MAX Update No. 29: Cardboard-aided Design

http://www.motherearthnews.com/green-transportation/100-mpg-car-curved-windshield.aspx

Don't pay the ransom, I escaped! Wow, it's been a busy month for me, and I apologize for the lack of updates recently.

The last weekend in May was MAX's farewell public showing in its Escape from Berkeley trim, at a fun, wonderful event called the Maker Faire.

We were there to show the flag and drum up business for Escape from Berkeley II. I figured if the Escape folks were willing to give us five grand for winning the event last year, the least we could do is encourage others to join in the fun this year. So we pulled off the streamlined body bits and put back the stylish-but-slow fenders and lights and all, and drove down to San Mateo, Calif., for one last hurrah.

Now we're back, and we have to knuckle down on the streamlining. In order to reach 100 mpg, we’ll have to get MAX down to the drag coefficient of a typical modern sports car.

The drag coefficient (aka “coefficient of drag”, abbreviated Cd) is a comparison of the drag of an object versus a flat plate of the same frontal area. A Mazda Miata, for example, has a Cd of 0.38.

MAX gets better mileage than a Miata because (among other things) MAX is so small it doesn't have a lot of frontal area. But MAX’s Cd is about 0.7, which is pretty terrible. That’s about the same drag coefficient as a shoe box.

MAX new windshieldObviously, we have to make a lot of improvements, and one feature we can improve is a curved windshield. Hey, if you were making a windshield for a shoe box, it would look a lot like MAX's windshield does now — a flat panel right across the front of the cockpit.

But unfortunately a curved windshield will blow our $10,000 budget, because there's nothing off the shelf that will fit MAX (the windshield is only 33 inches wide — more than a foot narrower than the Miata windshield, for example) and custom-curved windshields cost a bundle.

So how about a split windshield, with a steep rake and a deep V to emulate a curved windshield? It'll be pretty cheap, and it would add to MAX's old-timey personality. I think I like it ... though I wasn't willing to commit the glass cutter before I saw how it looked.

Cardboard is a nice medium for conceptualizing design features, but it has its limitations. It should come with a sticker that reads, Warning: Remove Cardboard Before Operating This Vehicle. Nowhere would that be more important than the windshield …

Photo by Jack McCornack

 


Browse previous MAX Updates.
Read the introductory MAX article, Here Comes the 100-mpg Car.
Visit the Kinetic Vehicles website for more technical details on MAX.