Thanks Don, very good info.� I've been thinking about building my own Quick-N-Easy roof rack for my 85 tin top and wanted to factor in aerodynamics into the decision.� Of course, it might "blow" off all the empirical data by making a (sortof) aerodynamic box (maybe 10" tall or something) to hold lightweight floppy things like inflateable kayaks and paddles and even camp chairs and whatever.� Maybe the large Vanagon frontal area pushes the slipstream high enough above the roofline and potential homemade "Rocket Box" or whatever they call them....hence no apparent decline in mileage.� Anyway, it's not a huge outlay of cash and effort to give it a try for extended cross-country expeditions.� Would be bummed by a -5 MPG result, but a couple MPG reduction would be acceptable.� Still thinking about my design....rounded frontal end on my "box" seems appropriate.� Also a factor is garageability with the higher roof.

Any perceptable increase in wind noise? Whistling and that sort of thing?

Rich
San Diego

--- On Mon, 10/24/11, Don Hanson <dhanson928@GMAIL.COM> wrote:

From: Don Hanson <dhanson928@GMAIL.COM>
Subject: Aerodynamics related to fuel consumption (for an 84 tin top)
To: vanagon@GERRY.VANAGON.COM
Date: Monday, October 24, 2011, 5:29 PM

� For appx. 3 weeks I ran with my Quick-N-Easy roof rack on my vanagon,
having to carry some long stuff.���It's a full width two-bar rack, with the
cross bars made from Alaskan yellow cedar, appx. 2x4" and just a little
narrower, side to side, than my stock mirrors.� The 'bars' have large radius
corners.���I was working about 60mi round trip from home, but otherwise
driving in the same area and at the same speeds I do in 'real life' (when I
am doing what I want, not working for pay)

� My vanagon is a 5sp with a 2.0 liter Jetta inline gas motor and I've
always kept track of my fuel mileage, every tank for about 4 years now.
I've averaged ~23mpg really consistently.���If I use premium fuel without
corn, I get almost 2 mpg more.� If I drive at 75 all day, I get a few mpg
less.� On my 4 or 5 fill-ups while sporting that roof rack, my gas mileage
declined by almost 2 miles per gallon.

� Then, two tanks ago I took the rack off...it is Quick and Easy, so why
not, plus I'm out of work again so no need...The gas consumption again is
22.++ or 23 and 'small change'....� So there it is, a statistical sample of
one, but it is accurate.� I fill at the same pump, letting the same auto
shut off stop the flow (and spew some backwash out on the station's
driveway) each time.� I fill at about 275 miles run.� I had the same weight
load aboard.� I only carried a long ladder one time (30 miles) on the roof.

� In case anyone is interested in how aerodynamic drag sucks down the gas...