Posted by Jerry on May 30th, 2004 — Posted in History, Journal, Technology
After receiving a great email from Joseph Harriott with a lot of detail about the aerodynamics, I thought I’d better let you know what I have found with the models. I have read in several sources that leonardo probably got his idea from a flying toy that has been traced back to about 100 years before Leonardo’s time. One can only guess at the way the toy was made, but it was likely to have been a version of a propellor on a stick or straw (perhaps bamboo). The email pointed out that IBM have built a version based on Leonardo’s drawing and he pointed me in the direction of the site related to the Pierre Gianadda Foundation’s Leonardo exhibition.
So to my version. Firstly, using an idea from a spinning top for propulsion, I made a basic model using thin dowel and cardboard. I tried using a disc with a slit cut and one side turned up and the other down – this resulted in a blast of air, but insufficient lift. then i added a further half circle and was quite amazed at the increase in lift. The model as shown lifts off for short hops. That is, it lifts itself clear of the launcher, rising about a foot or so (about 30cm) before landing on its point and falling over. I also tried considerably larger rotors cut from the lids of two pizza boxes, but found that there was too much inertia for the rest of the model, and I broke several strings, and then switched to fishing line – but that broke the main vertical shaft. So back to the original design, but I shall try larger ‘system cards’ for the rotor. I’ll let you know how I get on. Meanwhile – here is the basic model:
My model of Leonardo’s helicopter
Cheers
Jerry
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Posted by Jerry on May 14th, 2004 — Posted in History, Journal, Travel, Writing
The Brits have a real penchant for anything related to the Arthurian legend and the quest for the Holy Grail. And now it seems that a mysterious 18th Century inscription has set people again wondering if the Grail might yet be found. Now some of the best codebreakers have got together to see if they can read the inscription – including past and present codebreakers from Bletchley Park and its present day version, GCHQ.
It may of course just be a special message to a dear departed loved one. Some of those who have begun to examine the inscription feel that it contains Classical allusions, but it remains to be seen whether there is enough of the inscription to provide a key or way into the code. The inscription is on a monument at Shugborough Hall in the grounds of Lord Lichfield’s estate in Staffordshire, UK, and The Guardian has a picture of the inscription here
Cheers
Jerry
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Posted by Jerry on May 4th, 2004 — Posted in History, New media, Technology
The internet has come up with a range of standards in relation to information about information – meta data standards. The best known of these are the Dublin Core meta data standards But the issues that led to the Dublin core standards are not new. The Rosetta Stone (196 BC) – just 200 years after Plato, and during the Greek administration of Egypt revealed something really interesting – the existence of meta tags almost 2000 years before the Internet.
The two languages in three scripts on the stone revealed the difficulties of applying consistent language standards across an empire. Just as Web pages today specify a language an script to be aplied, so too, the Rosetta stone includes as part of the inscribed decree, the stipulation that it is to be set stone, in the three scripts: heiroglyphic, demotic and Greek.
What we have in fact is a meta data standard that specified the platform (a stel of hard stone), the language versions, the authority of the specification, (Ptolemy V), and its URL (each of the first,second and third rank temples). In web language these would look like this in the
part of the cartouche:
In other words about half of the dublin core meta data standards are incorporated into the Rosetta Stone. This must surely provide us with an insight into something fundamental about the nature of information, and the nature of official discourse. What is needed to establish the intelligibility and authoritativeness of a piece of text when it is removed from the body (speech) and placed into a third-party medium? This is not a new question – and it is the main subject of my next book …
The Rosetta Stone (in the British Museum, London)
Cheers
Jerry
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Posted by Jerry on April 30th, 2004 — Posted in History, Technology
Now here is a seriously good site – it’s a pity the slide shows are all in Italian – perhaps I could learn it during the downloads (Italian servers seem very slow) but it’s well worth the wait!
This site is an online museum display of renaissance engineers’ work housed at the Museum of the History of Science (Instituto e Museo di Storia della Scienza) and the site is divided into three main entry points: Filipo Brunelleschi; The Sienese Engineers and Leonardo da Vinci. The 3D modelling is good and there are excellent descriptions of Leonardo’s flying machines (as well as his robots, crossbows, machine elements, etc etc). There are again hints that towards the end of his life, Leonardo focussed on fixed wing gliders and hints that a student of his may have actually flown (and crashed, breaking his leg). As for Leonardo’s helicopter, while there are the usual gripes about the inadequacy of human power, it clearly points to the helicopter being derived from a well known flying toy that appears to have been around for about 100 years before Leonardo’s time. So the principle must have been okay, just a poor power-to-weight ratio.
Also, having designed a steam cannon, and several pumps – it’s a wonder that he didn’t come up with a viable steam engine as a motive power. It seems to be a case of all the elements but lacking the one concept to link them together. Other forms of power were seriously considered, such as clockwork and water power – but it seems that was one that got away lest the industrial revolution happen 250 years earlier than it did!
Cheers
Jerry
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Posted by Jerry on April 23rd, 2004 — Posted in History, Technology
Leonardo was certainly one of the greatest engineers of his time, but he was one of quite a number from whom he clearly learnt a lot. What he did accomplish was a good record of the engineering achievements, both his own and those of fellow engineers of the period – remember copyrights and patents weren’t as stringently enforced in those days – so, for example it seems clear that Leonardo borrowed fairly heavily from his contemporaries and immediate predecessors, such as Brunelleschi. And a wonderful exhibition of his work and that of his near contemporaries has been put together over several years showing a good cross-section of the achievements of the time in mechanical engineering, fluid dynamics and a whole host of conceptual groundwork for the achievements of our own time.
Brunelleschi was famous as the young engineer who solved the problem of how to build a big cathedral dome without central scaffolding (the cathedral of Santa Maria del Fiore – Florence cathedral). Along the way he devised cranes, very similar to today’s tower cranes, for shifting the stone blocks into position with considerable precision. Some excellent sketches survive of Brunelleschi’s cranes – detailed enough for working models to be built.
Brunelleschi’s crane
But possibly Brunelleschi’s greatest achievement was in the organisation of the logistics flow and workforce organisation that enabled construction to take place within a relatively narrow physical urban area and to enable construction to meet scheduled deadlines – on time and on budget – unlike so many renaissance cathedral projects! Check out the exhibition site – it’s well worth a visit
Cheers
Jerry
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