style thing with a substantial flat bit on the end, that will pull it back propperly. also the straight wand is the way to go.
had a go on Rod's bladerider, and doesn't that make it obvious that my boat is underperforming! you just sheet on, point it, it pops up to the right height and accellerates endlessly, without spontaneously launching out of the water, tipping over sideways or sinking back down. i think i hit over 20 on his velocitek, though it may have been lying. the linkages on his boat were working overtime, while mine were kinda stopped, lethargic. it was interesting to see my boat being sailed well by someone else also, and i know a couple of things. it can go quick upwind when sailed propperly, though probably not in less than 15 kts. It looks really bulky when foiling compared to all the other boats. its like the fat kid.
resolve to put it on a diet. failing that a new hull/wings.
new bladerider sail is an improvment, needs slight luff adjustment.

wand

i did a couple of maths and realised that some of my light-air trouble is possibly stemming from my technique, rather than from setup problems. (would be great if it turns out this is the case.)

Basically when i sit at the back of the boat and try and launch, i can get up to about 7 degrees angle of attack on the centreboard foil as the bow lifts up, and my boat's fat ass drags in the water. lifting off like this the wand starts moving the flap up, as the front of the boat starts to clear of the surface. in this configuration, with the flap down say 5 degrees out of 20, the centreboard Cl is 1.57 and Cd is 0.0193
If on the other hand i was to sit really far forward and keep the nose buried, i could keep the flap at say 15 degrees down, at the same stage of takeoff. in this configuration the centreboard angle of attack is 0 degrees, but with the extra flap deflection im still getting a Cl of 1.54 and a Cd of 0.0156. so this is better, same lift for about 80 to 85% of the drag. ill try it out on the weekend.

also i ripped off my crappy wand. finally. i laid up some new bits tonight that will allow me to adjust everything about the wand, and to use carbon rod and tube of varying stiffness and size. I have a choice of two wands to start with - a straight stiff one with flexible tip and a kinked, stiff one like the old prowlers, with a flexible tip as well. ill try both on saturday weather permitting. The aim of all this is to keep the flap at full deflection while the bow is within a foot of the water. the winning wand gets glory. and to stay on the boat. it is possible that they will both lose, in which case shame will be brought apon their families. and they both also die.

testing

went out today for a few hours to test the new modifications. conditions were like 3 to 12kts. anything above about 8 i was foiling, though probably needed 10 to go upwind and downwind propperly. everything worked well, no breakages, nothing moved at all. didn't capsize or crash, but i was playing it pretty safe. tried a foiling tack and almost threw myself off the back corner of the wing, holding onto the tramp lacing with my feet. it turns much quicker on foils!

The linkages work much better, and the rudder adjutment in particular is a massive step up from what i had. the wand vibrates when going slow, which is annoying, so ill take to it with the grinder and make it flatter on one side. also thinking about a flat surface on the end, so that not as much of it drags in the water.

i need a new sail.

im not quite happy with the angle of the centreboard. i noticed that i had the rudder trimmed back, flap up about 5 degrees, to the point where half the time it was actually pulling the transom down; you could see because the top gudgeon was touching the top of the gantry, rather than there being a small gap. seems to me the rudder foil could be smaller. before i go cutting stuf im going to make an F-box of sorts, a contraption that lets me adjust the rake fo the centreboard over about 5 degrees on the fly. also i want to put a small bulb at the T joint of the centreboard, to hide a wad of carbon uni that i will wrap around the leading edge at the T. the crack didnt get any bigger, but im not going to risk breaking this foil. so there's 2 or 3 projects to keep me busy(er).

linkages relinked

just a quick note: the boat is nearly back in one bit again!

all linkages are now stainless, after much swearing at (breaking of) expensive taps/dyes. there is less slack and the ends are more robust, especially the new flap joint which is a beast. see below, pretty self explanatory. i think the bladeriders have a similar thing, with the benefit of having a nice thick bullet fairing to hide all the shit in. i reckon ill have to fair it a bit.

the main foil appears to be at a good angle to the static waterline, about +1.5 to +2 degrees; i think the flap was just jamming in the 'up' position after the linkage broke within 10 seconds of leaving the ramp, giving me that 'sucking' feeling. also theres a 10mm long crack at the t joint of the new centreboard, not sure if its superficial or not. im keeping an eye on it. be sailing soon, should be interesting.