Good news, bad news…
Well, the good news is that our film crew, BHP Sport are here and filming in earnest with the very latest Sony HD equipment. Early footage looks stunning and they will be posting Video blogs here shortly. Simon and the crew from BHP are great friends of the project and have been filming progress since the early days in 2001.
The bad news, is that it is raining, hard! Not sure how much has fallen so far but we will get accurate measurements from our rain collectors in the morning. We will then have to reassess the situation
and how this has affected the drying time, sailable area, etc.
Today was another tuning and tweaking day, with stall tests on the main wing and tail flap angle adjustment for starting. Wool tufts are stuck to the wing to visualise flow and show when stall occurs. Even though real operating speeds are much faster than these static tests at low wind speeds, the results should be fairly linear.
Simon and Andy from BHP battling the rain...
Temporary wool tufts to visualise flow...
Rain radar - not looking good!
oh no i hope you do it !
Comment by EcObEaN — August 28, 2008 @ 3:55 pm
All the very best, Rich…
I’ve my fingers & toes crossed for sun & wind; following your awesome quest daily. And NEVER believe the forecasters!!
Em.
Comment by Em Collis — August 30, 2008 @ 10:10 am
The explanation provided under your “how it works” is quite incorrect in your comparison as to how an aircraft flies. A plane’s wing does not generate any significant lift above it, perhaps one-ninth at most. Nor does the behaviour above the wing push the wing upwards as you claim, that would require suction. Most of a plane’s lift comes from the angle of attack of the wing. Most stunt aircraft have zero incidence and possess wings that are equally convex above and below. There is little suction. To compare Greenbird to an aircraft wing was a very unfortunate choice and helps to perpetuate the airplane myth that air behaviour above the convexed wing creates lift by suction. In fact a sheet of chipboard can be made to fly….Bruce+++
Comment by Bruce — August 31, 2008 @ 10:55 am
Bruce,
Bruce,
You are correct that a sheet of chipboard can be made to fly very nicely with sufficient apparent wind and an angle of attack. It can generate almost as much lift as an airfoil at a given wind speed. What it can not do is generate lift with low drag which is why flat/rough shapes are not used for airplane or sailboat lift surfaces.
As for Richard’s explanation, he is trying to keep it at a basic level. As you know, explaining lift to people who have little understanding of hydrodynamics is not easily done.
Bob
Comment by Bob Dill — September 1, 2008 @ 1:04 pm