Radio Controlled Foiling America's Cup Catamaran: AC 50RC - Page 4 - RC Groups
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Apr 27, 2015, 06:48 PM
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DLord's Avatar

wing


Quote:
Originally Posted by John Xman
Doug,
I have thought allot about the wing build for this size based on my AC-86 Wing.
The leading edge for both Element 1 and rear flaps Elements 2 would be a "D" shape Carbon Fiber Tube. You would then cut slots into the back flat part of the tube and insert thin plywood ribs for the pivot ribs at 12" vertically, all other ribs 4" vertically would be balsa. No reason for any internal tube. I think the wing would be more like 3 1/2 lbs.

John Xman
Thanks, John. 3.5lb would be too heavy for an AC 4.8 rig. I doublechecked my calcs and 2.5 sure seems possible. The beauty of a carbon rig is that it could probably be built sealed.
But building the tooling is a massively expensive project and probably beyond me for a while(if ever). If I did it, it would be carbon tooling and fairly heavy/very stiff and optically smooth-no waves etc.. I might more seriously consider it down the line if the class gets going and we have a reliable manufacturer or three.
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Apr 29, 2015, 03:03 PM
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DLord's Avatar

D4Z-AC 4.8 Foiling Cat


Radio box loaded. All winches and servos are in main radio box except side to side ballast winch which is in sliding white box. Very powerful dual rudder servos. RMG switch to turn the whole thing on when sealed up right next to mainsheet winch:

click for best view--
Last edited by DLord; Apr 29, 2015 at 03:12 PM.
May 03, 2015, 01:46 PM
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D4Z-AC 4.8 Foiling Cat


Radio box cover installed ,rudders hooked up, all system winches and servos tested. And mast step added......All that's left is to fit the rig and run the lines for the ballast system and sheets. Rig complete. Getting close.......
Last edited by DLord; May 04, 2015 at 04:20 PM.
May 04, 2015, 08:38 AM
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Looking good Doug.

Since my last update I've test a couple of iterations of the wing, and combined with some changes to the jib I'm getting close to having a reasonable setup. The current wing is more conventional, along the lines of what John described.



Another change that I'm testing is a single central rudder, more like Ian's cats. The boat seems to be more stable in this configuration.

I'm thinking more about foils for this boat. I wondered if I could use some of the observations from my earlier attempts, in particular that the outward facing foils produced lift at relatively low speeds. I'm wondering about building a foil that has an outward facing foil close to the surface and an inward facing foil deeper. Could this work with the outward facing foil providing the initial lift and the inward facing foil taking over once the speed got up?
Last edited by rcmm; May 04, 2015 at 08:46 AM.
May 04, 2015, 10:42 AM
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DLord's Avatar

Ac 4.8rc


Might be a worthwhile experiment. But my suggestion, since your just getting into foils, is to go, as best you can, with a proven foil system with zero experiments. Duplicate(with his help?) Ians cat foil system using wands. I'd use a flap instead of all moving foil but Ians system seemed to work. Or go with a very wide cat using surface piercing main foils. Ian could sure help with that. If you go with simple then you're a step ahead and can refine the design from there. Ketterman says outward pointing foils are slow but his trifoiler using them did foil. Right now I think you'd be better off doing the simplest possible thing to get the boat in the air and then go from there.
Using surface piercing foils requires either movable ballast or wide beam to get enough RM. That's why Hydroptere is so wide. Hydroptere.ch is wide for a cat and very successfully uses surface piercing foils.
Last edited by DLord; May 04, 2015 at 10:55 AM.
May 04, 2015, 04:21 PM
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AC 4.8RC Foiling Cat


Quote:
Originally Posted by rcmm
Looking good Doug.

Since my last update I've test a couple of iterations of the wing, and combined with some changes to the jib I'm getting close to having a reasonable setup. The current wing is more conventional, along the lines of what John described.

Another change that I'm testing is a single central rudder, more like Ian's cats. The boat seems to be more stable in this configuration.

I'm thinking more about foils for this boat. I wondered if I could use some of the observations from my earlier attempts, in particular that the outward facing foils produced lift at relatively low speeds. I'm wondering about building a foil that has an outward facing foil close to the surface and an inward facing foil deeper. Could this work with the outward facing foil providing the initial lift and the inward facing foil taking over once the speed got up?
==================
Thanks, Jim.....
May 05, 2015, 05:58 AM
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Jim, that would probably be a lot of extra drag. Like Doug said, I would get it foiling first, then refine the set up.
May 05, 2015, 07:54 AM
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Quote:
Originally Posted by JIM CALDWELLA
Jim, that would probably be a lot of extra drag. Like Doug said, I would get it foiling first, then refine the set up.
Jim, I'm thinking of something like T-foils with the outward facing foils above the inward facing foils. Would this be extra drag?
May 05, 2015, 05:25 PM
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Yes, its extra cm of wet surface both the top and bottom area of the extra foil which means you will need extra power and speed to get up.
Now watch the second half of the video sailed by Dave Burke ,when his part starts notice he is going UPWIND and foiling. Then when he gibes and is going downwind he is STILL sheeted in and almost foiling. Once he get the hang of it and fine tuned he will have a winner!

2 One Metre mutilhulls (2 min 38 sec)
Last edited by JIM CALDWELLA; May 05, 2015 at 05:41 PM.
May 05, 2015, 07:15 PM
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DLord's Avatar
Jim, this is the cat I meant above when I thought it was Ian Holts design(post 50). It's Dave Burke's design with foils by Dave Creed.
May 10, 2015, 11:19 AM
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D4Z Finished!


The boat is done and ready for "dress"(platform+rig+ foils) pictures tomorrow if the wind is calm enough.
May 13, 2015, 10:50 AM
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D4Z-AC 4.8 Foiling Cat


Fitted the rig this morning. Needs work on the stand to allow the foils to be added and the shrouds and trapeze line was tangled as if someone deliberately messed it up. Can't imagine how I did that. But the rig fit perfectly and shes ready to sail shortly:

click for best view-
Last edited by DLord; May 13, 2015 at 03:00 PM.
May 13, 2015, 12:00 PM
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Dick L.'s Avatar
Looks nice Doug. I think you may find the pushrods for Ackerman steering issues. might be a bit much to worry about, and you may go back to a standard crossbeam between both rudders. Just seems to add another level of complication to the project. Good luck on your first sail.

Dick
May 13, 2015, 12:27 PM
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DLord's Avatar
Thanks Dick. The rudders each have their own servo and no mechanical or programmed Ackerman --yet. But later I can add it very simply thru the radio.
Tested the "Trapeze Power Ballast System" and it's very fast even with 15 year old RMG winches. Going to be fun (re)learning how to sail with one of these!
May 13, 2015, 02:36 PM
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shi# after seeing all this I may just have to build a cat.......


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