Into The Outback

Xenith sails successfully.

Yesterday, the solar car team started testing in the outback. We were set back by a rough transition to the new BPS, but today around noon the electrical system became fully armed and operational, and we started getting significant test miles on the car under race conditions.

 

The big milestones of the day were testing our sailing configuration and tuft testing. Sometime in the afternoon we attached many tufts of yarn over the surfaces of the car, to see if airflow was separating at any point on our aerobody. It wasn't a comprehensive test, but that wasn't the point - we ascertained that the flow over the array is very, very laminar, and the flow over the fairings is also very clean. The most interesting part of the test was the bubble, however. We were driving with a significant crosswind the whole day, which caused a large vortex over the back of the bubble foil when the car was pointed in the direction of travel,which of course causes a lot of pressure drag. However, when we changed the sail angle of the car to the full 7 degrees into the wind, we observed the tufts become firmly attached to the bubble surface again, indicating that the boundary layer had once again attached to the car. The final verdict is not yet in on the exact quantitative benefit of sailing, but this is a pretty significant success.

The goal tomorrow is to drive north in a full mock race day, with array stand charging in the morning, driving from 8 to 5 with a short mock control stop, and charging again in the evening. The numbers we got for power consumption over our excellent telemetry system today look very competitive, but another full day of testing tomorrow along with some other tweaks to the car will help us determine if it's the best. Here's hoping we can pull it off.