. My father, CA Saunders, was a young man in the early 1930s. He rode this Indian motorcycle from his homestead in Manilla, Iowa, to the gold fields in Utah to work in the mines. At that time, the only roads were dirt roads. The bike took constant repair to keep it running. He stayed at the homes of farmers who were happy to get the latest news from this adventurer. The first handlebar shields incorporated sound engineering principles. Note the tension struts extending from the front and reaching back to the upper edges of the shield—a very nice, minimalist design solution. Craig Vetter’s frame-mounted fairing led the industry years before the OEMs incorporated fairings as standard equipment. This move from handlebar mount to frame mount has one major drawback. Notice the large gap between the trailing edge of the shield and the rider’s helmet. Photo from Canada MotoGuide The Wixom handlebar-mounted fairing circa the late 1960s is an excellent example of a clear shield on a fiberglass body—photo from Jeff Dean’s site. Notice how Saeng’s Quantum fairing is so well proportioned for the rider. Also, note the close proximity of the rider to the fairing and the staged transitioned top corners… years ahead of the industry.		perspective the early years For the first motorcyclist, the search for the holy grail had more to do with keeping the bikes running and in one piece than rider comfort. Paved roads were few and far between, and a ride in the country meant facing streets so rutted that even riders on today’s machines would find them challenging. The importance of a smooth and quiet motorcycle air pocket wasn’t even a question in the early days of cycling, and as such, the search for the holy grail in air management came a little later. As paved roads expanded and ground speeds increased, wind resistance started to rear its ugly head. Riding a bare bike is fun, but fighting rain, bugs, and the high pressure of wind for extended periods has drained many a rider. It is at these higher speeds and longer durations that the search for the holy grail of air management began, facing head-on the question of how to create a comfortable air pocket. shields the first generation Adding a shield sounds like a simple solution; for some, it is. However, spinning the earth with your rear tire daily tends to reveal deficiencies in the air pocket that the short test spin off the showroom floor didn’t. Problems such as buffeting, noise, heat, and backdrafts, not to mention what you might encounter in a rainstorm or while riding into the cold of the night. Often, these previously unnoticed problems are severe. As the saying goes, necessity is the mother of invention, and American riders needed solutions. By the 70s, there came an explosion in fairing designs, and riders had a wide variety of fairings to choose from for the first time. None of the manufacturers were measuring the air pocket disciple levels, let alone advertising them. Editorial note: they still don’t promote disciple levels. So how was a rider to know what fairing was best? Remember, there was no internet, only ads and word of mouth. So, many riders, just like I did, bought and tried different shields. These shields fell into two categories: bar or frame mount. Before discussing capsule dynamics, we need to understand what it is about these two categories that make their air pockets so different. categories mounting defines the fairing type Fairings and shields fall into two categories: frame-mounted or handlebar-mounted. The apparent difference is that mounted units turn with the bars, and the frame-mounted fairings don’t. The subsets of these categories range from small sports to large touring. The sport class generally aims to take pressure off the rider’s chest and provide a low-drag, minimal capsule. However, the touring class fairings/shields protect most of the riders. For now, we will primarily focus on touring-class fairings and shields. Touring class shields are designed to either look over or look through. Look-over shields provide the rider with a less obstructed view of the road, but in many cases, they lack the quality of helmet protection offered by look-through shields. The more one moves from look-through to look-over, the more critical aerodynamics are, or, to put it bluntly, even a billboard makes a still envelope. For look-through riders, air management is more of an issue for their passenger… step seats and being further back can create major issues. The challenge for sports touring riders is making smaller shields perform effectively. Regardless of the class of fairing. All riders are riding in a fluid environment. Pedro Gómez-Esteban posted this great article on some fundamentals of fluid dynamics. As a heads up, your browser may need to translate from Spanish. I will cover more of the fluid dynamics side later in this article. note to readers We are currently adding information on how to get a smooth and quiet air pocket. This section will include windshield extensions, wind deflectors, induction venting, and micro-swirl generation. We will explore the relationship between external and internal air flows and how these components try to balance them, with many illustrations to help clarify every aspect. Stay tuned; there is a lot more great stuff to come.
Saeng fairings utilized the boundary layer to reduce drag and improve the air pocket. They also featured innovative design elements, including pop-off disengagement in the event of an accident, exoskeleton mounting, and self-defogging headlight coverage. Von Kármán vortex stream formed by the wind when meeting the Juan Fernández Islands in Chile ( NASA ) Wake turbulence. Note the turbulence lag after the stream leaves the surface. The problem with look-over shields is that the angle of attack needed to clear the helmet results in turbulent flow almost immediately. Patented on October 20, 1987, the Saeng Winglets were the first of a new generation of shield-mounted wind deflectors. The primary wing was adjustable in both pitch and bow, and the side wings could be positioned at almost any angle. The Winglets were a spin-off from the Quantum fairing project. The downside was aesthetics. The linkages were bulky and made for a cluttered array. ___		fundamentals How fairing types affect the air pocket. Design fundamentals are the essential ingredients that go into generating a capsule. They include but are not limited to angle of attack, rider/shield proximity, shape or form, and internal and external dynamics. I won’t deal with the boundary layer, laminar flow, wet surface area, and parasitic drag. Though such things can be significant, they are not, for the most part, essential in generating a quality air pocket. Remembering that fairing and bike design are configured for a specific mission is always beneficial. If your primary mission is to commute across town, the bike can be configured differently than one with the task of beating back hundreds of miles daily. Sure, they can both be used for the same mission, but one might be better suited for a light and agile configuration, while the other requires a more comfortable ride and a smoother air pocket. The same applies to off-road or adventure touring. Once you define your mission/s, finding the best configuration becomes much more accessible. At this point, it is wise to approach the issue cautiously. For example, the mission statement displayed in the showroom does not always align with actual performance on the road. This is not to blame the bike’s design team. Their job is to give customers what they think they want and to make that mission statement attractive so they can sell motorcycles off the showroom floor. The more experienced the rider, the more the manufacturer meets the mission statement. Specifically, an experienced rider knows how much fairing is needed to meet their requirements. For whatever reason, you have been brought to this page… Thank you for reading this far. We welcome you as we continue our search for motorcycling’s Holy Grail of Air Management. factor one The angle of attack: Like a kite or underside of a wing, the angle of attack is the deflection angle between the craft’s surface and the air stream. Many shields have pitch adjustments. It seems logical that the more upright the shield, the greater the deflection and the quieter the capsule, but this is often not the case. When a shield is pitched forward, it does push the air stream higher, but it also moves away from the rider, meaning the rider is further back in the capsule. One might not think this is a big deal, but anyone who has experienced a capsule close-up knows how quiet it can be. Finally, the more upright the shield, the harder the air stream will tumble back into the air pocket. This is why the angle of attack and proximity are interconnected. Which brings us to… factor two Proximity: There is an old saying… there is no replacement for displacement. This means a small engine doesn’t have the punch of its big brother. This is true with equal things, but there are always playoffs. As far as proximity and capsule quality, the old truism is inverse… There is no replacement for less displacement. This means the less distance between the rider’s helmet and the shield’s trailing edge, the quieter and calmer the capsule. The fairing type has a significant impact on this. By design, a frame-mounted fairing must be positioned further away from the rider, as it must clear the handlebars at full steering lock. On the other hand, a handlebar-mounted fairing tucks in close to the bars, placing the shield’s top edge much closer to the rider. You don’t see more handlebar fairings mainly because handlebar mounting focuses the wind load onto a pivot point, which can lead to wobbles. factor three Shape and Form: The angle of attack is usually thought of along one axis, the underside of a wing, for example. Fairings and shields are often double- or triple-axis forms. Consider the air stream a fluid; these ratios of curves determine how the air is stretched, compressed, and deformed in its journey to reunite with its fellow molecules. Generating an air capsule is a challenging task and bears no resemblance to an aircraft trying to slip through the air mass while causing as little disturbance and drag as possible. Touring fairings have to open a capsule quickly, and as you will soon see (illustrations are forthcoming), the internal dynamics are more akin to a war zone than a negotiation. This is an excellent way to transition to the next section. factor four Internal Dynamics: Think of the internal dynamics as an engine. The high-speed air around the fairing generates a suction, resulting in a back-draft or counterflow within the capsule. The rider notices this mainly over the shoulders and neck, but the counterflow occurs virtually on all sides of the capsule. This flow is not smooth and is often punctuated by internal crossflows from induction vents, deflections up through steering wells, and off objects such as mirrors. If this sounds like a real mess, you are right… It is. factor five External Dynamics: Everything would be much simpler if the air mass were smooth and still, but it is often far from that. The only soft air is in a wind tunnel or on a desolate back road at three in the morning. The air mass is generally an intergalactic storm, and the rider has to deal with crosswinds that will distort the air pocket’s wake zone.
Saeng introduced the Wing-Tip air deflector in June 2003. It was years ahead of its competition. The Wing-Tip had excellent performance but never gained widespread popularity. Today’s popular wind deflectors are nicely proportioned and provide a significant boost. This one is shown with an airLift trim. A windshield wind deflector has an ideal angle of attack. Increase the pitch too much, and the air stream will become more turbulent. Circa 1990, Saeng was experimenting with full-screen sub-duction venting. Discover the story behind the technology that was never released… Coming soon is “The Saeng Story”. _		cause Effect and Solutions: We don’t have much control over external dynamics. At times, switching lanes or increasing vehicle spacing lessens turbulence, but often, we have few, if any, options. Viewing the capsule and outer air stream as interrelated helps us understand why a smooth capsule is rare. What can we do to manage and improve comfort on long rides? It is not uncommon to buy a taller shield only to discover the problem was not solved. The purpose here is to share our perspective and hopefully help you avoid making the wrong decision. There are numerous helpful products on the market, many of which may be effective. The question is which product or combination of products will give you the most bang for your buck. We will discuss these product options and give you a better understanding of how they work and interact with the capsule. where to start You know something needs to be done when helmet-shake blurs your vision. However, did you know that even mild wind noise can cause hearing loss? Our first instinct is to assume the shield is too short, but is that the case? Some test by putting their hand on the shield. At the same time, others try sitting lower to see what a taller shield would do. If the test improves the capsule, a bigger shield should fix the problem… right? After the cost and effort of changing shields, the answer is often no, and the results are disappointing. The test wasn’t conclusive because the rider changed more than one variable at a time. You are scrunching down or placing a hand on the top of the shield, forcing one to lean in. In both cases, these actions cause the rider to go into a better area of the air pocket. hands It can be a misleading indicator. Deflection from a hand does not duplicate a taller shield. The contours of the hand make Micro-Swirls. The swirls boost deflection, so ironically, you may have proven airLift edging may be all that is needed. The real question should be, how do I choose the best solution? Several air management product alternatives don’t relate to the shield. For instance, changing bars or seating can position the rider and passenger in a smoother capsule area. Additionally, adding lower or side deflectors can effectively prevent capsule updrafts. Ultimately, the location of the shield’s top edge often indicates the necessary adjustments that need to be made. Usually, a deflector is best when the line of sight is six inches or more over the shield. However, if the line of sight is between two and six inches, add airlift™ edging. The above paragraph is a good rule of thumb, but it’s essential to look deeper into how each solution works. In the upcoming sections, we will analyze the differences between windshield extensions, windshield deflectors, induction venting, and micro-swirl technology. How each of them has its playoffs, and how they can work together to bring new levels of air pocket comfort. extensions Is more shield better There are several advantages to windshield extensions. One is that they are often removable, so the rider is not stuck with the looks of a taller shield or the extension itself when it is unnecessary. But the most significant advantage is that the extension is often adjustable in pitch. The fairing body usually determines the angle of the replacement shield. In such cases, a taller shield is not what you get. Instead, one gets a more extended shield, angled back, with very little increase in height. The extension circumvents this by allowing the rider to set the angle, thereby determining the amount of air deflection and where the extension’s top edge terminates. For many riders, this simple solution is all that is needed. The only drawback I see is that the extension’s width is often too narrow to protect the rider in a stiff crosswind. deflectors and windshield multi-foil deflection In its simplest form, a deflector is nothing more than a foil. However, the most common wind deflectors on motorcycles are adjustable in pitch, and some can also swing forward or backward. Their positioning on the shield, the gap between it and the shield, and the angle of attack can change their role from a simple deflector into a multi-foil system. The deflection action of the foil and the shield can interact much like an upper foil on a biplane, helping to prevent a lower foil from stalling. As such, the deflector changes the behavior of the air stream as it leaves the trailing edge of the shield. Besides providing its boost, it can also help the air stream exit the shield more smoothly. Adding a micro-swirl generator can also benefit the foil and shield. However, we will first explore back draft induction venting before discussing the added boost from micro-swirl layering. venting back draft induction venting Rifle Fairing popularized induction venting in the late 70s or early 80s, which reduces low pressure and improves airflow behind a fairing. Over the years, induction vents have increased in size. Today, many shields are mounted above the fairing body, allowing the air stream to be inducted along the entire leading edge of the shield and then channeled upwards. Induction backdraft venting helps reduce buffeting. There are two downsides to consider. Firstly, the inducted air must travel a considerable distance before interacting with the top air stream. Secondly, it bleeds the boundary layer, amplifying the impact of turbulence on the motorcycle. All-in-all induction venting to help stabilize the air pocket is a good playoff. Also, induction venting systems are compatible with wind deflectors for motorcycles and micro-swirl generators. Work in progress. This journey for The Holy Grail of Air Management is far from over. We will be posting more on tuning air capsules, so stay tuned. In the meantime, please feel free to leave comments, suggestions, or corrections via the contact page. All the best to our fellow riders.