Home Workshop Performance

Posted on May 14th, 2009 in Driving Emotion,Opinion,tools by Julian Edgar

Our ‘Building a Home Workshop’ series (starts here) has been very popular. So what’s the workshop like after being in use for 9 months? What’s been learned about its performance in that time?

Firstly, the excellent.

The lighting system (an expensive and very powerful system using a lot of suspended metal halide luminaries) is well worth the time and money involved in its installation. You can be working in the late afternoon and as evening falls, not even notice the change in lighting. You can work as efficiently in the middle of the night as the middle of the day.

The internal layout – the position of power points, machine tools and workbenches – has also proved excellent. The ‘island’ workbench is particularly effective, as is the proximity of the welding bench to the main workbench. 

The tall headroom is also noticeable every time I swing a piece of tube or even carry the ladder. Talking about the ladder, the storage of items high up (clearing floor space) has also proved to work very well.

Now, the bad.

I chose to install two skylight panels on the north-facing part of the roof, down the end of the workshop furthest from the roller doors. These work well in that the summer heat build-up caused by their presence is limited but they still provide a lot of light. However, I should have used one more panel so that the back wall of the workshop (where the machine tools are located) was evenly illuminated. As it is now, on a cloudy day, the drill press, grinder and hydraulic press are a bit dim.

Ventilation is also not sufficient. Even with the two roller doors up, the twin whirligig ventilators working and a fan moving air within the workshop, the build-up of fumes while brazing or welding is excessive. This is one aspect I think I will have to change – either adding an extraction hood and exhaust fan over the welding bench or placing an opening window in the far wall.

Finally, the concrete floor has proved to be very soft, not just in the second batch (which I always knew was soft) but also in the first batch. To avoid damaging the floor, items cannot be dragged across it and nothing can be hammered on it.

Overall? Very happy indeed.

An extraordinary man – and his car

Posted on May 12th, 2009 in automotive history,Opinion by Julian Edgar

I am not usually one to read business or financial thrillers; there’s too much I simply don’t understand. But Delorean, written by Ivan Fallon and James Strodes and published in 1983, is simply a helluva book.

The history of the Delorean DMC12 car is widely known – we’ve done a fairly typical story ourselves (see here) – but it’s the background financial and personal shenanigans that make for fascinating reading. 

The authors are ungenerous of John Z Delorean, but any feeling that they’re being mean just for sensationalism quickly goes out the window when we start learning about the financial approaches taken within the company.

The company – funded effectively by the British taxpayer – threw money around with an indefensible largesse, while Delorean himself appeared to have delusions of grandeur (the latter perhaps required of someone propping up a house of cards). 

Also rather interesting is the skeleton company set up to apparently channel tax-free money to Colin Chapman of Lotus (Lotus did most of the development work on the car) and to Delorean himself.

Used to dealing with ethical and sober companies, the British government – and its agencies – simply couldn’t believe what they were seeing happening to their money. But, caught in a political bind, they kept handing Delorean more and more!

The authors are financial experts – not automotive writers – and there a few automotive technology errors and shortcomings.  Tech detail on the development of the car itself is also only briefly covered (although even that coverage is often interesting).

But if you want to read a book that shows how one man can manipulate situations to his advantage – or, perhaps more generously, a book about the burning ambition of a man who would do anything to succeed – this is an amazing read.

The (lack of) pace in retail change

Posted on May 7th, 2009 in Opinion by Julian Edgar

The pace of change in the retailing of goods seems to me to be progressing awfully slowly.

Despite the massive impact of the web, and the much lower real costs of accessing information and shipping goods, many shops seem to be stuck in a time that I thought was long past.

Or, would be long past by now, anyway.

The other day my wife and I bought a tent. The tent needs to match very specific criteria. It needs to weigh under 5kg, be a ‘four season’ design, and have room for three people and their gear. It also needs lots of tie-downs. The tent will be used in cycle touring both in Australia and internationally.

Now there are a few things in this list that make sourcing such a tent difficult.

Firstly, most tents sold in Australia are two or three season tents – fair enough, given our relatively mild climate.

Secondly, in light-weight tents, the majority are tight two-person tents, or very tight three-person tents. (Or of course single person tents.)

Thirdly, there are few tents around the thousand dollar budget that we’ve found is needed to buy a quality tent of this type.

We’ve been looking and assessing tents for about a year. In that time, we’ve visited about fifteen different camping shops in three states. As expected, none of these shops had on display a tent matching these specs. All could get such a tent into stock, but didn’t have anything for us to look at.

What was completely unexpected, however, is the poor quality of advice we were constantly given. After stating the criteria and why we had devised such criteria, the camping shop staff invariably asked: “So, where are you going on your trip?” (as if we were buying a $1000 tent for a one-off trip!) and then proceeded to try to sell us an inferior tent that they just happened to have in stock.

After this happened about the tenth time, I got jack of it and decided the tent would need to be bought sight-unseen. I found a suitable tent, did substantial on-line research, and then sent out about 15 emails, one to each of the tent’s Australian retailers. In the email I simply asked for price and availability of the tent I had in mind.

The first surprise was how long some shops took to reply – in one case, over a week. The second surprise was that most shops just quoted the recommended retail price, and said they didn’t have any in stock but could get them. (Glad I didn’t bother visiting those shops, then.)

However, one dealer, at a relatively remote country location, came back with a good email. He could get the tent no problems, it said. The current model was $XXX (about 15 per cent under recommended retail), but he also had a previous model that broke down rather differently, adding potential versatility in the way it could be carried. Both tents could be sent free freight to wherever I was in Australia. Any questions or advice needed – please email or call.

I rang the next day and discussed in depth the purchase, the criteria, our potential use. The man knew the tent well – he hired them out. He also was an experienced touring cyclist, as well as being very familiar with snow country – the worse conditions for a tent.

We paid by direct bank transfer, got a quick email acknowledgement and a few days later had the tent – direct-shipped not from the shop but from the wholesaler.

I don’t know if where we bought our tent there is a bricks and mortar shop – or he works out of his bedroom. And why would I care? He had the best advice, best price, free freight and direct-shipped from the distributor, saving valuable time.

A retail shop where you can touch and feel the goods has obvious advantages. But the more specialised the goods, the less relevant a retail shop seems to be.

As I said at the beginning, you’d think that by now things would have changed far more than they evidently have…

Are all deflections bad?

Posted on May 5th, 2009 in electric,pedal power,Suspension,testing by Julian Edgar

One of the automotive ideas that seems to be taken as gospel is that the chassis and suspension arms should be stiff – that is, neither should deflect when subject to load. In fact, if I’d had a dollar for every time I’ve read that ‘good handling depends on a stiff chassis’ I’d be richer than I am.

But I think that, especially for ultra-light vehicles, this notion is simplistic.

Firstly, every structure deflects under load. That deflection may be small, but it occurs. Even the Sydney Harbour Bridge has an allowable deflection under maximum load of 4.5 inches (114mm) in the centre of its span.

Secondly – and more importantly – chasing reduced deflection will add substantially to weight. The corollary of that – the lightest possible vehicle will always have deflections.

Finally, not all deflections are bad.

Let’s start off with the last. Most cars use rubber bushes that are designed to have differing stiffnesses in differing planes. One reason for this is so that wheels can move fractionally backwards when they meet a bump, reducing harshness. Another reason is that in some (many?) suspensions, if the bushes didn’t have ‘give’, the suspension would lock up solid during travel.

Passive steering suspension systems – the first well publicised was the Porsche ‘Weissach’ axle of the 928 – often use bushes that deflect, or links that give an effectively ‘non-stiff’ suspension in some planes.

Going backwards to the second point, getting rid of measurable deflections in chassis and suspension arms will result in a major increase in weight. In ultra-light vehicles (eg those powered by human legs, a small petrol motor or an electric motor), and especially those made from chrome moly steel tube, deflections under major loadings are often able to be seen by eye.

For example, the peripheral torsional wind-up of a front suspension arm might be 5mm or more under maximum braking, and under max cornering there might be 3 or 4mm of bending in wheel supports. In a human powered vehicle (HPV) with a recumbent seat and front pedals, boom flex under maximum pedalling force can often be 10mm or more.

So does all this matter? In some cases (like boom flex, that subtracts from the power available from the rider), yes it does.

But in other cases – not necessarily.

What is required is that the structure is never stressed to the point of failure, and that the vehicle dynamics remain consistent.

I have been musing over these ideas in the context of the HPV I have been building.

I know that under brakes the beam front axle will torsionally wind-up, reducing the static castor of the front, steering wheels. That might lead to steering dartiness under brakes – but for the fact that when the front brakes are in action, the vehicle has some dive, that in turn causes a rapid increase in castor.

On my previous recumbent trike design (called the Air 150), I had difficulties in getting rid of steering twitchiness. The problem felt all the world like toe-in bump steer, where I’d put on some steering lock, the machine would roll slightly – and the outer wheel would toe-in, giving a sharper steering response than requested. That was the theory – but I found this odd when on the workshop floor, toe-in on bump was small or non-existent.

But I now wonder if the outer semi-leading suspension arm wasn’t flexing sideways a little with the sudden application of the lateral force, which in turn caused “turn-in steer” as the suspension arm and the steering tie-rod flexed through different arcs.

Certainly, at the very early stage of testing I am at with my current HPV ‘Chalky’, there’s no steering twitchiness on turn-in – and the front suspension is laterally much stiffer than the previous design.

(I fixed the Air 150’s twitchiness by setting the suspension up with either static toe-out, or toe-out on bump – but the problem returned when carrying really big loads. If the arms were bending laterally, perhaps it just needed even more static or bump toe-out to compensate?)

And I guess that’s the point. In a vehicle – any vehicle – there will be dynamic variations that don’t match the static settings.

(Many years ago, I remember having a wheel alignment done on my Daihatsu Mira Turbo. I was happy with the alignment machine’s read-outs – but then the mechanic got me to sit in the driver’s seat. On that simple car, the suspension settings immediately changed!)

If the weight of the vehicle has been has to be kept to an absolute minimum, and so major deflections occur in the suspension and frame, the trick is to optimise the direction of those deflections so that they don’t subtract from – and possibly even add to – the on-road experience.

That’s a very different notion to ‘keep everything as stiff as possible’.