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Old Dec 18, 2009, 03:55 AM
k4s
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There will always be resistance to one body moving thru another,that is simple physics,it will never change...However...There is a reason a needle is sharp on the leading end.
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Old Dec 18, 2009, 04:03 AM
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this is also the same reason why a hull with a narrow or pointed front section will nose dive on a downwind leg during a gust way ahead of a hull with more volume up front. thats one of the trade offs
ed
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Old Dec 18, 2009, 04:13 AM
k4s
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It didn't slice through the water it pitched and rolled just like every other displacement hull because the design was compromised by sail area and stability.

Compromise is the most important part in this.
A hull that is moving thru water using power from a lever,countered by ballast on an opposing lever,that presents a fine or sharp edge to the water will always move more easily than one which is blunt and bludgeons its way forward.A boat and its motion is a result of a combination of ideals.

No one is arguing your wrong,taken as individual ideas all you say is correct,when variables such as water viscosity,roughness.wind strength,angle of attack etc etc are thrown in the mix theory can and in most cases will change and compromise becomes essential to function at full potential.

This of course is only my opinion...I'm more than happy to be wrong and continue sailing my pointy boat.I love the way it slices the water at the bow and the way the water peels off in an almost sensual arc.

Happy sailing
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Old Dec 18, 2009, 04:56 AM
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The Physics of a needle through cloth is irrelevant but if your theory is correct sharp = speed Try dropping a needle into a glass of water and observe what happens most importantly time it. Then drop the same needle into a glass of treacle (syrup). The needle will not spear to the bottom of the glass on both ocassions in the same time, the path of the needle will not be straight in either case. The needle will leaf flutter or at least veer through the water but will probably stick into the treacle and maybe fall over, rest on the surface, whatever. but it won't slice its way to the bottom. Despite its needle sharp point, the bit after the very pointy bit, the "majority" of the body will have the majority influence.
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Old Dec 18, 2009, 05:11 AM
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Theory is a wonderful thing Robert
I'm sure as soon as it has been put into practice on an IOM design and proves successful, we will all be convinced. Some good hundreds of designers over the years have come to where we are at now in design. A few have tried the hull types you mention and they have been no better than failures. Please prove everyone wrong

p
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Old Dec 18, 2009, 05:25 AM
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My point is actually to prompt folk to think about what they are doing and understand their boats before forking out more money to come second. Given genuinely identical boats the better Helm will win, so if one arms oneself with an identical boat at best one will still only come is second, what is the point of that? If you are sailing for the sake of sailing and enjoying your boat there is no point in abiding by the rules which stop the class from being sailed correctly. Maybe within the current rules the ultimate boat has already been designed. If that is the case this is the pinnacle of the class right here right now. If 2009 was "The" year for IOM. That's a bit sad, every other class that has had it Heydey has dropped into decline thereafter. Knowingly following the lead boat round a course isn't racing and certainly isn't fun.
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Old Dec 18, 2009, 06:04 AM
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Originally Posted by pchicken View Post
Theory is a wonderful thing Robert
I'm sure as soon as it has been put into practice on an IOM design and proves successful, we will all be convinced. Some good hundreds of designers over the years have come to where we are at now in design. A few have tried the hull types you mention and they have been no better than failures. Please prove everyone wrong

p
I have seen very good boats going back 10 years, they didn't fail because the hull was wrong, they had badly set sails, poor quality sails and more often the helm and their course management was wrong. Revisit some of the broad shoulder designs that keep the rig up right and stop the bows from burying with decent set of sails and foils and I reckon that better boats are already out there. I proved in 1999 I could beat the best in our region sailing a borrowed club boat, just by balancing trimming and adjusting the sails it had. I will happily design build and race IOM when I am not expected to hang around and wait for the others to catch up, just to make it a bit fairer on them. Racing is only racing if you are allowed to not only beat the competition but humiliate them. Go sailing for fun but do not race if you are contented coming second.

I have actually pulled out the drawings I did in 1999, once the Waveney is done I might even mould one or two. If I build 2 and fit them both with switchable jib trimming who here would be happy to race me without trying the Jib trimming? I bet after the very first tack when I pull out 2 boat lengths in that tack, every single winner would be reaching for the switch. I am not interested in racing people happy to be half a pond behind me I want to out think and out sail my competition all the way to the line.

The Waveney has, waiting to be fitted, independant Main and Genoa controls with tacking and backing functions. Ever sat there head to wind, sails flapping like a Tart's Drawers while the fleet pulls further ahead? Proper sail control will sail the boat through a tack and doesn't gobble up all the boat speed to satisfy a drag happy rudder.
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Old Dec 18, 2009, 06:10 AM
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I would very much like to see Mr May put his theory into practice. If there is a club racing IOMs near him, they will likely let him come to play to compare and prove him comprehensively wrong.
Water and air are different when considering the effects on an aeroplane flying through air and a hull in water. The aeroplane if surrounded by air. Half of the hull is immersed, the other half in air. The water that has to be moved has somewhere to go, and forms waves. The aeroplane creates pressure differences in its medium. (But come to think of it, wasn't Concord rather pointy). The long pointy bow allows for a gradual displacement of the water that has to be shifted sideways, the air above allows for some upward movement. The teardrop has to move the lot in one go.
Needles rarely need a stabilising device such as a fin since in normal use they are externally directed, typically by a hand.

The difference between theory and practice is that in theory, there is no difference but in practice, there is.
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Old Dec 18, 2009, 07:45 AM
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Originally Posted by mfr02 View Post
I would very much like to see Mr May put his theory into practice. If there is a club racing IOMs near him, they will likely let him come to play to compare and prove him comprehensively wrong.
Water and air are different when considering the effects on an aeroplane flying through air and a hull in water. The aeroplane if surrounded by air. Half of the hull is immersed, the other half in air. The water that has to be moved has somewhere to go, and forms waves. The aeroplane creates pressure differences in its medium. (But come to think of it, wasn't Concord rather pointy). The long pointy bow allows for a gradual displacement of the water that has to be shifted sideways, the air above allows for some upward movement. The teardrop has to move the lot in one go.
Needles rarely need a stabilising device such as a fin since in normal use they are externally directed, typically by a hand.

The difference between theory and practice is that in theory, there is no difference but in practice, there is.
I was actually proved comprehensivley right in 1999 at a South West open meeting. My very first go on the sticks with a borrowed IOM and I was half way up the first beat before the 5th boat was across the start line, come the finish the nearest boat was only halfway up the last beat. Its 40 miles to the nearest club to here and with absolute respect to those who enjoy sailing there I would beat them again with any boat of any age just by knowing how to trim a boat and by not following them around the course like a herded sheep.

If you could choose to be in an aeroplane which would you rather be in once the engines have been turned off. The thin pointy Concorde with its wings designed for Mach 2 or an ASW 17 with its blunt nose and tapering along behind hull designed to sail through the air with no power? I'll bagsy the Glider thank you very much.
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Old Dec 18, 2009, 12:14 PM
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Exactly. The Concord was designed to go fast through its medium, knocking a hole in the air as gently as possible. The ASW is, by comparison with earlier gliders, very pointed at the front for much the same reason as opposed to something like the Franklin PS2. It also appears to have, among other things, a rudder at the back end, rather than relying on variable geometry wings.
The only way to prove your concept is to make one, with hull and other bits n pieces within the existing rules but carrying your control system, and trial it against someone with at least your own ability. Just dont forget that the IOM rules were deliberately intended to ensure long-lived designs that emphasised the skippers ability rather than his wallet.
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Old Dec 18, 2009, 12:47 PM
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There has been very little new in model boating since 1880 when folk like Dan Hatcher started extending the keels of boats away from the Hull, what i am proposing aren't my theories they are things that have been tried in the past and proven sucessful then forgotten or for those new to the sport never known about. It is easy to find proven designs that are 60 years old that incorporate the things I am trying to discuss. Most folk won't think about their modeling until someone has taken a few more quid of them with the latest radical design. IOM is about money because there is so little ability or willingness to try something new for one's self. How many folk on this forum are capable of designing their own boat? how many people here could build one? Until they have an understanding of their models they can't do either. Until they can try something for themself they will have to be content with being in 2nd place or spending lots of money.

I am deliberatly stirring the pot but that is because I see a fantastic class of boat being restricted by rules that work against their aims. They handicap the good so the mediocre don't have to try.
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Old Dec 18, 2009, 01:05 PM
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Mr May,

With all due respect I have not heard a more arrogant statement on ones abilities at radio sailing. One race does not make a summer I'm afraid!
Maybe a trip to Chelmsford, Eastbourne, Gosport, Manor Park, Bourneville or even up north to Birkenhead or Fleetwood may let you find some competition as you are indeed a cut above the rest of all IOM skippers in the UK.
Imagine the better helm winning a race? I would say most would agree that is then a fair result. Those with one dimensional boats looking for the golden egg in performance instead of moving down the path of refined development usually fail more than not. Be imaginative and creative by all means as the IOM class allows for this. Unless you are prepared to prove existing designers and sailors wrong on the water, your theories and claims are just hot air. The challenge is there.
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Old Dec 18, 2009, 01:06 PM
k4s
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With respect Robert,
You see a fantastic class of boat BECAUSE of the rules being applied.
There is no handicapping of the good skippers...the playing field is damn near even across the board.What is actually happening is that the "mediocre" are incouraged to sail well to be on a par with the good.Being a "mediocre" skipper myself, the lift I get when I get it right all the way around the course and end up at the pointy(front)end of the fleet is what makes me continue to try and improve.
When a mistake is made,even by the best,the BLUNT end of the fleet is waiting.Generally good close racing.

The rules work,as is shown by growth within the class.
The rules make it IOM
The rules are equal for all.
The rules allow experimentation.
The rules encourage good sailing........I could go on but you get the point.

If it ain't broke..
Dont fix it.
Richard
(Next time you need stitchs,ask the nurse to use the needle blunt end first,its more aerodynamic that way,might hurt a bit more however )
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Old Dec 18, 2009, 01:22 PM
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Quote:
Originally Posted by Robert May View Post
The Physics of a needle through cloth is irrelevant but if your theory is correct sharp = speed Try dropping a needle into a glass of water and observe what happens most importantly time it. Then drop the same needle into a glass of treacle (syrup). The needle will not spear to the bottom of the glass on both ocassions in the same time, the path of the needle will not be straight in either case. The needle will leaf flutter or at least veer through the water but will probably stick into the treacle and maybe fall over, rest on the surface, whatever. but it won't slice its way to the bottom. Despite its needle sharp point, the bit after the very pointy bit, the "majority" of the body will have the majority influence.
Yes, you are right, regarding the needle, although - as usual - with caveats (a lot of them). The needle will travel slower in syrup than water, the needle will eventually start to leaf and flutter, but this is not so much because of his shape (although shape also has a role) but its mainly because of friction, speed and mass (and also on the length - and angle of the path in the fluid) . I can drop a perfect symmetrical NACA airfoil projectile in the same water and syrup containes than the needle and observe the same effects or worse (a foam foil will probably float without traveling any measurable amount of space in the water - it probably will start fluttering in the air too) or a lead projectile (of the same airfoil shape) shot from a high power gun (M1 Garand) will disintegrate at impact.
That said you are probably right with the independent sail control idea, although again with some caveats - same boat, same general set up ...., being able to control the jib will make sailing smoother. This is now, and probably will be for a long time, a mute point in the IOMs because class rules, but nevertheless you should still design and build a hull according to your ideas and test it against a "regular"/"traditional" IOM, if you are correct you will be able to see speed and handling improvement regarding the sail controls. You may also consider another class to test, and prove your ideas, the M will allow the independent sail control and so will the USOM.
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Old Dec 18, 2009, 01:22 PM
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Sorry gents but I am deliberatly trying to open the discussion beyond the 1O or so folk that bother to post down here, nothing does that like a bit of extreme gaunlet throwing. The aim of the MYA was to get 2000 members by the year 2000, did they achieve that I suspect not, if they did very well done. The same names that controlled model yaching in the UK 30 years ago are still controlling it. I am only stating why I don't bother with Model Yacht Racing, Would I mind being beaten, not for one second, would I mind being proved wrong, not at all. But if someone goes away and tries something different and improves just one place in a local race that would be reward enough for me.

I have won enough plastic and silver trophies to know that winning isn't the important thing, sharing ideas with others is.
This thread is now over 100 posts long and contains more than "oooh look at my boat"
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