Leonardo’s helicopter

Posted by jerry on November 26th, 2003 — Posted in History, Technology

Leonardo da Vinci was notorious for leaving out key details in his notebook designs – another aspect of his information security protocols (like writing backwards). But, given that at least some of his designs would seem to work, like his wooden air supply pipe for a diving helmet, it would seem reasonable to explore some of his other designs. The helicopter (yes power to weight ratio is clearly a problem) has a significant design flaw as it stands. At the moment, the pilot would push the capstan to rotate the rotor by applying force through feet to the floor. But once enough speed was achieved to provide lift, the floor would contra-rotate, leaving the pilot without anything to push against. Now picture Leonardo’s helicopter linked as a pair with a mirror image helicopter and now two pilots – they would be able to work together applying force against each other… I wonder if that might just get off the ground?



Fire twirling

Posted by jerry on November 25th, 2003 — Posted in Journal

Looks like a good day to ride the bike into work 🙂

Last night’s Irish music session began well but a drunk person put a damper on things – still the early return home meant that my daughter could test the new fire twirling stick she brought back from Melbourne…

It is certainly spectacular – and firewater gives a good yellow flame. I had a go myself and was amazed at the sound the thing makes! It was a perfect evening for it and the recent rain meant there was no danger of fire on the lawn in the event the stick was dropped.

Fire twirlers have found a niche in the folk music festivals and we have found that there is a similar sense of community among them – with plenty of common ground between the twirlers nd the musos – fire twirling is, after all, another form of dance.

The technology is simple – just an aluminium rod with a wooden dowel core in the ends, and the wicks are cotton wrapped in kevlar and screwed through the aluminium tube into the dowel – very secure. The centre of the tube is wrapped in rubber for increased grip – and to provide a good tactile signal that you are moving off-centre if the stick is out of immediate sight (eg when twirling behind your back)

The first light-up is quite spectacular as excess fuel is shed by throwing the stick high into the air and catching it – it seems to keep in line better if you spin the stick along its axis as you toss. And yes we did have a fire extinguisher on hand for safety.


Blogs and logs

Posted by jerry on November 21st, 2003 — Posted in Journal, Writing

It seems to me that blogs are a bit like digital soundings charting one’s course through an ocean of thought. How appropriate then, that the idea of keeping log books derives from a navigational technique that relied on nodal soundings to record one’s speed through the ocean. In a type of navigation called ‘dead reckoning’ the technique relied on one throwing a log, or wooden board overboard from the stern (or back) of the vessel, the board being attached to a rope. The rope had series of knots tied at 7 fathom (6 feet to a fathom = 42foot/12.5metre) intervals. Each knot, paid out from the reel over a period of 30 seconds (as measured by a sand glass) represented a speed of one nautical mile per hour. Observations were made whenever the wind changed in velocity or direction, and recorded in a book – called – you guessed it – the log book! (neat eh?) The distance (calculated by speed over time) and direction were plotted onto a chart, and thus one could navigate without recourse to the stars or a visible land mass.

The knots represent digital nodes, the wind changes: the threads of discussion or thought; the chart, the great canvas of ideas – So perhaps blogs are a kind of chart of ideas!


Majors Creek November 2003

Posted by jerry on November 20th, 2003 — Posted in Music

First impressions…

It’s raining. After a hot dry week the rain is sooooo welcome! And the motorbike brought me home without getting wet 🙂

Riding the bike is very like playing the fiddle. Just as you don’t ride a bike by steering the handlebars, you don’t play the fiddle by [merely] drawing the bow across the strings. In both cases you use your whole body. It is a question of balance and rhythm – and that is as much a function of your toes as your arms.

The celtic music folk festival at Majors Creek near Braidwood – a name that combines textile with timber – really delineated those fiddle players who were folkies from those who were classicaly trained violinists playing folk music. It is a question of feel. One violinist – a very fine musician – had a lovely tone, but seemed to be making hard work of the tunes. I suggested that this person walk while playing. Walk? Where? Anywhere! – even on the spot if you need to read the music dots! The music needs to flow from the way the whole body moves and feels the music.

Jigs – dancey pieces with six beats to the bar (or sometimes nine or twelve) – the best way to play those is to play the first two notes of the bar with a down-bow, and the next one up-bow – two down, one up and continue like this throughout the tune – this will guarantee (depending on decorations etc) that you will have a slightly stronger sound on the first beat in every bar – and the whole tune will have a dancey feel to it.

Reels – God they can sound boring if you keep it all even stresses – I treat them like polkas – yeah really! play the notes in pairs – two for each direction of the bow, and play them with a jaunty bounce – a kind of dah de dah de dah, rather than a dededede – and straight away they will have more life in them.

It was a great weekend – perfect weather, great sessions, and great Guinness!

Highlights were bands like “Mothers of Intention”, “Toe sucking Cowgirls” – nice harmonies in both – good arrangements in the first one. The fiddle workshop with Jane Brownlee was a real highlight, and the session later on Saturday night was awesome!

Jerry (with the 8-string hardingfele/hardangar fiddle)