The man from Tullahoma, Tennessee, greeted me in front of the old sausage-and-onions grinder stand behind pit lane at Daytona International Speedway. He'd recognized me from the "likeness" in my monthly magazine column, "TDC."

Turns out, he’d been a part of classic aerospace undertakings that I found fascinating. But there he was at the races. Many a career in technology, it turns out, begins on two wheels.

Rocket-engine performance changes during climb as atmospheric density drops (half the atmosphere is below 10,000 feet). To simulate this, monumental evacuated test chambers were built at Arnold Air Force Base near Tullahoma. Their vacuum was created and maintained by steam ejectors or powerful axial fans. I was treated to a description of installing 7-foot-long blades by means of their triangular “fir-tree” bases, closely fitting into corresponding machined sockets in the rotor discs—with the aid of a soft sledge. Thousands of horsepower would spin those axial fans. I had no previous idea that such monsters existed.

In the spring of 1944, the newly completed Altitude Wind Tunnel at NASA Glenn Research Center in Cleveland was given the job of devising fixes for the critical problems of the Boeing B-29 bomber’s air-cooled piston engines. Several of the managers of the elements of that program became NASA heavies when the organization took its new name in 1957. People with serious experimental backgrounds were valued because, when time is short and priorities high, textbooks take you only so far.

As my informant spoke, I envied him his opportunity to have been part of such a vast undertaking. They built whatever was required. But as one retired NASA veteran declared in his oral history, US spaceflight R&D might never receive that level of funding or wide social/congressional support again.

Engineers are, in my experience, alone. Can they talk to friends and family about deflagration of monodisperse sprays or carbide segregation in the intergranular zone? No, they must put aside their own constant concerns to share those of the people in their daily lives. They live in two worlds. If you understand just enough to show such people that you know their secret worlds exist, you can learn a lot.

I met and spoke with Dale Rathwell when he was a suspension/chassis analyst for Yamaha, back in the days when high-power racing motorcycles were doing things that the teams struggled to understand. Why did sawing a cross member out of a certain 250's chassis improve its lap time but only on one particular racetrack? Why did Honda's RC30 push in Europe but not on its home test track? Any model of motorcycle chassis dynamics must explain all the data, and that takes time. Sawing out a cross member is one thing, but creating a chatter-free new chassis design is quite another.

V-twin
The bike that Britten built: Except for connecting rods, pistons, clutch, and gearbox, that first 60-degree V-twin was entirely John Britten’s own design and manufacture—casting patterns, castings, machining, and assembly. Britten died in 1995, age 45.Cycle World archives

Rathwell’s background was academic. The battle against chatter was just beginning. On one occasion, Rathwell in a couple of sentences remade my understanding of suspension. He said dampers exist to control the motorcycle’s natural oscillatory modes—for example, heave (the whole machine bounces up and down), pitch (rocking), and chatter (a complex of tire and chassis natural frequencies). At all other frequencies, damping just interferes with the free movement of the wheels over pavement irregularities.

What he was saying was that the suspension dampers are there mainly to prevent the chassis from storing energy in particular modes of vibration, energy that could otherwise build up to a level that endangers stability or control.

This neatly explains why, when journalists are hosted by a damper manufacturer, they are often asked to drive a few laps on the test track in a uniquely equipped car, one which has no dampers at all. The car has the obvious problems we associate with too little damping, but it does certain other things very well. The ideal damper would damp the “forbidden frequencies” of the natural chassis modes but would interfere only minimally with motions at other frequencies. That ideal damper would also very likely be banned by race-sanctioning bodies; things that work well are seen as “destabilizing” and so are banned.

A day came when Harley-Davidson’s VR1000 Superbike, near the end of its funding, made one astonishing Daytona lap. I asked the team boss, “Where did that come from?” I should have known better, for the answer I got was, “It is the integration of a constellation of development programs carried out over the winter.”

In journalism, you mustn’t rely on a single informant. So I went and asked their consultant, Rathwell, the same question. He said no new parts were expected, so usable parts on hand were being pressed into service in whatever order they were found. He reckoned one of the resulting combinations must have accidentally been pretty good (the lap time was not repeated). The analogy that sprang to mind was the college student, short of time during exam week, sorting through dirty clothes to find the most wearable. I thanked him then for his candor. I thank him now for his insights.

Francois Decima was the Michelin tire engineer with whom Erv Kanemoto and Freddie Spencer worked during the crucial 1984 transition from bias carcass construction to the present semi-radial. Particularly intensive was development of the front tire. Decima pushed himself to the limit in that time, compromising his heart. His doctors urged him to take up an activity that required calm and relaxation. He chose pistol marksmanship, in which a person must stand still, control heart rate, maintain sight picture, and smoothly make the sear release.

As with so many others, such as Don Tilley and John Britten, I feel a void where our further conversations might have been.

Pursuing technological solutions can be powerfully addicting, with each small discovery adding to the absolute necessity of the next one. Human minds are pattern-seeking, but without relief from it we move relentlessly toward burnout.

Decima is no longer with us. As with so many others, such as Don Tilley and John Britten, I feel a void where our further conversations might have been. Decima had developed a theory to describe the self-steering action of tires, and hoped that Cycle magazine, through myself, would publish it. When I wrote it up, I was told to stick to the subject. It was edited out and later published by another writer. My story ended up as a travelogue: I visit a tire plant, breathe the mercapto-scented air, and have a ride in a rally car.

When I asked him what the pressure-versus-time profile of propellant combustion in guns looks like, he replied, “It is no different in shape from that of an internal-combustion engine.”

Sometime in the 1990s, I was in the media tent at Laguna Seca when I was greeted by a man in his 60s who, in the course of our conversation, revealed himself to be a retired Israeli automatic-weapons designer. Our very interesting conversation revealed him to have had a traditionally broad European education, rich not only in technology but also in history and music. Most remarkable was his statement that he regularly trained at a gym in order to be properly able to ride and enjoy his Honda CBR600RR. That is a serious older rider!

When I asked him what the pressure-versus-time profile of propellant combustion in guns looks like, he replied, “It is no different in shape from that of an internal-combustion engine.” In both cases, effective measures must be taken to limit the rate of pressure rise from combustion. In a gun, the propellant is not a fine powder (which would have a very high burn rate because of its very large surface area) but is made in the form of grains or flakes whose lesser surface area slows the pressure rise to a rate that the gun’s structure can survive.

In an engine cylinder, the rate of pressure rise following ignition is generally kept below Harry Ricardo’s advised maximum: 40 psi per crank degree. Rates higher than that, he observed, led to noise, harshness, or parts damage (an example of very high rate of pressure rise is detonation, which readily damages bearings). As an example, consider a well-developed racing engine with a peak combustion pressure of 1,200 psi. If it ignites its charge at 35 degrees BTDC and peaks at the desirable 11 ATDC, that is a total of 46 crank degrees. This gives as rate of pressure rise 1,200 divided by 46 equals 26 psi per crank degree.

The shape of the pressure-versus-time curve, the gun designer noted, is an initial very rapid fall as the piston or shell begins to move, becoming shallower in a sort of “kangaroo tail” at the low-pressure end of the curve.

While the sounds and the sights of racing are exciting and do contain valuable information, I have gone to the races mainly for the conversations.