CHAPTER RATIONALE FOR HUMAN-POWERED 1 VEHICLE DESIGN AND USE his book is about the design of vehicles with wheels that are powered by hu- Tman muscles alone. These can provide affordable, sustainable, and healthy transportation to people around the globe. The term Human-Powered Vehicle, or HPV, is sometimes used to denote a sub-class of vehicles including only high-performance bicycles or tricycles equipped with aerodynamic fairings. More generally, the term refer to any semi-recumbent bicycle. But the term should properly refer to any means of carriage, conveyance, or transport that is powered solely by human muscles. Manufacturers of bicycles, canoes, kayaks, and scooters do not market their products as HPVs, but surely all of these qualify for the name. Hybrid human-powered vehicles such as mopeds and electric bikes use human power in addition to other sources. While these vehicles are outside our definition of HPVs, they are certainly similar, in both technology and philosophy. Human-powered vehicles were originally designed for transportation, and that is still their most important use. HPVs today provide clean, quiet, and efficient transportation. In most developed countries, and in particular the United States, the primary transportation systems are powerful and inefficient, generating large amounts of air and noise pollution. HPVs may be chosen simply because it is pleasurable to travel quietly through the countryside, experiencing nature rather than blocking it out behind steel and glass. They may be chosen because in some cases HPVs provide mobility that no other vehicle can. Couriers in congested cities use bicycles because they are faster. Campers and fishermen in areas such as Minnesota’s Boundary Waters or Ontario’s Algonquin Park may choose a canoe because no other vehicle can traverse the lakes, rivers, and portages quite so 1 ASME_Design of Human Powered Machines_Ch01.indd 1 Manila Typesetting Company 04/01/2016 02:57PM Design of Human Powered Machines well. Many choose human power because it is significantly less expensive than other alternatives, or perhaps because it is good for their health. Athletes and those with a competitive bent can find many venues for racing. Perhaps the most compelling reason to use HPVs is sustainability: the environmental footprint of HPVs is typically much, much smaller than that of other modes of transportation. Despite these commonalities, HPVs are used by a variety of different people for a wide range of diverse reasons, including recreation, competition, cost, health, transportation, and concern for the environment. This book is limited to design of land human-powered vehicles. There are many reasons why the design and use of such vehicles is beneficial. In developed coun- tries, using an HPV in lieu of an automobile (or in lieu of a second automobile for a family) can save $5,000 to $10,000 each year, while improving health and reduc- ing emissions of greenhouse gasses and pollutants. Greenhouse gas emission will be reduced by more than 4,000 kg per year due to the corresponding reduction in energy consumption of more than 17,000 kWh. In addition, infrastructure for cycling is far less costly than highways designed for automotive traffic. It is appro- priate to look more deeply into the benefits of HPV use. Recreation HPVs, including both land and water vehicles, are frequently used for recre- ation. Often a bike ride or a canoe trip is a social event with friends and family. Quiet streets and rural roads can offer excellent cycling. The number of bicycle paths is increasing in many parts of the United States as abandoned railroads are converted into rail-trails and as local, state, and national parks provide more bike trails and paths. These facilities provide scenic routes for day rides, and can provide a sense of security for young riders, their parents, and others who are concerned about riding in traffic. Increasingly, the trails are long enough to use for multi-day trips. Streams, rivers, lakes, and coastal waters provide a rich range of environments for canoeists, kayakers, and rowers. A quiet pond or small stream may be an ideal place to get away for a while with a small paddle craft, while white water offers kayakers thrills and challenges. Many regions of the country have waterways that are restricted to human-power, either through law or in practice due to the nature of the lake or river. Competition Racing HPVs has likely existed as long as human-powered vehicles them- selves. It is easy to imagine a group of tough and intrepid cyclists racing their 2 ASME_Design of Human Powered Machines_Ch01.indd 2 Manila Typesetting Company 04/01/2016 02:57PM ASME_Design of Human Powered Machines_Ch01.indd 3 Manila Typesetting Company 04/01/2016 02:57PM Rationale for Human-Powered Vehicle Design and Use high-wheeled ordinary cycles over roughly paved roads in the nineteenth cen- tury. As bicycles became more advanced, the competition undoubtedly became faster, but perhaps no keener. Today, bicycle racing is an extremely popular sport in many parts of the world, especially Europe. Competitors can find venues for racing a variety of human-powered land and water craft, and several competitions have involved aircraft. HPV organizations provide many venues for racing re- cumbent vehicles, including very fast streamliners. Often these events showcase technological developments and design innovation. Many are local or regional events, sponsored by clubs. Of the more traditional races, the most well known is the Tour-de-France, an event restricted to diamond-frame bicycles. Two notable races that permit recumbent bicycles and streamliners are the Race Across Amer- ica and the World Human-Powered Speed Challenge. The Race Across America is one of the toughest races in the world. Competing individuals or teams start in California and race to New Jersey, with minimal sleep. The team record is slightly over 5 days for a faired recumbent bicycle, while the individual record is a little over 8 days. The World Human-Powered Speed Challenge held in Battle Moun- tain, Nevada, has hosted most of the land HPV speed records in recent years. On September 17, 2015, Todd Reichert set the men’s world record for the 200 meter flying start time trial with a speed of 137.9 kph1 (85.71 mph). This is quite remark- able, considering that top speeds for conventional racing bikes are usually under 50 kph (31 mph) and for recreational cyclists around 30 kph (19 mph). For vehicle engineers, racing is a means of validating and proving new de- signs and design modifications. Competitive cyclists tend to be strong and to ride frequently. They demand the best performance from each vehicle system and often ride vehicles to the limits of performance. Components and systems that continue to operate and function well throughout training and racing generally function well for many years of less rigorous use. In recent years, cycling compo- nent manufacturers have competed to develop better, lighter, race-worthy parts and systems. The most successful designs become top-tier components seen on the best competition vehicles. Lower-tier components benefit as the best tech- nologies trickle down through product lines. The bicycle or HPV consumer is the ultimate beneficiary of this process, as the quality of lower-end components has increased significantly over the last few years wit hout a concomitant increase in cost. 1IHPVA announcements, http://ihpva.org/home/, Accessed October 10, 2015. 3 ASME_Design of Human Powered Machines_Ch01.indd 2 Manila Typesetting Company 04/01/2016 02:57PM ASME_Design of Human Powered Machines_Ch01.indd 3 Manila Typesetting Company 04/01/2016 02:57PM Design of Human Powered Machines Economics While the physical challenges and excitement of racing appeal to some, econom- ics attracts more people to HPVs than perhaps any other reason. Human-powered vehicles, especially bicycles, are substantially less expensive to purchase, own, and operate than other vehicles. In the United States, a significant number of people with limited or no income use bicycles for transportation simply because they are affordable. This group includes students, of course, but it also includes many of our nation’s poor. It is not hard to find a rideable bicycle at a garage sale or thrift store for less than $25.00. What many people with incomes well above the poverty level do not realize is just how large transportation costs can be, partic- ularly with a transportation infrastructure that favors personal automobiles. The cost differential can be calculated relatively easily. Consider a commuter that lives seven miles from her workplace. Additional driving brings her yearly average up to 15,000 miles. She bought the car after graduation from college for $18,000, paying $4,000 down and financing the rest at six% interest. On average, the car gets 22 miles per gallon, and her average price for fuel is $2.60. Maintenance costs her on average five cents per mile. She is more fortunate than many city workers, as she has free parking both at work and home. Including insurance at $350 per year, her total operating costs are very close to average, about 45 cents per mile. See Table 1-1 for more details and assumptions. She decides to investigate how much money she would save if she sold her car and bought a bicycle. Her bicycle would cost $1500, plus an additional $250 for clothing and accessories. She would spend about $725 each year on bicycle maintenance, sports foods and drinks, and accessories. Because she makes some long-distance trips that would not be practical for the bike, she spends about $400 per year on automobile rental. Since she rides regularly, she also cancelled her $216 gym membership. Annual cost for both car and bike are plotted in Figure 1-1.