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Old Apr 03, 2015, 07:33 PM
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Radio Controlled Foiling America's Cup Catamaran: AC 4.8RC

Since the rules were just so dramatically changed for the full size boats AND since two of us have already built boats(as AC 55's from the previous thread) I wanted to come up with basic Rules that would be as close to the new rules as possible while allowing the two completed boats to be immediately legal. John Xman suggested length and beam done to a 1/10th scale. That worked well allowing the two completed boats to closely fit while maintaining the proportions of the full size boats.
AC 4.8RC:
Length: 4.8'=57.625" (rounded)
Beam: max 3.75'=45"/115cm( amended 8/2/15-)
Tentative rules based on my D4Z:
--movable ballast system legal and may exceed maximum beam-no restrictions,
-- foils may extend outside the maximum beam.
--rudders may be transom hung
--SA up to 1900sq"
--no channel restrictions
--no foil type restrictions
--no rig restrictions
===================
Directly scaled Model length is 1/10th fullsize, SA is 1/100 fullsize, weight is 1/1000th fullsize, RM is1/10000th fullsize.
NOTE: sailarea, weight and RM of the model cannot be equal to the directly scaled values from fullsize.
===================
As far as I'm concerned that is the Basic set of rules until more boats are built and an excellent foiling system or systems are developed and proven.
-No boat built under these basic rules may later be disqualified or modified in any way by later rule changes.
My primary direction now will be to complete and foil my boat with three different foiling systems as well as experiment with the Trapeze Power Ballast System. I would imagine Jim in Australia will be doing similar development .
The idea and absolute requirement for a successful RC Americas Cup foiling cat is:
1-that it foils in light air,
2-that it foils upwind,
3-that it routinely gybes on foils,
4-that it is capable of sailing a triangular or windward/leeward course faster than any comparable size monohull.
These will be tough requirements to meet but are essential for future growth of the class.
The D4Z below is one of the first two AC 4.8RC cats and is nearly complete and will be under constant development. Jim in Australia's prototype is under development but is sailing and has foiled for short bursts.
====
Scratchy 101 had a good idea and that was to not "bury" the original AC 62 thread because he thought it had a lot of good info. So here is a link to the end of that thread for those who want to check it out:
http://www.rcgroups.com/forums/showt...180752&page=48 opens on last page of old thread
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Old Apr 04, 2015, 05:01 AM
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AC4.8RC - Boat 1

A couple of videos to summarise my efforts to date.

My first boat:

AC 55RC Prototype - 6 (2 min 50 sec)
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Old Apr 04, 2015, 05:13 AM
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AC4.8RC - Boat 2

My second boat currently under development:

With outward facing L-foils:

AC55 RC (1 min 32 sec)


Same foils inward facing, but effective main foil area smaller:

A 55" Cat (AC) - RC (1 min 44 sec)
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Old Apr 06, 2015, 03:09 PM
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AC4.8RC /D4Z Rig

My D4Z rig is 90.4" from the water to the tip of the wingtip. 1825 sq.in./12.7 sq.ft(1.18sq.m) and it's reefable. Wingtip is 6.5" above top of mast. Mast is 81.5". As usual, my sailmaker is running behind-he just ordered 3 yards of 2.2oz Dimension Polyant ODL material yesterday and says I'll have them by the end of the month. I'm installing the corner reinforcements, battens and the reefing system. Will use an upper "gaff" like the Fire Arrow and a "wingtip" filled with foam like the Fire Arrow. Large sock luff. May install a canting rig system down the line.
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Old Apr 09, 2015, 03:28 PM
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Ac 48

Here is the first render I've seen of an AC 48. This one done Martin, editor of catsailingnews : http://www.catsailingnews.com/
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Old Apr 11, 2015, 12:11 PM
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Here's a 2 hour video here on "Foiling in the USA".
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Old Apr 11, 2015, 05:34 PM
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Quote:
Originally Posted by DLord View Post
Here is the first render I've seen of an AC 48. This one done Martin, editor of catsailingnews : http://www.catsailingnews.com/
If he didn't put the caption in the picture it could have been a rendering of the Oracle AC72 .....
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Old Apr 11, 2015, 06:33 PM
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Here's a "proportional" drawing from the link I posted in the other thread.
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Old Apr 17, 2015, 04:32 PM
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Quote:
Originally Posted by rcmm View Post
My second boat currently under development:

...

Same foils inward facing, but effective main foil area smaller:

https://www.youtube.com/watch?v=gAb1JuC1yD0
After looking at your video
it appears that foiling an RC cat ; could present some very difficult
challenges ? I would like to give it a try ; but i'll let you guys do some
more problem solving first .

Right now , i'm gathering info on how to foil with a kite-board ; read the
link below, and you'll see why it will be difficult for me :

http://www.thekiteboarder.com/2010/1...e-billy-floyd/

Bille
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Old Apr 17, 2015, 05:02 PM
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AC 4.8RC Foiling Cat

Bille, you've got courage and guts!!! Good luck with kitefoiling-I hear it's a blast.
Sooner or later several of us working on foiling cats will have a good system. Testing my D4Z will start around the first of June and pictures and video will be here.
There are at least three other guys working on foiling cats but not necessarily AC 4.8RC's. Should be an interesting year........
Hope it goes very well for you!
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Old Apr 17, 2015, 07:09 PM
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Quote:
Originally Posted by DLord View Post
... Good luck with kitefoiling-I hear it's a blast.
...
Hope it goes very well for you!
I've bin researching the foils for about a year now ; current weight-shift
control they use on kite-foiling; will NOT work for me because of the
fake legs.

Your name has bin on a Lot of Threads , i've come across in the last year.
I , "Hope" when i come up with a solution for my needs ; i can run them
by you in a (Pm , before i waist a bunch of time building something that
you would already know , (probably won't work) ?

I'll be going with mechanical linkage off my prosthetic(s), for turning
and height control.
================================================
Which brings to question for you guys :
How about a flap system to control your C/L with a servo ; until Ya
got the other stuff figured out ? It looked like --rcmm 's-- cat, it jumped
out of the water all at once ; if he could add lift slowly , after the cat got
up to speed ... ? Then all the other technology could kick-in ? Is changing
the AOA of the main foil ; a bit too sensitive right now , for an RC ? Feel
is a Lot in a bunch of different applications ; like me, i have ((O)) feel
from my legs, and my balance is all Visual. There is a considerable lag-time.
Could be the same for foiling with an RC ?

And last : any questions about composite and use of epoxy ; that's what
i'm Good at , so feel Free !! There are some epoxy's on the market, that
are just down-right dangerous to your health ; if not used properly (.)

Thanks : Bille
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Old Apr 17, 2015, 08:12 PM
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D4Z Foils

Bille, my D4Z cat is going to use very, very experimental main foils initially. If they work they will be quite simple and a version might work for you.
Generally foils fall in one of two main categories-fully submerged which encompasses wand controlled foils as well as UptiP foils(mostly) and Surface piercing foils which start out fully submerged but rise out of the water the faster they go until they reach an equilibrium due to speed. Both fully submerged and surface piercing foils use a trailing T-foil(or L foil) on the rudder or rudders that automatically creates pitch stability. I'm thinking that a surface piercing T foil like the ones below might work for you because they have automatic altitude control due to speed.
But any system like this won't be immune to inadvertent body weight movement though they should be a lot more stable in pitch than a current fully submerged kite foil.They should be extremely stable in heave(excellent altitude control). I'll be testing them in a few weeks.
You can PM or e-mail me anytime.
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Old Apr 18, 2015, 10:31 AM
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Quote:
Originally Posted by DLord View Post
Bille, my D4Z cat is going to use very, very experimental main foils initially. If they work they will be quite simple and a version might work for you.
...
.They should be extremely stable in heave(excellent altitude control). I'll be testing them in a few weeks.
You can PM or e-mail me anytime.
Fingers Crossed !
That is SO COOL ; and your correct, it just could work
for my application.
GOOD Work !!


Bille

Ps : I Like the work you did on your Hulls, as well !! ----- (where is the Thumbs-Up icon ?)
What are they made of ?
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Old Apr 18, 2015, 11:57 AM
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D4Z, an AC 4.8RC America's Cup Cat

Thanks, Bille. The D4Z started life over 15 years ago when I designed it, built the plug and molds and the first kevlar hull. Kevlar was ok until I wanted to modify it to be an "AC" boat but I'll never use kevlar again. The cross arms are torsionally reinforced carbon from the company that became Rock West Composites-the platform can't be twisted. Last June I thought it would be a kick to see if others would be interested in an America's Cup RC cat so I decided to modify the D4Z.
Almost done! Testing of the D4Z and Fire Arrow will start again in late May-June. http://www.rcgroups.com/forums/showt...2190004&page=4
boatdesign.net Fire Arrow thread: http://www.boatdesign.net/forums/mul...36058-135.html

PS it will be inititially tested with a "Trapeze Power Ballast System" for extra righting moment.
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Old Apr 20, 2015, 06:07 AM
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AC4.8RC - Boat 2 - Wing Sail

Some (very poor) footage of testing with a foam wing sail. The relative positions of the CLR and CoE are not quite right, and initially the sail was too tall. Will try a shorter wing and add a jib.

AC 4.8RC - Wing Sail 1 (1 min 10 sec)


Will add foils when the rig is sorted.
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Last edited by rcmm; Apr 20, 2015 at 06:13 AM.
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