Three-Wheelers

Thinking Outside the Box

by Paul Schmit of Luxembourg

From earlier times…

At the beginning of the 1950s, Luxembourg’s photojournalist and chronicler Pol Aschman captured a very unusual scene for his photo series titled “Streifzug Ösling,” translated in English “Excursion to the Ösling.” This does not refer to the mixed team of draught horse and cattle, where only the horse was driven by the farmer with a single jerk line and the ox just ran along besides, but to the wagon.

Such tongue-less three-wheel tipping carts were only common in the European lowlands, such the Northwest of France, the coastal areas of Belgium or the Netherlands, where they were called “driewielskar.” “Ösling” is the Franconia-Germanic name for the Ardennes, the original breeding area of the workhorse breed of the same name. This heavily forested landscape, which stretches from the north of Luxembourg into southeastern Belgium and western Germany, is characterized by plateaus with altitudes up to 500m and deeply incised river valleys. In this hilly area, draught horses were always hitched to farm carts with shafts or tongues.

However, this picture must be seen in the context of the time. It can be assumed that this wagon was brought to his homeland by a refugee during the post-war turmoil. Indeed, large parts of the villages and farms in Northern Luxembourg were destroyed during the Ardennes Offensive in the winter of 1944-1945, also known as the Battle of the Bulge. Furthermore, most of the farm horses had been confiscated by the German Wehrmacht during the Second World War.

Animal hitching in these days, where a lot was done simply from the poverty-out, should not serve us today as an excuse for the inattention towards animals or tempt us to neglect safety. The following lines are intended to raise questions about so-called modern hitches and explore new alternative concepts, without claiming to provide the only correct and universal answers.

Modern or not?

Nowadays, forecarts in combination with tractor implements are often seen as the modern way of using draft animals for agricultural work. During the renaissance of animal traction in Europe at the end of the 1980s, much horse-drawn technology was imported from the US into Europe or simply copied. Here, the forecart was, and often still is, presented as an American development.

But picture 2 shows that forecarts existed much earlier in Europe. This photo from the development department of the German agricultural machinery manufacturer FAHR (see also SFJ 48-2) shows a two-wheeled forecart. The photo dates from 1954 and shows the first tests under cold winter conditions. Forecarts were already known at that time and were offered as standard, in a much smaller version and with cast iron wheels, for mowers and binders. Here, the forecart not only reduces the front-end load on the tongue but also provides the power to drive the binder, thanks to a built-on SACHS single-cylinder two-stroke engine.

In addition, the stub-axle steering also reduced the steering forces required when turning the heavy binder. Equipped with a multi-perforated drawbar directly behind the axle, other applications would have been conceivable, but the first tractors, with similar hitch and power transmission systems, ultimately prevailed over animal traction in the following years.

But even back then, all the largest agricultural equipment manufacturers in Europe were intensively engaging with the technology from the US and incorporating it into their own developments. Therefore, it may be impossible today to determine exactly where the first animal-drawn forecarts were created.

A close look at today’s technology

Nowadays, nearly all American and European forecarts are built following the same design pattern. But this should not be a reason not to critically question this technology. In animal traction, incorrect balancing of forces can lead to so-called parasitic forces that burden the draft animal without contributing to the work itself.

These can be load-bearing forces on the collar or pack pad, or lateral forces caused by unsteady tongues or shafts. This means a double burden for the draught horse, which, as its name suggests, is intended to pull loads and should not carry any additional and unnecessary loads.

In an optimally designed implement, all forces and their moments are always in balance. Herein, the size of the draft animal(s), lengths of the traces and the corresponding hitching point of the singletree or evener must be considered. And that’s exactly where the problems begin, since very few series-produced forecarts have sufficient adjustment options to optimally tune the hitch for the various draft horse breeds.

As shown in picture 3, the load of the attached implement at the rear of the drawbar creates a lifting effect at the front end of the tongue (marked in red). This is advantageous because it reduces the load on the horse’s neck. However, if the forecart is used without equipment, the tongue loads are generally relatively high. If the driver also stands on the driver’s platform, instead of sitting above the axle, the tongue load increases even further (marked in violet). Here, our own measurements showed an additional load up to 15 kg at the front end of the tongue.

It has been proven that the draft effort of working horses fluctuates greatly and, depending on the work, pronounced force peaks can occur. This unevenness also affects the tongue load, since the draft force on most forecarts has a lever arm relative to the load center in the wheel axle. Accordingly, these force oscillations are transmitted not only in the direction of the traces, but also via the breaststrap to the collar (marked in blue).

In addition, as shown in picture 4, there are also uneven lateral loads on the front end of the tongue. These are caused by the movements of the attached machinery on the drawbar (marked in orange) or the unbalanced rolling resistance on uneven grounds (marked in green). The latter are larger the wider the track width and the smaller the wheels of the forecart.

All these discussed load on the horse’s collar overlap and can cause forces which, in terms of magnitude, can equal the draft forces in the traces. However, to date, this issue has received little or no attention.

Leave the beaten path

In addition to the three-wheeled cart described in the introduction, there existed also other animal-drawn farm wagons and implements of the same configuration in Europe. In France, the manufacturer ATELIERS POCLAIN, founded in 1927 by Georges Bataille in Le Plessis-Belleville, started in 1936 the production of three-wheel wagons, known as “Trirou Poclain.” Running already on large pneumatic tires, but with an overall low centre of gravity, these trailers were praised for their large loading capacity up to 10 t, but especially also for their stability and maneuverability. Production ended in 1952.

In Italy, Felice Repossi, who founded his company REPOSSI MACCHINE AGRICOLE s.r.l. already in 1898, patented in 1947 under the name “Fortuna” a three-wheel side delivery rake, which is still manufactured in Casorate Primo near Milano, almost unchanged to this day, by the fourth Repossi generation. Only the drive changed, from pure ground drive via the rear wheels, which still exists, to now also hydraulic or, since last year, even electric drive.

The three-wheel concept offers excellent maneuverability thanks to the large steering angle of the single front wheel. However, this single front wheel also has other advantages in terms of the previously discussed force transmission to the workhorse. Since the front wheel’s radial center line corresponds exactly to the horse’s direction of walk, the lateral forces, as described in picture 4, are eliminated. You can try this effect out for yourself by pushing a loaded one-wheeled wheelbarrow through rough terrain and then repeat this exercise with a two-wheeled wheelbarrow of the same weight.

Thanks to the decoupling of the shafts or tongue from the load center of the implement, no dynamic forces, as described in picture 3, are transferred to the workhorse. If the shafts or tongue are also equipped with a spring suspension, the corresponding load-bearing forces on the horse’s neck or back can also be minimized and pre-adjusted.

To use this single front wheel concept on different machines, a socalled mono-wheel forecart was developed by the author in 2013 within the non-profit association Schaff mat Päerd. By using 3D CAD, all parts could be optimized in terms of strength and weight. The forecart just weighs 62 kg and allows a turning angle of 105° to both sides.

Equipped with a mechanically operated disc brake, which has been continually improved, and a universal adapter, this forecart can be coupled to any machine. The only prerequisite is a so-called gooseneck drawbar on the implement with a coupling height of 850 mm.

A basic design feature of all newly developed implements are the large rear wheels, which, with very low rolling friction, have sufficient traction for ground drive. Additional attention is paid to consistent lightweight construction through thin-walled tubular frames. Our field tests have shown that in the case of the side delivery rake described above, the tractive power of one workhorse could be saved compared to the standard two-wheel forecart technology with heavy tractor implements, both running on small wheels.

To lower the rolling friction, the center of gravity of all implements is placed as close as possible to the large rear wheels. This also applies to the driver’s seat, if one is required. The rear seating position allows for a good overview of the machine’s operation. According to European farming traditions, walking alongside is also an option and advantageous in terms of overall equipment weight. If a seat is used, it is also equipped with a brake pedal, which is connected to the disc brake instead of the brake crank at the front.

As soon as the new developments from Schaff mat Päerd have proven themselves in the fields and there is interest from smallholders relying on animal traction, another founding member of this association, Albano Moscardo, develops in Italy market-ready equipment within his one-man company EQUI IDEA, based in Verona.

So far, mono-wheel forecarts have been delivered to Germany and Sweden. Additionally, adapters have been developed which enable the modern REPOSSI and MAINARDI side delivery rakes to be used with draught horses. Due to low demand, this option was no longer offered as standard by either manufacturer. Thanks to this collaboration between EQUI IDEA and both companies, these rakes were already delivered as far as Canada. Particular attention was paid during the design of both adapters so that they can easily be fit to the standard rakes with any drilling or welding.

A few final thoughts

However, the presented three-wheel concept is not without flaws. While in the first version of the mono-wheel forecart, the coupling to the equipment could only be accomplished after removing the shafts or tongue, a new coupling mechanism was subsequently developed, which no longer requires this, but still requires some practice. Here, the drawbars on the two-wheel forecart are much easier to handle.

Another disadvantage, which is becoming increasingly apparent, is the very small quantity of horse-drawn equipment produced in Europe, compared to the US. In recent years, most of the European manufacturers, which started in the past three decades, have already been forced out of the market again.

The development costs and the construction or testing of prototypes can rarely be justified. Therefore, from a purely economic perspective, the development of these alternative solutions is more than questionable. However, the non-questioning of our current technology cannot be a suitable way forward either.

Paul Schmit
Schaff mat Päerd asbl