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]

Re: helicopter not equal rocket



At 12:55 PM 8/20/99 -0400, Michael Edmiston wrote:

We (at least me) acknowledge the Bernoulli-ists
view and we agree those equations work and have value.

OK, good. We agree on one thing.

But we are at a
loss as to why we are not allowed to view the wing as a reaction
engine.

According to your definition of reaction engine, the wing is a reaction
engine, so by definition you are correct: you can view the wing as a
reaction engine. End of discussion.

The jet engine gets thrust by causing air to be thrown out its
back. The wing gets lift by causing air to be thrown downward.

1) As I have said before, a machine-gun model produces no upwash. It
therefore cannot account for the observed dependence of induced drag on
airspeed, ground effect, and wingspan. Most conspicuously, it cannot
account for the decrease in induced drag when two airplanes establish
formation flight (wingtip to wingtip).

2) To say that some air is thrown downward is not wrong, but it is grossly
incomplete. It begs the question of *how much* air is thrown downward. It
could be a paper-thin sheet of air thrown downward with great velocity, or
it could be a huge pillar of air thrown down quite gently. Unless you have
a way of predicting how much air is affected, your theory is quite
inferior to the orthodox theories that provide quantitative and intuitive
predictions of the amount of upwash and downwash, near and far from the wing.

You may be suffering from a variant of the bullet fallacy; see
http://www.monmouth.com/~jsd/how/htm/airfoils.html#sec_fluid
for more on this.