Comments on: the Assassin’s Holroyd foils http://foilermoth.com/blog/2010/02/01/the-assassins-holroyd-foils/ foilermoth Sun, 11 Sep 2011 21:40:53 +0000 hourly 1 http://wordpress.org/?v=3.0.5 By: Niki http://foilermoth.com/blog/2010/02/01/the-assassins-holroyd-foils/comment-page-1/#comment-474 Niki Thu, 11 Feb 2010 08:51:15 +0000 http://www.foilermoth.com/blog/?p=195#comment-474 I agree with Darren! The foils are very thin, so the drag should be very low. Becouse of this thin shape the thickness of the material looks much more than BR or Mach2 foils. So also weight is much bigger than the others. Also a reason of this is the lengh of Assassin Foils! They are quite a gib distance longer than the others. Flying high is a good advantage so hope this is also a Pus for Assassin foils! I do not have experience in strong wind conditions, but in light winds the foils are excellent! I agree with Darren! The foils are very thin, so the drag should be very low. Becouse of this thin shape the thickness of the material looks much more than BR or Mach2 foils. So also weight is much bigger than the others. Also a reason of this is the lengh of Assassin Foils! They are quite a gib distance longer than the others. Flying high is a good advantage so hope this is also a Pus for Assassin foils! I do not have experience in strong wind conditions, but in light winds the foils are excellent!

]]> By: Nico http://foilermoth.com/blog/2010/02/01/the-assassins-holroyd-foils/comment-page-1/#comment-470 Nico Wed, 10 Feb 2010 13:46:29 +0000 http://www.foilermoth.com/blog/?p=195#comment-470 Hey guys, I am the owner of the Katana. Gerold is true saying that the idea of the same system with 2 screws to assemble the foils was dated back in early 2008 with reflections from Olivier Gouard designer of the foils for Katana and Sabrosa moths. What happened to me on the Katana is the loss of the main foil during the first Katana sail in only 8 knots of wind and the loss of the rudder foil in 25knots wind at UK Nationals 2009. So I had to face this major breakage with our system mainly because the screws were only 10mm inside the main foil and mounted with helical coil thread insert. To fix it, I had to glue with structural epoxy both main and rudder foils to the vertical parts. Now the foils are definitely fixed and it is really really strong ! I think Olivier had not such problems on his Sabrosa with the same foil system. So I don't know the load amount calculated with the Holroyd foils, but you should be very careful to the length of the screw going inside the vertical part to be sure the fixation is strong enough. Cheers Nico Hey guys,
I am the owner of the Katana.
Gerold is true saying that the idea of the same system with 2 screws to assemble the foils was dated back in early 2008 with reflections from Olivier Gouard designer of the foils for Katana and Sabrosa moths.

What happened to me on the Katana is the loss of the main foil during the first Katana sail in only 8 knots of wind and the loss of the rudder foil in 25knots wind at UK Nationals 2009. So I had to face this major breakage with our system mainly because the screws were only 10mm inside the main foil and mounted with helical coil thread insert.
To fix it, I had to glue with structural epoxy both main and rudder foils to the vertical parts. Now the foils are definitely fixed and it is really really strong !
I think Olivier had not such problems on his Sabrosa with the same foil system.

So I don’t know the load amount calculated with the Holroyd foils, but you should be very careful to the length of the screw going inside the vertical part to be sure the fixation is strong enough.
Cheers
Nico

]]> By: Darren http://foilermoth.com/blog/2010/02/01/the-assassins-holroyd-foils/comment-page-1/#comment-268 Darren Fri, 05 Feb 2010 02:34:09 +0000 http://www.foilermoth.com/blog/?p=195#comment-268 believe me there is a lot involved in getting the foot just right without adding too much drag, our foils are very very thin. But in the lower wind range no torpedo is unbelievably fast and worth the work. check out sam and andrew brown testing in no wind, they were sailing at about 3 knots until they pumped the boat onto foils. http://www.youtube.com/user/Assassinmoth believe me there is a lot involved in getting the foot just right without adding too much drag, our foils are very very thin. But in the lower wind range no torpedo is unbelievably fast and worth the work.
check out sam and andrew brown testing in no wind, they were sailing at about 3 knots until they pumped the boat onto foils. http://www.youtube.com/user/Assassinmoth

]]> By: NW http://foilermoth.com/blog/2010/02/01/the-assassins-holroyd-foils/comment-page-1/#comment-267 NW Thu, 04 Feb 2010 21:47:18 +0000 http://www.foilermoth.com/blog/?p=195#comment-267 Hi Darren, thanks for the response! The BR/Mach2 "mortise and tenon design " interface has (to me) some intuitive integrity because of the amount of material that needs to deform for a failure to occur when doing a cantilevered load test like the photo showed. The (so far as i can tell) "flat strip/tab" ( shallow mortise, shallow tenon?) design that the assassin and katana images have seem to me to lack that deformation volume. In my head I anticipate the "tabs" prone to buckling if they fail - but I really haven't seen pictures of the intersection of the foil and vertical close up to really understand it.... So I'll readily accept that all my instincts are probably and completely plain wrong. I believe you about the potential massive loads that have to be endured by any successful foil assembly. Consider the momentum of a hull and 80kg sailor at 25 knots... coming to an instantaneous stop. Hi Darren,
thanks for the response!

The BR/Mach2 “mortise and tenon design ” interface has (to me) some intuitive integrity because of the amount of material that needs to deform for a failure to occur when doing a cantilevered load test like the photo showed.

The (so far as i can tell) “flat strip/tab” ( shallow mortise, shallow tenon?) design that the assassin and katana images have seem to me to lack that deformation volume. In my head I anticipate the “tabs” prone to buckling if they fail – but I really haven’t seen pictures of the intersection of the foil and vertical close up to really understand it…. So I’ll readily accept that all my instincts are probably and completely plain wrong.

I believe you about the potential massive loads that have to be endured by any successful foil assembly. Consider the momentum of a hull and 80kg sailor at 25 knots… coming to an instantaneous stop.

]]> By: Darren http://foilermoth.com/blog/2010/02/01/the-assassins-holroyd-foils/comment-page-1/#comment-266 Darren Thu, 04 Feb 2010 21:32:47 +0000 http://www.foilermoth.com/blog/?p=195#comment-266 NW Doesn't really prove much that picture, we do regular tests the same. We have broken foils testing on the water that handle more than 90kg tip load in the above asymmetric testing. If you ventilate one side and round up inducing more AOA quickly, the loading is absolutely massive. We will be doing some destruction testing soon, we will get some video, but we are expecting well in excess of 100kg on one tip. NW

Doesn’t really prove much that picture, we do regular tests the same. We have broken foils testing on the water that handle more than 90kg tip load in the above asymmetric testing. If you ventilate one side and round up inducing more AOA quickly, the loading is absolutely massive.

We will be doing some destruction testing soon, we will get some video, but we are expecting well in excess of 100kg on one tip.

]]> By: NW http://foilermoth.com/blog/2010/02/01/the-assassins-holroyd-foils/comment-page-1/#comment-262 NW Wed, 03 Feb 2010 20:56:43 +0000 http://www.foilermoth.com/blog/?p=195#comment-262 The acid test is the mach 2 "castrate the builder if it fails test" as seen here: http://www.mach2boats.com/images/stories/foil%20bedn%202.jpg if assassin or katana could/would post a similar picture it would clear up some doubts... The acid test is the mach 2 “castrate the builder if it fails test” as seen here:
http://www.mach2boats.com/images/stories/foil%20bedn%202.jpg

if assassin or katana could/would post a similar picture it would clear up some doubts…

]]> By: Gerold http://foilermoth.com/blog/2010/02/01/the-assassins-holroyd-foils/comment-page-1/#comment-261 Gerold Tue, 02 Feb 2010 21:03:56 +0000 http://www.foilermoth.com/blog/?p=195#comment-261 Hi Felix, here I have to disagree with you: > The main foils jont is very unique as it connects on a wider area and features two screws. Olivier Guard (Sabrosa) was/is using exactly this type of joint since before the worlds in Weymouth 2008. His foils are used for his own Moth design and also for the Katana. You can see it on his schematic video at around 00:27. http://vimeo.com/3366064 Cheers Hi Felix,
here I have to disagree with you:
> The main foils jont is very unique as it connects on a wider area and features two screws.
Olivier Guard (Sabrosa) was/is using exactly this type of joint since before the worlds in Weymouth 2008.
His foils are used for his own Moth design and also for the Katana.
You can see it on his schematic video at around 00:27.
http://vimeo.com/3366064

Cheers

]]> By: Darren http://foilermoth.com/blog/2010/02/01/the-assassins-holroyd-foils/comment-page-1/#comment-256 Darren Mon, 01 Feb 2010 23:43:02 +0000 http://www.foilermoth.com/blog/?p=195#comment-256 Hey Felix, The upper wing bar tie downs go over fwd strut and down around opposite lower wingbar. Also try rolling tiller over, looks like one slot is wider than the other. ps, you never showed how skinny the Holroyd's are! Cheers Hey Felix,

The upper wing bar tie downs go over fwd strut and down around opposite lower wingbar.
Also try rolling tiller over, looks like one slot is wider than the other.

ps, you never showed how skinny the Holroyd’s are!

Cheers

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