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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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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06.07.09
Posted in Miscellanea, Velomobiles & HPVs at 10:12 pm by smalghan
You would think a bike locked up to a utility pole at high noon on a sunny Sunday in the heart of Fells Point would stay still, yet this morning I found out otherwise.
Sometime in the thirty minutes in between glances outside “just to check,” I was dumbfounded to find my bike vanished while I was upstairs.
Someone must have snipped the cable and thrown the bike into the back of a truck since the Kryptonite U-Lock tied the rear wheel to the frame and prevented it being ridden away. It probably took less than 30 seconds all told, fast enough that it’s possible no one walked by during the heist. There must have some witnesses though, as this occurred across the street from a senior center and it seems there’s always someone looking out the window.
So, on the off chance that you see the bike below, drop me a line. I miss it.
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03.31.09
Posted in Velomobiles & HPVs at 6:25 pm by smalghan
“Habits Equal Results”
“Persistence Pays Off”
“Sorry [GF], I can’t make any plans until next weekend”
These are all phrases, passed down through the ages by some very accomplished and intelligent people, that one keeps in mind while making steady progress towards a distant goal, especially when that progress comes in small pieces grabbed from whatever’s left of 24 hours in a day outside of a full day of contract work, the minutiae of daily life and beloved sleep.
Work on the velomobile has continued with some very satisfying results though at the expense of any progress toward rehabilitation of the MR2 and, for better or for worse, any blogging activity.
And so I present, for your viewing pleasure, RESULTS:
So much progress has been made that this picture is already obsolete: control bars have been bent up, the steering mechanism significantly modified, the whole machine dismantled and rebuilt several times as well as many lessons learned.
Most of the sheet metal parts, such as those that constrain the NuVinci, the upper control arms, and the swingarm shock mount have been found inadequate and led to redesigned parts. In the case of the front suspension, a significant review of what the hell I was thinking six months ago had to be undertaken as the suspension didn’t do a very good job of constraining the wheel while the NuVinci mounts, in a subtle effort to compensate, interfered with the sprocket mounted onto the machined flange of the NuVinci enough that a chain would not fit. Just as well then, since the NuVinci control box would, under certain conditions, get crunched by the upper control arm.
Some of this was due to the difficulty involved in machining the NuVinci as it frustrated nearly all efforts to fixture it well enough to machine the flange. What inititally was only supposed to take Nolan a few weeks and one sixpack of Guinness (in cans) ended up costing a month and a half, several conversations with a wizened old German machinist, several trials with both lathes and mills, handing it off to another friend with the appropriate CNC machining center and a comped dinner. In addition to the Guinness. Even then, the numbers on the drawing couldn’t be met and so a few mm here and there ultimately resulted in interference. I thought machining the flange would be easier than using an adapter to pick up the brake disc mounting holes and bridging the distance to the sprocket with an adapter but that now looks like an improvement to make in the next version.
While those parts are being made I will occupy myself with the cargo racks and the exoskeleton.
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10.19.08
Posted in EVs, Velomobiles & HPVs at 10:11 pm by smalghan
So as Martin and I were running around town shaking down the eMR2 the transmission went out.
There was a little jumpiness from the drivetrain creeping in earlier in the day but I figured it was due to the worn engine mounts. Just before drive was lost the jumpiness was particularly bad but sometimes you just have to let something break to figure out what’s wrong.
Drive was lost taking off from a stop with a little pop and a zizzing, as if a spline was stripped, yet the transmission shifted OK. None of the gears would work, simply producing the zizzing noise. It’s hard to believe the coupler failed but it’s certainly possible. The other possibilities include a stripped spline on the shafts or a catastrophic failure of the final drive.
So instead of videos of the car in action, I’ll have to entertain you with pictures of the transmission teardown when it happens in a week or two.
In other news, the bamboo/balsa frames for the velomobile came in and look beautiful but were built with the wrong thickness balsa core. Recovery options are being conjured up.
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09.28.08
Posted in Miscellanea, Velomobiles & HPVs at 10:48 am by smalghan
Last Sunday the Jones Falls Watershed Association held its annual Rally for the River to draw attention to the health of the river that runs right through the middle of Baltimore City.
The Jones Falls powered Baltimore’s early industrial beginnings and as a consequence became a dumping grounds for all kinds of waste, both industrial and human, resulting in Baltimore leading the country in typhoid cases around the turn of the century.
The solution? Bury the river! In a prime example of employing the most elaborate and expensive solution to avoid solving a root problem, three tunnels were dug starting at what was then the northern end of town and chanelled the river underground until it empties into the harbor. They typhoid problem did subside, but then the river remained just as polluted as it emerged into the Chesapeake Bay.
The river is actually hard to spot as it winds its way through the deep valley that’s shadowed by the shuttered mills and factories built more than a century ago, a strange development for a waterway that was so pivotal to the city’s beginnings. The flip side is that following the river reveals some very quiet and secluded areas that make it hard to believe you’re still in the city.
This year the festivities included the closing of the northbound section of I-83, the freeway built on top of the tunnels that channels the river. This affords a great opportunity to notice things that usually pass by too quickly when travelling by car.
In addition, that same day cyclocross races were being held in Druid Hill Park. It was the first time I got to see a cyclocross event in person and it looked a lot more interesting and fun than roadracing. Now I’m looking at adding yet another bike to the fleet.
Below are pictures from the day in chronological order. Enjoy!
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09.10.08
Posted in EVs, Velomobiles & HPVs at 8:53 pm by smalghan
A trio of 451mm wheels and several piles of folded sheet metal and machined parts have accumulated in piles around the place as I anxiously await the frame to arrive. I’ve been hesitant to release too many details as the design evolved since it seemed to only encourage more confusion than clarity (have you ever tried to explain what a velomobile is to the unfamiliar in the first place?) but since the prototype is being built up this is a good time for a summary.
But first, here’s a picture of the chassis CAD model.
The structure is made from a bamboo plywood/balsa core sandwich structure which, once hot-press laminated, is cut out by a CNC router. No tooling, no welding, no coping of strangely angled tubes.
All three wheels are independently suspended, which sounds like a great idea until it comes time to buy three mountain bike shocks at retail price that, pound for pound, must be more expensive than Formula 1 Konis. They don’t cost nearly that much to OEMs, which I’ll take advantage of next round.
One of the features I’m most proud of is the tilting mechanism. The front shocks are connected to a linkage that allows the rider to control the tilt of the vehicle independently of steering angle. Steering is reacted trhough the rear wheel, freeing up room at the front of the vehicle and allowing a much tighter turning circle than if the front wheels turned.
Since the electronic transmission idea got shelved (a story for another time) I looked for a system that would allow a wide speed range, could be shifted at rest and had enough speeds that the desired cadence could be dialed in perfectly. The closest mechanical analog turned out to be a NuVinci CVT combined with a Shlumpf MountainDrive, which give an overall gear range of more than 6.
In other news, Smokey the inverter has been nursed back to health and will be heading stateside in only a few days!
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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.
