Posted by Jerry on June 11th, 2004 — Posted in Journal, Steam, Technology
Now this is something I didn’t expect to see – I’ve seen various kinds of machines built with lego, but a working steam engine made from lego is a new one on me – I’m impressed at this guy’s creativity, and what’s more, it appears to work.
Daniel Hartman has various versions of the engine, including single and double cylinder versions, and single and double acting. They use square pistons and seem to run quite well on compressed air or with a vacuum cleaner. It seems a great way to demonstrate the basics of steam engines.
This is an animation of Daniel Hartman’s double-acting twin cylinder engine The whole site is worth a close look 🙂
cheers
Jerry
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Posted by Jerry on June 7th, 2004 — Posted in History, Journal, Technology
Another quick update on my model of Leonardo’s helicopter – I have made a larger diameter rotor and achieved a couple of flights across the room. The rotor diameter is now about 18cms (about 7.5 inches) and made from cereal box card. The helix winds one and a half times around (one circle plus a half, with the lower circle split along the radius to the centre and the extra half attached with masking tape. There was some sag, which I rectified with a masking tape brace – you will notice that Leonardo’s helicopter design had string braces to support the rotor structure – I guess he had problems with sag too 😉 Anyhow here is a picture of my model (current configuration as flown). The drive is the same spinning-top launcher that I was using before.
And Leonardo’s one for comparison:
Image as displayed on the Leonardo Museum in Vinci – they also have a model based on Leonardo’s helicopter, but using fabric rotors the way Leonard’s original envisaged.
Cheers
Jerry
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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 22nd, 2004 — Posted in Technology, Travel
It’s amazing what you find when blundering around the net – This person suggests (reasonably enough) that since the Psion 5MX supports Java 1.1 then it might just support a java multimedia player. He suggests that the Psion 5MX might just be capable of playing .AVI and .MOV files. I have yet to install this, but I’ll have a play and see if I can get it to work 🙂
Anyone else tried this?
Cheers
Jerry
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Posted by Jerry on May 17th, 2004 — Posted in Journal, Technology
Even at microscopic levels its about engineering! Nanomachines (tiny machines made up of a few molecules) have gone back to renaissance machine elements to come up with simple elements that can move in complex ways – and where it doesn’t necessarily matter if you get the odd atom in the wrong place!
While nanomotors made from variations on carbon ‘buckyballs’ have been made before, a walking robot is a whole other ball game!
A series of scanning electron microscope pictures of the spinning rotor of a nanomotor fabricated in the lab of UC Berkeley physicist Alex Zettl. The entire electric motor is about 500 nanometers across, 300 times smaller than the diameter of a human hair.(Credit: Zettl lab)
Then DNA and RNA molecules have been formed into a working motor powered by the reaction by which we turn food into energy in our own bodies.
Now New York University chemists Nadrian (Ned) Seeman and William Sherman have come up with a microscopic robot made from DNA strands. New Scientist explains that the robot walks along a track – also made of DNA – which is covered in spikes to provide footholds. Of course actually seeing the robot is tricky at these sizes. But if you think of ‘seeing’ in the phenomenological sense as that which can be sensed, then these guys get around the seeing problem by looking for footprints – and finding them using a DNA ‘fingerprinting’ technique.
There will of course be many doomsayers who want to announce that this is the worst thing since white bread, I reckon the challenge will be to come up with ‘under what conditions can we…?
Cheers
Jerry’
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