Wednesday, December 11, 2013

Turboprop update, and a Hot Air Oscar nomination

ATR600 - image from atraircraft.com My attention was recently drawn to an impressively fuel-efficient turboprop aircraft, the ATR72-600, which is claimed to be about one third more energy efficient than Bombardier's Q400 turboprop, which I featured on page 35 of SEWTHA.

HotAirOscar-ATR72 I've consequently written an update on turboprops, celebrating this achievement, but in the interests of balance I feel I should also nominate the advertisers of the ATR72-600 for this year's Hot Air Oscar for the most misleading "green" infographic, for this astonishing picture [at left] showing the difference between the fuel consumption of the ATR 72 and the Q400 on a 250-nautical-mile journey. As the numbers in the picture show, the ATR 72's fuel consumption is 70% of the Q400's, but the volume of the three-dimensional blue barrel shown is 30% of the volume of the orange barrel — a 2.3-fold exaggeration!
blue barrel:orange barrel
ratio of diameters91:134=0.68:1
ratio of heights 118:179=0.66:1
ratio of volumes
(as depicted)
=0.68×0.68×0.66
=0.30:1
true ratio of volumes
(735:1043)
=0.70:1

1 comment:

Ray Blanc said...

This reminds me of a similar mistake by the EU parliament related to the size of the EU budget http://t.co/i44fk7qh