Green Flight Challenge Final Results

by DEAN SIGLER on 10/13/2011

Steve Williams, CAFE Foundation board member and e-totalizer guru, released the final results for the NASA Green Flight Challenge sponsored by Google, held at the Charles M. Schulz Sonoma County Airport from September 25 through October 1, 2011.  Figures show a profound difference between the two electric winners and the two gas-powered and hybrid runners-up.

All competitors flew extremely clean motorgliders with demonstrated lift-to-drag ratios between 25:1 and 35:1.  Possible explanations for the large differences in energy use include low cooling drag for electric aircraft and the efficiency of electric motors – but the differences are still surprising.

Note that a little over 11 US gallons of gasoline (energy equivalent) were used to fly seven people (Embry Riddle’s Eco-Eagle flew with only one pilot) over a total of 725.5 miles (Embry Riddle flew a shorter total distance on both “runs”).  This is an enormous achievement for all concerned and a significant increase in efficiency over even the best general aviation craft available today.

Congratulations are in order for everyone who participated in making this event a grand success.

Efficiency Competition
  Pipistrel e-Genius Phoenix Eco-Eagle  
Fuel used 3.82 3.82 gallons 100LL
Energy used 65.4 34.7 3.8 kWh
Equivalent fuel used 1.94 1.03 3.98 4.10 gallons (auto fuel)
Flight time (for speed) 1:47:16 1:48:27 2:25:01 2:00:48
Flight time (for mileage) 1:49:37 1:50:23 2:25:43 2:04:07
Distance (for speed) 192.0 191.0 186.7 142.5
Distance (for mileage) 195.9 193.7 187.8 148.1
Mileage 403.5 375.7 94.3 72.2 ePMPG
Speed 107.4 105.7 77.3 70.7 MPH
Speed Competition
Fuel used 6.61 4.19 gallons 100LL
Energy used 68.3 37.5 3.0 kWh
Equivalent fuel used 2.03 1.11 6.90 4.47 gallons (auto fuel)
Flight time (for speed ) 1:41:55 1:47:45 1:22:11 1:43:21
Flight time (for mileage) 1:44:10 1:50:24 1:22:57 1:44:53
Distance (for speed) 193.0 192.7 188.4 143.9
Distance (for mileage) 196.8 196.2 189.5 146.2
Mileage 388.4 352.4 55.0 65.5 ePMPG
Speed 113.6 107.3 137.5 83.5 MPH
           
Score 72.7 68.3 35.1 25.2  
           
Score = 1/( 1/Speed + 2/Mileage )
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