In the past two months a couple of people here have built aerocaps and have posted some short term test results. There has been an A-B-A test posted by one of them and this data has been posted on the home page of ecomodder as being conclusive, a 4% increase in fuel efficiency.
In all fairness, I have made claims on the other end of the number line, a 20% increase in fuel efficiency. I should have reported this percentage as being able to achieve as high as a 20% increase in fuel efficiency, which I truthfully have on a few occasions. I am sure if I were to perform an A-B-A test this number would not hold and my percentage would be lower.
The wind tunnel testing I have had done on the Aerolid is all I can offer. In the A2 wind tunnel test the Aerolid achieved a delta Cd of -0.062. This test was with the lid on my 2006 F150 which Ford says has a baseline coefficient of drag of .42. I plan to do an A-B-A test but not until the weather warms up.
So as I try to get the Aerolid to market, the incorrect 4% fuel efficiency improvement which greets one who signs onto ecomodder and sees Fubeca's A-B-A result, which in all fairness to Darin, I feel is extremely flawed due to atmospheric conditions at the time of the test. The following information was compiled by Darin in 2007 in a report on how cold weather effects fuel efficiency and he claims aerodynamics are effected by the density of cold air.
http://ecomodder.com/forum/showthrea...leage-220.html
Within this thread you will find a link to an earlier thread at MetroMPG.com in which data he compiled is presented showing the declination in fuel efficiency as air temperatures lower. He also goes further in reason number 9, Aerodynamics, how aerodynamic drag increases by 2% with every 10 degree drop in temperature.
I owe Darin and and the good folks here at ecomodder a great amount of thanks for getting the Aerolid alot of exposure. Inversely, a reported 4% gain in fuel efficiency is all an aerocap will get you is not the kind of exposure you want if you are looking to get an aerocap to market.
I cannot offer an A-B-A result yet. All I can offer are the two wind tunnel tets which were done on the Aerolid. I can also offer my road test results which showed a solid 15% increase in fuel efficiency during the two years I ran the Aerolid on my 2006 F150. Check out round.boater's fuel log since he got his Aerolid in May of 2009.
So Darin let's work together to get closer to the truth. Fubeca and Chaz have worked hard on their lids and I hope they do not get dismayed by poor fuel efficiency results due to cold weather. If they can hold out until spring, they will be pleasantly surprised.
Bondo