The Twike Challenge
by Victor Muñoz, firstname.lastname@example.org
There is a vast gap between a 30 lb. bicycle and a 3,000+ lb. car. And balancing on two wheels at automotive speeds is a bit too much of a thrill for many non-motorcyclists. The Twike was developed precisely to help fill this void of options.
It was designed by engineers and architects concerned to combine some of the extreme energy efficiency of a bicycle with many of the comforts, performance and safety characteristics of a car. The Twike has the latter's all-weather protection, the relative safety of a recumbent seating position, and the power to flow with traffic even on steep hills. It can carry two adults plus a hundred pounds of cargo. Yet both driver (or "pilot," as Twikers are called) and passenger can each contribute as much human power as they wish to the motive energy of the vehicle. It is light enough that the human inputwhile not practically sufficient by itselfcan be a significant boost to its range. Certainly, the human power purist may object to the fact that the vehicle is 80 to 90 per cent motorized, but then the Twike was not designed to replace the bicycle. (Why would we want to do that?) It is the conventional automobileone and a half ton battering ram that it isthat requires replacing wherever possible. The typical car driver needs some of his or her excuses taken away. Incorporating many of a car's useful urban virtues but without its inherent wastefulness is the Twike's mission and challenge. Apart from that, it also takes all the fun out of driving a car!
14 Years in the Making
One of the first Twike prototypes, a purely human powered version, was presented at the 1986 Vancouver Expo by its Swiss designers, who were then students at the Federal Institute of Technology (ETH) in Zurich. The student project won an international award for innovative design in alternative energy vehicles at the Expo. Since, it has been through many stages of development and refinement. (The name, by the way, was derived from "twin bike.")
There are now about 500 Twikes in Europe, mostly in Switzerland and Germany, and a handful in the US. Until recently there were two incarnations of the company, S-LEM and Twike A.G., but in the fall of 1999 they merged into SwissLEM A.G. (LEM stands for Light Electric Mobile.) The company's initial marketing strategy centered on distribution through a network of small locally owned Twike Service Centers/Dealers. Ralph Schnyder, who was part of the original design team is still among the company's leaders. His team's dedication over the years to the challenge of introducing such a radically new idea in transportation is truly remarkable. In the next few years, the company hopes to make a significant entry into the US market, again by working through small local Twike Centers. There are already a handful of Twike pioneers in Washington, Oregon, Indiana, Vermont and Connecticut. EVsNW Inc. in Seattle, which specializes in electric power-assist bikes ("ebikes"), is currently the licensed US distributor.
As part of the EVsNW Coop, I had the chance to visit the original Twike center in Gelterkinden, Switzerland in the spring of 1998. I was there to take an assembly course from Ralph and to learn as much as I could about the Twike in my brief six day visit. Nestled in a narrow valley in the foothills of the Alps, the village of Gelterkinden reassured me as I approached it for the first time that any vehicle produced thereabouts could not avoid contending with steep grades. (This had been a problem with some early flatland-made electric vehicles I had previously owned.) Ralph and his family lived in a beautifully restored 500 year old stone barn. A trained architect, part of the impetus for his involvement with the Twike was the need to reduce acid rain, which apart from its other ill effects, is fast defacing ancient buildings throughout Europe. Being an avid three-wheeled recumbent biker and designer, of course, offered another reason to pursue the idea.
Let's face it, most of us are never going to enjoy pedaling up a steep hill, let alone in rain, wind and snow, with impatient traffic tailing you or whizzing by. The Twike was engineered around the notion that one should be able to pedal a vehicle, use city streets, keep up with city traffic, carry a passenger and luggage, without having to brave the elements or forgo the most basic comforts of a carbut do so at least 20 times more efficiently than any conventional internal combustion vehicle. At 80 watt-hours per mile (without pedaling), the Twike gets the equivalent of 300+ miles from the energy stored in one gallon of gasoline, converted to electricity. Any pedaling you do is icing on the cake.
The vehicle comes with either a Plexiglass or a laminated safety glass windshield, windshield wipers, the standard array of automotive lighting, defrosters, horn, 3-point seat belts, an aluminum ultra light aircraft frame and roll cage, and a removable Cabrio top (Twikes are fun in nice weather too!). The single front wheel is steered by a tiller controlled with the pilot's right hand and arm. The pedals are mechanically connected to the rear axle, but freewheel when the axle is turning faster than the pedals. Both pilot and passenger, neither, or either of the two can pedal with or without the motor. With a curb weight of almost 600 lbs. However, it is not practically possible to go more than a few miles an hour, even on the flat, exclusively on human power.
The highly ergonomic seats with excellent lumbar support are fully adjustable to accommodate a range of different leg lengths and preferred reclining angles. Both seats tilt forward to access the luggage area behind which is wide enough for about five full bags of groceries. Most driving functions are controlled by the pilot with a single joystick-like tiller includingbesides steeringacceleration, braking, signaling and cruise control.
A shifter on the center console permits three driving modes: 1) forward with motor and pedal input, 2) forward with motor only, and 3) reverse with motor only. A five speed gear shifter on the pilot's left allows the pedal drive different ratios. The pedal drive is geared to provide useful input at speeds up to 25-30 mph. Beyond 30 mph the vehicle would be operating almost entirely on electric power. Although capable of 52 mphand with amazing car-like accelerationthe Twike's efficiency was designed to peak out at about 25-35 mph, exactly those speeds most suitable for urban cruising.
The accelerator button, controlling motor power, is just above the regenerative braking button on the joystick. It has two user programmable performance stages and cruise control. A typical driving pattern is to hold down the accelerator button until your desired speed is achieved, then tapping the regen button once lightly will maintain the current speed for easy cruising, allowing you to concentrate on pedaling and watching the road. Any subsequent brake action or further accelerator button pressure cancels the cruise control, returning complete manual control to the pilot. No, piloting a Twike is not quite like riding a bike or driving a car...but like something entirely different, yet still very intuitive!
With three independent braking systems, the Twike is not short on stopping power. Rear hydraulic brake drums are activated by the pilot's back pedal action. Front mechanical disk brakes are controlled by a lever on the left control handle. Both trigger stop lights. But in addition to these conventional braking systems, regenerative motor braking is also available on demand at the light touch of the regen button on the steering joystick. In typical operation, the regen brake is the most often used brake, especially for planned stops. Even without the other brakes applied, it can bring the vehicle to an almost complete stop at two different levels of intensity, selectable by increasing pressure on the regen button, while at the same time recovering electrical energy for the batteries that would otherwise be wasted as heat on brake pads. Moreover, it can easily be locked at a user selectable level with the built in cruise control, an invaluable feature for extended down hill cruising in steep or mountainous terrain. (Remember, the Twike hails from Switzerland.)
Getting into the Twike requires tilting the entire canopy forwardjet fighter-like. Admittedly, this can be a bit awkward at firstI compare it to getting into and out of a bathtub. But every aspect of the Twike was designed with functional efficiency in mind, aiming for strength and safety but without succumbing to the usual automotive temptation to pile on mass. The outer skin is a single piece of molded Luran S plastic supported by an aluminum cage. The load bearing part of the frame consists of a continuous, undrilled, U-shaped, 3 inch diameter aluminum tube, to which all other structural members and components are clamped with cast aluminum brackets. Keeping this tube undrilled or unwelded enhances its strength. The one piece motor/transmission unit and two battery modules sit very low to the ground at rear axle level. 75% of the weight of the vehicle is resting on this axle, the rest, on the front wheel, thus keeping this independently suspended vehicle stable.
Power on Demand
Though the original prototype of the Twike was pure HPV, obviously to successfully flow with traffic the Twike had to have a motor. The designers chose a 336 Volt AC Synchronous propulsion system, powered by two (or, optionally, three) battery modules, each consisting of 280 C-size NiCad cells. Each module is further broken down into seven sections and each of these has its own battery monitoring electronics, sensing voltage, current in and out, temperature, and state of charge. A central processing unit collects information from each section of each module, and software processes the information for display to the pilot and for controlling performance and charging characteristics. An inverter takes the 336 Volts of stored DC power and converts it to AC for the motor. AC motors easily lend themselves to regenerative braking. The high voltage of the system enhances efficiency.
The software permitsamong other things and as previously mentionedthe user to set different parameters governing the performance of the joystick buttons, making it easy to customize acceleration and braking performance, thus balancing efficiency to individual taste. The vehicle can charge on either 220 Volts AC or 110 Volts AC (the latter with a small step-up transformer).
One of the outstanding features of the Twike, a product of it lightness and energy miserliness, is thatunlike many electric vehicles of the past and even many yet to comeit can recharge on ordinary house current at a very fast rate: 1 hour on 220 Volts, 2 hours on 110 Volts. Larger EVs require either a very expensive, uncommon, extremely high voltage and/or current electrical service,or can take all night to charge on conventional household circuits. The three battery module version of the Twike can travel up to 45 miles on a single charge. But because of its fast and universally available charging capability, the vehicle can achieve 150 to 200 miles a day with repeated charging stops. The record is over 350 miles in a day in Europe, where, of course, 220 V is much easier to come by.
In the scheme of things, human input can account for, at best, about 10% of the motive power necessary to move the Twike. Nevertheless, that's a vastly greater proportion than would be the case if we tried to move even a small gas car partly with sweat.
The '98 Challenge
Although providing an alternative to the car for common urban commutes and errands was the original idea behind the Twike, there is a growing enthusiasm for its touring potential. It so happens that an enjoyable cross country trek would only be pleasantly punctuated with stops every 40 or so miles. Twike clubs have been formed in Switzerland that sponsor village to village tours, rating restaurants in part by the friendliness of their charging facilities.
To date, the ultimate Twike tour, however, was the Twike 98 Challenge. In the summer of that year it made EV history. Over the course of 11 weeks, six Twikes accomplished a 7,000 mile journey, starting in Bern, Switzerland, traversing Germany, Czechoslovakia, Poland, Russia, the Baltics, and Finland on their way to Nordkap, the northernmost point of Europe, 200 miles north of the Arctic Circle, then back through Scandinavia, Belgium, and Germany to where they began. Comparable to going from Seattle to Boston, and then back again and then on to L. A., the trip consumed for each Twike 550 kWh or about $44 in electricity costs (at .08 cents/kW) (Ed. note: Rates have undoubtedly gone up since this writing). Proving their ruggedness, the little vehicles survived the untamed roads of the former Eastern Bloc with no more than occasional flat tires. In the world history of EVs there is probably no other instance of an EV (let alone six of them) covering such a distance in that block of time. The six Twikes were averaging nearly a hundred miles a day. The high voltage in Europe certainly helped. But even half that distance in a day is still far more than most Americans travel.
There is a marvelous photo documentary on the Internet at www.twikeklub.ch/challenge98/fotos.htm. American documentary film maker, Michael Patterson also went along for the first 1,000 miles or so and produced an engaging video of this first leg of the Challenge. There is something really amazingly cinematic in the night scene of Twike after Twike passing in review before the camera and a crowd of spectators... A copy of the film can be obtained from Michael by contacting him at email@example.com.
One issue that immediately occurs to car drivers, looking at the Twike for the first time, is safety. (Cyclists are apt to look at it in a very different way.) With such a thin skin not much stiffer than the plastic of a gallon milk jug and so light an aluminum frame, what chance has a Twike in a collision with an SUV? In the case of a side impact, there is undeniably very little between a Twike occupant and the bumper of a heavier vehicle, although front and rear collisions are buffered by fore and aft crumple zones. The vehicle has been crash tested in Germany and is considered the safest motor-cycleas it is usually registered in most states and countrieson the road. That's not saying much, of course, to someone accustomed to travelling wrapped in a ton or more of steel.
But there is another dimension to the concept of safety that may be, however fitfully, beginning to take hold as part of a more thoughtful general notion of what urban transportation should be. The idea that, in deciding what vehicle is deemed "safe," we should only be concerned about the safety of the occupant is self defeating. By that logic, the vehicle you are driving should always be bigger than what everyone else is drivingthe hell with pedestrians and cyclists. They don't deserve to live.
Few vehicles need to be as big as they are to perform their function in an urban setting and there is quite often in that setting other human flesh involved in accidents besides that of an occupant in a vehicle. The Twike was designed to be kind to what it may hit. There is no comparing the damage done to the human frame and flesh by the soft, pliant nose of a Twike and the steel cage of even a "safe" car like a Volvo, backed by six times as much mass... Walking shoes and bicycles are "safer" than Twikes, but not much else is.
Is it Worth it?
The Twike is one of the most unique and ambitious vehicles in the world. While I was visiting the Twike facility in Gelterkinden in March of 1998, I witnessed the rollout of a specially painted edition headed for Japan, to Honda R & D. (Who knows what they had planned for it?) As the world's most energy efficient two passenger motorized vehicle, it represents the extreme expression of an idea.
Customer satisfaction is high and used Twikes are still quite rare and fetch high prices. New Twike prices can range from about $16,000 to $20,000, depending on options. Not a HPV, nor quite a car, many find it difficult to assess. My experience has been that the chance to ride or pilot a Twike noticeably changes the tune of some price skeptics from "That's a lot of money for something with pedals" to "How can I afford one?" Both expressions acknowledge the price, but the second begins asking the right question.
Walter Breitinger of Valparaiso, Indiana and Ron Manganiello of Burlington, Vermont are two intrepid North American Twike pioneers. Walter is now pushing 20,000 km on his Twike, which he dubbed Verde, through the subzero winters and 100+ degree summers of Indiana, day in, day out. Ron, an energy efficiency expert and ardent cyclist, got tired of pedaling a bike in New England blizzards, but felt there had to be some better alternative than a car. So after experiencing our Twike, during a visit to Seattle, he and his wife, Ellen, packed off to Switzerland and actually participated in the assembly of their own 1999 model.
The company is committed to unstinting quality and engineering and to innovation (the next generation of Twikes will probably sport Nickel Hydride batteries), but it is also concerned to use as much recycled and recyclable material as possible. There is a conscious effort to avoid components manufactured in countries where labor is exploited. Much of the electronics are made in Germany, Japan and the US. (T. B. Woods of Pennsylvania makes the inverter, the heart of the electrical system.) These factors coupled with the still limited, hand-assembled, production help explain the cost. All the same, it's common to see a lot more money wasted on vehicles with a lot less vision.
Note: In the meantime in summer 2000, the Twike Company founders Ralph Schnyder, Christian Meyer and Peter Zeller started a new company for software and product development (www.dreifels.ch). They are also involved with the Velocity Dolphin electric bicycle (www.velocity.ch).
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