High Performance MPX Foil/Self-righting Trimaran-The Test Model

[Doug Lord]

Fire Arrow Foiler / MPX Foil System Testing and Development

This is a set-up I used on all my production RC models, but by the time I remembered it, it was too close to the first sail so I postponed installing it.The set-up allows any RC boat to point higher than if they use the "conventional" jib boom pivoted at about 20% of the chord of the foot aft on the boom. I used it in racing before I started producing models and it gives two or three degrees improved pointing. I'm hoping to get the Fire Arrow to tack on foils(almost impossible with her weight so I'm told) and the only way it will be remotely possible is to improve ,where possible, every aspect of her upwind set-up. The problem is adding the Hoyt jib boom after the fact and I may wait until I test the boat with the mast step moved aft(already done) to see if that is an improvement. So far, the only way I see to install the Hoyt jib boom involves surgery and will not be adjustable. But I'm thinking a lot about it so I may come up with a better solution.
The Hoyt jib boom acts as a vang as well as permitting the forestay to be on the centerline and changes the jib shape advantageously when eased. It really works well.....


Picture 4 shows the typical rc model set up and the way the Fire Arrow is set-up now:
click for best view---

 

[Doug Lord]

Fire Arrow Foiler / MPX Foil System Testing and Development

For those that may have missed it here is Fred Monsonnec's article about the Fire Arrow in his "Foilers!" e-zine. I want to thank Fred again for doing this article!
https://foils.wordpress.com/2014/08/22/fire-arrow/

 

[Doug Lord]

RC Foiler

More of Chris's fantastic machine(see first video on previous page) :
https://www.youtube.com/watch?v=wPFGM-fbhsw

 

[PerthMini40man]

I have seen that you are hoping to remain foiling through tacks and gybes. I have once or twice managed to stay up on the foils during a gybe but more by luck than skill. I have never come even close to foiling through a tack, and do not believe it is possible without a heavy boat that has a lot of momentum. Some photos and a video taken today are attached here, and show some attempts at foiling through a tack. I did, however, get the boat foiling closehauled a few times, and have found this is possible in steady wind, when I can set the sails to the right amount of power.

http://youtu.be/U2MMMAphR3c

 

[Jim Caldwell]

Ian, how is the T foil cat coming along?

 

[Doug Lord]

Fire Arrow Foiler / MPX Foil System Testing and Development

Ian, thanks for the video. About 15 years ago, my F3 would gybe on foils easily and I got it to tack on foils a couple of times(over 2 years). Another F3 owner was able to do tacks on a more or less regular basis. One little thing that helped was getting the forestay on the centerline. The F3 sailed at 7.5 to 8lb and had enormous righting moment due to the foil system and oversquare platform(LOA 56" beam 72" foil tip to foil tip).
There's a good chance the Fire Arrow will be able to tack and gybe on foils.

Heres your video embedded:https://www.youtube.com/watch?v=U2MMMAphR3c&feature=youtu.be

 

[PerthMini40man]

Ian, how is the T foil cat coming along?

I am afraid not. I am currently getting a 10rater ready for the Nationals in January and this is taking up much of my spare time. I have started on a second set of T foils but they are far more complicated to make than the static foils. One thing we have noticed so far is that over an average sail (upwind, reaching, downwind) the cat is actually faster without ANY foils than with foils fitted. So when the boat is not foiling, the drag is significant. Not easy

 

[Doug Lord]

RC Foils

That was pretty much the experience with full size cats before 34. The story of "Off yer Rocker" was very interesting-they used wands on a narrow platform and didn't gain much ,if any, speed on foils. The new "Whisper" cat and Dario Valenza's experimental A Cat, both with wand based foils, seem fast but it's hard to tell from a promotional video.
How are you going to control altitude with your new foils?
I'm going to try very experimental "Curved Twisted Surface Piercing T-foils" on my D4Z cat-they're so simple it's worth a shot.
PS- the idea will be to use a very fast movable ballast system(in suitable wind) and attempt to sail the boat at between 4 and 10 degrees angle of heel which will get the windward main foil out of the water, at 10 degrees both the windward main and rudder foil are clear.

 

[PerthMini40man]

You'll need to be careful with the design of your moveable ballast system, as any protrusions beyond the outboard surface of the hulls will be seen as a hazard at rc yacht clubs and most likely banned. They won't like the idea of your ballast track ripping into hulls of other boats. Your hulls also look very fine in the bows, so you silicone rubber bow bumpers will be very fine, and will likely incur the risk of frequent knocking off unless impact is head-on. This is a common problem on fine bows, but again it is essential at any rc yacht club for insurance reasons.

 

[Doug Lord]

RC Foilers

The "Trapeze Power Ballast System" has been used on some of my RC models for a long time without any trouble. Where problems might occur is if the "International AC 62RC Class" or its feeder Class, the AC 55RC, take off(which is not likely) because then they'll be numerous boats with movable ballast sailing at all kinds of levels of control or lack thereof. But I think "good" problems like that can be solved. It's my opinion, so far, that rc catamarans have suffered by being in a class where they race against trimarans. When the limits are length, beam and SA it seems like the tri will always have the advantage. But the America's Cup has opened up an opportunity for a cat only class or classes. Right now we have two guys building 62's and two guys-me and a guy in Australia- building AC 55RC's which are supposed to be like the AC 45's are to the full size AC 62's. These classes are based on the development of foiling RC catamarans and for the classes to be viable these boats must foil upwind and downwind, gybe on foils and maybe tack on foils. The use of movable ballast on RC cats will be a speed producer and really enhance performance.
I think I can build a cat that will do that but the class(s) will not exist ever if ,for any reason, those performance levels can't be reached. It would be great if you could take some time and check in at the RC groups thread or the AC 62RC thread here-your comments would be most welcome. We're trying to do something that is difficult and hasn't been done before-it could fail or it could succeed beyond our wildest hopes.
You're 100% right about bumpers-if I was to produce any model for competition they'd have bumpers. But the Fire Arrow and D4Z are basically just test boats for the time being but bumpers(or "crash sections") can be added if things change.

http://www.boatdesign.net/forums/projects-proposals/international-ac-62rc-class-51540.html

AC 62RC Class/ AC 55RC Class proposal thread: http://www.rcgroups.com/forums/showthread.php?t=2180752&page=34

Melges 24RC with working asy spin and Trapeze Power Ballast System, and the "Super Scow 36" with the same ballast system.

 

[Doug Lord]

Fire Arrow Foiler / MPX Foil System Testing and Development

See the previous page for the history on the development of this new foil. It is a "Curved Twisted Surface Piercing T-foil" utilizing the iFlap(an intrinsic 15 degree
flap-first tested on the Fire Arrow ama foils).
This particular foil shape was conceived of as a surface piercing T-foil utilizing the iFlap to create almost the same function as a wand controlled t-foil. The wand causes the flap to go max down for takeoff and when it reaches its designed flight altitude the wand neutralizes, reducing drag. Well, this foil should work the same way: the 15 degree intrinsic flaps produce high lift for takeoff but when the foil reaches its designed flight altitude the flaps are above the waters surface ,reducing drag.
Seeing this thing in 3-D finally was a real rush-as much as I imagined what it would look like was nothing compared to the real thing. If it works as good as it looks to me it will be just terrific.
The foil was first conceived for the Fire Arrow main foil to replace the wand controlled foil experimentally, but its first use will be on the D4Z cat where its simplicity is the greatest benefit-if it works well. It may easily allow the cat to fly the windward foils thereby allowing the D4Z to foil on only two foils. All that will be seen on video one way or another!

 

[Doug Lord]

Fire Arrow Foiler / MPX Foil System Testing and Development-Ctwist Foils

Here are some shots of the new foil and both together. The first one weighs 97g and the second weighs 85g:

click-

 

[Doug Lord]

RC Movable ballast

This was posted in th AC 62RC thread on the German forum:
https://www.youtube.com/watch?v=4u5_D3kRe6k&feature=youtu.be

 

[rcnesneg]

Ok THAT is cool! Mini hobie cat with a swinging ballast!

 

[Doug Lord]

Looks to me like the guy may have some sort of sensor or gyro moving the weight as well?