Readers' Submissions

Mental Meanderings

  • Written by BAH
  • May 12th, 2012
  • 10 min read

Recently there have been a few subs talking about how bad the country of Thailand is. In many subs there is often an undercurrent of ill feeling. My personal experience with the place involves a love / hate relationship, and I think this
is reflected as mirror image in the place I come from – I have love / hate feelings about there as well, often with the love / hate being 180 degrees apart. In my case I love my country of birth (Australia) but in some ways it's
not too attractive, my advanced years telling here. It's . . . boring, it's insular, there are too many rednecks, politics is a shambles in recent years – you can't trust any politician to deliver or for that matter to be honourable.
The press has gone mad, they are a bunch of sharks who couldn't think analytically to save themselves. It's expensive to live, old people are invisible, and for one experienced with travel in South-East Asia, it doesn't offer
enough (any) err. . . sensual pleasures. In Thailand if I'm a bit bored of a night, any night, I can walk out the door and be totally entertained for as long as I like – have a massage, visit a bar, or just watch. In my country
town in Aus if I walk out the door on a Friday night I can take my AK47 with me and spray the whole town – I won't hit anyone – this is true. And it's not like it's a small town either!

So a visit to Thailand is good – lifts me out of the doldrums, gets the blood pumping again. But hang on a moment, it's also a fact that towards the end of my last trip (3 months) I had the feeling that I'd had enough
for a while. Things were getting me down, dogs were getting me down, the roadside rubbish and general filth was getting me down, the lack of sanitation in public places (e.g. those towels in public toilets for Christ’s sake, what more
efficient way is there to spread disease? I don't touch them, but it's depressing that local people think it's OK). The broken footpaths, the eye level awnings, the motorbikes parked wall to wall on footpaths, the vendors and
builders using the footpath as convenient places to carry out their business. I went for a walk at 7 AM before the vendors and motorbikes had arrived – it was really refreshing to have a clear walkway. The constant bad behaviour on
the roads and police indifference to it. The lack of government systems, especially a reliable justice system. The constant feeling of being the odd man out, and the noise, noise, noise, oh Jesus, you can't escape it. Of course many of
the things I don't like about Australia these days exist in Thailand as well – for example you can't trust any Thai politician to deliver or for that matter to be honourable, worse than in Australia because at least we have
a justice system and government systems that work moderately well to keep the bastards honest.

Getting around Thailand is a problem for me. Trains are cheap and safe, and even though the trains themselves are rubbish, the service is crap and infrequent, it is my conveyance of choice – kinda restricts the variety of destinations
though! Taxis are an option for medium distance travel, not too expensive, but even there I've had to tell the drivers to restrict their speed and stop lane changing, motorbikes very dangerous, tuktuks short distance only and also dangerous.
Private car? OK if your woman has one, I refuse to drive in the place – read too many horror stories. Buses?

The irresponsibility of bus drivers. OMG. Let me tell you about my last trip on a bus in Thailand. It was from Korat to Bangkok – first leg of my trip home. I fronted up to the bus station, bags, bike-in-a-box, not in a position
to be too picky about what bus I selected. Bought a VIP ticket and was shown upstairs to my least favourite seat – front left-hand side – gotta be about the most dangerous place to sit on a bus 'cos when it falls over that
concrete electricity pole is comin' right at me! Another unfortunate aspect of that location is that I can see the driver (using his mobile phone) and in particular I can see the speedo. The driver is carrying on his shoulders the lives
of 50 or so people, but he's driving the thing like it's his own personal transport. He's lane changing, jerking on the wheel so the bus rocks alarmingly, he's charging up behind other vehicles way too fast so that if they
don't get out of the way when he honks he has to stand on the brakes, he's taking to the side of the road to pass other traffic, in short he's an irresponsible prick who should be banned from the road. Passenger comfort is a
concept he just hasn't ever thought about, let alone been trained in. And tell me, why does the steering wheel move 30 degrees in each direction before the bus responds?

One part of the trip Korat-Bangkok passes through an area north of Saraburi which is hilly and the road bendy. I freaked out here because the driver was taking risks with our lives to a greater extent than I've witnessed previously.
On the downhill sections he was driving foot to the metal, the speedo was hitting its stop at 120 km/h and we were still accelerating, I'd guess to at least 130 km/h (I shouldn't have looked at it but it's one of those visual
attractants you just can't resist, like cleavage but not pleasant). This driving technique happened several times. Sure, not such a high speed in a well designed, well maintained bus on proper roads, but that was not what I was travelling
in or on. The sheer height of these buses is frightening, so much so that a recent delegation of European dignitaries refused to travel in one.

The road in that area is good, but Thai good, not really good, so the bus started rocking from side to side as well as rocking fore and aft (fore and aft fortunately, as I'll explain later). The sideways rocking was strangely rhythmic
(as opposed to random) and related to the irregular road. As an engineering type like myself knows, there is a phenomenon called 'natural frequency' which can have you undone before you know it. Let me digress here to tell a story
about natural frequency.

A long, long time ago (early 1970's) in Maribyrnong, Victoria, Australia there existed an establishment called Repco Engine Development Co. It was the descendant of the Repco Brabham Engine Co, where a bunch of young petrol heads
including me toiled away. Raison d’être for REDCo was to produce an Aussie F5000 engine, which we did and it had some success on the track, being based on the Holden 308 V8. A side project was to produce tuning kits to suit the
standard 308 for road going vehicles and boats. This meant lots of testing, endurance testing. For that purpose we had an excellent dyno, inherited from Repco Brabham and locked away in a soundproof building. The test engine was driven remotely
by operators who looked on through several layers of toughened glass. Engine blowups were not unknown (have witnessed a few spectacular eruptions, unfortunately no movies exist of such events!). Check the pic for a view of what we could see
through the glass – a 308 at full noise . . . . Magic eh!

Now a little detail regarding 'natural frequency'. Most rigid bodies or the 'system' to which they are attached to have a natural frequency because they are elastic, and will vibrate at that frequency if excited by
some means. In an engine the crankshaft itself is elastic and has a natural frequency (meaning it will vibrate rotationally (torsionally) at a particular frequency), but the frequency is modified by the 'system' – conrods,
pistons, flywheel, and importantly at the nose of the crank the Torsional Vibration damper. The excitation comes from the pistons jerking up and down and the explosive forces on said pistons. A bus is a 'system' consisting of the
large mass of the body, the springs between it and the axles, and the tyres which are springs between the axles and the road. Most engines have a TV damper which typically consists of an inner metal hub bolted to the nose of the crankshaft,
a ring of rubber on it, and an outer metal ring over that and compressing the rubber. No method of constraining the outer ring needs to be employed as the rubber holds it in place. It works by the rubber absorbing energy and in conjunction
with the outer ring it damps crankshaft torsional vibrations. In a complicated rotating system such as an engine there will be several engine speeds at which torsional vibrations may be a problem and on the 308 we found such a speed –
spot on 4400 RPM. In a car mounted situation you rarely have an engine speed being held for a long period at wide open throttle (maximum excitation), but in a boat you may hold a particular engine speed for many minutes, hence the endurance

One testing regime we used consisted of holding engine speed for a time at wide open throttle – maybe 3 minutes, lift the speed, hold, lift, hold, and so on till you have covered the useful range of engine speeds in 100 RPM increments.
The exhaust system during such testing gets to be a nice rosy red colour. During the first testing of this engine with one of our proposed kits installed we witnessed an unexpected event when we held 4400 RPM. The crankshaft vibrated torsionally
so violently that the rubber in the damper melted (took just a few seconds), the outer ring was then free and rotating at 4400 RPM and it proceeded to pound around in the area of the nose of the crank, producing a lovely fireworks of sparks.
Fortunately it was constrained by the front belt pulley. If it had come off it would have demolished the room. Not a massive 'blow up' but spectacular nevertheless. Cool! In previous testing on a Repco Brabham engine we had measured
the amplitude of torsional vibrations and reckoned it to be +/- 15 degrees on that engine – a figure hard to believe and you can imagine that this might wreck the camshaft and accessory drives which are driven from the nose of the crankshaft.

Why am I labouring on with all this? It's about unexpected things happening if a 'system' is excited in a particular way. The bus from Korat was being excited in a particular way by this idiot driving at ridiculous speeds
on an uneven road surface and it felt to me like we were entering a zone where the sideways rocking motion was about to get out of control – approaching the bus's natural frequency. I alluded earlier to the fore and aft rocking
– I reckon that was what saved us – the sideways movement was 'spoiled' by the fore and aft motion, producing a damping effect on the rocking. And don't think I'm exaggerating here, that rocking was enough
to make the bowels loosen like nothing else. In my travels around Thailand both on my pushbike and in vehicles I've seen more than a few buses and trucks lying on their sides off roads, having scraped along gouging at their structure
and obviously killing people, and if you read the Bangkok Post regularly you will read about many bus and van crashes and the associated killing of many people. A while back I conversed with a bus driver in Udon (at his home) who boasted that
at new year and Songkran he regularly drove without relief Udon – Bangkok and the same on the return trip – it's a 12 hours minimum stretch, and of course he was boasting about the good times he achieved on those trips –
pedal to the metal.

Did I submit to the indignity of shitting my pants on that bus? Not that time, the sphincter was well and truly tightened, fortunately. Oh, and at REDCo we never did get to market a 308 tune-up kit, company politics and accountants got
in the way – it is ever thus . . .


Fascinating stuff, and I for one enjoyed the technical explanation.