Peter Rawlinson, Tesla Motors vice president and chief engineer
You've talked about "alpha" and "beta" designs, which aren't auto industry terms. What do you mean?
PR: Alpha vehicles are notionally 80-percent representative of the production vehicle we intend to build. Beta cars are 90 to 95 percent representative.
Not all the systems will be at the same stage of development in each phase. The suspension is all there already on this alpha body, and so is the body structure.
We have four alpha cars identified to crash-test, along with more betas. We don't necessarily have to wreck them that early; it's to verify that our work and modeling bears out, to correlate our computer-aided engineering (CAE) models to actual performance. The beta cars give us deceleration-pulse data to time the airbags.
What's been the most challenging part of designing the Model S so far?
PR: It's been balancing the growth of a new team while simultaneously designing and engineering a brand-new car, in an extraordinarily tight time frame. We're now a team of more than 100 engineers. You could almost think of it as difficulty cubed.
2012 Tesla Model S body-in-white
Many companies would balk at simultaneous design of a new platform and a new powertrain configuration. We're adding a new and unconventional type of platform architecture, with the battery pack in the floor as an integral component of the car's safety structure.
We're particularly proud of the pack, in fact. It works both electrically and mechanically, with cells grouped into bricks, bricks into modules, both in parallel and in series.
It was a challenge to get the geometry of the electrical components to fit within the mechanical requirements of the pack layout: Where to put the seat-belt mountings, for example, so you can have through-bolts, and where to place the cross-members to contribute to the side-impact crash structure.
And your biggest remaining challenge in getting the car out the door?
PR: We're focusing on delivery of the program we laid out. We've got lots of bases covered already.
Our crash tests will start soon, and carry on in phases through 2011.
But, frankly, we're on track. We know what we're doing.