Re: IHLG Flappers

From: <dgbj_at_aol.com>
Date: Mon, 12 Feb 2007 16:18:57 EST

Kurt,
 
"My Cat 1 or 2 models do not climb up in any kind of half loop. My feelings
is the shortest distance
between two points is a straight line, therefore I design and trim a model
so it travels in basically a
straight line, from the release to the top of the flight path."
 
Wow. The implication of that is that there is no lift at all. The only
accelerational forces would be gravity pulling straight down and drag
decelerating the glider, also straight down. The physics would be just like a thrown
rock, except that it rolls out at the top, not bad if you can make it work. In
that case, there would seem to be no force to actuate the flaps. The wing
is flying at the zero lift angle. The wings must be breaking because of a
high attack angle at the instant of launch, caused by the location of the
towhook.
 
A straight line is not necessarily the shortest distance between two points.
 If the object is not constrained by an outside force, yes, but we have
gravity and aerodynamic forces at work here. If it takes a lot of energy to stay
on the straight line, it may take longer. A familiar example is the
brachistochrone, the smooth curve joining two points along which a bead might slide,
subject only to the force of gravity, in the shortest time. The discovery
of this curve was one of the first discoveries in calculus, done by James and
John Bernoulli, brothers of the guy who has caused us so much trouble.
 
Gary


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Received on Mon Feb 12 2007 - 13:24:54 CET

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