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Diary Jan/Feb 2013

I once spent a morning with a high-falutin’ barrister from some stupidly expensive London chambers. I was due in crown court as an expert and he wanted me up to speed before some equally expensive defence barristers got their teeth into me and ruined his case. But he wasn’t with the programme himself because he’d been drafted in at the last moment to replace another who’d gone sick and wasn’t in the least bit au fait with such things as GPS navigation and sonar systems, so, on arrival he was given a three-quarter-inch-thick sheaf of papers to learn and chucked in at the deep end. This he flopped onto the desk, having bid a hurried hello, and proceeded to strum through it at impossible speed with one hand like Johnny-5 soaking up ‘input’ whilst making coffee with the other. Still reading, he struggled free of his overcoat and jacket then lowered himself into a seat and sipped his brew. Twenty minutes later he looked up and started asking me questions, his coffee barely touched.

What rapidly became apparent was that, from a cold start, he’d digested every detail and was already ahead with dates, relationships, happenings and circumstances whilst I struggled from the off to keep up with him as he probed and questioned and designed his courtroom strategy. I felt as though I was in the presence of a superior being – a very superior mind, at least.

He was mind-bogglingly clever – some people just are – and when I was a kid some people were mind-bogglingly thick too, but it’s not allowed nowadays…

Youngsters of our modern age may be treated as though they’re brainless but woe betide them if ever they try to do it for real.

When I was at school we had Biggles – now where’s he got to, you may ask?

Who else read the ninety-odd, oft-preposterous volumes by Capt. W. E. Johns as a young boy and absolutely thrived on them? I did. So where is Biggles today?

Erm… bit of a problem with the do-gooders nicking our books, I’m afraid. You see, Biggles and Algy and Ginger weren’t overly fond of anything Aryan, or Teutonic and occasionally looked askance at anyone not pure-bred European either. They smoked cigarettes and women were just that in their world – women – and such thinking must be thoroughly stamped out nowadays.

You could argue that Biggles is a kids’ book and early-stage xenophobia may set in but what about Huckleberry Finn? That had our American cousins in a proper quandary for ages because one of the lead characters is named after Guy Gibson’s dog – soon to be posthumously renamed for the new movie, I’m reliably informed – but Twain’s work is part of the fabric of American society so what to do? What they did was serve up a bowdlerized version with a view to getting more youngsters into Twain. This terrible disrespect of great literature was then justified by arguing that anyone interested would soon read the original anyway therefore nothing is lost. So give them the original in the first place, you fools! How stupid is that?

Of course, modern students are utterly incapable of realising that what happened in the book they’re reading might not necessarily be real, which is why readers of Harry Potter are often scraped off the front lawn with a smashed broom wedged up their sphincter and so much as a sniff of Macbeth causes whole classes of English literature students don tartan skirts and start unseaming innocents at the bus stop from the nave to th’ chops. See what I mean about treating people as if they’re thick?

When I was at school we had swots, nerds and bookworms on the one hand and duck-eggs, thickets, dimwits and knackers on the other. Then you had the rich kids with lunch money to burn opposed by those who smelt a bit funny but were endlessly adept at parting said lunch money from the rich kids. Life was so much simpler then with the nuggets bound for grease-monkey or can-laddie duty in the pits or shipyards and the clever ones off to college to be clean people like doctors or accountants. There were those who couldn’t write their name but were good at woodwork so that was OK – joiner for him. And others who would have their leg off with a tenon saw if left unsupervised for five minutes – bureaucrats in the making, every one of those. But now look at the state of the place.

Don’t ever mention anything that sets one apart from the next. Being rich, for example, is a no-no because that makes the poor feel all victimised, and being poor is equally verboten because it has some sort of negative social stigma attached. Being blind isn’t a disadvantage; it’s just an alternative lifestyle, as is having no legs or no brain. Don’t mention religion unless you plan to include them all and if marriage is on the agenda best you work out all the possible permutations of two (and it’ll soon be three – you mark my words) humans doing the wild thing before opening your mouth. Anything vaguely different or exciting is being mercilessly bleached out of mankind during childhood in an effort to expunge even the faintest hint of stereotyping thus forging the most glorious irony... the bland, standard-issue non-person.

Their very own stereotype!

I’m afraid that little Johnny is just not allowed to be stupid any more. In fact, he’s not allowed to be anything at all. No matter that he may be a square peg, he will go into that round hole even if it means having educational psychologists look up his bottom with a microscope and extra spelling lessons though he’s clearly going to sign the marriage register with an X. Teacher will never, whatever she does, admit that Johnny won’t fit the allotted pigeonhole or be able to tick the boxes on her target.

So – here’s a simple test. Should teacher tell you that little Johnny is ‘helpful around the classroom’ you can forget about paying expensive specialists to diagnose which previously undiagnosed syndrome is impeding his path to being the next Prime Minister. I’m afraid he’s just thick as pig’s poo and will be going to work in a boiler suit.

There, that’s that dealt with…

But the reason I got to thinking about all that stuff is because learning is a strange thing that waxes and wanes and pulses like a strange light in our workshop. It no more follows a rigid set of rules than falling in love. You know… we’ve all seen it, the Perrier-bottle-shaped bloke with a goddess on his arm or the suave, surfer type latched onto something that looks like she morphed into a partridge at an early age. It’s all very peculiar and when our lot set out on a new adventure, whether it’s sorting a gas turbine or mending air intakes, we never know until we get into it just who is going to take on the job and make it their own – it just has to come out in the wash. Along this often stony path, as Donald might have described it, we’ve had to learn how to recover wrecked material, fix systems, design tooling, negotiate with sponsors, entertain our audience and now we’ve had to learn how to make sponsons from scratch but they're not just floaty boxes stuck on the sides, they're actually serious pieces of engineering in their own right, as Donald Campbell historian, Neil Sheppard explains.

I'll let Bill cover the actual build of the sponsons, what I will attempt to cover here is their history. Bluebird's two outrigged sponsons, and their attached planing shoes form the two forward planing points of Bluebird K7, and as such are responsible for transmitting significant loads and stresses to the main hull of Bluebird. Although the actual load bearing part of the sponson remained pretty much unchanged throughout their life, their appearance changed significantly as K7 was modified to extract more performance and extend it's safe operating envelope. Bluebird K7 was designed as a conventional three-point hydroplane supported on a three-point stability triangle. Unlike Crusader, however, the Ventnor convention was adopted as in previous prop-riders such as K4, i.e. two forward and one aft plane (replacing the 'prop'). There are advantages and disadvantages to this method, but in hydrodynamic terms the former far outweigh the latter. Pitching stability is improved with two planes forward, and the extreme front loadings are halved compared to a single front plane. Transition from the displacement to the planing phase is improved by the two sponsons, which increase lift forwards of the CG.1, 2 Directional control is also improved because an aft rudder can be employed, yielding better low-speed control and reduced loading because it is further from the CG than one mounted forward as on Crusader. Even more importantly, since it is behind the CG it introduces a positive stabilising moment in yaw. There are, however, also disadvantages. Firstly, the craft is prone to a phenomenon called 'tramping' whereby disturbances in the water’s surface can induce an alternate rocking movement about the axes of the stability triangle. The nose of the craft therefore describes a motion with both rolling and yawing components. This results in an overall increase in incidence (pitch-up) of the craft which is proportionate to the severity of the tramping, i.e. the tramping amplitude.



K7's upper sponson fairing's were initially shallow non-load bearing semi streamlined aluminium structures with a perceptible gradient running front to back, so minimise aerodynamic lift, and move the aerodynamic centre of pressure back towards the area directly above the end of the planing shoe. Following initial trails at Ullswater in 1955, when K7 proved unable to successfully plane, it was decided that K7 displayed too much aft buoyancy, and not enough at the front, and that the siting of the forward spar connecting the front of the sponson with the nose of the main hull was too low. A major redesign was called for, which involved lifting the forward spar, and alerting the pick-up point and associated fixing between sponson and front spar. This necessitated the inclusion of towers, approx. 10 inches tall to connect the two structures. The fairing's were redesigned to shroud these towers, and now incorporated two 'humps' at the junction of forward spar and sponson. This modification proved successful, and K7 was able to break the WSR 4 times in the period 1955 - 57. The modification however meant a deterioration in their aerodynamic lift characteristics, making Bluebird more prone to pitch up, and lowering the angle of pitch at which K7 would take off. With this in mind, as the speeds got higher, in 1958, the Norris Bros, in conjunction with Prof. John Stollery decided to redesign the upper part of the sponsons, to incorporate deeper fairing's along their full length, and rid them of their unsightly hump. This not only improved the look of K7, it also had a significant effect on reducing front end aerodynamic lift. These were cleverly designed by Ken Norris so that their upper surface presented a negative incidence to the air stream, thus increasing aerodynamic download and reducing lift, which was reduced by nearly 60% at level trim and by ≈35% at = 6° pitch. This configuration proved very successful at raising Bluebird's safe operating envelope beyond 250mph, and remained essentially unchanged for the rest of K7's life. It is interesting to note that K7 suffered the odd ding throughout its life, and the sponsons, and spars being outrigged from the main hull, and therefore exposed suffered more than the rest of the boat. The Starboard sponson aft fairing was creased in 1957, during her transit back from the USA, and in December 1966, K7 suffered two bird strikes which afflicted both port side spars.



The surfaces in contact with the water in a hydroplane referred to as 'planes', 'shoes' or 'wedges' and their design is of crucial importance to the craft. They need to produce maximum lift to support the weight of the hydroplane, but to do so with a minimum of drag to allow the craft to achieve the highest speed possible with the thrust available. The surface area of the planes in contact with the water, the so-called 'wetted area', and their immersion depth depend on the angle the wedges present to the water’s surface and on speed. As speed increases, both the wetted area and immersion depth reduce as the upwards force required to support the weight of the boat is generated by 'sweeping' across a greater surface area of water in any given second. At very high speed, the wetted area is relatively small, around 10–20 square inches, and the immersion depth is around 0.1". The planes have a flat profile As Bluebird's planes were flat, they had a dead-rise angle of zero degrees. Because of the very high and frankly bludgeoning forces, the planes need to be very strong. They also need to be very rigid so that they maintain consistent planing performance in the face of severe buffeting. Additionally, their design was such that they minimised pitching oscillations (porpoising) if the craft encounters disturbed water. The specific hydrodynamic data to design the wedges were derived from NACA technical data.On the basis of the expected loadings, the angle of attack of the front wedges was chosen to be 3.75° and the rear 2.5°. The length of the wedges was designed to be 72" and their width 12". This configuration resulted in a theoretical drag/lift (D/L) ratio of 0.08.13 The reciprocal of this ratio L/D is therefore 12.5 and is defined as the 'planing efficiency'. This figure means that the planes produced 12.5-times as much lift as drag. However, in discussions between the Norris brothers and Tom Fink it was felt that the planing efficiency would, in practice, be lower than this.



Following Bluebird’s crash, Ken and Lewis Norris and their associates performed extensive analysis of the crash itself and the performance of the craft on the final run.Included in this is a detailed re-working of the calculations of lift and loadings at the planes in the light of more up-to-date NACA technical data published in 1957. At a speed of 312 mph and a loading of 1,780 lb for each front plane and 1,070 lb for the rear, the wetted area for each front plane was 13.2 square inches and 12.6 square inches for the rear. The immersion depth was a tiny 0.072" at the front and even less at the rear, 0.046". From this, it is possible to conclude that the wedge angles were too steep for optimum performance of the craft, particularly when operating at speeds in excess of 300 mph. It is important to reflect here that the original Bluebird K7 configuration was designed in 1954 on the basis of planing data available at the time.It could be argued that the sponson fairing redesign in 1958 offered an ideal opportunity to make modifications to the wedges, but perhaps this was not considered because K7 appeared to be performing very satisfactorily during that period. Also, Bluebird only had an anticipated life of a few more years and, perhaps, two more records. In addition, it would have involved significant engineering effort – and considerable cost – to carry out the work at a time when Campbell was focusing all-out on his Bluebird CN7 LSR effort.



A full description of K7's structure, and the forces acting upon the boat can be found in my book, Donald Campbell, Bluebird and the Final Record Attempt.

*

Creating the sponsons has been a very long job, in actual fact it began way back in 2006 as soon as the boat was donated, lock, stock and barrel to the museum. At last that gave us the security to crack on with the expensive stuff.

But the first problem was understanding exactly what had to be built. It’s easy enough to look at the pictures and think you get what’s happening but in all the time we’ve been doing this we’ve only ever found a handful of images offering clues to what goes on inside a sponson and not one of those tells the complete story. Then we had a heap of drawings that only served to confuse. The sponsons were drawn several different ways, as were many parts of the machine. There’s multiple ideas for such items as the main frame, spars and planing wedges and with the boat fully clothed you’d never know what was inside. That wasn’t a bother with the main hull and spars because we could simply have a look but it didn’t help much with the sponsons. Then there was the theory that the original sponsons were still in existence, buried somewhere on the old Norris Bro’s site at Burrell Road. Now wouldn’t that be nice – if someone could just take us to wherever that’d happened and we could dig them up. But we never really bought into that theory.

Think about it, a pair of 13ft canoes, each one so heavy that it’d take a couple of blokes to lift it and made of scrap metal that could be readily turned into cigarette and beer tokens. Imagine the size of the hole needed to bury them. It’d take a few blokes a few hours with time enough to wonder why they were burying money and surely there’d still be someone around to tell the tale who wasn’t counted in and wished they had been.

Those sponsons are in the foundations of the new building, we were told. So what did the building inspector have to say about that? It’s a nonsense to suggest that anything of such material value would have been binned by working men then or now.

Another tale had them vanished in the night when half of the yard was sold off to Ready Mixed Concrete leaving them marooned on the wrong side of the fence. Ex-Norris Bro’s employees were extensively interviewed in the quest for clues and gradually the most likely account was pieced together. It seems that towards the end of 1967 (as Christmas approached and the staff wanted a few extra quid) the sponsons were lying about the place as was the fuselage and wings of XM691 so it was suggested that the whole shebang be carted off to Coley’s scrapyard and weighed in. Ken was consulted and agreed and a day or two later a truck arrived and took it all away. In fact I knew all of this already because back in 2001 I’d asked Ken what happened to the sponsons and he told me they’d gone for scrap. So, barring a miracle, the originals are long gone and are probably in our fridges at this very moment wrapped around Coca-Cola and supermarket lager. Never say never, mind you, and in the meantime we had a couple of corners missing off our boat. It was time to get down to business.

It soon became apparent that at least one constant ran through all the available design data – the sponsons are rectangular in cross-section and along their whole length is stationed a series of bulkheads of varying sizes, while running down each corner is an aluminium extrusion in the form of a 90 degree angle formed to follow the sweeping contours of the sponson. If you took a slice through the middle of a sponson this is what you’d see.



Those extrusions became our first problem. You see, they’re a non-standard size and even if they weren’t they’re certainly not available in the material specified. It was easy back in the day because Britain was developing the V-bombers and everyone in the alloy business was vying with one another to be the top supplier so just about every conceivable grade was readily available in every possible size and section. Fast forward half a century and you can have about six sizes in five grades and get around that in the design stage, Mr Designer.

Well that was no bloody use! Try to rationalise what was specified to what’s available today and you may as well start from scratch and design the sponsons all over again. What people seldom realise is that each sponson is a small boat in its own right with its own weight and balance considerations and it has to perform accordingly. You’d never dream of rebuilding an aircraft for flight by throwing whatever was available into the wings, would you. It was actually easier to go in search of the real material than to start thinking about how to redesign the parts with modern stuff so that all the numbers stacked up.

So where to buy inch and a half by inch and a half by three-sixteenths angle-bar in DTD 363D alloy? It simply doesn’t exist.

The answer was surprisingly simple – have it made. It sounds ambitious but in actual fact it turned out to be quite straightforward. We were put in contact somehow or another, I forget now, with a bloke called Pete Isom at his company, Transtar Metals. Pete could not have been more helpful. He speaks fluent metal and it wasn’t long before we were talking to a mill in California, which seems to be the aerospace alloy capital of the world, by the way. All we had to do was pay for the tooling and, in exchange, they would ship us eight extrusions of the required section in the preferred material. They got to keep the extrusion dies and we got to keep the material and everyone won. In the end the material worked out at about a hundred quid a length and it was exactly what was specified on the shopping list.

Result.

Next came the sides, bottoms and tops for the sponsons, which are just big, rectangular boxes, at the end of the day, but they’re almost thirteen feet long too and that’s a smidge over your average 8ft sheet. In fact, nowad