Saturday, March 1, 2008

Is Bigger Always Better? (Part II)

Upon reader comments and personal review, I realized that my previous post may have been a bit misleading in that it gave the impression that if we are to build an off road vehicle, smaller is the ONLY way to go. This simply isn't true. There are several factors we have to consider; breakover angle being just one of them. It will be the overall combination of characteristics that will make our vehicle(s) out-perform in various conditions. The discussion of breakover angle was merely an illustration of one of those little known, yet critical characteristics an engineer must consider in the development process.

There are many reasons why building a larger vehicle is preferred. The following is a brief sampling of a few of them.

1) Safety. With a longer, wider stance, the vehicle is more stable. With a larger vehicle you can easily (relative to a much more compact design) incorporate crash structure and still accommodate the vehicle components (engine, transmission etc.) in an efficient manner.

2) Space. As mentioned, locating critical components is easier in design and also allows easy access to the parts later for service. More passenger space. More room for gear, whether it be for a weekend trip with the family, tools and equipment for work, or necessary supplies for an all out off road adventure like the Baja 1000.

3) Lower Cost. This doesn't apply for everything involved in manufacturing a vehicle, but a significant portion. Speaking in extremes, as certain components get smaller (ie: electronics) they become more difficult to produce, which means greater expense, particularly if the desired size requires a new part to be designed. In the other extreme, some components can become expensive at an exponential rate after a certain point as they get larger. A good example here would be wheels. After around a 20"-22" wheel, the price for wheels and tires to fit them skyrockets (sometimes the tire can cost more than the wheels!) Therefore, this is something that has to be well managed to find the best compromise between size and cost.

When parts aren't heavily restricted in terms of size/spacial requirements you have greater freedom in choosing components, their material makeup, and method of manufacture and availability while balancing safety, quality, cost and performance of the parts.

These freedoms and availability of off the shelf or easy to produce parts are two of the agents that enhance your speed to market.

That speed to market will be the most critical of criteria and core to the success of Local Motors, which means this first vehicle we develop will have to strike a balance between many characteristics with size being one of the most crucial, if not the most.

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