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

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You bet!

 

MPX Test Model

This is an update on the specs on my nearly complete MPX Test model:
1) Name- Fire Arrow

2) LOA-72in.

a. mainhull-60.75in.

b.planing portion of ama=34in.

c.ama LOA=50.75in.

3) Beam-81.6"

4) Mast 102.5in. (2"chord wing mast)

5) Sail Area:

a. Main+ Mast + Jib= 3454sq.in.

b. Main+ Mast + Code Zero=4244sq.in.

6) Foils:

a. Mainfoil(wand controlled flap)-Span=23.75in., Area=39sq.in.

b. Rudder foil-Span=19in., Area=29sq.in.

c. Ama foil(one used at a time)-Span(from bottom of ama- a surface piercing, soft "L" configuration)=16.5in., Area(from bottom of ama)=39sq.in.; varies with speed and load.(Inspired by the TNZ AC 72 main foil with refinements that allow it to behave as a surface piercing foil with a wide speed range that- hopefully- won't require manual angle of incidence adjustment while sailing.)

7) Weight-target=16.8 lb/max 4 lb above that-Estimate 18lb.

8) Foil loading at takeoff=.184lb/sq.in.(F3-.188)(lighter=better)

9) SA/Lb(18lb displ.est) with Code Zero=235sq.in.(F3-208.5)(more=better)

10) SA(incl Code Zero) per sq.in. of mainfoil group area(81sq.in) at takeoff=52.39 sq.in./per sq.in.(F3-49 sq.in/per sq.in)(higher=better)

11) SA/WS(with Code Zero)=same as F3 at takeoff(even with the wide planing hull)--7/1 seahugging, 21.2/1 foiling.

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>Preliminary testing has encompassed testing all foils to 3 times their calculated maximum load(estimated 50% reserve above that before breaking)

> Boat is designed as a scale test model of an 18 footer based on a hull I have in my garage.

click--

 

MPX Test Model

Painting disaster today-had to be stopped and main foil needs to be re-sanded -probably.

UPDATE-acetone is my friend-foil all cleaned up.....

 

May I recommend NOT painting while cheering on Oracle? All those jumps & heartstoppers are not roll & tip friendly.

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CutOnce

 

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You're so right!

 

MPX Test Model

One good thing about my little disaster in that I'm using "cheap" paint because I expect to experiment a lot with the foils-no point in big money on the foils at this point. Unfortunately, it was too cheap.......

 

Self righting in my eyes means righting by itself without outside assistance.
And so a bicycle also is self righting in a way if one considers the driver's effort.

 

MPX Test Model

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Thats what it means to me as well-as described early in this thread. The boat would use ballast plus the geometry of the platform to allow self-righting.
However, the priority of testing has shifted to the foil system which is the primary focus to start with.

 

MPX Test Model

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Discovered the problem-one I have never seen in 30 years of using "Krylon": the spray tip was missing! Checked a second can I bought recently for a different purpose and the tip was missing on it too! I should have noticed it. I got the new stuff today and compared the two and discovered the missing tips.
Now, the weather has turned and will be like this for two more days so this fiasco will cost FOUR days if the forcast is correct. I'm going back to ACE and get my money back* or at least point out to them the problem.
*can't find the receipt.....

 

For convenience maybe save a few used spray nozzles just in case they are needed.

 

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Thanks, Hoyt.

PS-I bought the paint at Ace and took it back there today. Unbelievably, they have no tips. So they gave me full credit for the paint-two new cans that DID have the tips!

 

MPX Test Model

Major discovery today! I drove down to the Port and on the way back stopped at Kelly Park and there ,to my utter amazement, was a guy flying a 4 rotor small electric helicopter equipped with a gyro stabilized go-pro camera and a gps system. I waited for the guy to land and talked to him and he is just starting a business using the little machine to take aerial video-he said the images are rock solid. Some of you may know that in another life I designed built and patented a video piloted helicopter for taking aerial video in 1984 so the guy and I had a lot to talk about. Anyway, he is going to take aerial video of the Fire Arrow when I'm ready! That will be so very cool.....
I'd post his name and company but chris ostlind has stalked me for years now and copies posts from this thread and posts them on sailing anarchy. Not only that he has contacted people I do business with to try to cause me problems with them-He's definitely off his rocker so I won't post the name here but if you're interested e-mail me and I'll give you his info.
This could be really spectacular video!

picture one of my videopiloted heli's circa 1984:

 

There is a local guy here that has run a business this summer harassing Canada Geese to keep them (and their ceaseless turd production) off our local public beaches. He's using a quad rotor helicopter and had been asked about re-hire for next year by the city of Ottawa. He has actually been able to reduce e-coli levels dramatically to the point where weeks of continual beach sanitary shutdowns have been turned into just a couple days this season. Who would have thought it?

Our geese are all heading to you in endless large hundred bird plus v-formations right now. Looks like World War II bombing raids taking off.


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CutOnce

 

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Thats fascinating. One of the applications we didn't have in our business plan!
The thing I saw yesterday was very impressive-small and zero noise and apparently takes excellent video.

 

MPX Test Model

This is an update of a previous post showing the max pressure for each configuration of the reefable MPX test model rig.
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> Note that max RM is 54.6ft.lb. However, that does not include downforce that could be generated from the main foil. This downforce can be turned on and off. If on, the max RM can go above 75ft.lb-an approx 37%+ increase. The center of effort is 4'-but could probably go down a bit on the reefed main though I'm assuming a flying angle of around 17 degrees there so I'll leave it as it is.
The following are the max pressures per sq.ft for each configuration at a max RM of 54.6lb.
Main + Jib + mast=3455.88sq.in. / 24 sq.ft..57lb./sq.ft.
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Main + Code Zero + mast= 4245.6sq.in. / 29.5 sq.ft..46lb./sq.ft.
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Main + mast=2707.2 sq.in. / 18.8 sq.ft. .73lb/sq.ft.
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Reefed main + mast=2105.28sq.in. / 14.62 sq.ft. .93lb/sq.ft.
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2nd reef(if added) main + mast=1497.6sq.in. / 10.4 sq.ft 1.3lb/sq.ft.
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The reefing protocol on the new boat is:

1) to remove the Code Zero and add the jib,

2) to roll a reef into the main and leave the jib

3) to remove the jib, and leave the full main and move mast step slightly forward,

4) to roll a reef into the main and leave the mast step forward.

5) 2nd reef if added.