Small scale prototype progress
I've had these videos for a few months but have had a bitch of a time getting them off of my iPhone in their entirety. Finally DropBox came to my rescue and so here they are. The quality isn't great, but you can see some of my progress toward turning an old R/C helicopter into the first small-scale prototype for the Streetliner. Since shooting these, I've actually reworked the rear swing arm in brass and have abandoned the profile-style chassis. Even still, this is a good look into where I started on the SSP. Enjoy!
Sidetracked, but not inactive
I got an email yesterday morning asking essentially "where the hell have you been?" and it's a very valid question. Things have been quiet here at Project Streetliner for the past six weeks or so — not for lack of activity, but for other priorities. The Mrs and I bought a pair of three-decades-old Honda motorcycles for a laughably small sum of money about a month ago. We wanted to be able to wander the tri-state area the way we can wander the Twin Cities on our scooters, and now we can. Or at least, we'll be able too after I do a little more wrenching. So work on the Streetliner R/C prototype has paused until I get these machines sorted out, but that should only be a few weeks. The flip side of this, however, is that these being my first interaction with the mechanicals of proper motorcycles, I now have a much better understanding of this sort of machine. This can only help me make better decisions on the Streetliner. As I've gotten more familiar with the simplicity of these machines (especially these early '80s Honda bikes we've got), I'm considering a lot more motorcycle components in my end vehicle. I've even toyed with the idea of changing from scooter to motorcycle drivetrain. The cost savings alone are pretty compelling. But that's a bit rash at this point. We'll see.
Sorry for the long silence, progress is indeed being made. In the mean time, please enjoy some snapshots of my R/C prototype in-progress. I've since re-made the rear swing arm almost entirely out of brass and abandoned the profile body, but these first efforts were very enlightening.
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.
Donor bike
So at some point in this process, I'm going to have to decide on a power plant forProject Streetliner. My plan is to purchase either a used scooter, or one or more wrecked scooters to scavenge for parts. The question is, which one? The thing is, as I've researched this project more in-depth, I've realized that there's more to be had from the right donor bike than just the rear end. Part of this project is to minimize the amount of custom engineering I'd have to do. Whatever I wind up with, I also want to stick to that bike (or at least that brand) as much as possible so that I can minimize the number of spare parts sources I have to manage. In a lot of ways, this ceases to be a scratch vehicle, and becomes an elaborately custom scooter. I like the sound of that! Components should really include:
Brakes
Obviously the rear brake disk and caliper are already part of a scooter rear end, so that's handy. But what could and really should also be harvested from a donor scooter are the front brake components (calipers, disks, wheels, lines) and both brake master cylinders as well. Ideally, I'd like to use a bike that has either two front wheels (such as the MP3) or dual disk front brakes on the single front wheel (such as the Aprilia Sportcity, or the Suzuki Burgman). That would ensure that the brakes are already balanced and matched to the wheels and that the master cylinder is already beefy enough. Some maxi scooters also include a parking brake, which would definitely come in handy on a 3-wheeler.
Wiring, switches, controls, telemetry
Harvesting the wiring harness, gauges, and other goodies out of the bike would save a ton of work. It'd be pretty dumb not to utilize the gauges, the hand controls, and other switches and such that have already been engineered to work together on the bike. Why wire up a custom circuit for turn indicators when there's one already built into the donor bike?
Wheels and tires
There really isn't much interchangeability to scooter wheels and tires. There's not the aftermarket for rims and such like there is for cars. So I'm likely to be stuck with the wheels and tires native to that scooter. One exception I know of is the Piaggio QUASAR engine line that is shared between Piaggio, Vespa, and Aprilia bikes. The 12" wheel of the Piaggio MP3 could be plausibly swapped for the 16" wheels of the Aprilia. The main advantage there is that swapping to the larger size effectively makes the end gear ratio higher (and therefore adds to fuel efficiency).
So when it's all said and done, the only parts of the donor bike I wouldn't be utilizing are the front fork, lights, the handle bars themselves, the majority of the chassis structure, and the seat. That's it! The last lingering question for me was engine size.
I'd originally envisioned this project to utilize a 250cc scooter engine such as what's shared between the Vespa GTs 250, Piaggio MP3 250 and Aprilia SportCity 300i. That, or a similar 250cc engine from Honda, SYM, or Kymco. A 250cc motor is kind of the sweet spot between performance, weight and fuel economy in the scooter world. The MP3 seems an ideal choice for the obvious reason that it's already a leaning trike. The MP3 also comes in 400cc and 500cc versions should the need to up-size arrive.
Speaking of which, I'm pretty sure at this point that up-sizing is inevitable. This is mostly because of the likely weight of Project Streetliner. My design criteria is to stay below 600 lbs curb weight. Scooters in the 250-650cc engine classes tend to weigh in between 340-550 lbs. Thing is, it's not speed I'm concerned about, it's economy. You see, a small engine having to work really hard will usually get worse fuel economy than a slightly larger engine that isn't having to work so hard. (For example, on a racetrack a BMW M3 gets better fuel economy than a Toyota Prius when both are driven at the Toyota's quickest speed.) So if my vehicle does indeed weigh 600 lbs, a 400cc engine will likely get better mileage (and conveniently give more power) than a 250cc.
So that brings me to my latest bit of hands-on research. I stopped by the local Suzuki dealership to look at a Burgman 400 — a bike considered by the folks who like such machines as the premier maxi scooter on the market. It seems perfect! The Burgman is the front runner right now for a couple key reasons. It already gets the mileage I'm shooting for, weighs in at 474 lbs, has dual front brakes, and a great reputation. Looking it over, it's now the definite front runner in my search for a donor bike. What's more, Suzuki has sold a boat load of them so there ought to be plenty around in the secondary market. That certainly can't be said for the MP3, I'd wager. Anyboy have any other suggestions?
Shape Study #3
This is Project Streetliner Concept #3. After watching Gizmag's fantastic video on narrow and single track vehicles, I wanted to explore a form that was as narrow as possible. More specifically, I also wanted to explore what the original kernel of my idea would look like. That is, if I took a Piaggio MP3, stretched it into a recumbent form factor, then built an aerodynamic body shell around it, what would I have? Well, I'd have this. It's very trim and very shapely and definitely pays good homage to its Velomobile roots. Of my concepts so far, it would stand to reason that this one would be the most efficient in terms of aerodynamics, but I'm ambivalent about something so narrow. This is mainly because of low-speed stability and the need to put a foot down or not. Riding a normal MP3 is really no different than riding a standard 2-wheeler except that under just the right circumstances, you can lock the tilt at stop lights and things like that. That works for those situations, but there are times when you need to unexpectedly stop and catch the bike with your feet. If you're already leaned over, locking the tilt isn't going to keep you from falling over. However, if the front wheels were a bit further apart (like Concept #2), I'm optimistic that an on-demand tilt lock would keep the vehicle from tipping over in a sudden stop situation, even if the vehicle is fairly well leaned over.
As much as possible, I want to avoid having to Fred Flintstone this vehicle (that is, have my feet hanging out the bottom), including when I need to back up. But that's a separate problem.
All in all, having shaped Concept #3 I think that I'm getting closer and closer to a final idea and that this idea will ultimately be somewhere in between Concept #3 and Concept #2. It'll be restricted to half the width of a conventional car, but that's still quite a bit wider than the Piaggio MP3's current wheel span. Perhaps that'll indeed be the sweet spot.
Suspension concerns
I have a couple of concerns about this suspension geometry.
I understand it, and see how everything connects and moves, but my concern is about the rebound and dampening. The wheels are obviously able to move up and down as well as tilt on the a-arms, but with the shocks hooked to each other it would seem like the suspension travel of one side is dependent on the other side being planted. This is disconcerting. The last thing you need on a leaning vehicle is wonky suspension. Sure this arrangement tilts just fine, but what happens when you're deep in a lean and run over a pothole? Does the vehicle shoot one direction or another? It's enough of an issue in traditional 2-wheel vehicles. So this is something I've got to get figured out during the prototyping process.
My prototype roadmap is as follows: Final concept » small-scale component prototyping » small-scale radio controlled, fully-functional prototype built mostly from R/C car components » large-scale prototype built from bicycle components and driven either by pedal power, electrics, or moped engine » full-scale chassis prototype with full drivetrain » polished full-scale vehicle made from chassis prototype and finalized.
Last night I swung by R/C Car Kings, a descriptively named shop in Burnsville, MN just up the road from my apartment. They've got every R/C car component known to man or beast in there. Fantastic stuff. I'm only just starting to understand the ins and outs of automotive suspension and as I've said before, I really want to engineer as few components for this vehicle as possible. Thankfully John, their resident suspension engineer, was on hand to walk me through my options. He expressed the same concerns I have about the pivoting, linked suspension on the design I've been referencing. He walked me through the different types of car suspensions and suggested either a king-pin set up (similar to what the Piaggio MP3 uses) or even a trailing springer suspension. Both are a tad tricky as they require me to essentially hang the entire front suspension (in terms of dampening and rebound travel) on the steering knuckles along with the brake calipers and wheels. It's not impossible, it's just complex. Anybody have any insights?
I really need to get better at Google SketchUp
I've used it for a handful of things, but am very out of practice. Before this is all over, a comprehensive 3D mockup of Project Streetliner will be a very good thing to have.
Piaggio MP3 mechanism in LEGO
Parallelogram tilting mechanism (such as the Piaggio MP3) demonstrated with Legos. I need more Legos!
