Reference Keith Mitchell's question in an earlier post ...
"Also, I noted your comment about controlling fore-aft stability by designing a very forward CoG. Again, based on your illustration, the relatively small size of the sponsons in relation to the craft overall and the projected weight, how have you overcome possible forward buoyancy issues and problems arising from a reluctance to plane - somewhat K7-like before the cobbled-on tail-weight 'solution' -------?"
Keith, I can't give away all our trade secrets but I'm happy to share some information that you will hopefully find helpful. Throughout the three-year period of very intensive activity which culminated in Quicksilver's design configuration being finally settled in December 2007, the team used software that allows us to see how much of the boat will be in the water in the displacement condition, and where the static water-line will lie (in other words, what the static trim condition will be). This has been invaluable in enabling us to predict how the craft is likely to behave as it makes the transition from the displacement condition to the planing condition.
Scale-model tests of various kinds also helped us to verify the various performance estimates.
The shape of Quicksilver, and its weight and weight-distribution, are conducive to the craft getting on the plane. It is, however, always going to be a very marginal thing to get on the plane when you are designing a boat that has a theoretical top speed of 400 mph, because the kind of boat you want at 0-100 mph is very different to the kind of boat you want at 300-400 mph.
Our boat is modular in construction, so if we have got it a bit wrong we can change it very rapidly and easily by unbolting bits from the hulls and bolting alternative bits in their place. If we have got it a lot wrong, it's not so straightforward and we will have a big problem on our hands, so we have worked very hard to ensure we'll get it right.
The only way we will find out for definite is when we have got to a position where we can finally run it on the water.
Quicksilver
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quicksilver-wsr
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Re: Quicksilver
I can answer that one right away, Mike, because it is a burning issue for a lot of people and a lot of folk have wondered if we are being blinded by technology and not seeing the grim truth - and that is that time is marching on and we have been at this a very long time!
When I first started on what became the Quicksilver project, way back in November 1988, I felt that a WWSR bid was more do-able than a land-speed bid, because it was pretty clear that any attempt on Richard Noble's existing record was likely to involve developing a supersonic car. A monumental job (as the ThrustSSC project subsequently proved). In my simplistic way, at that time, I reasoned that if the current holder - Ken Warby's - boat was made predominantly of wood, then surely this was a do-able type of venture that could be achieved on a limited budget and with the limited access to technology that we at that time had.
However, once I got started on the venture, working with Ken Norris, Ken set a very different tone. He felt that it had to be a technology-based project. Furthermore, he didn't seem to pay any attention to the idea of using wood, so that was my early preconceptions out the window!
There are obviously various ways to skin a cat. We have gone our route because of our project's history and because of the people we have had working on the project. That is not to say that an alternative way would not work, and the approach taken by Ken Warby illustrated that you don't need an army of design engineers or a warehouse full of supercomputers to get a WWSR.
When the Norris brothers did all that work with the Bluebird CN7 car, only to see the Americans come along and blow them away with their jet-powered cars, there were plenty who could have reasonably argued that it would have been better if the Brits had built a "backyard special" akin to Craig Breedlove's and Art Arfons' cars. But can you imagine the Norris brothers building a backyard special? Unlikely.
So the tone of our project was set a long time ago and that's the way we operate.
I wouldn't want you to run away, though, with the idea that the software I referred to in my last post was somehow on a rocket-science level. The software in question is used daily, as a matter of course, by professional hull designers the world over.
No doubt there will be more posts on the "Who needs all that technology?" debate, going forward. I don't expect everyone to agree with our approach, but there is no way we would consider changing course.
When I first started on what became the Quicksilver project, way back in November 1988, I felt that a WWSR bid was more do-able than a land-speed bid, because it was pretty clear that any attempt on Richard Noble's existing record was likely to involve developing a supersonic car. A monumental job (as the ThrustSSC project subsequently proved). In my simplistic way, at that time, I reasoned that if the current holder - Ken Warby's - boat was made predominantly of wood, then surely this was a do-able type of venture that could be achieved on a limited budget and with the limited access to technology that we at that time had.
However, once I got started on the venture, working with Ken Norris, Ken set a very different tone. He felt that it had to be a technology-based project. Furthermore, he didn't seem to pay any attention to the idea of using wood, so that was my early preconceptions out the window!
There are obviously various ways to skin a cat. We have gone our route because of our project's history and because of the people we have had working on the project. That is not to say that an alternative way would not work, and the approach taken by Ken Warby illustrated that you don't need an army of design engineers or a warehouse full of supercomputers to get a WWSR.
When the Norris brothers did all that work with the Bluebird CN7 car, only to see the Americans come along and blow them away with their jet-powered cars, there were plenty who could have reasonably argued that it would have been better if the Brits had built a "backyard special" akin to Craig Breedlove's and Art Arfons' cars. But can you imagine the Norris brothers building a backyard special? Unlikely.
So the tone of our project was set a long time ago and that's the way we operate.
I wouldn't want you to run away, though, with the idea that the software I referred to in my last post was somehow on a rocket-science level. The software in question is used daily, as a matter of course, by professional hull designers the world over.
No doubt there will be more posts on the "Who needs all that technology?" debate, going forward. I don't expect everyone to agree with our approach, but there is no way we would consider changing course.
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KW Mitchell
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Re: Quicksilver
Nigel - there is no doubt in my mind that if Ken Norris had been alive today he would have adopted a multivariate approach embracing computer analysis, scale models and empirical testing. Your approach sits well with that philosophy.quicksilver-wsr wrote:Reference Keith Mitchell's question in an earlier post ...
Keith, I can't give away all our trade secrets but I'm happy to share some information that you will hopefully find helpful. Throughout the three-year period of very intensive activity which culminated in Quicksilver's design configuration being finally settled in December 2007, the team used software that allows us to see how much of the boat will be in the water in the displacement condition, and where the static water-line will lie (in other words, what the static trim condition will be). This has been invaluable in enabling us to predict how the craft is likely to behave as it makes the transition from the displacement condition to the planing condition.
Scale-model tests of various kinds also helped us to verify the various performance estimates.
The shape of Quicksilver, and its weight and weight-distribution, are conducive to the craft getting on the plane. It is, however, always going to be a very marginal thing to get on the plane when you are designing a boat that has a theoretical top speed of 400 mph, because the kind of boat you want at 0-100 mph is very different to the kind of boat you want at 300-400 mph.
Our boat is modular in construction, so if we have got it a bit wrong we can change it very rapidly and easily by unbolting bits from the hulls and bolting alternative bits in their place. If we have got it a lot wrong, it's not so straightforward and we will have a big problem on our hands, so we have worked very hard to ensure we'll get it right.
The only way we will find out for definite is when we have got to a position where we can finally run it on the water.
Echoing other's comments, thankyou for taking the time to answer our queries. Enquirers do not always appreciate that posing what they regard as a simple question on a Forum can involve considerable time and effort to those answering it.
Keith
Re: Quicksilver
How easy it would have been to let the museologists, bureaucrats and HL-effers cart K7 off for a spot of automotive taxidermy. But that was never going to happen.
Case in point Bill-just watched a bunch of museumologists "conserving" a steam loco for display in the new Transport Museum in Glasgow-take a firebox throatplate riddled with rust like a colander,spend 3 weeks gently hand rubbing it with a 2"brass wire brush,then coat it with preservative-result?-a holed firebox which could have been repaired in 1/100th of the time with a grinder,some steel plate and a mig!-end product? a "mummified" loco which has no chance of ever steaming again and will never sound,smell,or be able to perform it's intended purpose-how sad
"I hate two faced people-don't know which face to punch first!"
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Renegadenemo
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Re: Quicksilver
A brass wire brush, eh?
Don't fret, they'll have to revisit that soon enough because brass is very soft and made of three metals all dissimilar to the steel of the firebox. They're clever, these museologists.
Don't fret, they'll have to revisit that soon enough because brass is very soft and made of three metals all dissimilar to the steel of the firebox. They're clever, these museologists.
I'm only a plumber from Cannock...
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
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quicksilver-wsr
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Re: Quicksilver
The "dissimilar metals" problem don't just afflict restoration projects, of course. It is something any "new build" design team must constantly bear in mind, and accommodate with workable solutions, to avoid future problems with corrosion.
Not only do many materials corrode, over time, just by being in contact with one another, but they also expand at different rates when exposed to the inevitable temperature variations seen in operational service.
On Quicksilver we have a high-tensile steel spaceframe made from tubing manufactured in the same factory (Accles & Pollock, Oldbury, West Midlands) as Bluebird K7's. Whether we end up putting aluminium skin on it as the Norris brothers decided to do with Bluebird in the 1950s, or go "high-tech" with carbonfibre skin instead, in both cases those materials have a different coefficient of expansion to steel, so there are all kinds of interesting challenges relating to maintaining watertightness.
All part of the fun.
Not only do many materials corrode, over time, just by being in contact with one another, but they also expand at different rates when exposed to the inevitable temperature variations seen in operational service.
On Quicksilver we have a high-tensile steel spaceframe made from tubing manufactured in the same factory (Accles & Pollock, Oldbury, West Midlands) as Bluebird K7's. Whether we end up putting aluminium skin on it as the Norris brothers decided to do with Bluebird in the 1950s, or go "high-tech" with carbonfibre skin instead, in both cases those materials have a different coefficient of expansion to steel, so there are all kinds of interesting challenges relating to maintaining watertightness.
All part of the fun.
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Renegadenemo
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Re: Quicksilver
Personally I'd not go near carbon for a one-off boat. It's just too difficult and costly to mess with compared with good old tin and if choccie sauce is good enough to keep the juice inside Airbus fuel tanks as well as putting a stop to all dissimilar metal woes it would seem sensible to splash some of that in the gaps too.
I'm only a plumber from Cannock...
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
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quicksilver-wsr
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Re: Quicksilver
Bill, noting your comment alongside the current Pic of the Day about K7 not being symmetrical about her centreline ...
Readers might be interested to know that this is something we have to be very careful about with Quicksilver, because if the exterior skin of the craft is not symmetrical about the centerline - and if the engine, too, is not pointed precisely along the centreline - the boat will be constantly "fighting" the rudder control inputs that try to maintain a straight course along the lake.
Since rudders do, in any case, contribute massive drag for water-speed contenders, rudder control inputs inevitably create even more drag, and excessive rudder use can create so much drag as to prevent a boat from achieving a record.
At lower speeds, of course, it's not too much of a problem, but at very high speeds the rudders should ideally be doing very little turning or correcting, otherwise the attendant drag will spoil the speed-record attempt.
The bigger a boat is, the harder it is to build it with everything pointing in a straight line. But the laws of dynamics - and in particular, aerodynamics and hydrodynamics - dictate that you really need to do so if speeds of 300 mph-plus are the objective.
The Swiss air force kept several WW2-vintage Junkers Ju52 transport planes in service for literally decades after the war ended. One of those Swiss aircraft had one wing that was 18 inches longer than the other - the legacy of accident-damage repair, if my memory serves me right.
It flew perfectly well, though, as the Ju52 was a lovely, elegant, slow-flying aeroplane.
Readers might be interested to know that this is something we have to be very careful about with Quicksilver, because if the exterior skin of the craft is not symmetrical about the centerline - and if the engine, too, is not pointed precisely along the centreline - the boat will be constantly "fighting" the rudder control inputs that try to maintain a straight course along the lake.
Since rudders do, in any case, contribute massive drag for water-speed contenders, rudder control inputs inevitably create even more drag, and excessive rudder use can create so much drag as to prevent a boat from achieving a record.
At lower speeds, of course, it's not too much of a problem, but at very high speeds the rudders should ideally be doing very little turning or correcting, otherwise the attendant drag will spoil the speed-record attempt.
The bigger a boat is, the harder it is to build it with everything pointing in a straight line. But the laws of dynamics - and in particular, aerodynamics and hydrodynamics - dictate that you really need to do so if speeds of 300 mph-plus are the objective.
The Swiss air force kept several WW2-vintage Junkers Ju52 transport planes in service for literally decades after the war ended. One of those Swiss aircraft had one wing that was 18 inches longer than the other - the legacy of accident-damage repair, if my memory serves me right.
It flew perfectly well, though, as the Ju52 was a lovely, elegant, slow-flying aeroplane.
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Renegadenemo
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Re: Quicksilver
The wetted part of the boat is fine in terms of symmetry despite the frame being 3/8ths of an inch adrift since birth. The Samlesbury boys just offset the pointy end to put the bodywork back in the middle.
It's the cockpit rails and modified foredecks that are all over the place. It's almost as though they had Sid make one side while Bert did the other and the pair didn't like one another.
Sid and Bert did the air intakes too. They put over 6mm of shims between the formers and the outer skin at the top and grew the bottom of the inlet ducts an inch and a half for reasons they took their graves.
Worked though, didn't it...
It's the cockpit rails and modified foredecks that are all over the place. It's almost as though they had Sid make one side while Bert did the other and the pair didn't like one another.
Sid and Bert did the air intakes too. They put over 6mm of shims between the formers and the outer skin at the top and grew the bottom of the inlet ducts an inch and a half for reasons they took their graves.
Worked though, didn't it...
I'm only a plumber from Cannock...
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
"As to reward, my profession is its own reward;" Sherlock Holmes.
'It ain't what they call you, it's what you answer to.' W.C. Fields.
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quicksilver-wsr
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Re: Quicksilver
Yes, it worked - and how! ... seven records - and that's all that really counts in the final analysis.
Structures like that, with the best will in the world, are impossible to get spot-on in terms of symmetry. With all the distortion that takes place when welding along the length of the hull structure, and the cumulative effect of a hundred-and-one minor variations in the tolerances of the various fabricated parts that are added to it, it's inevitable that things will go a little askew.
No two Spitfires are identical. On each and every one there was a little bit of a geometrical variation as certain parts were "made to measure" with a rubber hammer and an assortment of hand-tools. At the opposite extreme, when they build one of today's modern equivalents, like a Joint Strike Fighter, they typically only need one tiny shim in a whole airframe!
But certainly ... back to a water-speed contenders ... it is better with a new-build boat like Quicksilver if things can be built as true as possible, because aero and hydro forces increase as the square of the speed, so the better-aligned things are, the less will be the drag attributed to rudder inputs.
Structures like that, with the best will in the world, are impossible to get spot-on in terms of symmetry. With all the distortion that takes place when welding along the length of the hull structure, and the cumulative effect of a hundred-and-one minor variations in the tolerances of the various fabricated parts that are added to it, it's inevitable that things will go a little askew.
No two Spitfires are identical. On each and every one there was a little bit of a geometrical variation as certain parts were "made to measure" with a rubber hammer and an assortment of hand-tools. At the opposite extreme, when they build one of today's modern equivalents, like a Joint Strike Fighter, they typically only need one tiny shim in a whole airframe!
But certainly ... back to a water-speed contenders ... it is better with a new-build boat like Quicksilver if things can be built as true as possible, because aero and hydro forces increase as the square of the speed, so the better-aligned things are, the less will be the drag attributed to rudder inputs.