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

[Doug Lord]

Fire Arrow Foiler / MPX Foil System Testing and Development

Some shots of the Ctwist foils and radio box temporarily mounted on the D4Z proto. When finished they will go up about 6" higher. These foils were conceived of for the Fire Arrow and if they work on the cat a somewhat similar foil will replace the wand controlled main foil:
More detail here: http://www.rcgroups.com/forums/showthread.php?t=2180752&page=36
click--

 

[Doug Lord]

Fire Arrow Foiler / MPX Foil System Testing and Development--Self-Righting

When I started this thread it was to develop a "high performance self-righting trimaran". That is the reason for the dihedral and "curved pieces" that support the amas. That gets buoyancy quite high and coupled with masthead flotation makes it almost impossible to capsize the boat. I assumed pitchpole could be a serious problem but in the second video(I think) I was having trouble with an overly sensitive(and very powerful) rudder and when I tried to gybe the rudder force caused a wanabe pitchpole. The boat went so far over I was sure she was going all the way, but the buoyancy of the main hull bow saved the day-I think she went almost 45 degrees.
The project sort of got hijacked by the new foil system which I considered was of more immediate need in development. Now that we know the foil system works 100%, it is just in need of refining to reduce foil areas, where possible, and strong wind testing along with testing the reefable rig.
One problem is that in building the boat one of my personal priorities was to do an excellent finish which I got fairly close to but at the cost of extra weight.
The initial system was to make the boat self-righting for a singlehanded 175lb. sailor. The boat can be sailed in the same breeze singlehanded as it can with a crew because of the ability of the main foil to add RM when necessary. The key to making it self -righting was to add a 175lb bulb at the junction of the daggerboard and main foil or to add the bulb(for testing purposes only) just above that juncture by clamping the lead bulb in place.
On paper that works and would still allow the boat to foil-especially with the bulb at the mainfoil/daggerboard juncture. That amount of ballast works because of the high buoyancy in the curved pieces at the end of the dihedral cross arms. It would primarily be there to guarantee recovery from a pitchpole since the arrangement of the amas pretty much prevents capsize even w/o the ballast. With the ballast the boat would theoretically be immune to capsize or pitchpole in "normal*" foiling.
So this year we will push the limits and see what happens. As mentioned earlier the evaluation of her capsize/pitchpole recovery will be diminished by the extra weight-equivalent to 3 175lb people and 29lb of supplies.
But we'll see what happens. This is one of the things that can be accurately tested on a model so the results will be interesting. Unfortunately, I can't do the singlehanded test because of the weight.
NOTE: Here is a link to a thread I had forgotten about that pretty accurately describes the self-righting characteristics I want to achieve with the Fire Arrow: http://www.boatdesign.net/forums/multihulls/ballast-self-righting-trimarans-43264.html

*there is always a set of conditions that can invert any boat but the range of conditions in which this boat would be self-righting is pretty wide.

This first picture is a screen shot from the video done by an SA guy in order to ridicule the boat after the second picture below. The actual measured angle of the picture is 40 degrees but I think it was a bit higher before it started to recover. If the boat had a "normal" skinny main hull it probably wouldn't have recovered:

 

[Doug Lord]

Movable Ballast Flight Control

I've just found a forum that specializes in "open" software development for flying machines like RC quads. I'm hoping that maybe they can help with modifying a quad flight control system to control a "Trapeze Power Ballast System" to allow a boat using it to sail at a pre-selected angle of heel. The possible application immediately is for the D4Z cat and especially for the Crossbow fl test model and full size version.
The possibility exists that the system could replace the wand on the Fire Arrow using the mainfoil flap to maintain a preset angle of heel.
A system like this would have tremendous applications on any on-deck or trapeze power ballast system and would allow smaller RC models to be controlled easily using movable ballast. If these guys are interested and can come up with something for me to try-depending on cost- I'll use it on the D4Z as a test.
It could be really something.....

 

[oldsailor7]

Doug, If you go to the "Hobby King.com" website you can buy for an incredibly cheap price, a three axis, solid state gyro which will control a suitable servo to do what you want.

 

[Doug Lord]

Flight Control

Paddy, a long time ago I tried gyro's and "heading hold gyros" but they didn't work. Part of the problem was the interface with the Guyatt(RMG) winch which wasn't suitable with the gyro(a long time ago). I'll look at this and if it is cheap enough I may experiment with it. The thing is with something like this I spent a lot of money 20 years ago trying to make it work and I'm hoping I can hook up with some software guys that could guide me through it now(if I can afford it).
Thanks for the suggestion!

UPDATE- just found a "Flight Controller" on Hobby King for only $27! But ,though I'm pretty RC savvy, at first glance I don't have a clue how to use it. I'll go to the manufacturers website and see if I can understand it. http://www.hobbyking.com/hobbyking/..._Flight_Controller_w_FTDI_DSM2_Comp_Port.html

 

[P Flados]

Given all the quad copter development, it just seems like there has to be some very compact, low power, reliable technology that could "cross over" to out sport.

The gyro should be able to provide accurate and high speed signals needed to keep attitude changes slow.

The above would be combined with a secondary input from either a manual control or a wand / ultrasound height above water signal. This should be able to produce near "rock steady" flight in small chop, or a very smooth roller coaster ride in bigger swells.

 

[Doug Lord]

Flight Control

In all the rc boats I've built(except one) using a "Trapeze Movable Ballast System" it was actually a lot of fun to manually(by radio) control the ballast.
But the new D4Z and the AC 62RC may need an automatic system for racing(assuming we agree that its class legal) but the most important application to me would be on smaller RC boats and on the Crossbow fl where an auto system would be a requirement with some people.
On the Fire Arrow and/or on the smaller version it could just control the main foil flap for less drag than a wand that is "flapping" the main foil flap in the smallest waves.
A workable electronic system would make an RC Moth a viable possibility-I tried it once "manually" on a 36" microMOTH and it was extremely difficult and then some.

 

[Doug Lord]

Fire Arrow Foiler / MPX Foil System Testing and Development---Inspiration!

This is from the front page of SA and it is about the beginning of DSS(Dynamic Stability Systems) written by Gordon Kay of Infinity Yachts. For anyone that has an idea they want to test in sailboat design one of the best ways is to do a Radio Controlled model. Hugh Welbourn(inventor of DSS) came to visit me in 2011(see picture below of him holding the main hull) and we discussed the Fire Arrow foil system which he thought was a great idea. It was at a time in the project that I needed encouragement and I sure got it!
--
(Particularly relevant with the second consecutive victory just now by Wild Oats XI in the Sydney-Hobart ocean race using a DSS foil)
-read the full article here: http://sailinganarchy.com/

The story of how we got from there to Dynamic Stability Systems is a long one, with the odd twist and turn and a modest amount of patience, forbearance and endeavour but it has never been dull!

We started with radio controlled models on wind swept lakes in the wilds of Dartmoor, freezing our arses off in the name of “secrecy”; then we built bigger radio controlled models, then we stuck a foil on one side of a 23ft sports boat in Australia, then into a 40ft boat in Australia, then we built a 27ft scale “model” of the 100ft design that we could actually sail then we stuck a foil in a 30 fter and then a 38 fter.

From here we built a 25ft DSS sports boat, with DSS as the starting point rather than as a retrofitted addition. From here the Quant guys got interested and built a 28ft lake racer then a series of Quant 30′s for the Swiss Lakes. Other projects include Speedream and all the way up to Wild Oats fitting a DSS foil and then finally, acceptance in the IMOCA fleet.

Quant 28 DSS(from the article) :

https://www.youtube.com/watch?v=s9ilCx8B0A0

 

[hoytedow]

Happy New Year!

 

[Doug Lord]

Thanks Hoyt-and Happy New Year to everyone!

 

[Doug Lord]

RC Cat Rightable by Radio after Capsize

This is one cool small RC cat. In addition to movable daggerboards the rig cant is radio controlled ao the boat can be righted after a capsize. Some other versions of a small RC cat tend to roll over bow up but not this one. See it righted from a capsize twice starting at about one minute in:
(Thanks to Wolfgang for this great find)
In trying to learn more about this boat I found another video posted by Wolfgang that shows the "roll-over bow up" behavior so common with these little cats. And, unfortunately the righting system doesn't help in that case. See at 3:16 in: https://www.youtube.com/watch?v=HF3nrcn7U50#t=249

https://www.youtube.com/watch?v=f3dqP9IMJYQ#t=150

 

[Doug Lord]

Fire Arrow Foiler / MPX Foil System Testing and Development

Well, I've been considering another change that will allow further experimenting. On the full size boat, the UptiP ama foils will be retractable and because of that they can be longer which seems like it may be beneficial in rougher water. The problem is that I'm not going to make them movable by radio on the model so if I test a longer version it will be adjusted for the anticipated conditions on the day we sail. The current ama vertical position is great for most of the conditions shes been sailed in so far. There is a slight roll in the last video as the lee ama foil goes thru a quartering wave amplified by a powerboats wake. Probably wouldn't have rolled with a deeper ama foil.
The only thing I'm considering is lengthening the daggerboard portion of the foil so in rougher conditions we can try the foil maybe 3" deeper to see if it makes a difference. I guess I would only have to lengthen one of the foils so it can be adjusted down at the sailing site. Looks like Dan and I won't be able to sail the Fire Arrow before late March or early April at the earliest so I have the time.
We'll see.......

 

[Doug Lord]

Experimental Foils

Here are some shots of the D4Z cat with the Ctwist batfoils and the rudders for the final fitting. Now mostly cosmetics left to finish cat. If these main foils work the Fire Arrow main foil will be tested with one:

click-

 

[Doug Lord]

I posted this in the "under 20 trimaran" thread because it could have applications on many small tri's designed for it. It is ,however, specifically for use on the Fire Arrow in place of the UptiP ama foils for extremely shallow water:

I accidentally discovered today a foil idea I had in 2012 for use on a multihull sailing in very shallow water. It would make it possible for the Fire Arrow to get most of the benefits from ama foil lift in 1' or less water. Basically, it's DSS for multihulls-I talked it over with Hugh Welbourn(inventer of DSS) and he agrees it could work well. The foil was originally conceived of to be fastened to the bottom of a small flat bottom ama, but if I was to do it I would make it so it fit the Fire Arrow trunk and it would be able to be adjusted vertically a small amount. So, depending on what course looks feasible in the Everglades Challenge this foil might replace the UptiP ama foils for this race. The foil would not be fully retractable but because the amas are a few inches above the water when the boat is level, de facto retraction happens by simply leveling the boat. There are other challenges to make the Fire Arrow suitable for the Everglades challenge but a potential big problem has been solved. One disadvantage of this shallow T-foil is that it would increase the beam from 22'(with UptiP ama foils) to about 26' with these foils.
For the Fire Arrow the foil would simply be a T-foil inserted into the ama foil trunk and designed to operate close to the bottom of the ama. It would be designed to lift 80+% of the weight of the boat in relatively shallow water with a little help from the ama. Not as good as an UptiP foil but good enough to allow lots of speed in shallow water.
==========================
UPDATE: For those that may not be familiar with DSS it's important to emphasize that the T-foil in the sketch is not just any T-foil- it's set-up to operate close to the surface and to the bottom of the ama.
The separation shown between the top of the foil and the bottom of the ama is probably the maximum that would be used. More separation and the foil would have to be smaller or have a flap and an altitude control system. Operating close to the boat and close to the surface it doesn't need any form of altitude control.

 

[Doug Lord]

Foil Systems Research

Sun night live coverage again-Moth on Foils! thread. UPDATE: very light air
------------------------------------------------------------
Right. This is a simply spectacular video of Day 2 at the Moth Worlds-WIND!
https://www.youtube.com/watch?v=4cuZkpiRLTg#t=10