Initial Specifications

I've been thinking about building an electric three wheeler for many years, but I've only been seriously looking at the figures, components and performance for a few months. I was following the development of a new electric vehicle motor from a start-up company (really a one-man operation) called EnerTrac on Long Island. The motor is the largest hub motor currently available, and designed for converting motorcycles up to 400lbs to electric power. The EnerTrac website is here:

EnerTrac Corporation Home Page

The public discussion during the motor development went on here:

Markcycle's Endless Sphere Hub Motor Thread

As this motor came into existence, I realized that it would be a breakthrough powerplant for a high-performance electric reverse trike, that is, a three wheeler with two wheels at the front, provided my vehicle was under the motor's maximum 400lb vehicle weight rating .
 
That's now the big challenge- keeping the Moonray under 400lbs. It would be rather straightforward to build it out of mild steel square tubing, and then put a wood and fiberglass body over it, but it will weigh 600 or more pounds so constructed. Components, materials and construction techniques all need to be carefully selected and executed to keep the weight down.

Batteries are the single heaviest component. Traditional lead-acid batteries with sufficient power to deliver the 300 amps the motor can take at 120 volts or so would weigh over 500 lbs. The lightest of the new Lithium-based batteries (from A123 Systems and used in cordless power tools) would be about 100lbs for the same amount of power, but they are still incredibly expensive- probably $10k for a pack of them, once I figured out how to get all of them put together. They are hard to deal with, requiring precision assembly of hundreds of about C-Size batteries into a large traction pack, and given the cost and complexity of that, it isn't the way I'll go.

In the last year or so, large format (about 1/4 the size of a car battery) Lithium Iron Phosphate (LiFePO4) cells have become reliable and widely available. They are half again as heavy as the best A123 batteries, but they are less than half the cost, and will be just fine for the Moonray. Moreover, all the skittishness, horror stories and dire warnings the EV community lavished upon early users of these batteries seem now to be quieting down as they are being installed and used to great satisfaction. Jack Rickard, in particular, has greatly contributed to the available information about these batteries by installing, testing and driving them in his converted Porsche kit car- and publishing his data for all to see. The batteries are fine, and they won't need an expensive or complex Battery Management System in the Moonray. Initially, I wanted a 100 mile range, which would have required about 240lbs of batteries. No matter how I work it, that much battery weight puts the vehicle way over 400lbs. I even lost 70 pounds myself, and it isn't enough to make up the difference. I just can't carry more than about 165lbs of batteries, which will cut the range to around 50 miles, but it has to be that way. At least the battery pack will be cheaper...

The design is simple to describe, but the devil is in the details. I will be using the front suspension from a Suzuki LT250R Quadracer ATV, and the rear suspension (swing arm) from a 1985 Kawasaki KZ125 motorcycle. I'll be adapting air-adjustable spring/shocks units from Honda motorcycles- the pair from the rear of a CB900F in front, and just one of two rear shocks from a GoldWing 1100 on the Kawasaki swing arm, which uses only one spring/shock unit. The air-adjustable units will allow me to balance the trike and trim the ride height. I have both the LT250R and KZ125 frames, and I could conceivably just weld them together to make a chassis, but that isn't why I got them. I needed the dimensions of the suspension attachment points to duplicate for my own custom chassis, which will be fabricated from Chromoly 4130 steel. I actually considered welding the motorcycle and quad frames together to build a "mule" chassis to test the motor and battery systems, and it would be a good idea in the abstract, but I think those systems are reliable enough that it would be a waste of time.

Since I'm not a computer-assisted design (CAD) guy, I'll be working with paper and pencil making the Moonray. If I had a CAD-versed collaborator, that would certainly improve the process, but its OK as is and I can't afford the time or expense of the CAD learning curve for this project. To compensate, I'm building the entire vehicle in 1:3 scale, which I am good at, and it does solve problems and refine the design to go through the exercise. The exterior shape will be determined mostly by the wind, but also by the components, configuration, and the available parts I choose, like exterior lights, a canopy, etc.  Still, I have a vision of what I want, and some references for styling and aerodynamics that I'm going to follow. First my drawings:

 Moonray, 2009- Tom Alvary

Now the three-wheel designs I think are the best to emulate:

 

California Commuter, 1980- Doug Malewicki

The Polliwog, 1963- Bob and Bill Summers

There are many others, but these are my favorites, and the direction I'll be going. Note the similarities between these two vehicles, which could not have been more different under the skin. Clearly, they had the same (and in both cases, record-setting) approach to the air flowing around them. Interestingly enough, the Polliwog is actually a four wheeled vehicle, with the rears in tandem (one behind the other) on a bogie, and front wheel drive. Yet another breakthrough Summers Brothers design. More about them later and elsewhere...

I'll flesh out my reasons for each choice as we go along, but the initial specification is:

Length: 11-13 feet
Wheelbase: 85"-95"
Width:  49"
Front Track: 43"
Height:  45"
Weight: 400lbs Empty
Capacity: 240lbs.
Speed: 75MPH
Range: 50 Miles

Components and construction materials and details are being collected on a spreadsheet to make it easier to see and juggle the total weight of the vehicle. That's going to be where the all the action is, and on the model, until the basic problem of coming in under 400lbs can be solved...

Process & Project Management

Building something as complex and expensive as an electric vehicle requires planning and good work flow management to stay on track. Its a hobby, yes, but it won't be any fun if it never gets done or costs far more that I anticipated, or both, and in any case I will surely hear about it from the family, which won't be too much fun, either...

I will need to be very practical in getting tasks handled on time and within budget. I also need to be thorough to get both the details and the major issues addressed without undue delays. For now, while I have the luxury of putting some things off, and I can still experiment and learn to a fair degree, but progress must be made consistently to stay on track. I'm less concerned with the time I'm spending now than with the money, so I'm basically finding the more common components cheaply and solving problems I can handle myself. As the Moonray becomes more complete, that will have to change, but for now I am accumulating parts, studying other people's designs, and evaluating materials. That's fun and relatively cheap, but at this point I need to start building something.

I've decided to build at least one 1:3 scale model first, so that I can validate the design and refine it at minimal cost before I start spending full-scale time and money on the Moonray. I'm not a CAD guy, and I don't think it is practical to become one (another steep learning curve?) within the next few months, so I'll be making the Moonray the way I have made models, furniture and structures all my life- on paper, and then with rulers and calipers. I'm a pretty fair modeler, with 40 years of experience in everything from assembling plastic and paper kits to scratchbuilding flying planes, rockets, model railroads and architectural models. Its fun work for me, and it will be satisfying to have something come together quickly that I can see and test. I will also likely save some expensive and frustrating trial-and-error work on the full-size Moonray by developing the model until at least the obvious problems are fixed. I could also really use a well-finished model to raise money, sponsorship and support for the project as the design nears completion and the really expensive bits need buying.

Part of the value of writing this blog is that it focuses my thinking, and creates the archive of managing the project through its various phases. While its far more time-consuming to document and post the process online than it would be to just do it, there's good karma in blogging it and I hope it is fun and informative to see. It also puts my work out for review and suggestions, which can only improve the final product. This has already been going on at the Endless Sphere EV website where I participate in an online discussion group for electric trike builders. Ultimately, maintaining the blog also helps me stay on task with the project. Its not a job and I don't want to make it a chore, but its a pretty big project and anything I can use to help manage and move it along is a good thing.

Finally, there are three pieces of advice I've heard about car projects that make great sense, and I'm determined to stick with all of them on the Moonray project:

1. Do some work on the car every day, even if its just 5 minutes. It will probably never be 5 minutes, but its a great practice to get into, and doing it ensures that project won't stop, which is the most common way projects never get finished. 10 minutes a day is over 60 hours a year, and even a minute a day will keep the Moonray alive.

2. Write down every penny spent on the project, from paper towels to transportation. Without doing that, budgeting and costing is pretty much meaningless, and having detailed expense records will be a great benefit in many situations, from proving up an insurance valuation to selling the vehicle. 

3. Try to map out the time line from now until completion, and keep it current and realistic. Well, that's good advice for any project, but too many hobbyists, (and businesses for that matter,) don't follow it enough.

My current road map looks like:

12/2009-1/2010:
Complete the 1:3 scale Mannikin and suspension component models.
1/2010-2/2010:
Complete the model chassis structures and finish the model.
3/2010-4/2010:
Revise and finalize full size design; create workspace and production schedule
5/2010-8/2010:
Build subframes, suspension, steering and hard points
8/2010-11/2010:
Layup the Monocoque body, and complete the chassis
11/2010-2/2011:
Build and test the drive, brake and electric systems.
2/2011-4/2011:
Finish systems and final assembly- lighting, paint, etc.
4/2011-6/2011:
Begin testing and operation.

As always seems to be the case with long projects, the closer-in tasks seem rushed and the later ones seem to be easier than the amount of time allotted. I also note that EVERY commercial EV project misses its deadlines and winds up with a delayed product, but those folks are working on many other things I don't need to worry about. At any rate, we shall see...

Project Goals

Even building a very small car is a pretty big undertaking for an individual, especially since I have no experience in several of the subject areas where expertise is required- hub motor and LiFePo4 battery systems, composite design and fabrication, etc. There is plenty to learn, a fair amount of work that will probably need contracting out, and hundreds of details to handle. Inevitably, there will be some trial and error getting things right, which can get really expensive and time-consuming. The trick is to do as little of that as necessary, but more than that, good planning and effective project management are critical to the Moonray hitting its targets.

First, a very clear set of project goals needs to be formalized, which will then largely dictate a set of specifications for the vehicle. These specifications aren't etched in stone; in fact they have already moved around quite a bit and I expect that to continue. Being practical is important, and when I learn the limits or costs of materials and components, being flexible enough to modify the specifications around what is easy, hard or likely impossible is essential. The goal is simple:

"Moonray will go faster and farther than any commercially available electric vehicle in its weight class, and will be practical to operate as a street-driven daily commuter/runabout EV."

Notice that it is "faster and farther" because coupling those two things, and producing a licensed, insured road vehicle, is critical to defining the project goal. There is a class of EV single-seaters, somewhat lighter than Moonray, that compete for distance. They are called Electrathon racers, and they go very far, like 50 miles, on a single car battery, but they are slower than the 'ray, and not practical or even licensed for street use. There are also a few even faster EVs, which are designed specifically for bagging speed records, but they aren't licensed, either, and I don't want a race-only vehicle. The Moonray aims to be the fastest street-licensed trike in its weight class, leaving the ultimate speed and distance marks to no-compromises off-road-use-only vehicles that you really wouldn't want to commute or run errands in, anyway. Moonray isn't a contest vehicle; its for daily use.

A secondary goal for the project is to showcase recent EV technology, and to show particularly how much can be done by the hobbyist with essentially off-the-shelf components. The batteries I'll be using have only really been available for about a year, and they are improving rapidly. The motor has been available for a couple of months. Without those leading edge components, Moonray simply wouldn't be able to achieve its goals, but they are neither terribly expensive nor hard to come by. What I'm doing isn't rocket science, either. Anyone with the time and skills to do meticulous work, or the modest money required to buy other peoples' time and skills, could easily build something very similar. I'm not making plans or kits, though, because its my hobby and not a business. I'm not an engineer and I'm not willing to have my work certified by one so that other people can confidently rely on it. The Moonray will be a demonstration of what is now possible, not necessarily a program for how to do it.

My other goals for the Moonray are logistical: I want it in service by the spring of 2011, with a total cost at or under my budget projections. I have a budget in mind, but it still has to be validated. I don't have unlimited time or money to spend on it, and frankly I'm not aware of any project with neither time nor economic constraint that turned out satisfactorily. Limits on resources seems to be a necessary ingredient to the development of anything good. 16 months from now feels like a reasonable amount of time, but let's see where we are in a few months. I'll talk about my budget once I understand it better, and have cleared it with my family.

So that's it: farther and faster than any commercially available lightweight street-legal EV, on the road by Spring 2011, and within the yet-to-be-determined budget. Piece of Cake. Let's get started...

The Beginning

Every project starts somewhere. Mine began in junior high school, more than 30 years ago, when I stumbled across a picture of Buckminster Fuller's Dymaxion Car. I had to special-order the only book then in print that had pictures and descriptions of Bucky's work in transportation, and I promised myself one day I would drive something as cool as that, even if I had to build it.

Well, the Moonray is no Dymaxion Car. Bucky's landmark design seated 4 to 6 people, had a steerable tailwheel, and nothing else like it has ever been made, and perhaps with good reason. The Dymaxion was marginally unstable at speed, and it rolled over twice, once with Fuller at the wheel, and again with a different driver after a collision with another car. Bad publicity from the second accident pretty much finished any hope of production for the car, but that could have been a blessing, as the car had real design problems that even today don't seem solvable. Interestingly enough, the surviving car (of the three prototypes Fuller built) is finally being partially restored in England, and the restorers are also going to build a 4th car- a running replica of the original design. Hopefully that car will answer some old questions about the Dymaxion. Regardless, its a supreme achievement, particularly for a designer with no experience in the automotive industry. The last Dymaxion design that Bucky left on the drawing board, however, (as is so often the case in these matters,) was even more innovative than the built cars: that car was all-electric, with a separate motor powering each of its 3 wheels, and an all-wheel steering control system. It was quite an avantgarde vision for 1935, and if I had unlimited funds, I'd be picking up right there and trying to build something like a modern iteration of it, but that's not my Moonray.

The Moonray is a very different machine- its a featherweight (400lbs) single-seat trike designed to be three things: First, a tangible demonstration that recent Electric Vehicle (EV) technology advances, particularly in Lithium ion batteries and hub motors, now permit a hobbyist to buy standard components and build a practical, roadworthy vehicle that isn't expensive or hard to live with. Second, the Moonray is an electric hot rod in the purest sense- it combines commonly available parts and techniques with exotic bits and thoughtful work to produce something with exceptional performance and looks that just couldn't be purchased. Third, the experience of building Moonray will give me a priceless education in EV technology and operation at lower cost and risk than if I had made a bigger vehicle, or converted an existing automobile to electric drive.

Since Bucky Fuller's work in the 1930s, many people have designed and built light auto- and motorcycle-based trikes, usually borrowing from the patented work of Walter H. Korff, who designed the Duo-Delta trike, below. This breakthrough design uses an intact motorcycle with the front fork removed, coupled to a two-seat frame and front suspension. My project is to make an even lighter single-seater that is practical enough to use as a commuting vehicle, or just to run around in. I wanted to take advantage of the 40 years of advances in design, aerodynamics, materials, construction and EV components since the Duo-Delta to produce a vehicle that is lighter, cheaper, and goes faster and farther on less energy than anything commercially available. That's the essence of hot rodding, and since most of my cars have been modified in that way, more than anything I want to build a hot rod EV.

Now that I have Walter Korff's incredible 1980 book, Designing Tomorrow's Cars, I'm not only very confident that the Moonray can hit those targets, but I'm deeply indebted to Mr. Korff's thorough, excellent work, and his commitment to sharing it. Its very impressive that a technical and design treatise with so much current, even topical information was actually published almost 30 years ago, but it isn't surprising considering the breadth and depth of Mr. Korff's experience. Among many other things, he was the aerodynamicist who shaped the streamlined body on the Summers Brothers' 1965 Bonneville salt flats racer Goldenrod. This innovative car is widely considered the greatest hot rod of all time- it still holds international speed records, and was the fastest wheel-driven vehicle on earth for over 25 years!  After decades of sitting outside and kicking around on display, Goldenrod is also now being carefully restored, at long last, for the Henry Ford Museum.

 

Thank you, Mr. Korff, for your pioneering work in vehicle engineering and aerodynamics, and for pulling it all together and publishing it for the rest of us in this tidy book. I will carefully consider every word of it. From that foundation, we can really get somewhere.

So we begin...