4 Meter mono foiler project

At the top of the thread you mentioned retractable foils.

One thing that the big Swiss foiler (Mirabaud project) did to enable retractable foils was to move the front foil in front of the mast. Otherwise the retracted main foil interfers with the boom as you are launching, leading to capsize or worse.

It would mean a bigger side load on the rear vertical foil while in float mode, but it could be worth it to make beach-launch easier. With a semi-balanced rudder design ( i.e. hinge line at about 25% of the area) the tiller loads could be tolerable.

Another feature of the Swiss foiler is that it seems they have wands on both the front and rear foils. Look closely in the photos and I think you can see wands at the back of the boat as well as the front.

Kudos for carrying this project so far.

KP

 

I'm pretty sure that had more to do with "shared lift" then retractable foils. and on my design thats not really a consideration , at least not on this version.. I do want retractable foils, but I'll be happy to retract them just to the boom and no higher, having 35-40cm of foil sticking out of the bottom of the boat is still better then having 100cm.

As far as rudder, I would have that just slide up and down vertically in some kind of housing, same as the main foil. have some drawings of it somewhere already.

I can't seem to find any rear rudder wands, but even so, I personally think that would be overkill on a hydrofoil this small, its not like people sit there working the rudder trim tab the whole time or something, its easier to do the fine tune adjustments with bodyweight and sailtrim than constantly messing with the flow over the rudder lifting foil. That gets adjusted once or twice a leg if that, not constantly.

thanks, if i could only get some actual physical stuff going, virtual sailboats are cool and everything, but they don't float very well.

 

and here is the drawing

I'm still trying to figure out how to have dual tillers that control the wormdrive, If I can't figure that one out I'm going to have to do midboom sheeting damn AOI.

 

These pictures are of the first aeroskiff system: the extension tiller was rotated to change the MAINFOIL flap angle. The knob on the front of the tiller controlled rudder flap angle. On my new boat the rudder foil flap and rudder foil angle of incidence will be adjustable.
The little rotating "mast" on the center of the tiller holds two flexibly attached carbon tubes(one now broken) that are then flexibly attached to two delrin collars that slide on each extension tiller. This holds the leeward tiller up. The arrangement makes it easy to control flap movement manually since counter clockwise movement was "Up" flap on either tack; some systems result in different rotation from tack to tack. Each extension tiller is connected to a so-called stainless steel universal joint which is then connected to a machined stainless rod that takes a short rod in the center connected to the push-pull cable.That rod was bent a while back...
This is built heavier than necessary but allows excellent flap control; perhaps you can adapt it to your worm...
In the sailing pix you may be able to see the end of the extension tiller just above the rack seat on the leeward side. The end was angled up about 6" to give better leverage and control.

 

does that thing fly? or does it just have a lifting rudder? Thanks for the info, something to look into for sure.

 

It flew three times-but not well-before I donated the hull to a sailing school.Since I had play in the push-pull cable and linkage it was a handfull with manual control. I'll use wand control+ manual on the new version. The foils and many parts of the boat are being used on the new boat.

 

I was thinking some kind of gearbox mounted to the end of the tiller with 3 miter gears in it. Turn either tiller extension and it turns the gear that turns the treaded rod (mistakenly called it a worm gear on my last diagram). I think it would work, light, strong, easy. I would just keep trying out different bevel gear ratios until I found one I liked. Could also do the same thing with a worm drive, put the gear on the treaded rod and connect the drive screw to the two universal extensions.

 

Sam here is a closeup of the business end of the extension tiller. Uses a motorcycle hand grip. After a bunch of experimentation I found this best for me.
Zero degree flap position=vertical. Top aft=boat up(flap down).

 

WOW, that is awesome

 

Works for me. This is a technique you may or may not have heard of. The hand grip structural member is a "bent" carbon rod made with unidirectional 6k carbon tow. I developed this technique about 15 years ago on models.
The roll of tow is available from Aircraft Spruce and Specialty-a must have catalog for projects like yours and mine.( www.aircraftspruce.com ) The part number for the 6k tow is 01-00307. It is invaluable for many jobs.
Anyway,this is how to make a "bent" carbon rod from .125" to .375" OD:
Once you decide on the diameter order silicone tube with at least a .125" wall and an ID the same as the rod you want to make and cut the exact length.(McMaster-Carr is the best source for small quantities of silicone tube that I've found). Then build a jig on a flat board to hold the silicone tube in the shape you want. Calculate the strands of tow you'll need on this basis: 45 strands of 6k tow per .25" diameter. Then wrap the strands(right off the roll) around two headless nails with the distance between them 4" longer than the rod you are making. When you have the right number of strands cut the tow and tie the two ends with a square knot.
Find some stiff but not too stiff wire twice the length of the distance between the nails and bend it in half. Bend each end of the wire over about .5" from the end. Stick one end of the wire thru the loop formed as the carbon tow goes around a nail. Then pull the wire so that the carbon tow loop is at the bend at the halfway point of the wire. Get a pair of vice grips ready to use. Mix your epoxy and pull the carbon tow off the two nails with the wire and coat the tow with epoxy so that the strands are all wet.Don't get epoxy on the ends of the wire! Stick BOTH ends of the wire thru the silicone tube and grasp them with the vice grips and pull the tow slowly thru the silicone tube. When two inches of the tow is hanging out each end of the tube use scissors and cut them off. Clean your scissors, the wire and the silicone tube with the strands in it. Then place the tube in the jig you made earlier and in a while you'll have an exceptionally strong "bent" carbon rod.

 

I'm going to just stick with long 3/4'' graphite kite sticks covered with kevlar/carbon sheath, for me the right tiller is a lot like the right putter in golf, I get used to them and I can't use anything else, I'm so used to having a long *** driving stick resting on my shoulder. You can get the tubing from any kite shop, its super light and strong, and cheap (2m for $10), and the kevlar/carbon sheath from Solar Composites..... I'm even thinking of using this method for building my Gantry.

 

so, I've been working on everything that was left, and finally got to the end....sail ended up right at11sm and looks to be the perfect size for the boat foils are a little shorter than a moth, it will be better for retractability and can't crash from so high up. like the gantry (55cm) and after messing with the dual tiller thing for way to long just went back to single tiller/midboom sheeting because of the AOI control.... the mast and boom ended up about perfect at 6.5m and 2.4m. just have to finish up some things on the drawings and should be time to start building..... put the main foil a little further forward than normal for a little shared lift and a bigger footprint.

Any impressions:?:

(I'm blaming the crapy picture quality on Rhino Osx, but in reality I think its that I haven't figured out how to get good renderings out of it yet, hopefully in a couple of years they will have a manual or something )

 

Nope, that's not the "end" you are seeing, it's the end of the fantasy sitcom portion of the programming. Now you get to move on to the reality TV episodes and the industrial documentaries as you get to inhale noxious gases, clean yourself repeatedly with nasty solvents and find out the numerous areas in which the fantasy world theory doesn't agree with reality.

You are starting the part I love where you get to resolve problems on the fly and really make things work in the real world. I've found keeping a couple of project streams active at once is a moral booster - when you get stopped dead on one stream, you can shift to another and keep the ball rolling. You can't instantly fix every problem you encounter - supply issues, delivery times and god forbid cash (out)flow are show pausers, but there are always areas where progress can be made.

It may be worthwhile to break out your project management tools and break the overall project into tasks and mini-projects. I don't like the "one big project" management method where your tools try to convince you progress overall is behind due to one failed milestone. I'd rather mentally feel good about completing four minor projects with one other project element late.

 

Simple idea for dual tiller extensions

Sam:

I've been thinking about a t-foil rudder for the Falco for a long time, and every current implementation of t-foil angle of attack adjustment is way too complex. After months of percolation, my thoughts came down to this:

1) I'm too busy/dense to think about opposing rotation directions for each extension. This means your cone gear implementation won't work as I just don't think fast enough to compensate. I like to keep my head out of the boat.

2) Trying to deal with bicycle-style grip shift stuff out at the end of the extensions will make them too heavy and clunky for me. I'm much like you and I only like very light tiller extensions that don't get in my way. This leads me to want to rotate the whole extension for t-foil angle of attack, isolating the mechanism to the tiller end.

3) I've assumed I would only need/want ONE soft wire "pull" control cable coming from the headstock, therefore one direction ("push") of the bell crank mechanism is under constant tension due to a spring/bungee at the rudder end.

4) I like precise detents delineating rest stops in the adjustment. I'm big on consistency and measurement, so this is critical for me.

5) As always, simplicity is elegance to me, so the design needs to be simple and bombproof.

6) I'm a dual extension guy. My Laser 5000 has a single extension and center sheeting and I hate it more and more after sailing the Falco with dual extensions.

So, here is a hand sketch of my idea. I have NOT prototyped this out yet, but will be doing it this winter. I hope you can project the scribbled 2D perspectives into 3D - I just don't have time to do this in a CAD environment.

Item 1 is a bicycle style cable in sheath. It terminates in a housing on top of the tiller, and the cable continues forward to the tiller-embedded wheel, wrapping around the wheel inside the tiller.

Item 2 is the "wheel" - basically a hub with a smooth cable channel, and the outside edge is crenelated with detent notches. The axle of the hub projects out from the sides of the tiller, providing attachment points for the extensions.

Item 3 is the embedded spring/detent ball that engages the wheel from inside the tiller.

Item 4 is the soft rubber extension attach allowing complete movement of the extensions, while also providing a universal joint for rotation of the extensions

Item(s) 5 are the tiller extensions.

Given the cable "push" direction is handled on the rudder by tension, the tiller end only has to "pull" the cable.

All details of cable travel length and tension can be adjusted by larger or smaller hub wheels and tensioning method on the rudder end. At the rudder end I expect a bell crank with one arm attached to a bungee, and the other attached to the cable.

 

Sam, just out of curiosity, what is your rationale for the gantry rather than just extending the hull? I've read some comments by mothies that when taking off in light air and using your weight to pitch the bow up that the gantry can be a drag.
Of course using something like the f-box can make that pitch-up unnecessary.
What are your thoughts?
Drawings look good.