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Hmmm.. Raspberry Pi

There's nothing like a bit of technology to get a geek's mouth watering.

Unfortunately, much of today's modern technology is very much "shrink-wrapped" -- hidden behind shiny plastic cases, super-tough glass screens and seemingly impervious proprietary screw-heads.

Of course a real hacker will see such things as minor distractions as (s)he dives deep under the covers to find out exactly what's inside and how it all works -- before modding it for their own purposes.

However, there's a new bit of kit about to be launched that will offer hardcore hackers and even curious onlookers the chance to get their hands dirty for a very low cost and with some potentially astounding results.

Read more...

DH Comet deja vu?

Modern airliners are increasingly being built from hi-tech composite materials such as carbon fibre, rather than the old-fashioned aluminium alloys of the past.

Composites usually consist of a reinforcement, made from carbon, aramid or glass fibers, and a binder in the form of a chemically or heat-activated resin such as epoxy.

The result is a incredibly versatile set of materials that can deliver previously unattainable strength-to-weight ratios, resistance to fatigue and other benefits. By careful selection of the reinforcement and the binder, the individual characteristics can be tailored to suit the precise application involved.

Unfortunately, although these materials have been used for decades in applications such as boats and high-performance cars - their use in airframes is still relatively new and, it would seem, is not without problems.

Recently there have been several reports relating to structural defects occurring in the new generation of composite-based airliners.

Just today, Qantas has grounded an A380 after finding cracks in a wing which is likely attributed to previously reported flaw that causes wing-cracking.

The new Boeing 787 has also encountered cracking problems, reportedly related to its use of hi-tech composite materials.

Experts acknowledge that one of the problems with composites is that they don't always give warning of imminent failure in the way that metal components do.

Although, if regularly stressed beyond its limits, some composites such as aramid (Kevlar) will start to delaminate, others, such as carbon fibre, often fail with no warning at all.

Crack-testing, a method commonly used to spot problems with aluminium components, is simply not a reliable way to pre-empt failures of many composite materials.

On the weekend I was talking with a guy who is involved in the manufacture and maintenance of composite full-sized airframes. He said that most of the time they simply use "the tap test" -- something that involves tapping the structure and listening for a change in the sound.

I guess that doesn't sound too reassuring -- but it's also the way they used to check train wheels a century or so ago.

Given the massive size and passenger-loads of the latest generation of composite airliners, I sure hope that we don't see a major crash due to previously undetected structural failure.

Personally -- I think I'd rather fly in a 747 until these things have a few more hours on them.

After all, they thought the De Haviland Comet was safe -- until they started falling from the skies with a form of metal fatigue nobody had anticipated.

Have your say in the Aardvark Forums.

Forums Are UP!

Woohoo.. better late than never (I hope).

I'm afraid you'll have to re-register and there are bound to be issues but at last we can get the discussions going again. Remember the word "aardvarkrox" when you go sign up.

The Aardvark forums.

And yes... the Sci-Tech headlines links are updated again today with some great stories!

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