ORIGINAL: onewasp
Quote "I rest my case. Quote
Not so fast______
"The effect begins to be noticeable when the aircraft's altitude is within 1-1.5 times the length of its own wingspan and, when the altitude is within about half a wingspan of the ground, the effect can increase lift by as much as 40%."
Yet another source, ______ yours is NOT conclusive____merely familiar to you.
There are MANY others and they do not all agree with one another.
You are perfectly correct. Mine is not conclusive. It is however the current knowledge required to obtain an airman certificate from the FAA. The 2nd edition asa source from the late 80's early 90's may no longer be correct. The asa dictionary of aeronautical terms is currently in its 4th edition and I'd be willing to bet that the definition has been updated. The quote "within about half a wingspan of the ground, the effect can increase lift by as much as 40%" is correct by all the sources I've read. All the sources I have read indicate one wingspan above the surface. Could you provide that source that clains 1.5?
BTW the asa news release for their New Forth Edition dated February 7, 2007 cites the same sources that I cited, as its sources. "All specific to the aviation industry, the terms have been gathered from the regulations, the Pilot/Controller Glossary from the AIM, and glossaries from government handbooks and manuals."