| Re: F16 wings
[Re: Jalani]
#219290 09/12/10 11:53 PM 09/12/10 11:53 PM |
Joined: Jul 2002 Posts: 539 taipanfc
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Posts: 539 | | | | Re: F16 wings
[Re: taipanfc]
#219291 09/13/10 12:10 AM 09/13/10 12:10 AM |
Joined: Feb 2005 Posts: 1,382 Essex, UK Jalani
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Posts: 1,382 Essex, UK | Wings can extend behind the hull - nothing in the rules says otherwise
John Alani ___________ Stealth F16s GBR527 and GBR538 | | | Re: F16 wings
[Re: Stewart]
#219294 09/13/10 01:50 AM 09/13/10 01:50 AM |
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Posts: 539 | this would work almost.. Grandfathered boats need conform to the "grandfathered class rules".. The question would then be .. Can a Tiapan 4.9 (with wings) sail in a official T 4.9 regatta as a T4.9? If not then the boat is not grandfathered and must conform to all F16 rules... Quite simple really.. True, but i could make a Viper narrower, put wings on and still meet the F16 class rules, have greater leverage and have the wings extended out the back of the boat to help "launch it" downwind. | | | Re: F16 wings
[Re: taipanfc]
#219295 09/13/10 01:59 AM 09/13/10 01:59 AM |
Joined: Jun 2001 Posts: 1,021 Australia macca
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Posts: 1,021 Australia | this would work almost.. Grandfathered boats need conform to the "grandfathered class rules".. The question would then be .. Can a Tiapan 4.9 (with wings) sail in a official T 4.9 regatta as a T4.9? If not then the boat is not grandfathered and must conform to all F16 rules... Quite simple really.. True, but i could make a Viper narrower, put wings on and still meet the F16 class rules, have greater leverage and have the wings extended out the back of the boat to help "launch it" downwind. Or, simply allow the curved boards and then you don't have ugly wings hanging off the back like an afterthought.. Sure I have the position that the class rules are too open, and encourage cheque book racing. Thats why I don't understand why the class won't allow curved boards? Every time I bring up the rules issue I get told that you all love to freedom to build your F16 how you want, yet when I point out that there is an area of development you are restricting... the excuse is that it would be a quantum change in the boat! Well hang on a second: The A class' have yet to prove that curved boards are a quantum change so why not allow the development within the freedoms of the F16 class? | | | Re: F16 wings
[Re: macca]
#219298 09/13/10 02:38 AM 09/13/10 02:38 AM |
Joined: Feb 2004 Posts: 3,528 Looking for a Job, I got credi... scooby_simon Hull Flying, Snow Sliding.... |
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Posts: 3,528 Looking for a Job, I got credi... | this would work almost.. Grandfathered boats need conform to the "grandfathered class rules".. The question would then be .. Can a Tiapan 4.9 (with wings) sail in a official T 4.9 regatta as a T4.9? If not then the boat is not grandfathered and must conform to all F16 rules... Quite simple really.. True, but i could make a Viper narrower, put wings on and still meet the F16 class rules, have greater leverage and have the wings extended out the back of the boat to help "launch it" downwind. Or, simply allow the curved boards and then you don't have ugly wings hanging off the back like an afterthought.. Sure I have the position that the class rules are too open, and encourage cheque book racing. Thats why I don't understand why the class won't allow curved boards? Every time I bring up the rules issue I get told that you all love to freedom to build your F16 how you want, yet when I point out that there is an area of development you are restricting... the excuse is that it would be a quantum change in the boat! Well hang on a second: The A class' have yet to prove that curved boards are a quantum change so why not allow the development within the freedoms of the F16 class? Let the A Class guys spend the money on R+D !
F16 - GBR 553 - SOLD I also talk sport here | | | Re: F16 wings
[Re: taipanfc]
#219299 09/13/10 02:50 AM 09/13/10 02:50 AM |
Joined: Feb 2004 Posts: 3,528 Looking for a Job, I got credi... scooby_simon Hull Flying, Snow Sliding.... |
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Posts: 3,528 Looking for a Job, I got credi... | Wings are best for the narrower Taipan 4.9s which were grandfathered in. These platforms are 2340mm wide, so can 16cm wings can be added to each side to add righting movement.
And if my intuitive maths are correct, there would be more righting movement on a Taipan with wings compared to a standard 2.5m Viper due to the Mast step being relatively closer to the leeward hull.
And in relation to the wing rule, is there anything to stop you in the rules having these wings extend aft of the hull (skiff style)? You get LESS RM as the mast is closer to the Pivot point; the leeward hull is the pivot point. by moving the mast towards it you are reducing the RM from the mast (and the hull). Cats pivot on the leeward hull. To get max RM you want as much of the mass on on the windward hull (or close to it, or further away from the leeward hull). RM can be broken down into these components (no wings) 1, Boat: 1/2 beam x mass (assuming boat is symmetrical) 2, Crew component = (beam +0.93 (average COG of a person)) x 75kg (average person weight) x no of crew on the trap + beam x 75kg x no of crew NOT trapping Now add wings (we will calc the wing RM as a step) 1, Boat RM stays the same (but remember that because the beam is MUCH less RM drops) 2, "empty wing" rm = beam + 1/2 width of wing x mass of wing. 2, Crew component = (beam + wing beam + 0.93 (average COG of a person)) x 75kg (average person weight) x no of crew on the trap + (beam + wing beam) x 75kg x no of crew NOT trapping
Last edited by scooby_simon; 09/13/10 02:59 AM.
F16 - GBR 553 - SOLD I also talk sport here | | | Re: F16 wings
[Re: Steve_Kwiksilver]
#219300 09/13/10 02:55 AM 09/13/10 02:55 AM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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Posts: 9,582 North-West Europe | Steve is correct here guys.
He's got the correct intepretation of the class rules and indeed most rules are written to be self-correcting.
Wouter
Last edited by Wouter; 09/13/10 02:56 AM.
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Re: F16 wings
[Re: taipanfc]
#219307 09/13/10 05:54 AM 09/13/10 05:54 AM |
Joined: Apr 2003 Posts: 1,669 Melbourne, Australia Tornado_ALIVE
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Posts: 1,669 Melbourne, Australia | You been on the Moth a bit too much Taipanfc.... :-P Decreasing beam from hull to hull despite the addition of wings will reduce your RM significantly. The pivot point for a cat is over the centerline of the leeward hull. By adding wings you through more beam (and weight) leeward of the pivot point. You are also brining the weight of the windward hull closer to the pivot point. Even reducing the beam by a little bit makes a big difference. So, a Taipan 4.9 would be better investing thier money into a set of wider beams, tramp and stays, forgetting about wings. If the class rules alowed a max beam and then wings, by all means go for it. If it is just max beam, increase the beam of the hulls. Jump back on a cat mate, you know you want too :-) Sorry, could not resist. | | | Re: F16 wings
[Re: Tornado_ALIVE]
#219312 09/13/10 07:14 AM 09/13/10 07:14 AM |
Joined: Jan 2005 Posts: 6,049 Sebring, Florida. Timbo
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Posts: 6,049 Sebring, Florida. | That's the Foiling Cat I've been looking for!
Nice photoshop, now, can someone make it happen for real?
Blade F16 #777
| | | Re: F16 wings
[Re: Timbo]
#219316 09/13/10 07:22 AM 09/13/10 07:22 AM |
Joined: Jul 2002 Posts: 539 taipanfc
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Posts: 539 | TA, happy to be proved wrong. But logic is that the beam width is made to be 2.5m for a Taipan with the addition of wings. So distance from pivot point is same for Taipan and Viper. But mast for Taipan is 1.17m v 1.25m on Viper closer to pivot. So effect is similar to a wheelbarrow but efforts are reversed. You can move more weight on a wheelbarrow the closer it is to the pivot point, that is the axle. You certainly moved a lot of dirt over the weekend so should have lots of practical experience . Is this logic right? | | | Re: F16 wings
[Re: Tornado_ALIVE]
#219317 09/13/10 07:24 AM 09/13/10 07:24 AM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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I'm sorry Stephen, you post contains so many errors that I don't even know where to begin. In short, if a student would submit something like that as his final report then he would have failed the course basic mechanics.
Wouter
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Re: F16 wings
[Re: taipanfc]
#219319 09/13/10 07:26 AM 09/13/10 07:26 AM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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Posts: 9,582 North-West Europe | The weight of the luff wing will also go a long way in correcting for the less then optimal position of the mast. Yes, it weights less but its leverage is also significantly more. The intent of the rules is to allows freedom of design without leading to an unfair advantage either way.
I think this result has been pretty well achieved in this case without the use of complicated rules.
Wouter
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Re: F16 wings
[Re: Wouter]
#219322 09/13/10 07:30 AM 09/13/10 07:30 AM |
Joined: Apr 2003 Posts: 1,669 Melbourne, Australia Tornado_ALIVE
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I'm sorry Stephen, you post contains so many errors that I don't even know where to begin. In short, if a student would submit something like that as his final report then he would have failed the course basic mechanics.
Wouter
Sorry Wouter, I sail rather than read about it. Can you fix it for me. By the way, if I was writing a report it would be nowhere near as crude as this. | | | Re: F16 wings
[Re: taipanfc]
#219329 09/13/10 08:06 AM 09/13/10 08:06 AM |
Joined: Feb 2004 Posts: 3,528 Looking for a Job, I got credi... scooby_simon Hull Flying, Snow Sliding.... |
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Posts: 3,528 Looking for a Job, I got credi... | Scooby_Simon, been a while since high school physics so please excuse the cloudy brain whilst i remember, but are you considering the calc as a 2nd class or 3rd class lever? If 2nd class, then you are correct, but I always thought as 3rd class. The crew is the lead weight lump at the end of the wing/lever pushing down. The force from the sails/wind/mast is on the middle of the lever pushing up. If you can move this force point closer to the point, the more effective the force pushing down.
Am i missing something? All forces balance on the leeward hull. All mass is at a distance from the pivot (leeward hull). If you JUST have a boat; you can assume the mass (in pivot terms is spread accross the boat. The windward hull is "beam" away from the pivot; the boat is symetric and so 1/2 mass of the boat is acting at the beam. If the boat-beam is reduced (because you have wings to make it back up to the same overall beam), you have less RM from the boat (1/2 mass * beam(remember smaller + (some RM from the wing). Crew provides the same mount of RM as they are the same distance from the pivot. IF you have wings on the boat, the mast is not in the middle of the boat (+wings) and so the mass of the mast provies less RM. Also; as the boat heels; the mast moves to the otjer side of the pivot more quickly and so reduced RM again. Heeling moment (from the sails) is balanced at the leeward hull. The heeling moment we are "balancing" is at 90 degrees to the RM and we balance at the leeward hull.
Last edited by scooby_simon; 09/13/10 08:08 AM.
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