Foiling C-Class

[TTS]

This is the S.A. link to Fed Eaton's new foiling C-Class Cat. He will try to sail it in the ICCC in September and might sail all 3 cats. http://www.sailinganarchy.com/fringe...20Andidote.htm

Tom

I've written Magnus(crew) who I've known for years to see if he will send me some more detail or post it here himself-we'll see.

[Munter]

Holy peoples foiler - I wouldn't want to see them ventilate the front lifting foils and pitchpole that! I image that the solid rig doesn't deal with cartwheels quite as robustly as a moth rig.

Good luck to them.

[high on carbon]

Well we're pretty careful with the boat I can say that much. That having been said it's a lot less lively than Alpha the previous boat.

With 4 foils in the water roll and pitch stability is greatly improved, as is low speed drag. So we take it easy down wind. even when we get the foils clear of the water she comes down pretty slow relative to a moth and the long buoyant bows help cushion the landing, and then we get right back up flying again. (Not to say it doesn't scare the crap out of you when it happens)

We still have a lot to learn and a lot of details to sort out about how to sail the boat near it's potential. We're very happy with our progress so far and it's a testament to Steve Killing who designed it that we had it up and flying on our first outing under power and then our first outing under sail we also go it up and flying nicely.

I've already been asked so I'll give you the basics here on design details.

4 foils in the water, all T-foils.

We extended the tubes off the transom (Our rudder gudgeons) to help extend the wheel base a little bit on the boat.

The front foils have flaps independently controlled from each hull like a prowler moth, this fundamentaly controls ride height. wands with a mechanical linkage.

We also have flaps on the rudders, linked together and adjusted by the rotation of the tiller extensions, this helps to control primary angle of attatck etc.

We fly at about 10 knots boat speed, so 6-7 knots TWS

We can easily have positiove control on the foils by our actions to give the desired effect for heeling etc.

The boat costs more than my house, 2/3's is the wing so we're cautious at times, mostly for the sake of the wing.

From here to the competition in September I will not tell you about the performance of the boat. Period. For fairly obvious reasons, so please don't ask. Nor will I get roped into any extended discussion about how to do it better etc etc. Too distracting right now and we have a development plan that we're following.

Following the race, no problem. I'll talk about all of it.

Until then I encourage you to simply come and see the boats and the racing for yourself if you're interested in very cool boats.

RCYC, spet 17th-23rd, Toronto

Cheers

H.O.C aka Blunted aka the wing man on a C-cat

[eponodyne]

I'm very curious and very interested in the 'flaps' on the rudders, I've often thought that it might be helpful to build these into centerboards to help move things to windward.

[Munter]

I might be wrong but I think the reference to flaps on the rudder was about a flap on the trailing edge of the horizontal lifting foil, not like a trim tab on a keel.

[eponodyne]

o hell, that doesn't do me any good

[yipster]

what would do good to the C class cats ( and my curiosity ) is some more publicity
sites, specs, links and the like as there is very little to google up on.
cant make it to Toronto so please keep me posted

[tspeer]

Originally Posted by eponodyne

I'm very curious and very interested in the 'flaps' on the rudders, I've often thought that it might be helpful to build these into centerboards to help move things to windward.

Adding a flap to the centerboard won't move the boat to weather. It rotates the bow more off the wind because the lift on the board is dictated by the sail trim, not the board configuration. This has been covered many times on this board. Look for references to jibing boards and trim tabs.

Check this out. Comments by Rohan Veal on his visit to Toronto AND his sailing of the C Class foiler with "Veal Heel":
www.rohanveal.com
Rohan at the helm:
c_class(2).jpg

[Erwan]

Hi Dough, Hi High On Carbon,

I love the rear beam of your C-cat, do you you think the same kind of beam can be used with a boat with a normal rig ? (ie: a main sail with a track on the beam), or is it possible on your C-cat because there is no leech tension on the rear beam ?

Thanks

Hi Erwan, I'm not involved with the foiling C-class presented here other than to hope they do well! I don't see why that type of beam couldn't be used if it was properly engineered for your application.

[Erwan]

Hi Doug,
Sorry I though you were in the loop according to your former comment.
More explicitly, my ideal A-Cat would have curved beams, both of them plugged more or less vertically in the hull.
The target was to reduce the freeboard area of the hulls, while maintaining beams above water especially the aft one for downwind in choppy water. (According to the news A-Cat in the pipe, it is probably a bit obsolet)

A few years ago I asked advices to a composite engineer, (He made one of the first carbon mast for A Cat in 1986).

His answer was, even if the fiber can be curved, the stress and forces involved in the beams will not necesserally follow the curve.

That is why it is a very pleasant surprise to see a C-Cat with such beams.

Extremely interesting pix from SA: "wing tips" on a C-class wing tip:
http://www.sailinganarchy.com/forums...=post&id=50329
--------
Magnus, if this is your boat is the area of the tips included in the 300 sq.ft. SA?

[Retired Geek]

Doug,
this is just a 10 min quickie to show you how it changes the performance...this was set up simply with no attempt to show real performance or sailing angles...basically it provides an increase in CL, reduced CD, a better span efficiency and LD
RG