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

Doug you cannot disprove a criticism by simply saying "absolute nonsense" and then give no reason for why.

A foil moves

1. fore-aft (accel/decal)
2. side to side (leeway)
3. up/down (heave)
4. around the vertical axis (yaw)
5. around the horizontal axis (pitch aka "AoA" change

So clearly there are 5 degrees of freedom.

And we know from the analysis that the both the Ccats and the AC boats did, that what controls heave on obtuse angle foils is the increase in spanwise flow disrupting lift, NOT the "uptip" (which isn't an uptip but is just the tip) coming out of the water nor a reductionin lift as the boat rises.

Both High On Carbon and Tspeer have corrected you on this claim when you have made it elsewhere.

Now from a spanwise flow perspective the "bend down" tip results in a reduced AoA for the diagonal flow which means that you will see a dramatically increased drop in vertical lift. And this in turn will cause "pogoing" (ie heave

Why? because frankly you can do a piecewise analysis of the foils:
[lLIST]one is the section with the normal J/Acute angled foil
[*]the other is the "turned down" tip which in essence n "open" or "obtuse" angle.[/list]

We know from the experience of Hydros, Artemis and Fill Your Pants that open or "obtuse" angled foils require constant AoA trimming to avoid out of control heave oscillations

So what is "nonsense" in this analysis? Other than your hopes that it is nonsense?

 

New spring loaded foil

Hi Doug, you might be interested in this. I think it has been developed by the people with sail rocket. its a spring load 1 piece foil/flap thing.

Here's the website:

http://www.rocketfactorytrimarans.com/foiling-for-trimarans-1/foiling-future-focus/

and here is the video:

http://vimeo.com/22887842

Good luck with the final parts of your build.

-Curtis

 

Great find Curtis! I also found an illustration for "DSS for multihulls"- a concept I mentioned in this forum about two-three years ago. This must be a Tony Grainger
render:
PS-Curtis, how is your boat coming?

click-

 

Curtis, this was my original "DSS for Multihulls" concept to be used on my 18' "Dream Flyer" trimaran-the foil would act as a foil and as a planing surface at different times like Hugh Welbourns DSS foils. The foil attaches to the bottom of a flat bottom ama at about the same F & A location as the ama foil on the MPX.
Sketch #2 was done as a combination of "DSS for Multihulls" and a diagonal surface piercing foil. I came to the conclusion that the left illustration(straight foil attached to flat bottom ama) would be better for a daysailer but the second illustration may have some potential:
click--

 

New foil systems

Hi Doug, the Dss system for the ama's does look promising . It wouldn't be used with a flying main hull though would it? I think its best potential would really be used on a bigger (25-35ft) Tri where you're less likely to be sailing on the float.

My Boat is really close. The last couple of weeks I've been moving back into my house so not much big stuff has been done but I have all the dagger boards complete. The push rod slides nicely in the center-board. I have sails (that I made my self) and they have great curve (especially the jib). Now that the work benches are set up I can cut off the extra (and very heavy) braces on the cross beams. that will definitely happen sometime this coming week. I still have to sort out my winch mount because my non continuous winch system was never going to work.

I put the boat on the stand today (it arrived along with furniture) with all the decks and cross beams etc. and it really looks the part. I just need to get some time to put it all together.

weight is still in the back of my mind though and at the moment I'm 100g off the main hulls acceptable weight and waterline limit. the cross beam fixing should solve that though. I'll post some pictures of it set up sometime soon.

It probably won't be sailing for a while though. I have exams and assignments for 3 weeks intensively so homework is the priority....

Keep us all posted on your's!!

-Curtis

 

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Curtis, I can't see why not. The foil is equivalent to adding buoyancy to a small ama so I would think the main hull could fly with this system. You'd probably need(at least) a rudder foil and maybe a foil on the daggerboard. The disadvantage of it is when it is compared with a full flying ama-the "DSS" system has significantly more wetted surface. Someday I may be able to experiment with it.....
You can post your boat pictures here when you're ready especially since there is some similarity between your system and the MPX foil system.

 

On some of these things I would expect the big part doing the lifting while you sit on the small parts. So if it fails one way round, flip it upside down and try again

All this talking. When do we see ?

 

MPX Test Model

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Hi, Fanie-long time no see.... Unfortunately, Real Life dictates when I can work on the boat. I should have time to work on it for two or three weeks a few hours a day-or less. She's getting closer........

 

Hi Dough, this life interfering with boats is a crappy business...
I'm burning to get mine going as well, I hate it when things don't work out. By the time the boat is finished you're too bloody old to sail the thing. Perhaps we should have had fathers that built boats and we just finish their almost finished projects for them.

 

Well, Fanie- I actually helped my Dad finish his 47' Grebe project(for 8 years) and learned a whole lot in the process. I have no kid to help-but I'll get it sooner or later.... Here is the finished boat in front of our house on Pensacola Beach:

 

Rather not get a kid to help you, if you think boats are expensive... .
Somehow it's different when you help dad (and tell him how to do what ).

Big boat to park in front of the yard, you can't see the sea...

 

I would think that "DSS for Amas" would run into some IP issues with the ORMA boats that were using horizontal lifting foils for increasing RM a long time ago

 

MPX Test Model

Got a good picture of the jib on the blue background tarp-the only full picture so far of the jib. My sailmaker made a mistake on this sail by cutting a hollow leach-something I've never gone with. After we sail with this sail-and if we need it he will design and build a new sail with the proper leach.
Nit picking things done today but making progress....

click-

 

Doug said "
It would be at least three years from now before I could do a full size version of this boat,"

Come on Doug. You can do better than that. I may not be here in three years

 

MPX Full Size---CHANGE!

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Me too.....reality's a *****. But if I am I will have made a friend happy now and would be able to do the new hull then.