MAX Update No. 29: Cardboard-aided Design

| 6/9/2009 12:51:57 PM

Tags: MAX, 100 mpg, Auto X Prize, gas mileage, aerodynamics,

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.

Roo Trimble_2
7/8/2009 12:09:57 PM

I like to use blue masking impatient to cut all that cardboard see lots of tape on my project at ! Cant wait to see the body: also any tips on cutting a curved windshield? my first try was a disaster... hope to see MAX done soon! Roo

6/26/2009 4:37:19 PM

Hi Jack it was more about Max being 33 inches wide, the Tango is 39 inches but looks to be narrower at the screen area and also seems to have A posts! I guess I was wondering if you could just purchase one windscreen for your aero shaped MAX rather then the standard kit. If the plan is to provide a ongoing kit then yes I would agree split screen would be easiest. Looking forward to the next update. From another builder cheers Adrian

Jack McCornack
6/25/2009 8:50:26 AM

Adrian, the Tango windshield is awfully narrow, I doubt they found one off-the-shelf that fit their car. I'm presuming that Commuter Cars Inc spent what they needed to have custom windshields made, and that's not in the cards for MAX. The Tango is a $100,000 car and MAX is a $10,000 car, and the Tango is designed to be factory built and MAX is designed to be built at home. For a homebuilder, I think a split windshield will give the best bang for the buck, but time will tell, and what the hey, I might as well send Commuter Cars an e-mail and ask.

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