New rendering with roof
Nothing big here, just some new details. This rendering shows an adjusted cockpit position, door opening, and A-pillar spread. I'm considering flopping the door to the other side as left side impacts are more common on motorcycles. That would also mean a curb-side exit in the states.
3D accurate renderings
So as things keep moving forward on the proportions and details of this design, I've noticed that my three-quarter renderings aren't as accurate to the profile views I've been working from. I am not a CAD pilot. I don't have the right software or the right experience to model this in 3D for real yet. That'll probably happen before I'm done, but what I did want to see is what this design might look like from different angles. So what I did was take some advice from Twitter and pull my profile views into Google SketchUp. Now while Greg (on twitter) was suggesting I model the whole thing in SketchUp, it won't give me the kind of results I want for the sheer amount of time I have to put into it. All I wanted was better perspective renderings I could use in Illustrator. This was this was the result:
What I think is particularly interesting is just how much the forced perspective changes the visual relationship between the wheelbase and the width of the body. In the front view, you can see just how far apart the wheels are, but in the other views, they look like they're right on the body. It's also interesting how it looks really mean from some angles, and just a tad messerschmitt from others.
Entry/exit cutlines and mechanism
People have been asking how getting in/out of the Streetliner is going to work, so I've rendered what that might look like. In concept, the canopy (when attached) will hinge along the right-hand side of the vehicle, and a car-style door will open on the left-hand side of the vehicle. (I've also added a lip to the wheel pants to kick the wind off the surface of the wheel just a bit. I really like the look of this detail as well.)
Thoughts on the canopy
While discussing the Streetliner with my collaborators at work, the subject of the canopy came up. That sparked an idea for me. Rather than having to form (or pay to have formed) a singular canopy, it'd be a lot simpler to build the canopy in sections. Each of those sections would be much smaller and much easier to make. I think I could pretty easily create forms and heat-bend polycarbonate panels for the windows and windshield. In fact, in this configuration, a glass windshield might even be viable if it weren't too expensive to get fabricated. But beyond ease, having a roof on the canopy would mean the cabin would be cooler. It's also that much meaner looking. I like that too.
Concept finalization
I'm gaining more and more momentum when it comes to finalizing the Streetliner concept. I'll be putting together a more comprehensive full spec post later, but for now, here's an update on the exterior design. I feel like I've finally found the art deco mojo I've been looking for all along. While the updates are subtle from concept Echo, a lot has gone on under the skin to help me arrive at this, the most finalized shape to date.
Most significantly, I realized that my seat and human analog were actually too large, as was my representation of the ATV drivetrain — each by about 20%. This meant that I could shrink the wheelbase as well as the cabin size by significant amounts. I had previously been concerned about the front to back balance of a rear-engine design, but these new proportions make it seem like it won't really be an issue.
I accounted for a "jack shaft" that will inevitably be required to get proper rear wheel sprocket alignment. It also allows me to more easily monkey with the final gear ratio to the rear wheel. Additionally, it allows for easy fitment of a belt-drive, which will require much less maintenance than a conventional chain. I reworked the rear suspension in such a way that I can still get a lot of travel, but I don't have to build a whole subframe back just to intersect the shocks. I've essentially just extended the rear swing arm. What may not be obvious from the side rendering is that there are arcs involved that would allow the shock(s) to be centerline instead of at either side of the swing arm. In the rendering there's a ghosted wheel showing the full 6" suspension travel. The jack shaft is inline with the pivot for the rear swing arm, which should keep things nice and smooth.
Front and rear, I've simplified a few things, and added others. Most noteworthy is the addition of a rear window, which is something I hadn't had in the concept previously. The view won't be great, but it'll be much better than nothing. I'm thinking that rather than a rear view mirror, I'll utilize a rear-facing camera built into the high brake light assembly. That will have a better view than any mirror system that would conceivably work (although I did have a hilarious rear-view periscope idea). I also abandoned previous modern-style brake lights and turn signals in favor of more conventional round lights. This is actually more in line with the classic design language from cars in the eras I'm trying to emulate. In the end, I'll be somewhat limited in what I can find off the shelf, but standard round light will actually look better, in my opinion. I was designing those other signals and lights almost in a vacuum. I think they were cool looking, but in the end, such modern details would look out of place in this shape, I think.
Lastly, I finally paid some real attention to the front cross-section of the vehicle. I was able to resolve the shape such that I now have a completely flat front suspension parallelogram, but still enough body and wheel clearance to get about 40º of tilt out of the vehicle before the wheels bind or the body touches the pavement. I know for a fact that I've never put 40º of lean on any two wheeler I've ever owned, so this ought to be plenty. What's more the cabin ought to be pretty comfortable, with little compromise toward comfort. It should just fit me, but with some reasonable room for comfort.
So let's hear it. What does everybody think? If you've got other ideas, now is the time for them. As far as I'm concerned this is the design I'm moving forward with. I'll hopefully be starting a small scale foam shape prototype today and I'll share progress as soon as there is any. I'll also be doing some small-scale safety cage models, likely in brass tubing, for structural testing and evaluation by people who know more about this crap than I do.
Design concept Echo
It's little more than doodles at this point, but this is Concept Echo for the Streetliner. Of all the concepts I've rendered 'till now, this one is easily the closest to what I've seen in my head in terms of its sensibility. It's got some wonderful '30s and '40s era automotive cues, but also some modern flair. Most of all, the rear end is really feeling the streamliner locomotive, art deco vibe I've wanted to always have present in this vehicle. The next step, I think, will be to render it in floral foam, then shell and paint a mockup. I'll be doing this at a much larger scale than before, set off of 4" wheels and built onto a sort of mockup under-chassis that should let me fit a number of test body shapes moving forward. Think of it as the small scale prototype for shape and aesthetics, rather than mechanicals (that's a separate, ongoing thing all its own). 
New 3/4 rear renderings
I've never really rendered the Streetliner from this angle, but I'm loving the way it looks from behind. No tail lights or turn indicators, obviously, but the shape is very pleasing. This is based on the ATV drivetrain I've been thinking through lately.
Design Concept Beta in Foam
I spent some time today knocking up a quick shape study in floral foam to get a sense for the new shape in 3D. Really like it so far. Want to do a larger version over top of my prototype chassis when the time comes.
Design Concept Beta
Based on the entry/exit concept discussed in my previous post, here's a 3/4 front rendering of what that new, evolved shape might look like. Any thoughts?
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.
