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The metaphysics of the wind
The metaphysics of the wind
Aerodynamics
Life on the move means life in the wind. The wind is a constant companion, friend and rival, burden and pleasure.
Thomas Schmieder
05/19/2004
We motorcyclists are the ones who get the air moving, we always feel a headwind. A real rogue this wind. Always comes from the front, the warm smell of freshly cut hay blows under our helmets, the scent of spring flowers wafts over. But also shipped
in a mild breeze purposefully pollen grains into the nose of
Allergy sufferers, careless insects bombard eyeballs. And provides us with a sensual experience: the pleasantly cooling breath in summer, the bitingly cold autumn storm ?? what does the driver notice of it in his fully air-conditioned cabin?
It takes strength, the wind. From 80 to 100 km / h
the air resistance becomes the strongest of all driving resistances. A gentle breeze turns into a thundering storm, tugging on the head and neck muscles and consuming most of the gasoline used at top speed. No wonder, because double the speed means four times the air resistance. At 200 km / h the inhibiting forces are already sixteen times as great as at 50 km / h. On longer stretches of the autobahn, the cruising speed will sooner or later be around 140 without a fairing. More costs too much fuel and power, pressure and wind noise become too strong. In general, with increasing speed we perceive the air to be much colder than it actually is (wind chill effect). How different types of motorcycle perform in practice and in the wind tunnel in terms of wind protection and acoustics is explained by MOTORRAD technician Waldemar Schwarz starting on page 40.
One result: luxury tourers almost make you forget that you are plowing through the air at twice the speed of a hurricane. The electrically raised windshields on a Honda Pan European or Yamaha FJR 1300 are steep and large in the airstream. Isn’t that just a question of faith? see page 48; it then takes revenge when the suction pulls forward, the current of air falls behind the mighty panels and crawls coolly from behind into the neck, which is uncomfortably stiff the next day.
The search for speed. If you want to be fast over the long term, you have to buy its power from the wind. The world record hunt by Ernst Henne, who recently celebrated his 100th birthday, will not be forgotten. After several world records since 1929, it reached a phenomenal 279.5 km / h in 1937. The full casing of the 500 series BMW with the vertical shaft compressor boxer almost completely surrounded the lying Henne ?? “The hen and the egg”. Only the head peeked out slightly, crowned by the helmet with a long, aerodynamically effective duck tail. Newfangled hump suits have no other function.
Wearing one of these, Loris Capirossi set a new racetrack record a few weeks ago on the home stretch of the Circuito Catalunya in Barcelona during test drives. His perfectly wrapped Ducati Desmosedici ran 347.4 things. But being quick on the straights isn’t everything, like
prove the famously good drivable Honda RC 211 V and Doktor Rossi on the Yamaha YZR-M1. The former superbike champion Carl Fogarty liked to feel that
“Honest airflow,” Foggy categorically refused high-arched bubble panes. He only settled on the fast courses at Hockenheim or Monza
from the stopwatch to better aerodynamics ?? the theory of the flow behavior of gases ?? convert.
The knowledge of the “aero-drama”, as a mechanical engineering professor once called it, was already realized in the fully disguised GP racers of the 1950s. Its all-round bow fairing hid the front wheel and thereby tamed the turbulence that a wheel with a free flow would otherwise cause. “Blue whales” stood in a row next to “dolphins”, their nicknames make sense, because streamlining helps in water as well as in air: Physics also summarizes gases and liquids as “fluids”? Both states of aggregation are variable in shape and differ in density and compressibility.
The legendary Moto Guzzi V8 from 1957 slipped through the wind, the around 80 hp produced by its complex 500cc engine was enough for a top speed of around 280 km / h. But the protective shields of such racers that extend far beyond the center of the machine
crosswind offered a lot of attack surface including relentless lever arm. After a series of serious accidents, they were finally banned. It is as buttoned up as the GP bikes of the time Kawasaki ZX-12R, but is much more mobile despite noticeable sensitivity to crosswinds. Its shape, optimized in the wind tunnel, allowed it to break the 300 km / h limit straight away.
It is difficult to break the power of the wind, to push the air away, to compress and divide it. We don’t drive through »nothing« when we sweep the autobahn, but through physical matter, also noticeable in the air pressure: One cubic meter of air, i.e. 1000 liters, has a mass of 1.2 kg at sea level at 20 degrees Celsius. We have to go through this. Fortunately, because without the oxygen it contains, 280 grams, an internal combustion engine just won’t run.
Bend to the wind? Doesn’t have to be at all. Even a tank bag can work wonders on a naked bike. But care is particularly important when it comes to accessories, the wind is an ungracious judge. From page 50, Ralf Schneider gives tips on how to avoid nasty surprises
as well as preserving painful losses. Well constructed
Universal windshields and retrofit windshields, such as
from MRA or JF Motorsport, for example, allow a personal
Adaptation of the draft shield to the respective requirements.
Only patent recipes are difficult. Individual size and stature are too different, keyword: torso length, sitting posture, clothing and helmet also play an important role in this windy topic. Especially the type of machine, as editor Stefan Kaschel shows from page 36. Where are the footrests, how wide are the handlebars and at what height, do you sit more on or in the motorcycle? So trying is better than studying? advice that should not be ignored.
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