Foiling radio control trimarans

Aligned, marked and glued all the floats and crossbeams today.

 

We have recently sold two One-Metre kits to New Zealand. One of them is already on the water and foiling.

I am currently fitting out a new Mini40 which has a few changes. Hope to have this on the water in 2 week's time

 

here is a video of the Z-foils in 2016
impressive balance between the front and rear foils (see 3:50 mark for example) as a common problem seems to be the bow lifts too high then collapses.
Does anyone fix the rear T-foil and use flaps for rudder control?

 

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Looking forward to more of your great video-especially the mini 40!

 

This is the new Mini40, coming together in the Philippines. Lots of small changes compared to the previous design, the biggest being that this one bolts together so that I could bring it with me from Australia! Have fitted 2 RMG winches into this so that I can play with overlapping genoas in light winds - this is actually permitted under one of the class rules for speed trials. Hope to have it in the water in the next two weeks

 

Cool! Ian, whats the thinking behind the white foil?

 

Hello Skyak - sincere apologies for the (very) late reply, but I have not been in this site for a year as I moved to the Philippines for work reasons. However I am back now as - whilst I am still in the Philippines - I have a new boat to fit out here in Manila.

The angles of the foils are all at 45 degrees, and there is no sweep-back or sweep-forward. We recognise that wand-controlled or gyro controlled foils would potentially make a more efficient foiler but based on our experiments, we find that fixed foils give us more hours flying with less breakages - in fact none of our foils have broken (touch wood). So we rely on beam of the boat - or the distance between the front foils - for our stability upwind.

Since I am a bit of a loner in the foiling world, I just sail for the pleasure of it, and so do not sail windward leeward courses. I do plan to take the new Mini40 to the UK at Christmas and sail at Gosport with the other UK Mini40s. They sail windward/leeward courses, and I am sure they will beat me in light winds if I just sail with my foils. The extra drag of a second foil (compared to a single centreboard) is significant. The foils also slow down tacking in light winds.

I have 4 sets of foils to try out here in Manila so will give you an update when I get on the water

Rgds

 

Cou

Couple of reasons:
1/ When the boat heels when sailing upwind, with the normal kinked foils you suddenly get a lot of lift because the foil has become almost horizontal, so the boat flies up out of the water, stops and comes back down. Not good. With this foil design, the lift reduces slightly as the inner end becomes almost vertical
2/ as the boat rises, the inner end comes out of the water first, so maximising the distance between the foils at high speed, so increasing stability

Will it work? No idea . . . .

 

Well, good luck with it!

 

Our Z foils are designed to be used only in a decent breeze - they are not light weather foils. They bring a One Metre trimaran to the same maximum beam as a Mini40. The increase in power upwind in a breeze is significant.

 

It's not an RC tri but it is a most impressive wand controlled foiler:

 

The new tri is now on the water and looking promising. Only light winds (6mph) so far but it has got up on its foils. The tests with an overlapping genow are also very promising and I will continue with this for a while longer. I am also experimenting with low aspect ratio rigs to see how they perform, keeping the centre of effort as low as possible, but I need more wind to understand if they have an advantage. They are certainly easier to set and less susceptible to mast bend/flex when sailing

 

This is Michael Scharmer's Mini40, to which he has successfully added wand-controlled T foils to the floats. These will now take his boat outside the class rules because it is now too wide (by about 15cm) but the system is clearly working. He is using the concept developed by NMO in Spain many years ago. Its a good system

 

Hello UpOnStands
We have considered fixing the rear T foil and having an independent rudder but never got round to designing it. In effect, the rudder could be located behind a skeg that has the T foil on it. The advantage of our current system is that we can rock the rudder forward and back in a tapered rudder shaft tube to adjust the angle of attack for the T foil. We adjust this angle of attack on the shore, it does not change while sailing. Not sure how to adjust the angle of the T foil on the end of a skeg. Fine tuning the T foil is very important, and needs a slight adjustment (more pull-down force) in strong wind.

 

A bit more wind today so had on a new smaller overlapping jib plus a new fat head mainsail - I made both sails last week. Later on I changed down to the conventional jib that meets the max sail area rules. Started off with our normal Kinked foils and then tried out for the first time the U foils. They let the boat skid sideways quite a bit when foiling so added the centreboard, and this made quite a nice combination. Learnt a lot about the boat today and its all heading in the right direction