Over the years I have built plenty of simple structures that I’ve wanted to be both light and strong.

Those structures vary from little brackets that might be holding something in the engine bay, to complete human-powered vehicles that I trust my life to.

In all cases, the starting point for the design is to consider the forces involved. How does the force of gravity act on the structure? What direction do braking loads act in, or short-term transient loads like suspension forces? Will this tube be placed in bending (not so good) or is it being subjected to compression (good) or extension (better)?

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Right now my confidence is at an utterly low ebb.

I have been working on my new recumbent, touring bike design and now, after almost two months of thinking, designing and constructing, have abandoned the project in its current form.

The machine has several strict criteria it must fulfil: it needs to be able to be folded into a package (say) 1 metre x 50 cm x 40 cm; it needs to be able to carry a lot of camping gear; it needs to be stable; and it needs to weigh less than 20kg. Oh yes, and as I have previously indicated, it needs to use a recumbent seat and have a lot of gears.

My first on-screen design looked a bit like this. A delta trike, it used (two and then) three air springs, allowing interconnection of the front and rear suspensions. The machine used chain-twisting front-wheel drive and rear wheels that could lean, parallelogram-style. The leaning ability could also be locked out for low speed travel.

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Regular readers will know that I am a voracious consumer of second hand books.

eBay, the Lifeline BookFest (no less than a million second-hand books for sale, and all proceeds benefitting charity!), bookshops (both new and used), garage sales – the sources are endless.

The other day one of the books that lobbed into my post office box was an orphan – a single volume of one of the Newnes Motor Repair sets of the 1950s – and perhaps the early 1960s. The book – Volume 3 of probably a 6 volume set – covers commercial vehicles, tractors and general car repairs (but the latter only the subject titles from ‘B’ to ‘E’).

I was browsing it, looking at the different designs of the (mostly) British vehicles when something suddenly hit me.

The names!

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Whenever I write a blog that makes judgments about how people choose to live, I am greeted by a paroxysm of indignant outbursts.

How dare I question the lifestyle decisions people have made?

Well, I dare to do so in just the same way as I make judgements about lots of matters: I don’t see any reason why lifestyle choices should be sacrosanct.

One of the underlying philosophies in my life has been that I believe that the paid work I undertake should contribute to the betterment of people. That does not mean that it should contribute in some massive manner, but it should – no matter how small in impact – be beneficial.

When I was a school teacher, I very much took this to heart. My love of teaching Geography – and its ability to provide a holistic intellectual framework for analysing our world – I consider to be very valuable. Therefore, I believed – and believe – that my teaching of that subject helped my students better understand their human and natural environments.

(In this I am of course not alone – in my experience, most teachers enter the profession with the implicit belief that they can help others see things in a different, better way.)

As a journalist I have also always had ‘education’ as my underlying theme.

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As I write this, I am on holidays – something that also won’t be the case by the time you actually read this!

In addition to doing four AutoSpeed stories, I’ve been spending the time cudgelling my brains over my upcoming Human Powered Vehicle project – a front-wheel drive, delta (two rear wheels, one front), recumbent, leaning trike.

I’ve looked through the articles I’ve previously done in AutoSpeed on recumbent pedal trikes (including the tadpole trike pictured above), and have been furiously scanning the web.

Recumbent bikes (where the rider sits back in a reclined seat, the pedals in front of him or her) make up only a tiny minority of bikes worldwide.

Recumbent trikes make up a small minority of that tiny minority – and recumbent, delta, leaning trike designs can be counted on the fingers. Of two hands.

Thus web searches have tended to return to the same sources, taking any one of a number of routes to get there.

As a result of the small number of web pages dealing with this topic, I have had a chance to re-read my posts to an online recumbent bikes/trikes forum, one that has a specific area for homebuilders. Before I was banned, I was almost pleading with those who had developed recumbent trikes to do some testing and measurement of their machines’ performance, so that the tiny community of scattered builders around the world could actually compare designs and see which approaches were best.

Seems an obvious request, but it was met with refusal.

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Back in this blog I mused about how little power is actually needed in a car. My benchmark was not acceleration or top speed. Instead, it was the ability of a car to climb hills at the open-road speed limit (here in Australia, 110 km/h).

Based on dyno tests and the hill-climbing performance of my diesel Peugeot 405, I decided an at-the-flywheel figure of 35 kW/tonne was about the right minimum.

I applied that idea to electric cars, where for reasons of lightness, battery power consumption and cost, an electric motor that errs on the side of smallness makes sense.

A number of comments were then made that this was completely wrong, that electric motors don’t work in that way (apparently, an electric kilowatt is different to a petrol motor kilowatt!) and so on. However, I saw no evidence that suggested a power/weight ratio of about 35kW a tonne was not the minimum for a car to be competent on the open road. (And a reasonably aerodynamically slippery car, at that.)

Recently, I’ve driven three cars that have a instantaneous power output display on the dashboard. These are all Lexus hybrids – the LS600hL, the GS450h and the RX400h. The latter’s display is shown above.

With this gauge I was able to see exactly how much power was being transmitted to the wheels, irrespective of torque curves, throttle position or anything else.

The actual power going to the wheels.

The RX400h weighs-in at 2040kg – say with my body mass, 2130kg.

Typically, I used in normal driving – even sporty urban driving – an indicated 50kW or less. That’s just a little under 24kW/tonne.

Getting into it more strongly, 75kW showed on the dial – but I stress, this was now going harder than most people would drive most of the time. That’s a power/weight ratio of 35kW/tonne.

To get 100kW (or higher) showing on the gauge, you had to be clearly pushing the car hard.

And 200kW? Full throttle and with lots of revs – completely unlike 99 per cent of daily driving.

I already know from the Peugeot that, if the car is being driven well, 35 kW/tonne is enough for open road driving – and now I know that it’s also sufficient for even quite sporty urban driving.

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I hate to sound negative but long experience has taught me that if a reader emails that they have a great story for us, the very high likelihood is that it will never happen.

About once every two weeks I get an email.

Hi, I’ve invented a new type of turbo. I am sure you’d like to cover it.

Or,

I’ve developed a breakthrough fuel – you make it yourself. You should do a story on it.

Or, even,

You haven’t done a new car test on my car – it’s a XYZ. Would you like to drive it?

On the off-chance that something will actually eventuate, I always email back a semi-polite reply.

But then the turbo man doesn’t want to send me any real-world test results, or the person who makes their own fuel suddenly goes very quiet, or the person with the new car lives in remote, outback Western Australia.

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People who have been into modified cars here in Australia have for decades known of the incredible bargains that can be had from Japanese-importing wreckers.

Because of the speed with which Japanese drivers discard near-new cars, the drivelines – or even complete front halves of cars – can be bought amazingly cheaply. Engines and gearboxes boasting late model technology, for less than the cost of having an old clunker rebuilt. It’s simple – buy a locally-delivered car and then install a new Japanese-import driveline having much greater performance. Over the years I’ve done this twice – and both times got a tremendous car for the money.

And now there’s a whole new and exciting Japanese-import field opening up.

Because Japanese manufacturers have led the world in the creation of hybrid petrol/electric cars – the first was built over 10 years ago – and because many were sold locally in Japan, hybrid car parts can now be sourced out of Japan at the same ridiculously low prices.

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I recently bought 300 old model engineering magazines.

As a novice owner of a mill and a lathe and an oxy acetylene set, I thought I could potentially get a lot out of these magazines. Plus, when I was a kid some 30 years ago, I was a member of a 5-inch gauge live steam model railway society – I have always maintained a very high affection and regard for model engineers.

But I think I’ll have to give up on reading these magazines.

Why? Well, they are just so damn depressing!

I always knew that model engineers were talented, but these guys (and they’re almost all ‘guys’) are just so good that they make me feel utterly ineffectual, ignorant and incompetent.

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