Fire Arrow Foiling Trimaran Test Model - Page 4 - RC Groups
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Dec 25, 2014, 05:37 PM
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Fire Arrow Foiler / MPX Foil System Testing and Development


This is the roughed in "Curved twisted Surface Piercing T-foil" for use on the D4Z cat(AC 55RC Proto Class). This foil was originally conceived of to replace the wand controlled main foil on this boat. If it works well on the cat ,I'll definitely make one for the Fire Arrow but with an upside down asymmetrical foil in the center with a fence on each side(see post 32) .
PS-Seasons Greetings, Merry Christmas and Happy New Year!
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Jan 17, 2015, 03:19 PM
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Heres a link to an article about a guy who added two real short hydrofoils to his canoe. Not exactly like my system but very cool! Check out the facebook video for a shot that shows the foils lifting the boat: http://smalltrimarans.com/blog/?p=12406

Slue Foot Sue (4 min 38 sec)
Jan 17, 2015, 04:02 PM
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Fire Arrow Foiler / MPX Foil System Testing and Development


Fire Arrow summary page on boatdesign.net:
http://www.boatdesign.net/forums/mul...36058-124.html
Feb 03, 2015, 01:16 PM
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Quote:
Originally Posted by Doug Lord View Post
UPDATE:

Target Weights(corrected for scale in previous post) :

1) Main hull = 3.858lb
2) Amas(for both)=1.25lb
3) Mast and Sails =1.05lb
4) 2 "curved pieces"(ama extension)=1.25lb
5) 2 cross arms = .74lb 1.1" OD CST carbon
6) 2 foilsets = .74lb
7) "crew" = 3.9lb
8) Ballast = 3.9lb

All up---16.688lb


updated 1/10/11---Corrected for new length of 60.75" which allows one foot to equal 3.375"
======================
It's interesting how sometimes you can discover something new even though it's been right in front of you for a long time. That's the case with a characteristic of the Fire Arrow and it's ability to self-right. The original designed sailing weight was 16.688lbs,its final sailing weight was 21.13lb. At the 16.688 lb weight,3.9lb was "crew" and 3.9lb was ballast to go in a bulb at the juncture of the mainfoil and daggerboard. The excess weight-4.44lb (caused by the way the boat was built and finished)-plus the original designed weight was 21.13lb.,which, without ballast, would equal 3 175lb people and about 24 lb of miscel. supplies on the full size 19 footer. I mentioned, just a little while ago, that I probably couldn't test the self-righting of the boat as I had originally hoped to because of the extra weight and that is probably true though we'll try adding an extra 4lb to the fin(removably) and see what happens.
I've mentioned in several posts what went wrong and what went right-the most important part of "what went right" was that the boat foiled in a 5mph breeze with all that extra weight. And that means that if the boat had been built to its original design weight it would have surely foiled(fairly obvious) and what that means is really cool: not only would the boat have foiled it would have been likely to be self-righting! That means that this boat is real close to being a self-righting keelboat FOILER! And we're going to try it with an extra 4 pounds on the daggerboard to see what happens-there is a high likely hood she would foil with the extra weight and she might even self-right from a pitchpole.
When I first started building models I always built them too heavy if I did an excellent finish on the boat-the only way for me to build a boat very light and with an excellent finish is to build tooling and build the boat out of molds-that's how I did the F3-the worlds first production RC foiler that I designed with the Bradfield foil system. I built six of them all coming out about 6.5 lbs for a 56" long by 72" wide foiler with 1668 sq.in.of sail.She would also take off in a 5mph breeze or lighter.
The point of this is that I now know for sure, beyond any shadow of doubt, that a self-righting foiler is a realistic possibility-maybe not the Fire Arrow now but I still have a bunch of tooling that I can use to build a much lighter version of the Fire Arrow that I know for a fact will foil and be very highly likely to self-right from a pitchpole! The geometry of the Two Stage Ama and high dihedral crossarms makes it virtually impossible for the boat to capsize in the normal way-in fact the boat is self-righting from a knockdown past 90 degrees-with no ballast! And with ballast she would be self-righting from a pitchpole.
Fire Arrow testing resuming in ,hopefully, June.
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Last edited by DLord; May 29, 2015 at 03:20 PM.
Apr 13, 2015, 05:04 PM
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Fire Arrow and my friends Osprey


Both these boats are similar in length and beam fullsize: Osprey is 18' X22' wide(foil tip to foil tip) and Fire Arrow will be 19.5' LOA with a 22' beam. Both boats use three hydrofoils in the water and both are capable of using the foils to generate extra righting moment. Osprey is designed to foil nearly flat and Fire Arrow is designed to foil at a 10 degree angle of heel.
Osprey was designed by my friend and mentor Dr. Sam Bradfield who taught me a lot about foiler design but gave me the gift of his infectious enthusiasm for foiling. He passed away not too long ago.
Here is a video of Osprey:
Osprey Hydrofoil (3 min 4 sec)
Apr 13, 2015, 07:00 PM
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Nice video - and boat.

Doug - I'm still not understanding the concept of having a need for a foil borne boat to be so wide for stability. I'm not sure why, but what is it that prevents a more narrow boat from successful foiling? While at the start of the "foiling fun craze - MOTH" - ???? - I could see that there might have been an idea that wider was better. But with "A" Class boats now foiling, and at 7-1/2 feet wide by 18 feet long, I'm not understanding where the wide beam is needed? After all - a Moth seems capable of foiling with a center board/foil and rudder foil - and virtually no beam, except what is needed/provided by the trampolines for skipper to add to righting moment. To me the Moth is an issue of balance - whereas any multihull - tri or cat already has the balance supported by the foils and one or two rudders. With wands (as in the video) there is no need to have issues with adjusting foil attack angles, since the wands seem to handle them. If the cross-blades are of significant size (perhaps with disadvantageous surface drag) what is accomplished by the wider stance? As for hull size/length - they still need to be big enough to carry weight of crew, rig, etc. and also to perform when winds don't promote foiling - so that is a given.

Did you ever take the MicroSAIL Foiler and 'try" to narrow it's beam? How far were you able to reduce beam but still promote foiling? If I proceed with my possible purchase of one locally here, that would be my first trial - sliding foils closer to the main hull. What would/should I expect by doing this?

Obviously Spring is finally showing up - so I'm back to considering the purchase of one of your old foilers - so thought I would ask first.

Dick
Apr 13, 2015, 07:22 PM
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Dick, on a boat like the F3, Rave and Osprey the foils are used to develop all the righting moment for the boat by way of dual ,independent wands: as the boat begins to heel the windward wand causes less lift or even downforce from the windward foil and the leeward wand increases the lift from the lee foil. You can think of it as torque about the cl axis. The further apart the wand controlled foils are the less work the foils have to do to keep the boat level-it's that simple.
Wand controlled foils can function well on a narrower cat IF the boat utilizes movable ballast(crew on trapezes) so the dual independent wands don't have to provide all the RM-like the UK "Whisper".
---
On the Fire Arrow, all of the initial RM is due to the distance the CG is from the lee ama foil. The main wand controlled foil initially develops the lift required to lift the main hull but as it's doing that it is unloading and the ama foil is automatically loading up. When the main wand controlled foil on the Fire Arrow is 100% unloaded the induced drag of the foil is drastically reduced and the main foil and rudder foil work together automatically to control pitch. Because the main foil is unloaded it has tremendous reserve power to control pitch in conjunction with the rudder T foil. However, the Fire Arrow system can be set -up to allow the main foil to do all of the above AND automatically generate downforce that can result in a dramatic increase in righting moment or just react to gusts. It may seem complicated but is actually very simple and automatic.
---
I never tried to reduce the beam of the F3 because ,thanks to Dr. Bradfield, I knew exactly what would happen: the boat would slow down because of the extra work the foils would have to do OR I would have had to add movable ballast(weight) to maintain the same "wide-stance" righting moment. It would be a serious mistake to move the foils closer together.
---
One of the cool things about the Moth is the technique pioneered by Rohan Veal-"Veal Heal" where the boat on foils is heeled to windward.
It's not just like "windward heel" on a windsurfer or any other boat: it allows the whole weight of the boat including hull, mast, sails and crew to move to windward increasing the righting moment by about 40% from straight and level.
--
Hope this helps-ask away to clarify........
====
Note to Dick ,4/15/15:
Dick, just in case you get an F3: a foiler needs to be reefed ,with respect to the true windspeed, sooner than any other boat. The reason for that is that it is usually travelling at a multiple of the true windspeed . There's a manual that went with every F3 suggesting when to reef.
Last edited by DLord; Apr 15, 2015 at 07:05 PM.
May 23, 2015, 02:28 PM
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Fire Arrow Foiler / MPX Foil System Testing and Development


Getting ready to resume Fire Arrow testing. Since last year the primary testing was in 5mph(4.34knots) or less and the boat did very well, this year will be done only in stronger wind. The original rig was designed to be reefable by rolling the bottom of the sail, but there is no need for that this year so I removed the lower panel. That allows a 20.5" section of the mast to be removed, lowers the CE of the rig and removes 598.5 sq.in. of sail area(4.16 sq.ft.). Total sail area last year was 3390 sq.in.(23.5 sq.ft.) and this year will be 2791.5 sq.in(19.4 sq.ft.).
That's an 18% reduction in total sail area.
The removed panel can be added back if required, but, from a testing perspective, I don't think it will be necessary.
-
The first two pictures show the main reefed by removing the lower panel. The second two show the sail reefed by rolling up the lower panel and retaining it with velcro:
Jun 28, 2015, 05:34 PM
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Fire Arrow


Fire Arrow, Jul 24th 2014-first full foiling, 5mph breeze:
Jun 28, 2015, 05:36 PM
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Fire Arrow


Fire Arrow, July 24th, 2014, 5mph breeze:


UptiP Ama foil:
Last edited by DLord; Jun 28, 2015 at 06:50 PM.
Jul 06, 2015, 07:35 PM
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Foiling Self-Righting Trimaran


One of the original parts of the Fire Arrow concept was to make the boat self-righting-which would make it a self-righting foiler. Many, 4 years ago, thought the idea of a self-righting foiler was nuts and ,not only that, impossible. Well, I have a problem with the test model in terms of excess weight so might not be able to effectively test the boat with the original 3.9lb keel bulb. But now I know beyond a shadow of a doubt that a foiling keelboat is possible so a foiling, self-righting trimaran is possible as well. I've known since last year that the boat will carry the weight on foils.
Heres a thread on rc groups about the Quant 23, the worlds first foiling keelboat:
https://www.rcgroups.com/forums/show....php?t=2434531
The boat was designed by Hugh Welbourn a friend and all round brilliant naval architect.(and inventor of DSS!)

Another thread about the Q23 on boatdesign: http://www.boatdesign.net/forums/sai...cow-53468.html

And on SA: http://forums.sailinganarchy.com/ind...owtopic=166624
Last edited by DLord; Jul 06, 2015 at 08:13 PM.
Jul 07, 2015, 08:52 AM
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Fire Arrow Foiler / MPX Foil System Testing and Development


First set-up with all changes including experimental aft mast, main foil flap endplates,reduced AOI on ama foils, elimination of iFlap on port ama foil, 4 full battens and reefed rig. This is her heavy air setup.
100 0722 (0 min 26 sec)
Jul 07, 2015, 08:56 AM
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Fire Arrow Foiler / MPX Foil System Testing and Development


Reefed rig, mainfoil flap endplates, full battens, mast aft experiment and more:

Jul 07, 2015, 12:00 PM
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Question: If all it does is sit on the lawn for eleven months and two weeks and doesn't sail, is it a boat or a lawn ornament?
Jul 10, 2015, 06:26 PM
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Let's see something you built


How bout it tom.


Quote:
Originally Posted by Tom Corbett
Question: If all it does is sit on the lawn for eleven months and two weeks and doesn't sail, is it a boat or a lawn ornament?


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