More Inverter Smoke

The eMR2 hasn’t rolled too many miles since the pack capacity dropped off but I still manage to have some fun running around the neighborhood.  After a trip to the dog park, I was jockeying the car around in the parking space outside of the garage when the sickly-sweet odor of roasting electronics filled the air.  The car would still move forwards and backwards and the 12V DC-DC converter was still functioning but I went ahead and rolled it into the garage.

Opening up the inverter revealed a couple of capacitors that were swelled and ruptured, leaving their burnt entrails across the board.

I don’t know what these capacitors do but I’m hoping that replacing them is all that’s needed to get back on the road.  I have read it’s reasonable to expect capacitors to dry out and fail after some time even if they haven’t been used.  I suspect these Siemens inverters are about 20 years old now so it may be that they just came to the end of their functional lives.

Hopefully its not any bigger problem than that.  I’m in the process of removing the board and taking a closer look.

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Taken for a Ride

Some recent road work close to home unearthed a section of streetcar track, a remnant from an era where every American city worthy of mentioning had its own (private and profitable) surface rail transportation  system.  That era ended with the acquisition of the Baltimore system, along with scores of others, by a holding company called National City Lines (NCL) that proceeded to tear up the tracks and replace the streetcars with vastly inferior buses.

This episode (more like tragedy) is well documented in the movie “Taken for a Ride”, a film I finally got to see this past weekend when a spare 90 minutes fell into my lap.  Check out the movie here and then read in more detail about how the Philadelphia system succumbed  here.

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Reflections

A year ago I had just returned from the 6th annual velomobile seminar in Copenhagen freshly inspired by ideas about human powered vehicles from all around the world.  That was just the beginning of the transformation as less than two months later my son was born and I embarked on the lifelong adventure of fatherhood.  At the same time my wife became a mother and it’s been fascinating to see how each of us look at the world a bit differently than in the B.C. (before child) era.  So how does this all relate to the Turanga mission of sustainable transportation design?

If anything, the urgency to fill the need for people to get around comfortably and in a healthy manner has only increased.  Bike lanes and pedestrian ways are becoming a standard part of road planning and bike ridership continues to increase.  I notice a lot more bikers here in Baltimore and “sharrows” are popping up everywhere.  Whereas previously I didn’t even imagine the need to take along a passenger in a velomobile, today I can’t fathom designing one that doesn’t have a comfortable space for a little kid to watch the world go by while being pedaled to the market, library or just for fun.

Just as importantly was listening to the input of my non-biking wife as her concerns are representative of a large segment of people who would like to get around via human power but have a low tolerance for the risks that transportation bikers take in stride.

Though I occasionally find the non-biker’s perspective annoying, as a designer there is much value in resolving problems that enthusiasts simply tolerate.  For example, eye height level has been a frustrating issue to tackle as a tall velo lends itself to a (so far) slightly awkward aesthetic that would alienate a typical velomobile enthusiast regardless of the fact that in the big picture, having the rider feel comfortable in traffic is beneficial to all riders and helps make the velo a true car substitute (though it doesn’t help that cars have gotten significantly taller over the past ten years).

Electric assist is another issue that bike enthusiasts aren’t too keen on but, as evidenced by my friend Mark who uses a Catrike with BionX to navigate the hills of Berkeley, not having to pedal all the time is a strong incentive to use a (nominally) human-powered vehicle all the time.

But taking a step back, the real design problem is not the fact that the designer doesn’t necessarily agree with what some customers want but rather is still working to synthesize a solution that satisfies apparently contradicting criteria.

Through many iterations a solution is slowly emerging though, and the resulting product will be far better for it.  With the addition of a fourth wheel, rear wheel steering has been ditched while the tilting function is much improved.  Overall the design is far simpler to ensure that more people can make the economic jump from bike to velomobile. Those are the just the rational points but there are plenty of features that will make the Turanga velomobile the most enjoyable way to get around town whether it’s raining, snowing or sunny outside.

Next time I’ll run down the myriad updates the eMR2 has been through, it’s finally driving like I dreamed it would!

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55km in a Leitra

dsc01212After 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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AC Forums Back Online!

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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Google Matching Donations to Engineers Without Borders

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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6th European Velomobile Seminar-the Turanga Presentation

designseminar-smallHere 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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Biking with Kids

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…

DSC01153

…another Leitra on the tour with a Burley-type kid trailer attached DSC01179

…and finally this fantastic contraption:  DSC01145

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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Harald Winkler’s MEUFL Velomobile

                               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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6th European Seminar on Velomobile Design

designseminar-smallThe 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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