Entry and exit: its ramifications on exterior design

There’s been a lot of activity on the Streetliner drawing board this week. If you’ve been following along, you’re familiar with the shape above. This ’30s era race car inspired shape is what I’ve been showing people when they ask about what I’ve got in mind for this project. I love it, but I knew all along that this shape would inevitably change and evolve.

Likewise, one major aspect of the Streetliner’s design had yet to be worked out in concept: entry/exit. How the hell do I get in and out of the thing? It’s not that entry and exit is terribly complex, but in figuring out a good way to get in and out, it meant big adjustments to the exterior design of the car. So like any design undertaking, this needed criteria.

  • The integrity of the safety cage needs to be maintained as much as possible
  • Getting in and out has to be simple. No folding myself up snaking through impossible openings
  • I must be able to exit the vehicle even if the primary door system fails


So starting with the current exterior design, a handful of things have been adjusted since I first penned Design Concept Alpha. The overall length increased, the front wheels got larger, the wheel pants got longer and no longer turn with the front wheels. I really like this shape overall. The snout shape of the front end is very pleasing, the rear has a lovely duck tail quality, and I especially like this design because the vehicle looks even better with its canopy on. All of that shape, however, is mated to an underlying safety cage and chassis:

With arches as the vertical pieces, the safety cage design is pretty straightforward. Heavy duty curved bulkheads are connected by heavy duty rails, then everything is cross-braced in a truss of smaller diameter steel. The angled front and rear main plates actually create rudimentary “crumple zones” where impact damage would send the motor assembly and or front suspension components under the vehicle in the event of an impact. This design is structurally sound, but it has one major flaw: how the hell do you get in and out of the thing? The height of the cockpit opening lip is right at 36″ in this design. I’m pretty tall, but that’s still quite a height to throw a leg over while getting in and out. I also realized that I’d only given myself a 24″ deep opening front to back. I’m not a whole lot narrower than that myself (it’s winter weight, I swear!). So the practical concerns of getting in and out of a high, narrow opening are pretty significant. But even beyond entry acrobatics, with such a narrow opening, I wouldn’t be able to see my hands or any cockpit gauges. That top opening needs to grow and dammit, I need a door. The tricky bit is how do I add a door without compromising the safety cage?

One thing at a time. I added an approximation of the front suspension “box” and see where and how that should tie into the frame. I lowered the bottom rails to tie in to the front and also simplify the rear subframe where the mono-shock would attach. I also moved the main roll hoop back just slightly where previously it was implied that it would overlap my shoulders. Upon further reflection, I realized that this being a single seater, I only need one door. Even though my diagrams here show the opening on the left side, I think I’m going to opt for the right side having the door. Since the majority of motorcycle accidents involve people violating your right of way from the left, it makes sense to me to leave the left side solid. That written, the underpinnings of the door as I’ve envisioned it are as substantial as the major parts of the cage. That way when it’s closed and latched, the door becomes part of the safety cage. I like to think of it like the harness that comes down and locks in when you get on a roller coaster. Solid. Also, thinking about an impact scenario, that’s a force into the cage, so if the door is structurally captive against being pushed through the opening, it ought to be as good as solid. With the door opening on one side of the vehicle, the canopy (when attached) could hinge along the opposite edge — making for a very easy time getting in and out.

With that adjustment made to the frame, the body shape needed adjustment, as you can see below. The opening needs to be increased to meet my design criteria for being able to exit the vehicle in a pinch through the top without using the door. The bottom profile of the body shape also needed to be adjusted to account for the front suspension box.

Now with the shape updated, I like it even more. The larger top opening not only gives the whole vehicle a better proportion. It looks smaller and more trim overall. Before now, with the length being about that of my MINI (which I know, isn’t exactly big), the Streetliner has looked strangely large. Now it looks much more like the race car cabin scooter it was always meant to be. I also reshaped and shortened the wheel pant to account for the door opening.

I really felt like the new shape came into its own with the canopy in place. Not only was it less bubble-shaped, but it completes the curve created by the tail. I can also imagine much better visibility and comfort within the cockpit. That led me to consider some alternate front end shapes. One of which was the sloped, Ferrari GT-style nose. It would borrow its hood scoop aesthetics from a different era than I’d previously been thinking, but I really like it. Forward visibility would be better and overall aerodynamics might be a tad stronger with this sloping approach.

All that remained at this point was to add some visual interest to these basic shapes. This included sculpting the rear and adding a sort of LeMons-style front lip to the wheel pants. I really don’t want to overlook subtle details throughout the shape. Sure, a perfectly smooth Velomobile kind of shape is terrifically aerodynamic, but without at least some minimal sculpting, I think the shape would look like it were stuck in the ’70s and just generally unfinished. These details will surely evolve as the project progresses, but I’m loving it so far.

As I look back on the progression, it’s amazing how much influence a little thing like a door can have, but all for the better! This shape still has a lot of classic Italian sensibility, a lot of race car mojo, and plenty of salt flats shape credibility. As much as I love the ’30s sensibility of Concept Alpha, I like this even better. But more than that, I’m glad to have another big piece of the conceptual design puzzle in place.



Cal Poly students create streamlined trike capable of 2,752 mpg

The Black Widow, as it’s called, is the winner of the Shell Eco-marathon. Looks the business doesn’t it? What’s thoroughly amazing is that they did it without any electrical propulsion at all. Just a 3 hp Honda 4-stroke engine no doubt geared to the ceiling. Good stuff. More details here.

Donor bike options

Last weekend I laid fresh eyes on Kymco’s Xciting 500Ri and think that it could be a very viable contender as a Streetliner donor bike. Up to now, I’ve been leaning toward the Suzuki Burgman 400. The Burgy’s mileage is good, the motor is powerful, it’s a twin disk brake up front (meaning one disk/caliper set per wheel) and it’s a popular bike so the second-hand market should be pretty good. However, the Kymco has more than a few things going for it. The weight is the same, the mileage is similar, two front brakes, 12V accessory plug-in, good looking gauges, it’s got an extra 100cc of engine, but most interestingly an adjustable twin-shock rear suspension. The Xciting is also a bit less expensive, but still with Kymco’s proven Taiwanese build quality. In fact, I can’t help but feel a tad more confident in the Kymco, as they have so much more experience with scooters than Suzuki does.

But back to the suspension, which is what I’m most interested in. The rear suspension on the latest generation of the Burgy is a mono-shock underneath the frame. The Kymco uses the more traditional twin rear shock setup like I have on my Vespa GT. Previous Burgy models used a similar setup. What I’m wondering now is which will be better in my intended application? It’s easy to assume that the more sport bike style mono shock underneath the newest Burgman models is in fact an upgrade. But it could just as easily be a cost-saving measure. I’d probably have to ride both bikes to see if there was a difference in feel. But beyond the performance in the stock bike, how would that rear suspension behave plugged into a likely heavier vehicle with completely different geometry? A beefier shock will likely be needed. Will I be able to easily source one for the Burgman? The more traditional twin shock setup on the older Burgman models and the Xciting seem to offer greater flexibility. There’s already a nitrogen shock upgrade available from Kymco. But more than that, with the mount points so straightforward, I could conceivably use almost any shocks I want. In order to tune the suspension on the Streetliner, I’m going to need both dampening and pre-load adjustment. Although the current Burgman shock has seven levels of pre-load adjustment, it may not be the correct dampening. Fitting a different shock may involve some serious modifications. One of the guiding tenants of this project is to do as little engineering as possible, so the idea of having to re-engineer that more complex subframe to accept a different shock is not appealing. The sacrifice is that if I’ve got quite a bit of room above the engine for storage in the body of the vehicle. If I’ve got to have shock mount points above the motor, that could encroach on some of that space. But in the end, it’s not about maximizing cargo space, it’s about maximizing efficiency, comfort, safety, riding fun, and style.

Planning and project management


I’m incredibly fortunate in my job to work with a fantastic project manager. I’m learning everything she’ll teach me about managing web development projects, but she’s also been kind enough to give me some tools and tricks for this project as well.

So while I’ve been quiet here on the site in terms of updates, I’ve been working diligently on the planning pieces of Project Streetliner. Some of that initial work has involved breaking down the vehicle into its key components and delineating which pieces will come from a donor vehicle, which will be repurposed off-the-shelf parts, and which will need to be fabricated from scratch. The break-down so far:

Component Donor bike Shelf parts Custom Fabrication notes
Body Shell X The body shell will be constructed out of fiberglass over hand-sculpted foam. At this point, both pilot entry and mechanical access have not been designed. It’s also undecided at this point if there will be an inner wall of fiberglass creating a “helmet” structure around the pilot.
Body Mounts X These will have to be thought through in conjunction with the body construction. For best results, it’s likely that they’ll have to be built into the construction process so that the fiberglass is laid right onto the “tabs”
Headlights X At this point, I’m planning to repurpose small, round, hi/low headlights from another vehicle. A more “off the shelf” solution from JC Whitney or O’Reily’s might also be a good option.
Running Lights X Similarly to the headlights, these will be shelf items. Although, a custom strip of running light / turn indicator on each wheel pant would be cool too.
Turn Signals X Wiring and switching will be from the donor bike, but the lens assemblies will likely be either custom or off-the-shelf
Rims / Tires (front) X Taking my cue from both the Leanster and the TMW front end, I’ll likely utilize larger front wheels than will come on the scooter donor vehicle. This will also help with side-to-side shift during suspension travel (especially during leaning)
Rim / Tire (rear) X Part of the engine assembly. Duh.
Brake disks / calipers (front) X Both the TMW and the Leanster utilize inverted ring brake rotors. This makes the steering knuckle possibly easier to fabricate but I’m not sure. Ideally, I’ll be able to utilize the brake calipers and rotors off the donor vehicle.
Brake disk / caliper (rear) X Part of the engine assembly. Duh.
Steering knuckles / hubs X X This is probably the trickiest part of the whole build. The hubs will have to be customized to the rims and then some sort of custom bracket for the brake calipers and rotors. Then of course, everything has to clear the rims.
Tie rods X Tie rods will likely just come from some other vehicle source. Hopefully I can consolidate “shelf parts” from one particular vehicle or consistent source not likely to go away over the years.
Steering bottom end X This will be a combination of shelf parts and tie-rod parts. The Leanster has the ideal design, most likely.
Steering column / U-joints X X The input to the tie rods will need to be fairly upright, but the extension to the hand controls will need to be fairly flat. But the hand control input needs to be pretty flat as well so that the tilt will have the most intuitive lean control. The end design is likely a mix of shelf parts and custom bracketry. The most important thing is a minimal amount of slop in the mechanism.
Handlebars X The handlebars will have to be compact enough to fit within the body enclosure and placed in such a place that they’re both functional and ergonomically comfortable.
Hand controls X There’s no better way to use signals, kill switches, horns, starters, and so forth — or at least no good reason to re-engineer all that stuff.
Grips X X Depending on the aesthetic interior style, the grips will follow that look and feel. Also, they will include electrical heating elements for cold weather comfort.
Front Suspension Structure X Though the exact proportions will be customized for this application, I’ll be using the design from the Leanster verbatim. I still have to figure out just what joints use bearings/bushings and what kind are ideal. I also need to nail down the exact materials of the pieces.
Front Suspension sub-frame X This is simply the frame piece that connects the suspension box and swing arms to the safety cage. This will not only allow the two to be fabricated separately, but allow for alternate components to be tried if needed. Also, in the event of damage, minimizes the chance that I’d have to rebuild both components.
Front shocks X In both the Leanster and the TMW, the front shocks have had to be custom ordered from a manufacturer. Hopefully I can find something off the shelf, but I’ll have to be ready for this contingency.
Rear suspension / engine sub-frame X Part of the engine assembly. Duh.
Chassis / Safety Cage X Made from a mix of large and small diameter steel tubing, the safety frame will function as both the principle stiffening structure of the chassis, but also as robust impact protection for the pilot. The basic structure design for this has been drawn up, but no plans for entry/exit as of yet. The basic construction of the vehicle is that the drivetrain bolts onto the rear of the safety cage, and the front suspension assembly to the front. Boom. Vehicle.
Entry subframe X As of yet undesigned, this structure will have to be secure so that in a wreck, the opening protects the pilot without coming apart in any sort of hazardous way. Also, it needs to be robust enough so that emergency extrication from the vehicle in the case of a particularly nasty crash is possible.
Seat X Right now I’m leaning toward a Sparco adjustible racing seat. Depending on the comfort level, I’ll consider a solid frame aluminum raicing seat. Whatever seat I use, it’ll utilize a 5-point racing harness.
Interior surfaces X The interior of cockpit will likely be a mix of fiberglass and aluminum panels with steel reinforcements where needed. I may use an interior carpet for a softer lining. The key will be to cover up the exposed frame pieces from hazard. May even utilize some wood trim.
Windshield X The windshield design will ultimately depend a lot on the canopy design. It may be a permanent piece that the canopy attaches to, or the canopy may replace the windshield entirely. The windshield will also be paired with a soft-top for inclement weather.
Canopy X The canopy will be plexi and fully removeable. It will need some manner of venting / defrosting mechanism either by fan-driven air or outside air.
Radiator X Taken from the donor vehicle and installed in the front of the vehicle by simple, fabricated brackets, the radiator will need custom hoses run to the rear to the motor. The engine’s water pump will move the water ’round. I may utilize a small heat exchanger for cabin heat.
Wiring harness X From the donor bike. I won’t try to run it through the steel frame, but rather attach it.
Wiring mounts X A combination of steel tabs and probably just cable ties. Move along, the rockets and all that science is in another department.
Engine / transmission / final drive X Part of the engine assembly. Duh.
Wheel pants X Custom fiberglass pieces that at this point will not turn with the front wheels, but will tilt with them. This will likely neccesitate that they simply have holes shaped into them for the wheels and call it better than naked.
Wheel pant mounts x These will have to attach to the swing arms in order to tilt without turning with the wheels. Likely just steel bolting into reinforced points on the pants.
Instrumentation X X x The bulk of the guages will come directly from the donor bike, although I will likely re-bezel them into a custom dash. I’ll probably add a water temperature, oil pressure, battery volts, and lean angle. I’ll also likely add iPhone support for charging (using the iPhone for GPS and such).

A great piece of inspiration

Courtesy of the one and only Merlin Mann, this 43 Folders interview with Seth Godin is a great conversation about the video below and being “a person who ships.” Their discussion about overcoming the mental hurdles we all face when doing something new or different is truly inspiring.

Seth Godin: Quieting the Lizard Brain from 99% on Vimeo.

What Seth and Merlin spend most of their time talking about is Seth’s most recent book, Lynchpin. More specifically, they talk about the commodity of ideas and the real value of actually shipping whatever it is you make or do. I realized that with the Streetliner, neither the concept nor the design are particularly remarkable. What would make it an amazing would be to actually finish. That’s all. Completing the Streetliner at all will be a huge accomplishment. Being literally in the idea business, it’s easy to lose site of the fact that success is 99% showing up — that is 99% “shipping” whatever it is I do. Sure, I have to be creative and innovative, but it’s all pretty meaningless if I never actually ship anything. If I never get my prototype built, then the actual Streetliner is sure to never happen. With that in mind, it’s time to get back in gear. Thanks guys, that was just the push I needed.

Still going

It’s been a while since I’ve done a post, so here’s a quick update. The project is alive and well, I’ve just been particularly busy tending to other matters. I’ve added both a band saw and a table saw to my shop. The band saw in particular will help with my ongoing prototyping. So stay tuned, more updates to come.