Failed Projects Can Make Significant Contributions

I have written before about the many two-stroke development projects run by the world’s auto industry from 1985 through 1995. They came to pretty much nothing. Manufacturers were attracted by the low bulk, light weight, and reduced parts counts of two-stroke engines. But as the late professor Gordon Blair explained, they reinvented the wheel rather than taking the head start offered by existing knowledge. One by one, these interesting developments were cut off.

Yet one valuable contribution of this work did go forward: the fine-particle-size fuel injectors necessary to make direct fuel injection two-strokes practicable. These morphed into a technology for the similarly rapid mixture formation required by today’s GDI, or Gasoline Direct Injection, four-strokes. Because evaporated fuel in the incoming charge displaces some air, the cylinders of port-injected four-strokes are not filled as fully as they would be if air alone were taken in, and fuel is not added until all valves have closed. The deeper breathing made possible in this way is nothing new: In 1933, Bosch began development of direct cylinder fuel injection for the large-piston aircraft engines that Germany ultimately used to fight World War II.

Cadillac’s adoption of GDI allowed a smaller, lighter, more economical V-6 to do the work of its previous Northstar V-8.

In April of 1998, a group of investors and other interested parties were treated to the unveiling of new Norton-branded motorcycle prototypes at the tony Dorchester Hotel in London. To join the happy throng, I walked past a rank of Rolls-Royces whose liveried chauffeurs were actually flicking at imaginary dust with their handkerchiefs. We were directed to the rooms of play by female guides costumed as the “Norton girls” who famously graced the failing company’s magazine adverts in the 1970s. I had come to see the Manx, a 750 inline-four, and a V-8 spun from it, the 1,500cc 235 hp Nemesis. Among other technologies said to exist in these machines was partial retraction of the front wheel at very high speed, implemented to maintain adequate front tire load for safe control, despite the natural tendency of aero drag to blow super-fast bikes over backward.

This concept—whether or not it was actually implemented on the prototypes we were shown—long predates MotoGP’s use of both downforce winglets for the same purpose and the current fast-developing “holeshot” devices that temporarily hold down front, rear, or both ends of a bike, enabling it to accelerate and brake harder before either wheelie or stoppie sets the upper limit to it.

Engine designer Al Melling also spoke to me of another technology that has survived that set of failed Norton prototypes: the use of anti-high-side valves in suspension units. A highside results when the tires of a sliding bike suddenly grip and cause the bike to flip over its tire footprints, hurling the rider into the air and violently and completely bottoming the suspension. Melling spoke of a system that would hold the suspension bottomed rather than allowing rapid rebound to throw the rider even farther. Later I would learn that Showa, and possibly others, had later implemented this idea.

Further, and most significantly, these bikes were built on cast magnesium frames, the first examples on two wheels known to me, likely employing the insights of castings technologist John Campbell, and perhaps also the experience of the Cosworth casting process.

There have been previous attempts to cast one-piece motorcycle frames, a practice that now saves manufacturers the costs of cutting materials to dimension and manually or robotically welding them into a unit. The 250cc MGC, made in small numbers in France by Marcel Guiguet in the early 1930s was built on a cast aluminum chassis which integrated the steering head, fuel tank, and chassis beam into a single piece. For many years, there were continued problems with porosity and poor fatigue resistance in aluminum castings, but around the year 2000 the casting revolution inspired by the Cosworth process gave us the present durable, light, and inexpensive cast motorcycle chassis.

Quoting from John Campbell’s book: “…before the new (casting) process became available, the Cosworth cylinder heads intended for racing were cast conventionally, via running systems that were probably well designed by the standards of the day. However, approximately 50% of all the heads failed by thermal fatigue of the (exhaust) valve bridge when run on the test bed.

“From the day of arrival of the castings made by the new process (otherwise substantially identical in every way) no cylinder head failed again.” (p. 291, Castings, Second Edition)

Honda developed several successive versions of the NR500, its oval-piston eight-valves-per-cylinder four-stroke GP bike. Although it eventually made 136 hp at 19,000 rpm, it never won a single GP point—and points are given down to 15th place. One of its necessary technologies continues to serve on thousands of modern motorcycles today. The NR500 achieved very high rpm, as the hope of making it competitive with the then-ruling two-strokes depended upon being able to spin it at twice their rpm; therefore it had a great deal of engine-braking. Because engine-braking (dragging or hopping the back wheel on closed throttle, or making it slide out on corner entry) had already accelerated the mid-1970s downfall of MV’s advanced four-strokes, a cure was mandatory. This cure took the form of what we call the “slipper clutch.” A set of spiral ramps built into the clutch hub reduced the pressure of the clutch springs when the rear wheel drove the engine, allowing the clutch to slip rather than solidly couple the crankshaft to the rear wheel. Slipper clutches are now common on large-displacement production bikes and even appear on some smaller models.

The French fuels giant ELF, and later Honda, supported the development of a series of prototype F1-influenced advanced technology roadracing bikes with a variety of alternative front suspensions and other novelties. Their top championship result was Ron Haslam’s fourth in 1987. Because the early ELF bikes were aimed at 24-hour endurance racing, they were designed to achieve very rapid wheel changing by means of a single-sided swingarm; the rear wheel was mounted on a stub axle and could be removed by spinning off a single nut. After some use on certain Honda models, the single-sided swingarm has become a fascination that Ducati lovers cannot let go. The other ELF/Honda innovations have perished; either on the track, as in Honda’s 1984 NSR500, which carried its fuel in an underslung tank beneath the engine; or in the marketplace. Once hailed as “high-tech,” attractive curiosities, such as Bimota’s Tesi with its hub-steering front end, have not made a dent in telescopic fork dominance.

Some combination of function and fashion picks and chooses among the new technologies we humans propose. The results are often surprising.