I have recently been reading some engineering autobiographies relating to the early years of piston and jet engine development.

The first, The Ricardo Story: the Autobiography of Sir Harry Ricardo, Pioneer of Engine Research, is the story of the early years of life of a man who, working outside of the major automotive and aircraft engine manufacturers, made a huge contribution to the development of piston engines.

The autobiography, which covers the period between about 1900 and 1930, is especially interesting in the technical area of fuel octane and detonation. In fact, Harry Ricardo invented the concept of fuel octane rating – the resistance that a fuel has to detonation. In those days, what made a fuel effective was not much understood – to the degree that Shell was burning off, as waste, high octane fuels! Why? Because the measured specific gravity of these fuels didn’t match what was then regarded as the requirement for internal combustion engines…

Ricardo was able to physically observe detonation occurring, using windows into the combustion chamber and a moving shutter. He was the first to realise the positive implications of high-swirl combustion chambers, the first to use water injection (unfortunately not much covered in the book), and the first to build an experimental variable compression engine.

The book is written in a flowing, readable style and – for those interested in the technical aspects of his career – doesn’t get bogged-down in personal life meanderings. It’s probably best a book for those who already know something about those early days of motoring (and aircraft – the engine technology was not much different) and want to see more into a world when so much was unknown.

Another book that I have been reading is Engine Revolutions: the Autobiography of Max Bentele. As I write this, I am part way through the book – and what a fascinating treatise it is.

Bentele, a German, started his working career in the late 1930s on turbochargers. Turbos? Yes, the world’s first. He then went on to German jet engines – along with the UK’s Frank Whittle designs, again the world’s first – before the world of German engineers came crashing down in 1945 with the end of WWII.

He then migrated to the UK and then the US, working in the latter country on – among other engines – the Wankel rotary engine. It’s now not so much remembered, but US industry was very serious about the rotary engine and did much development on this design.

As I say, I am currently only part way through this book – but it is already enthralling. The non-English native language of Bentele shows a little in his prose; at times it is a bit stilted and the text more uneasily mixes the personal and professional. On the plus side, the technical detail is very high and these aspects are also well explained.

Harry Ricardo was born in 1885 and died in 1974, while Max Bentele was born in 1909 and died in 2006. Ricardo’s name lives on in the engineering consulting company that he began, but Bentele’s name is much less well known.

Two fascinating books.

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These days I seem to spend a lot of time flying from place to place, waiting in airports and so on. I used to read a lot of books (and still do) but with a smartphone, obviously your options are much broader.

One thing I’ve been spending a lot of that time doing is watching video courses. I initially thought I’d find plenty of free stuff online (you know, where professors have put their university lectures up) and while there is some of that around, very often the production is terrible and the lectures, well, pretty boring.

But there is one source of educational material that is proving to be a triumph. It’s not free and it’s not for everyone, but I thought I’d tell you about it. It’s the company ‘The Great Courses’, that sells video and audio material that comprises exactly what the name suggests – great courses.

I first bought one – Understanding the World’s Greatest Structures: Science and Innovation from Antiquity to Modernity – a few years ago and watched it with great enjoyment.

All the presenters for The Great Courses are university professors and the sections of the course are dubbed ‘lectures’. And in effect, that’s what they are. While there might occasionally be some video snippets and photos, the lectures are mostly the lecturers talking to camera in a studio. Boring? Nope! The World’s Greatest Structures has 24 half-hour lectures that cover everything from loads and structural systems to trusses, use of concrete and great bridges.

I thought it was pretty good but when I saw that my ten year old son was choosing to watch the same series that I’d dumped on his phone, I realised that the lectures were capable of working on all sorts of levels.

Another series, and from the same professor, is Understanding Greek and Roman Technology: From Catapult to the Pantheon. This course again has 24 half-hour lectures.

And I am not kidding in saying that this series has changed my life. I was never much of an ancient history scholar and to me, Greek and Roman ruins were basically just jumbles of old rocks. But interpreting Greek and Roman history through a mechanical and civil engineering perspective has made the history come alive. We’re aiming to go to Europe at the end of the year and we are now placing ancient technology sites on the itinerary, purely through having watched this course. (Yes, we’ve watched it as a family – it’s so interesting. And I have watched it all twice!).

Interestingly, having become excited about Roman times, I bought a book on it – but it was just as I remembered Roman history, a boring coverage of a sequence of emperors. Back to the technical videos!

Which brings me to the current course I am watching – Understanding Modern Electronics. It’s pitched at an interesting level. If you are a real beginner, I wouldn’t recommend it but if you know the basics of diodes, transistors, capacitors and circuits, it’s very good. For example, while I knew you could use circuit simulators, until the lecturer was constantly using them, I didn’t understand how effective they could be. (That is, free, online circuit simulators.) I am now up to the intricacies of op amps – while I previously understood them in general terms, I certainly couldn’t then have designed circuits with them. Now I can.

All the great courses are really expensive – until you get on the mailing list and buy them when on special. For example, as I write, one of the courses listed above is AUD$75 as a video download (AUD$85 in DVD form) and at those prices, it’s a bargain. (Normally, it’s $250 and $300, respectively.)

Especially if you travel a lot (or commute on public transport), I highly recommend these courses. No vested interest – just a happy customer.

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I think that suspension design is one of the most complex areas of automotive engineering. I am not thinking here about just spring and damper rates – but those are of course hugely complex in themselves – but of changes that occur through suspension movement.

For example, a wheel experiencing bump and rebound is likely to have a designed-in change in its camber – going into negative camber when in bump. This helps keep the wheel more upright when the body rolls in cornering (or at least the outside, most important, wheel anyway).

But what about something like anti-dive geometry? This set of suspension angles causes the car’s front springs to resist compression when the car is being braked.

So how does this work? Imagine a very simple front suspension system with a leading arm per wheel – an arm that runs longitudinally to support the wheel. (A Citroen 2CV is the only car I know of with this approach, but that’s OK.) The brake is mounted on the wheel, so the torque loads of the brake are fed back through the suspension arm.

The car drives along, and then the brakes are applied. The brake load causes the longitudinal suspension arm to try to rotate around the wheel, so applying an upward force on the suspension pivot. This prevents that end of the car from compressing its springs as much – more of the car’s weight is being dynamically taken via the suspension pivots than through the springs.

The result is that the car dives less under brakes.

Now as mentioned, not many cars have longitudinal suspension arms, so this arm is often actually virtual, being in effect created by (for example) the front wishbone mounts not being parallel when viewed from the side. If they form an angle that converges towards the rear of the car, anti-dive will occur.

So anti-dive sounds great… but there are also downsides.

Under brakes, the car does not behave as many expect it to – it doesn’t dip its nose as much.

Under brakes, the suspension is less springy – more of the weight (and so vertical acceleration of bumps) is fed through the suspension pivots and not the springs.

Under brakes, in many cases the geometry is such that the wheel moves forward, so meeting bumps more harshly. (And there’s already a higher effective spring rate, remember.)

And it goes on: under brakes and when hitting a bump, the steering geometry (eg castor) may not adopt the same angles as would normally occur if anti-dive were not present… so the car may react to bumps differently when being braked.

So should anti-dive not be used? No – in cars with soft suspension and a high centre of gravity, it can be very effective.

But then again, the amount of brake dive also depends in part on the stiffness of the slow-speed bump damping provided by the shocks.

You see? Every aspect relates to another aspect: not one suspension design criterion can be viewed in isolation.

It’s all very complex….

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Automotive aerodynamics keep changing.

Recently I read a paper on the development of some late model Audis. Much of the rationale behind the aero development was as you’d expect – minimising flow separation, keeping the area of the wake low, using a smooth underfloor – stuff like that.

However, a significant amount of effort was directed at reducing the size of the vortices being shed from the angled vertical surfaces – the C pillars in sedans and the D pillars in hatchback (or wagon) body styles. After all, if the wake size has been minimised, any further reduction in pressure drag comes from controlling these vortices – the whirling ribbons of air being dragged along behind the car.

Interestingly, much of the technique in reducing these vortices occurred under the car – the shape of the rear diffuser influencing the size of the vortices that were being shed. In fact, the differences between the body shapes (eg sedan and hatch) was such that the underfloor attachments needed to be tailored to suit.

And you can see another, more visible change, in aero occurring as well.

For a long time, the trailing edge of the upper car surfaces has been sharply cut off to promote better flow separation. So think of the roof extension spoilers used on the trailing edges of hatchbacks, for example. Or boot lid extension spoilers on sedans.

However, now the focus has clearly moved to additionally promoting clean separation on the side panels of cars. Take a look at the rear three-quarters of newly-released cars and you’ll often see a vertical crease on the corner of the car. This crease causes flow separation to then occur cleanly at this point, rather than the airflow wrapping around the rear edges. In fact, one Honda Civic I saw had a small vertical spoiler mounted at this location. I thought this factory attachment looked pretty trick – and doubly so when you think of its function.

If you do a lot of driving in slow-moving traffic, looking at the different styling approaches that manufacturers are using to achieve this clean side separation can keep you entertained for hours!

And finally, the way in which front and rear coefficients of lift are regarded is changing. The traditional wisdom has been that a low coefficient of lift (eg at the rear) promotes a stable car, and that a car with a higher coefficient of lift will consequently be less stable.

However, Mazda research indicates that this may not be as valid as first thought.

The trouble is that coefficients of lift tend to be averages – rather than taking into account fast changes in lift values that may occur due to transient changes in local airspeeds. What sort of transient changes, then? Well, the wind does not blow constantly as a steady stream: it contains gusts and other fast speed changes caused by roadside obstacles (and other vehicles) creating turbulence.

It is suggested that the reason that some cars are more aerodynamically stable than others – despite both cars having ostensibly the same lift figures – is due to differing behaviour under these rapidly changing conditions.

Car aero is a fascinating subject….

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My major job – training people in business and government writing skills – takes me all over the country. Usually that involves lots of flights, but recently I chose to take the Greyhound bus between Coffs Harbour and Port Macquarie.

The bus travel was actually very pleasant – though I didn’t envy the driver threading his way through the dusk traffic on narrow roads constrained by constant roadworks.

When I was sitting in the bus, I started analysing its ride quality over the often poor road surfaces.

To cope with the large variation in possible load while still giving the best ride quality, long-distance buses typically use air suspension. (This also lets the bus ‘kneel’ as people get on and off.)

The air suspension stiffness is set to give a natural frequency of about 1Hz – the best frequency for ride quality.

And, in the bus, the ride felt about right for a 1Hz natural frequency – the absorption of large bumps was superb.

However, sitting back and admiring the flowing scenery outside the window, I thought I could feel another ride quality characteristic – and this one was not so pleasant.

Superimposed on the soft suspension movements was a higher frequency judder. It was like riding in a conventional car travelling on a road that had long wavelength bumps – but a corrugated surface.

Rather than guess any longer, I whipped out my iPhone and, using the ‘Vibration’ app, recorded the ride accelerations being experienced by the bus body. The seat next to me was empty and so I put the phone down on the cushion and gently held it in place.

Ten seconds later I had a record, and a moment after that I used the software to perform a Fourier analysis, giving the dominant frequencies in the waveform.

This showed a peak at 1Hz (the air springs) but also another peak at about 10Hz. The latter was the juddering “corrugations” I could also feel.

But what was causing this higher frequency of vibration?

The higher speed juddering was caused by the natural frequency of the unsprung mass – the weight of the suspension acting on the “springs” that comprise the tyres.

But it gets more complex. How do the 10Hz unsprung weight vibrations get through the 1Hz air spring isolation? With the forcing frequency (10Hz) so far from the natural frequency (1Hz), wouldn’t the transmission be almost zero?

I am not completely sure, but I think it has to do with the massiveness of the unsprung weight. Was that rapid shaking of the huge tyres and suspension arms feeding a vibration through the suspension mounts that I could feel?

Reflecting on this, I realised that I’d felt all this before – but to a lesser degree. In 4WD passenger cars using solid front and rear axles (ie a high unsprung:sprung mass ratio) you can feel something similar… it’s a bit like the car is being shaken by the suspension. So the soft main springing was being subverted in ride quality by the high unsprung weight bouncing on the tyres.

Here’s another point: dampers need to control suspension movement at both the suspension and tyre natural frequencies…. but the requirements for controlling each mode are quite different. One requires damping of large amplitude, low frequencies (the movement on the body springs) – and the other damping of high frequency, low amplitudes (the movement on the tyre springs).

It would be interesting to talk to a damper manufacturer about the decisions in damper design that they must be making.

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For  more than 20 years I have contributed to various hobbyist electronics magazines – including as a columnist, feature article writer and co-designer of electronic projects.

Hobbyist electronics magazines are interesting publications. Over a long period, they have evolved a business model that is based around specialist advertisers. These advertisers, often those selling electronic project kits and parts, form a major component of the income that keeps the magazine alive.

How it works is this. The staff at the magazine design a DIY project (say an audio amplifier); the businesses that advertise in the magazine source and stock the amplifier kit – and the magazine readers buy the kit from the advertisers. And while they’re in the shop, no doubt pick up a lot of other bits as well.

This is superficially all well and good – an interesting magazine is produced, the readers get access to better quality DIY electronics than they otherwise would, and the retailer prospers.

I say ‘superficially’ because there are deficiencies in having such a close relationship between advertisers and editorial content. Indeed one such deficiency has started appearing – and it’s something so major that I think it potentially spells the end of this type of print magazine.

What happens to that business model when, through eBay, you can save perhaps 80 per cent of the cost of buying hobby electronics kits and parts? To bypass the local retailer and very cheaply buy a pre-built or kit amplifier module, or remote control module, or even just parts like plugs and sockets and integrated circuits… just by going to eBay and importing them direct from China?

The cost of pursuing electronics as a hobby has just fallen through the floor – but how can hobbyist electronics magazines trumpet that? If they did, they’d lose most of their advertisers – and Chinese eBay sellers aren’t going to be stumping up the same amount of cash to take their place.  

Rather like has occurred with traditional bricks and mortar department stores, the speed of change in Web-based retail has caught-out these magazines.

From someone who likes electronics hobbyist magazines, are there solutions?

Maybe.

Moving to a purely web-based medium will reduce publishing costs – but of course, readers will need to be prepared to pay real money to access the content. (And despite all the talk, you can still expect to lose a lot of your readers if you move from print to being pay-walled web-based – consider, a loss of paying readers AND a loss of advertising income…)

Or what about just embracing the change in manufacturing and retailing? How could this work? The magazine staff design kits and modules; these are then featured in the magazine; manufacturing of them has been tee’d up in China; and they are then sold directly from that source to readers. This would give the best outcome for readers – who would have world-class electronics design along with low costs. The magazines would lose the advertising income from retailers – but they’d get more readers.

But taking this approach would represent a very major philosophical change for those who own and run electronics hobby magazines – I doubt it will happen.

In the meantime, these magazines will keep publishing as if nothing has changed, designing and featuring kits that few will  buy, pretending that electronics as a hobby is how it all was 10 or 15 years ago.

Well, to put it more precisely, they’ll keep doing this until they run out of money…

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Back in February 2011 I wrote in a blog post:

Feedback from the audience can be detailed, it can be analytical and it can be highly structured. Alternatively, it can be very simple, very quick and anonymous.

At AutoSpeed we chose the latter, giving readers a 1-5 continuum they can use to assess every page of content on the site. Because it’s simple and anonymous, many people choose to provide feedback.

In fact, as this is published, we will have received close to one million page feedbacks! One million! That’s quite extraordinary – and from a writer’s perspective, it provides immense feedback value.

Well as you may have guessed, we’re just about to pass another milestone – an incredible two million feedback ratings on our articles.

That is, 2 million times, people have paused over the 1-5 ratings at the bottom of one of our articles, and thought: hmm what will I give this?

Perhaps you’ve been inspired and excited – or perhaps you’ve been pissed off and disgruntled. Or somewhere in between. Whatever your selection, it’s been noticed and factored into the mix of material we provide you.

Most AutoSpeed readers today are not those that have been following us for the last 16 years (although you, as a reader of this blog, are more likely to be one of those ‘long-termers’) but people who drop in and out. Either way, those stats go on to form averages for each article that I, as editor, look at long and hard.

Sometimes the rating is low – and I don’t agree with it. The article in question might be one that my experience suggests that over the long term, will go up and up. (Or of course I might just be completely wrong in my assessment of the article – it still happens.)

Another time, we run an article we have published previously and the new reader ratings are just extraordinarily high – much higher than when we first published it. Was the article before its time, I wonder?

And of course, other times, the ratings reflect just what I expect.

(And the average of the two million ratings? 2.87 out of 5)

Every time you read an AutoSpeed article, I encourage you to select one of the numbers down the bottom, the ones that tell me what you thought of the piece.

That way, the number will grow to 3 million….

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I am just back from spending 5 weeks in the US.

In a few issues’ time we’ll start our USA Diary series – covering the best technical and other sights we saw.

Our previous travel diaries (based on trips to the UK and Germany) have been popular, and we had high expectations of what we would see in the US.

And we certainly saw some fantastic things – Hawaii’s amazing volcanoes, the quite unbelievably good Smithsonian Air and Space museums in Washington DC, and the extraordinarily historic place at Kill Devil Hills in North Carolina where the Wright Brothers first flew a powered aircraft.

I also very much enjoyed the Simeon car museum in Philadelphia and the Tampa Bay car museum in Florida.

But I have to say that, overall, this family of two adults and a 10 year old did not enjoy the trip.

Why not? Well, there are two ways of looking at that.

You could say that our expectations were unreasonable – or you could say that we found the US very unlike its portrayed image.

The most major dislike that we developed was for its social inequity. In the US, black and Hispanic people have a level of wealth that is not just less than whites – it’s catastrophically less.

Some figures I’ve since found indicate that the median wealth of white households is 13 times as much as black households, and 10 times as much as Hispanic households. Not double, or triple – 10 and 13 times!

In fact, the quoted median net worth (that’s total household assets minus household debts) of black households in the US is just US$11,000. That figure includes house, car – everything. That number has also declined by a staggering 43 per cent in the last 6 years.

So what?

Well to our eyes, that social disenfranchisement and impoverishment was blindingly obvious in the beggars and the homeless in every place we went. It was obvious in the pay rates (US$8 an hour for an adult working in a fast food place); it was obvious in the housing; in the mad and the mumbling unfortunates that we saw on every bus and city train we took.

Now of course in our five weeks we couldn’t travel to every square kilometre of the US, but we did go to Honolulu, Chicago, Buffalo, Niagara, New York, Washington DC, Raleigh and Orlando. In most of these cities, we took public transport to outlying centres; and we often took long-distance trains between major centres. There was plenty of opportunity to observe the passing landscape – some places were worse than others, but none were good.

There are 95 million black and Hispanic people in the US – about 30 per cent of the population. So the statistic that the median wealth of these households is under $US13,700 doesn’t apply to just a tiny minority of people – it applies to a hugely significant number of people. And all this in one of the richest countries in the world…

No country is perfect, and Australia certainly isn’t. But I can say with certainty that based on what we personally observed, and based on the reputable statistics on wealth that are freely available, Australia is vastly more socially equitable.

We found it very hard to turn a blind eye to such unjustness – as most tourists and many US residents apparently do.

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Well, it’s nearly the end of the year, and I have been reflecting on my busy car modification 12 months.

All the modifications I have done have been to my little Honda Insight.

Fitting a turbo, water/air intercooler and making and fitting a new airbox. Installing a MoTeC M400 ECU, and then doing all the engine mapping on the road. Fitting a MoTeC CDL3 dash, and then upgrading to an ADL3 dash.

It’s been a huge amount of fun turning the all-alloy, two-seater Honda hybrid into a fuel-efficient turbo with about 70 per cent more power than standard from its 1 litre, 3-cylinder engine.

None of these mods was cheap, but all gave the results I’d been hoping for.

And in the last few weeks I have been playing with the suspension. And, so far, this has been cheap! I calculated the required specs for new springs front and back, sourced them at near zero cost, then installed them. That step was very successful, so then I fitted a new rear antiroll bar – this time, for a cost of less than fifty bucks.

The car is absolutely transformed in both ride and handling – and I am yet to fit the new dampers, which at the time of writing, are on their way from the US.

Sitting in the corner is the next Insight modification – a Tritium Wavesculptor200 high voltage electric motor controller. It will be used to run the Honda’s standard 10kW electric motor, although not always at only 10kW. Given the nature of electric motors, I should be able to over-rate it for short periods, gaining perhaps 20kW for huge short-term torque.

I plan on controlling the Wavescluptor200 using outputs from the MoTeC ADL3 dash. The dash – really, a digital control system that happens to have a display – has a full range of programmable maths functions and can use 3D look-up tables.

The new high voltage battery pack and battery monitoring system? I am yet to decide on these things.

I don’t know if I will achieve my final aim of 0-100 km/h in the Sixes and fuel economy in the high Twos (litres/100km), but the challenge is enormously exciting and rewarding.

In the meantime, we’re off to the United States for five weeks. We’ll be concentrating on the eastern side of the country, and have on our itinerary a long list of technical and automotive sights – and sites. We hope to next year bring you a series in AutoSpeed that describes some of what we see.

Finally, I also published another three books this year – if you are interested, search on Amazon under my name.

Have a safe and happy Christmas and New Year, and remember: for fun and challenge, nothing beats modifying your car!

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