02.23.10
Posted in Miscellanea, Velomobiles & HPVs at 8:24 pm by smalghan
After a full day of explicating the finer points of velomobile design at the European Velomobile Seminar on Saturday, it was time to hit the road and enjoy velomobiling around Copenhagen! My host Halfdan lives only two miles away from the Leitra factory so after a hearty European breakfast we drove over to check out our rides for the day.
While inside, I got a better look at a Leitra chassis being constructed of stainless steel and top flight components like a SON generator hub and a Rohloff. Since each Leitra is built to order with a variety of components and options, it may be possible that Carl-Georg has never built the exact same Leitra twice. The factory has several Leitra on hand as demos, mine was white and green with wheel fairings. Luckily, the bottom bracket boom was of the right length for my legs though the fairing was a little higher than I’d like for good visibility. I quickly settled in and in a few minutes our convoy started pedaling towards Copenhagen…
Over the nearly 25 years of production, the nearly 300 Leitras around the world have traveled more miles than any other velomobile. If it’s not quite the newest and sexiest velo out there, It’s designer and builder Carl-Georg Rasmussen has constantly refined it into certainly the most practical and livable vehicle whose virtues of practicality and livability are revealed over miles and hours in the seat.
Even with just a thin cushion, the fiberglass seat was quite comfortable. The fasteners are sited well away from any place where your body might touch them and the seat has just a little give to accommodate different body shapes. My ride was equipped with a Sachs 3×7 drive and drum brakes up front and both felt like they had done many miles. The brakes were not all that powerful but after a little practice, modulation became easier and it was at least possible to slow down smoothly. The Sachs system suited the Leitra well but it happened to keep shifting past the gear I wanted to ride in most of the time. For a while I tried to hold the gripshifter to keep it in gear but that became annoying and I just dealt with being in a gear just a little to high or a little too low. I can imagine the Sachs would be a good choice as the internal gears ensure you won’t be caught out in too high a gear at a stop and the gears were spaced well with a range that made only one front sprocket necessary.
Steering the Leitra is by dual joysticks that fell right to my hands. Unlike most trike steering systems, the joysticks in the Leitra don’t end up running into your leg with lots of lock; they do go through a slight arc but after the first few actuations it feels most like a fore and aft motion. I was surprised how tight a turning circle the Leitra could manage, even navigating around bollards at trail entrances or turning around on sidewalks was no problem.
The Leitra handles better than I expected, after my time with a Catrike Speed I was expecting that with the Leitra’s higher center of gravity and shorter wheelbase that lifting the inside wheel in a corner and putting daylight under the rear wheel under braking would be a common occurrence, yet neither happened. That can be explained by the far weaker braking power of the drum brakes on the Leitra but the more forgiving handling is possibly due to the slightly slower steering, soft front suspension and wider track. That extra stability really inspired confidence that the Leitra could safely maneuver around the odd pothole, errant pet or any other obstacle that might lay in its path.
The all wheel suspension proved its worth on cobblestone surfaces as well as helping to soften the blow of riding up on low curbs (even in Copenhagen!). The fiberglass springs don’t have quite the wheel control of a coil spring/oil damper setup but are much lighter, simpler and compact.
I half-expected the fiberglass shell to resonate to the point of irritability over the cobblestone stretches of downtown Copenhagen but it really wasn’t an issue. More visibility would be welcome, especially to sight the front wheels while maneuvering around obstacles but it’s a delicate balance to prevent the cockpit from becoming a solar cooker; it’s amazing how quickly sunlight and body heat make the interior warm and eventually a little too much so. Then one realizes the reason why the small, upright windows of a Leitra make so much more sense than the fully transparent canopy used on a Go-One, for example. For hotter climates, more flow-through air is required. Halfdan has had great success with the front intake duct he made to channel air directly to his face and neck. The real glass forward section of the windshield (which never fogged up, by the way) also deserves mentioning as it provides a scratch resistant surface for the manually operated windshield wiper.
Riding to Copenhagen is a very gradual downhill journey so the Leitra felt like it rolled well. The trip home though, felt more strenuous than it should have with the Leitra not coasting well at all. I figured it was due its general old age but once we got back to Halfdan’s house the diagnosis was simply underinflated tires. A short trip from his house to the factory revealed a huge difference and made the velo much more enjoyable. At least I got a good workout!
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12.20.09
Posted in EVs, Miscellanea at 8:05 pm by smalghan
After several attempts to restore function, at long last the AC Forum is back online. If you’re incorporating an AC drive into your EV conversion, this page will serve as a great resource.
Also, if you need back-end web page work at a reasonable rate, check out HLiNaK. I’ve used their services and am very happy with the results.
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12.05.09
Posted in Miscellanea at 2:01 pm by smalghan
Looking for a unique gift to give this holiday season? Until January 15, 2010, Google will match your donation to EWB-USA and significantly increase EWB’s ability to bring engineering solutions to people around the world that increase public health and strengthen communities. Click here to go to the Google donation page.
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11.20.09
Posted in Velomobiles & HPVs at 10:38 pm by smalghan
Here it’s already been a month and I haven’t yet posted the presentation I made at the velomobile seminar.
The paper, Design and Development of the Turanga Velomobile, can be found at the seminar proceedings site here and locally here.
A hardcopy of the slide presentation in pdf form can be found here (8.3MB). As an added bonus, these slides are actually formatted correctly, as opposed to the exported-to-PowerPoint-and-very-mangled version that I used for the actual presentation. I figured that Keynote 5.0 would have perfected this feature by now but no such luck. I did the best I could under the circumstances though, so check out video of the presentation here.
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11.12.09
Posted in Miscellanea, Velomobiles & HPVs at 11:49 pm by smalghan
I’ve never put much thought into getting around on a bike with a little one, but with the impending arrival of our own tiny passenger I’ve been taking a closer look at some of the ways parents take their kids along for the ride.
In Copenhagen, getting around on bikes is just what people do since it happens to be the most convenient, fastest and most flexible way to get around town, not to mention a great way to stay warm and fit. During a velomobile tour around the city the day after the seminar I noticed a very well-trimmed version of the typical kid carrier…
…another Leitra on the tour with a Burley-type kid trailer attached 
…and finally this fantastic contraption: 
Instead of packing the kids in the minivan to get to school or day care, it’s commonplace to see the kids being pedaled around by mom or dad in a family trike, a vehicle I had never heard of yet upon first sight thought it was the most handy bike ever invented. The design brings together substantial kid and cargo- carrying capability, the stability of a trike format, an upright riding position for mom or dad and the best seats in the house saved for the kids to watch the world go by under the watchful parent’s eye.
The most popular models are the Kangaroobike (pictured above) and the Mobii, both if which were ubiquitous around town. Both have seating for two kids and space for bags while keeping and rain and wind off of the valuable contents inside the bubble. They’re so sensible I couldn’t believe I hadn’t seen them before. An email to the makers of Kangaroobike revealed that they are considering entering the US market but have to become comfotable with the product liability regulations here before that happens. I can only believe they’d be a hit here, even at $3000.
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11.10.09
Posted in Velomobiles & HPVs at 3:51 pm by smalghan
The
velomobile conference served as the debut for several new velomobile designs from around the world and I found the most inspiring was Harald Winkler’s completely custom built 12kg velo, a vehicle so light that he began his presentation by carrying it on stage holding it high above his head.
Harald’s velomobile was designed especially for geting around his hometown which has smooth roads but is hilly and has a lot of intersections. Hence, the overriding concern was to reduce weight and make acceleration and getting up hills as easy as possible. His design incorporates a carbon fiber perimeter frame/seat structure, a delta layout using an offset chain run to drive a single rear wheel and a foam body, employing his self-developed MEUFL foam technology, that weigh little more than 1.5kg. Frontal area is extremely small due to its road-hugging narrow, low profile design as well as 16″ wheels that might just be the smallest ever used on a velomobile.
There were several other clever features such as custom made tires (larger diameter tires were sectioned and glued together to make high performance tires that are otherwise unavailable for 16″ wheels). a plastic steering u-joint with adjustable pre-load and most conspicuously, a couple of small propellers that produce a high pressure air bubble at the front of the windscreen, eliminating the need for windshield wipers to clear rain from the driver’s view.
As clever as the features included, the design is also notable for what it leaves out. There is no suspension nor typical crank assembly; the pedals are carried by an s-shaped carbon fiber tube that transmits pedaling force to a sprocket mounted to the left-side carbon fiber spar, leaving the volume between the seat and crank completely unobstructed. Besides making entry/egress much easier, to the user it becomes less a mechanical tool and much more a friendly consumer product designed to satisfy human needs first.
In many ways this vehicle would be impractical for American roads yet it fits its intended environment and Harald’s needs perfectly. It is a great example of minimalist ingenuity and made me realize how complex the current Turanga design is, despite the fact that simplicity was one of its guiding design principles. I’ve learned there’s always a little more that can be done to make less, if you catch my drift.
Harald’s paper, along with the other papers presented at the seminar, can be found here.
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Posted in Velomobiles & HPVs at 3:11 pm by smalghan
The 6th European Seminar on Velomobile Design, held in Copenhagen this past October 16-17, brought together velomobile enthusiasts, owners and builders from around the world to discuss the current state of the art and how velomobiles can build public visibility in proportion to the great utility that they can provide. Every paper presented offered enlightening perspectives on, for example, design technology like Ingo Kollibay’s Four Wheeled Velomobiles, increasing social acceptance like Antal Joo’s and Gabor Joo’s Possibility and Situation of Velomobile Riding in Hungary and Jurgen Eick’s depiction of living with a velomobile as a primary vehicle for the last 20 years (Caution, large downloads). Not to forget, I also presented a paper on the development of the Turanga velomobile.
The complete papers can be found here and I’ll be blogging about some of the most notable points of the whole trip over the next few weeks.
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08.31.09
Posted in EVs, Miscellanea at 10:38 pm by smalghan
Though the eMR2 couldn’t be there, this Saturday’s Power of DC autocross event hosted a variety of factory and conversion EVs from all over the east coast. Three Teslas, including a Sport model, tore around the course with the Sport model setting fastest time of the day by rounding the course in under 18 seconds. Though the Teslas set the pace, it was a Mini-E that set the record for the most runs as it rounded the track nearly all afternoon.
Among the conversions, surprisingly it was a VW Rabbit pickup that cut the cleanest path around the cones despite it’s nearly 3/4 ton of batteries. A sunburst yellow Destiny 2000 (based on a Pontiac Fiero chassis) gave it a run for the money but the Rabbit’s driver was an obviously experienced hand who could make the most of his car’s abilities.
Other interesting vehicles that ran the course included the WVU Formula Lightning racecar, a Porsche 944 conversion and a daily driver VW Jetta. Below the pictures are the times for all the day’s runners, courtesy of Chip Gribben.
AUTOCROSS
Saturday, August 29
place/et/driver/vehicle/runs
Production EVs
1) 17.761 – Dave Bolling – 2009 red Tesla Sport (31 runs)
2) 17.979 – Don Auker – 2008 blue Tesla (44 runs)
3) 18.718 – Tom Jamison – 2009 prismatic blue Tesla (19 runs)
4) 19.316 – Ken Barbour – 2009 Mini-E (64 runs)
5) 23.289 – Bryan Murtha – RAV-4 EV (5 runs)
Conversion EVs
1) 21.214 – Dave Cover – Porsche 944 (6 runs)
2) 21.948 – Alan Arrinson – VW Rabbit truck (13 runs)
3) 22.648 – Doug Stansfield – White Hyundai Tiburon (5 runs)
4) 23.441 – Bob Rice – VW Jetta (11 runs)
5) 24.842 – West Virginia University – Formula Lightning (9 runs)
6) 26.643 – Joe Lado – Destiny 2000 Fiero (24 runs)
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08.28.09
Posted in EVs, Miscellanea at 9:24 pm by smalghan
Finally, this past week I was able to enjoy commuting in the eMR2 v2.0, equipped with a new single speed transmission, motor coupler and batteries, every day.
There’s still some mechanical work to do, such as address the howling rear wheel bearing and sticky CV joint, but all the EV conversion components are performing as designed.
Pictures and video coming soon, as well as a report from Power of DC happening tomorrow in Hagerstown.
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07.24.09
Posted in EVs at 2:30 pm by smalghan
A couple years ago when the eMR2 was still in the design stage, there were two competing coupler designs: a simple dual spline coupler (described in a previous post here) and a more complex design that incorporated the spring cushion hub from a stock MR2 clutch.
Incorporating the cushioned hub would insulate the splines for shock loads and provide a little misalignment tolerance. After the experience with the straight coupler these durability advantages, along with a provision to securely clamp the coupler to the shaft to prevent any axial movement, made the additional cost of the design justifiable.
The clutch hub was harvested from an ACT performance street clutch disc and cost about $90.
ACT Street Performance Clutch Disc
The rivets fastening the friction disk to the hub were carefully drilled out. The rivets also serve as spacers for the hub plates and can be seen at the bottom of this picture:
Dismantled Clutch Hub
Substitute spacers with the proper ID to fit the 1/4″-28 screws that replaced the rivets were easily sourced from McMaster-Carr. They can be seen between the screw and old spacer.
The yoke was machined by Robert at Artistic Machining and then sent to Form Tools to have the spline EDM’ed. A shaft collar was also incorporated into the design to nail the whole thing down.
All the parts were put together with red Loktite and installed just prior to bolting together the motor and transmission.
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After a full day of explicating the finer points of velomobile design at the European Velomobile Seminar on Saturday, it was time to hit the road and enjoy velomobiling around Copenhagen! My host Halfdan lives only two miles away from the Leitra factory so after a hearty European breakfast we drove over to check out our rides for the day.
