ASC 33: Road Race Day 4 (part 2)

Although the American Solar Challenge is far from over, I’m getting a head start on my personal Gem Awards for the race. The “Beautiful Background Gem” goes to the National Trails Intermountain Region for its wonderful scenery. Running the race along the Oregon Trail was a brilliant idea!

Tuesday evening, Day 4 (picture credits: 1, 2)

The race chart below is similar to that previously posted, but based on official data to date. A small elevation chart is included at the bottom. The chart is constructed with reference to a theoretical car which drives at exactly 80 km/h all the way. Vertical position indicates how far behind that theoretical car the various teams are (in elapsed-time terms). Penalty minutes are added in at the right-hand side of the chart. Trailered vehicles are shown at the top left. Notice that Western Sydney are only 19 minutes behind Michigan, and ETS/Eclipse only 87 minutes behind Michigan.

In the Cruiser (MOV) class, Minnesota and Onda Solare are both still running well behind the 53.5 km/h required speed (shown by the dashed green line), and so are attracting slowness penalties (per regulation 13.3.A). In fact, Minnesota is below the 45.8 km/h threshold where Cruisers are given a zero efficiency score (dashed pink line). I’m not quite sure what the strategy for these teams is, but both Cruisers appear to be in trouble.

Also, the cars have been climbing, but the big climb is yet to come. Good luck to everybody!


ASC 20: Solar cars and the Oregon Trail

Given that the American Solar Challenge is going to be following the Oregon Trail this year, I thought that it would be fun to do a comparison between the “prairie schooners” of two centuries ago and the solar cars of today.

At the time of the “Great Emigration” of 1843, aluminium was known, but could not yet be produced on an industrial scale (that came in 1854, and was initially very expensive). Steel likewise existed, but the Bessemer process for producing it came later (1855). Fibreglass composites came a century later (1936), and carbon fibre later still. Modern electronics could not even have been imagined. The “prairie schooners” were built using a much older technology.

Prairie schooner and solar car – picture credits NPS (left) and Anthony Dekker (right)

Dimensions (W × L) 1.2 × 3 m (4 × 10 ft) for wagon bed Up to 2 × 5 m (7 × 16 ft) for entire car
Horsepower 4 to 12 hp 1 hp solar power for Challengers (SOV), up to 4 hp mixed solar/grid power for Cruisers (MOV)
Sustained speed 3 km/h (2 mph) 50 to 75 km/h (30 to 45 mph)
Empty weight 600 kg (1300 lb) 150 to 450 kg (350 to 1000 lb)
Load 900 kg (2000 lb) 80 to 320 kg (200 to 700 lb)
Motive power Horses or oxen Solar cells, battery, and electric motor(s)
Body materials Wood, cotton canvas Steel, aluminium, carbon fibre, fibreglass
Tires Iron Rubber, low rolling resistance

Prairie schooner and solar car – picture credits Albert Bierstadt (left) and Anthony Dekker (right)