I believe the general theme of today is that physics has something to offer any sector of industry—especially the engineering industry—that wishes to be considered part of the "clever country".
My business is very much at the lower end of the range of size and technology, and yet it has benefited considerably from the application of R & D, innovation, and international competition. The message therefore, is that if an industry as long-standing and traditional as a coach building small- to medium-enterprises can benefit from the application of R&D etc, what business cannot?
Small as it is, the business I run has been Australia's leading manufacturer of harness racing vehicles these last four decades, with sales of about 14,000 vehicles. Since we are in a racing industry, there is considerable pressure on us to improve the performance of our product, and we have been reasonably successful in doing so.
In the period 1980–1990, our new vehicle designs took an average 5.14 seconds (about 72 metres) off the mile rate of horses using them. We increased the best margin by which any Australian or New Zealand horse has ever broken a world mile record by 17 times, i.e., from 0.2 seconds to 3.4 seconds. More world records over the mile have been set in our vehicles since 1979 than in all vehicles of all other southern hemisphere sulky manufacturers combined since harness racing began in Australia some 170 years ago.
Our innovative designs have made Australia the only country in the world to licence its sulky technology to the home of harness racing, the USA, and we have done this notwithstanding the policy of the Australian Harness Racing Council which [was until recently]:
'The sulky shall neither by its design or manufacture give to any driver or horse a speed or distance advantage over any other driver or horse using any other sulky.' (AHRC November 1991)
If applied literally, that policy would have the effect of banning any but the slowest and least efficient sulky from racing since, by definition, every other sulky would give its driver a speed or distance advantage over the least efficient type.
Strange to say, that policy has never applied to harness or horse shoes, two areas where considerable performance enhancements have occurred. Even with sulkies, the policy was only applied selectively, so that, in practice, only the most advanced Australian sulky technology was suppressed in accordance with the principle, "Have foot, will shoot."
Leaving aside institutional obstacles to innovation for a moment, you may be wondering what can be done to a sulky to enhance a horse's performance. We need to ask, "What are the main performance parameters applying to harness racing sulkies?" They are:
WEIGHT
The effect of weight is easy to determine. A typical racing sulky weighs 25kg fully equipped. The driver may weigh between 50kg and 100kg, so varying driver weight by the equivalent of the sulky weight will give you a handle on the advantage to be gained from reducing the sulky weight, to as much as nil. As it turns out, the effect of driver weight is intimitely tied up with the effect of balance. Modern sulkies are 'negatively balanced', which means that the weight of the driver tends to lift the horse via the girth strap.To give you a bit of historical perspective on this weight question:
BALANCE
As mentioned, modern sulkies are negatively balanced.AERODYNAMIC DRAG
You have two items with greater drag than the sulky - the driver and the horse. More to the point, both driver and sulky are shielded from the airflow by the horse. It is therefore necessary to consider the drag of the “racing unit” as a whole, and to make such changes to the sulky as might reduce the total drag. For this we go to standard fluid dynamic drag theory and position the driver an optimum distance behind the horse to reduce the drag of both.AFFECT OF THE SULKY ON THE HORSE
This has three main aspects:
So then, theory aside for the moment, how DID we improve the performance of the sulky as effectively as we did?
The first major advance occurred with the introduction of negative balance in 1979. The use of shafts of hard-drawn stainless steel tube enabled us to achieve much more negative balance than wooden shafts would allow. The Time Trial Special transferred a weight of horse and harness equivalent to 15–20 % of the driver's weight to the wheels of the sulky, which naturally increased the rolling friction of those wheels in accordance with the usual formula of
drag = (weight x coefficient of rolling friction)/wheel radius.
An analagous situation occurrs when you mount a push bike. The weight on your legs is reduced to that necessary to turn the pedals, while the rolling friction of the bicycle wheels is dramatically increased. The net result is that you can travel much faster on a bicycle than you can run, since a wheel is a far more efficient device for carrying a load than a leg.
Since it is the case that a horse's energetic cost of locomotion is proportional to the weight carried on his feet, then it follows that this cost of locomotion will be reduced as we transfer weight from his feet to the wheels of the sulky.
Negative balance sulkies gave us 1.6 seconds average improvement over the mile, and the longest sequence of Inter Dominion wins in the 50+ year history of Australasia's biggest annual harness race—six straight from 1982 to 1987.
But truly it is said that he who rests on his laurels is wearing them in the wrong place, for in 1987 the OFFSET sulky made a spectacular entry onto the Australian and world stage.
But why offset? And WHAT is offset?
First it is necessary to know that all Australasian harness racing tracks are heavily underbanked. That means that the horse leans on the bend so that the angle between his vertical axis and the track surface is commonly 80 degrees or less. This causes the horse to throw his off-hind leg towards the outside of the track on the turns, and the offside hind hoof very frequently strikes the offside wheel of the sulky as a result. When you combine this tendency with the narrow sulkies common in Australia (about 30cm narrower than their northern hemisphere equivalents) you end up with a long narrow sulky of similar dimensions to a northern hemisphere work cart.
The second thing you must know is that, prior to 1980, the maximum width of Australian sulkies was in the order of 1.17 metres, whereas the maximum ALLOWABLE width was 1.3 metres. So then, a solution to the problem of wheel strike on turns was to make the sulky the maximum width and centre the wheels on the full lateral movement of the hind feet during a full circuit of the track, which movement is "offset" to the offside. The chassis of the sulky (shafts, back bend and cross bar) remained centred on the horse, and thus was born the offset sulky.
By offsetting the wheels, we could make the shortest possible sulky having a maximum width of 1.3 metres or less, allowing us to shift the driver into the drag ‘sweet spot' behind the horse, minimizing combined drag, and achieving the maximum negative balance.
The proof of the pudding is, of course, in the eating, and the offset sulky went on to achieve the greatest world-record breaking spree of any Australasian single-horse sulky in history.
It reduced the best margin over a previous world record by 17 times; it enabled a horse to break all world mile records for his age. gait and sex, and to achieve that on the smallest and therefore slowest of standard tracks, and it achieved the ultimate accolade for any new design—it beat American sulkies in open competition on American tracks with American drivers and horses.
Naturally, this being the "clever country", the offset sulky was immediately banned in Australia because it was clearly in breach of the anti-competitive policies of the AHRC, and in New Zealand because it was in breach of the anti-competitive policies of the HRNZ—which may be paraphrased as, "no competitive foreign sulkies will be allowed to be sold in New Zealand."
As a result of a sustained campaign by myself and others, the Australian bans were lifted in August 1992. In that same month, the first three starters to use the offset sulky achieved two 1sts and a 2nd. The two winners established new lifetime records and new Australasian Season's records, while the other starter was second to one of those, and the gap bwteeen him and the rest of the field at the finishing post was 44 metres (i.e. about 3.1 seconds). That result was not lost on the Kiwis, who have maintained the ban on the offset sulky until the present day, and WILL almost certainly maintain it until the patent expires and their local manufacturers can, once again, compete. There are, of course, trans-Tasman regulations, like the CER Act, designed to prevent this sort of thing, but they are, in my experience, totally ineffective.
In 1992 we had a shot at our first pairs, or 'team-to-pole' sulky. That is, a sulky which is pulled by two horses instead of one. This sulky was designed at the request of the organisers of the Brisbane Expo for one purpose and one purpose only: record breaking. I won't bore you with the details, suffice it to say that in its various forms, that sulky has set more world records over the mile (about eleven) than any pairs sulky in history, and it has done it with some very ordinary horses—indeed at least one of them an unraced maiden. Not only that, but it is the world's first pairs sulky to routinely achieve faster times than the faster of the two horses harnessed to it. That feat was never previously achieved once, let alone many times.
So how did we do it? What did I find out that other coach builders before me didn't?
A combination of two things: negative balance and the dorsal hitch.
The dorsal hitch was invented by the Greeks around the 6th century BC, and was the primary means of hitching chariot horses until the fall of the Roman Empire, about a millennium later. Following the re-introduction of the dorsal hitch by NASA Project Engineer, J. King, in 1969, it was observed that horses generally raced keener with a dorsal hitch than with conventional harness, although the matter was controversial, and the dorsal hitch has been banned world-wide in 1974. But that ban applied only to single-horse racing sulkies.
While the pairs sulky was happily setting better than one new world mile record per annum, on average, I returned to a problem which had defeated the world's coach building industry for a century or so: how to fit an independent suspension system to the twisting and warping chassis of a light sulky?
The answer proved to be the "Floating Link Suspension", a system which gives a 35 kg sulky about the same ride quality as a new auto travelling at the same speed on the same surface—no mean feat when you consider the relative difficulty of achieving a low unsprung weight on such a light vehicle.
Given the near impossibility of getting new indigenous race sulky technology past the powers that be in this often clueless country, I resolved to design a light work cart with the new suspension for the world market. Unlike race sulkies, work sulkies are essentially unregulated here or elsewhere. So this is the result: the Regal Brumby.
The suspension has been a howling success. It has won us a finalist's certificate in the innovation category of the 1999 Western Sydney Industry Awards and membership of the Australian Technology Showcase. It has given us exports to makets we have never penetrated before - such as Switzerland and Japan (where there is no harness racing), as well as enhancing our international reputation for innovation.
We did put up a variation for approval as a race sulky, but, after two and a half years of consideration it was—surprise surprise—banned!
Fortunately, the Australian harness racing authorities have no regulations for pairs vehicles, so our pairs sulky has been fitted with the floating link suspension and will be attempting further world records in Brisbane this year.
In January of this year we introduced yet another new sulky which we have called, rather grandiosely perhaps, the Millennium Mini. It is the first sulky in the world to combine the dorsal hitch, a single shaft vertical plane chassis, and full independent suspension, and it is specifically aimed at a number of markets all of which have one thing in common: they are NOT controlled by the Australian Harness Racing Authorities!
The Mini was designed to enable dogs and other species (such as miniature horses) from 23kg upward to pull an adult comfortably on reasonably level unpaved surfaces. This is a small but expanding market, and no other manufacturer has a vehicle remotely near the sophistication of the Mini, so we hope to achieve a useful degree of penetration of that market internationally—in fact the first Mini was sold to a retired engineer in Phoenix, Arizona, who described it in two words: "Pure genius!"
So, where to from here? Well there is considerable development potential in the Mini, not least in dry land racing of sled dogs, miniature horses, etc, and in its application to other species with draft potential, such as goats and alpacas. We also have another new vehicle under construction, which is schedule to make its track debut in September this year.
Looking back over four decades, I would have to say that we have been vastly more innovative in the last two decades than in the first two, and that the pace of innovation keeps increasing. But that is the way of the world these days. It is a matter of innovate or perish.
Copyright James S. Walsh
