Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Rebuttal of Denker's rubuttal



John Denker,

It is clear that you believe that a 500,000-lb aircraft holds itself up by
its bootstraps. Below I reproduce part of your rebuttal of our article
<http://www.monmouth.com/~jsd/fly/lift.htm>. This clearly contradicts the
data of energy consumption as a function of gross weight (at a constant
speed) that we published in our paper
<http://www.aa.washington.edu/courses/aa101/lift.htm>. These data were
experimental data for a Boeing 777, obtained from Boeing, and confirm that
the power required for lift goes as the load squared.


"The analogy to airplanes is this: Obviously, the airplane must expend
some energy to create the circulatory motion that is responsible for the
upwash and downwash. However, after the circulation is established, it
tends to perpetuate itself with only rather minor additional energy
inputs. The energy of the downwashing air bounces off the lower air and
returns in the upwash. (You should not imagine that any typical air
molecule makes a round trip. The energy nevertheless returns, after being
passed from molecule to molecule.)"(from Denker's rebuttal)


You also clearly believe that the downwash air is can be compared to
lossless supper balls and that the viscous air below can be compared to a
hard surface. What about the air accelerated down from far above the
wing. Lift is not a surface effect and any good simulation will show that
there is a great deal of air accelerated far above the wing. That would
have even a harder time transferring its energy to the bottom of the wing.

David Anderson
Dfa@fnal.gov