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

Fire Arrow Foiler / MPX Foil System Testing and Development

Here is an updated list of the modifications made since the First Foiling video on July 24th,2014. Number 11 added 7/18/2015-see bottom of previous page for more on #11. I've included page and post references. 2015 testing may start late July or in August 2015-God willing and the creek don't rise:
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1) Changed the wand tension system to allow maximum force on the wand when it is down(flap generating downforce).-page 111, post 1662
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2) Painted small black section on hull immediately behind each wand(as viewed from the side) to help the white wand to show up better in the video.
-page 111, post 1661.
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3) 5 full length battens added to main,GCD removed and mast extention added, peak halyard and downhaul purchase increased. -page 109,posts 1631 and 1632.
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4) A reefing system is now incorporated in the rig with a removable mast section and velcro fasteners to hold the rolled up main.-page 109, post 1633-1634 and page 110, post 1642.Update: the lower panel which was rolled as part of the reefing system has been completely removed for this years testing.
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5) i-Flap removed from port foil(still on stb foil) to see if I missed a step in ama foil development by not trying more area before I tried the i-Flap. The resulting foil has the same planform area as the foil with the i-Flap and a few degrees of washin towards the tip. -page 108,posts 1617 and 1618 and page 109 posts 1626 and 1630. Once I have these results I'll either add the i-Flap back to the port foil or remove it from the starboard foil. Then the process of changing the foil angle of incidence,first, and second changing foil area can start-modifying one foil at a time. The focus will be in reducing drag as much as possible within the constraint of light air takeoff which is the main focus of the Fire Arrow project.
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6) Considered adding aero drag reduction measures to the crossarms but postponed that due to a suggestion from Steve Clark,-page111, post 1653.
(While I greatly appreciate Steve's suggestion regarding aero improvements, I disagree with his assessment of the level of success achieved by the Fire Arrow in her first foiling video. My response to that: -page 116, post 1740)
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7) Added experimental endplates to the outboard ends of the partial span mainfoil flap. -page 112, posts 1667 and 1668.
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8) Added mount for a Velocitek Speed Puck to use to calibrate the i-GOTU* GPS tracker used since day one. -page 112, post 1670.
* see picture of the tracker and its installation on the boat page 113, post 1682.
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9) Moved the mast step aft as well as adding a second jib attachment point aft of the original. -see post 1772
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10) Re programmed the rudder so that exponential can be shut off. The programming used in the foiling video had two rudder programming options: either Dual Rate or Exponential but no "off". This was an overreaction on my part to the "over powered" video where excessive and fast rudder movement caused "pitch-ups" and was mostly responsible for the poor tacking evident in the video. The next time there will be Expo +Dual rate and "off".
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11) The daggerboard and rudder were shortened 6"-see post 2100 for more detail. This reduces draft making the Test Model much easier to launch.
It also reduces drag and slightly increases righting moment by shortening the heeling arm.
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So the major experiments for the next test sail are:
1) How does the port ama foil with the i-Flap removed compare to the starboard ama foil still using the i-Flap. Want to reduce area as much as possible w/o affecting low wind takeoff.
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2) How does the aft mast step position compare with the "normal" position?
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3) How does the boat handle with the reefed rig?
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4) How does the Velocitek speed puck max speed reading compare with the iGOTu max reading?
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5) Do added full battens help?
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6) Is there a noticeable effect on boat speed, tacking or pointing attributable to the reduced foil areas?

 

Fire Arrow Foiler / MPX Foil System Testing and Development

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Pulled both foils from the jig-both good-especially the main foil where the pushrod/flap works perfectly. See post 2100, bottom of previous page for pictures referred to above.
UPDATE: Final carbonation complete.Cosmetics tomorrow......Sailing Tuesday(maybe).
UPDATE: 7/20- Sailing postponed until Friday -excellent wind forecast for testing Fire Arrow-11knots-18knot gusts
UPDATE: 7/23-Test sailing on for tomorrow, Friday July 24th-wind guru forecast-10 knots-16 knot gusts.
UPDATE: 7/23-Center picture main foil and rudder finished after cut down, right picture main foil before cut down and before flap endplates:

 

Fire Arrow Foiler / MPX Foil System Testing and Development

The Fire Arrow sail area with reefed main and jib is 19.4 sq.ft with the center of effort about 4' above the center of lateral resistance.
The rig with the main only is 14.78 sq.ft. and about the same CE.
The maximum righting moment of the boat is 59.68ft.lb so:
1) Max theoretical wind pressure with main and jib=.77lb/sq.ft. which corresponds to a wind speed of about 14.25mph(12.39 knots)
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2) Max theoretical wind pressure with main only= 1.01lb/sq.ft. which corresponds to a wind speed of about 16mph( 13.9 knots).
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Rig can be manually depowered to handle gusty conditions and will automatically depower by twisting off the head. Wind Guru forecast for this Friday at 8AM is 12 knots with gusts to 19.

Note excessive twist in the main in only 5mph of breeze last July24th-it can be adjusted out but I was in too much of a hurry to bring the boat back in. This July 24th the rig will be smaller and the wind much stronger:

 

Fire Arrow Foiler / MPX Foil System Testing and Development

Today is the one year anniversary of the first foiling video of the Fire Arrow and Dan and I had hoped we could do the second one today. No such luck, though we were encouraged by the forecast from wind guru for 11-17 from the SSW. Unfortunately, when we left at 7AM the wind was from the right direction but the max measured on my Davis windmeter was 5-6 knots. And when we got to the site it was max 4 knots. Perfect for testing the damn cat but no good for the tri. Most disappointing.
Next chance of testing either boat is Tuesday.
UPDATE: Took the cat today-too much wind for the first sail. Next chance for either boat Friday-the last day Dan will be available this year.

 

D4Z-AC 4.8RC Foiling Cat

Had an "epiphany" of sorts a couple hours ago: to add the rack to the boat previously,the ballast module had to be undone, the guide wire undone, and the stb end piece had to be removed. Then the ends of the rack tubes had to be slid inside the retainer tubes and everything put back together-a big pain.
I figured out a way to make the retainer tubes allow the rack tubes to be pressed into place(and removed the same way) and came up with a "tube lock" that will slide over the rack tubes and onto the ends of the retainer tubes ,if needed.
This makes it extremely simple to install and remove the rack which is a great relief!

The retainer tubes are the white ones in the center going around the rack tubes:

 

D4Z First Sail!

Finally! I got the right wind(almost) to test the D4Z. Very light-max around 2mph but thats how I like to start with any new boat. She did well but I was hoping the wind would pick up a bit during the 2 hours we were there but it didn't happen. She moved surprisingly well in such light stuff and tacked well most of the time.

 

D4Z in very light air today-

Short video in no wind showing the Trapeze Power Ballast System:
https://www.youtube.com/watch?v=OpiBsSaUsvY

 

D4Z First Sail!

Tacking in no wind:
https://www.youtube.com/watch?v=usaHnldF4u8

 

D4Z First Sail!

I was patient while we tried to get light air for this first test. But 3 minutes or so after I saw how well she worked I was ready for more wind RIGHT THEN-not to be- but she's gona fly:

 

D4Z First Sail!

Max wind speed 2MPH----Max boatspeed 3mph!

 

D4Z First Sail!

More light,light air:

https://www.youtube.com/watch?v=9kfPt0FkpnY

 

D4Z First Sail!

"Z" in slightly more wind:
https://www.youtube.com/watch?v=u47mAtvINiI

 

Fire Arrow Foiler / MPX Foil System Testing and Development

Here's a very light air video-a bit over a year old-showing how well the Fire Arrow does in very light air:
https://www.youtube.com/watch?v=FF7cy8AoFnU

 

D4z

"Z" specs:
LOA-51.5" / 130.8cm
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Beam-33" / 83.8cm
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Mast-water to tip: 90.25 in. / 229cm
---mast: 85.25" / 216cm
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SA--1825sq." /1.17sq.m /11774 sq.cm.
---Main: 1209 sq. in./ 7800sq.cm.
---Jib: 616 sq.in./ 4000sq.cm.
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Weight(with empty ballast system) : 8.2lb /3.73kg./ 3719.5 g
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Trapeze Power Ballast System max extention*(from CB of lee hull to CG of ballast) : 40" / 1.02m / 102cm
* system is designed for the new 380 RMG winch but I couldn't afford it. With that winch the weight could move another 6-8" out. That would be a "must have" for racing.
--max ballast 3lb. / 1.36kg / 1360 g
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FOILS:

Mainfoil: 30.8sq. in. / .0199sq.m./198.7 sq.cm-- (Vertical lifting surface only. Sailed with either both or one in the water.-Windward mainfoil is clear at an angle of heel of 4 degrees. Since these are surface piercing foils , their area will reduce after takeoff.)
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Rudder foil: 11.4 sq.in/ .00735 sq.m / 73.5sq. cm. (Vertical lifting surface only. When windward main foil is just clear, windward rudder foil is still immersed.)
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Mainfoil Loading-nominal at takeoff:
--2 mainfoils wet: .105 lb/sq.in.
-- windward mainfoil clear: .21 lb/sq.in
(For reference: FA .188lb/sq.in, F3 .188lb/sq.in.)

 

D4Z, an AC 4.8RC America's Cup Cat

I found a problem with the boat this morning. The other day she seemed to maneuver real well especially considering the light air but something didn't feel right. So I set the it up to check the rudder throw again. Amazingly to me, the port rudder was set at 30 degrees each side, the starboard rudder at 25-and it wasn't centered when the stick and other rudder was! Now that's just carelessness and I'm not usually careless. But that's the way it was and I don't know why.
I reset them both to 38 degrees (no ackerman)which is what I thought I'd done originally but I had to re-drill the rudder arms so it's clear that I just didn't do it right the first time.