8,810 reputation
1730
bio website en.wikipedia.org/wiki/…
location United States
age 71
visits member for 3 years, 11 months
seen 47 mins ago

BS Mechanical Engr.
PhD CS(AI)
CS Prof (4yr)
Numerous consulting jobs.
15 yr at http://www.pharsight.com
Published book on CS & several articles
4 kids, 2 grand
Pilot(student)

P.S. The picture is a Beta-prime distribution. It shows the program speedup factors you can get if you see a problem twice in 2, 3, 4, and 5 samples.


Apr
15
answered Concerning the curvature of an airfoil (shape)
Apr
14
comment Photon as the carrier of the electromagnetic force
+ Very nice. It might help if you could explain some terms unusual to us ignorencia, such as "cross section", "branching ratio", and "off mass shell". Thanks.
Apr
12
comment Effective angle of attack of a wing
Maybe you're saying this and maybe you're not, but when the yaw angle is zero, the wind "sees" just the chord slope of the wing. When the yaw angle is 90 degrees, the wind sees the dihedral angle of the upwind wing (and negative on the downwind wing). In between, it's in-between.
Apr
12
comment Does a wing in a potential flow have lift?
@Christoph: You're right. Thanks for pointing that out.
Apr
11
comment Will this type of engine produce thrust?
@Akash: No need to get carried away :) The J58-P4 engine of the SR-71 generated about 16 tons of thrust, but there's no mention of "plasma".
Apr
11
comment Will this type of engine produce thrust?
@Akash: In principle, though your heater would have to pump out as much heat as a gas flame if you want to get noticeable thrust.
Apr
10
revised Static discharge out of 3 volts button battery
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Apr
10
answered Static discharge out of 3 volts button battery
Apr
10
revised Will this type of engine produce thrust?
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Apr
10
answered Will this type of engine produce thrust?
Apr
10
comment Make water droplets charged?
+ I think your mention of the Kelvin water dropper is right on target.
Apr
9
comment Whats the anti-torque mechanism in horizontal take-off aircraft?
@Jim: Lots of questions here about airplanes seem to arise because of not comprehending how heavy air is. In everyday experience, air seems ephemeral, but that's an illusion. It weighs about a $kg/m^3$ and even at low aircraft speeds it takes a lot of force to muscle it around. That force increases as speed squared, so it's practically as dense as water to a speedboat.
Apr
9
comment Whats the anti-torque mechanism in horizontal take-off aircraft?
It's just one of those things that pilots learn. Planes are usually designed with some built-in trim, to act as a compromise between different flight regimes, like takeoff (high power), cruise (medium power), and landing (low power). Like if you look at the rudder of a C172, you will see a little plastic tab near the bottom. That's a built-in trim tab so you need less right rudder on takeoff. As far as roll torque is concerned, the ailerons are plenty strong enough to manage it. It's not an issue.
Apr
9
comment Whats the anti-torque mechanism in horizontal take-off aircraft?
@Martin: Rotary engines on WW1 fighters were dangerous because of gyroscopic precession. i.e. hitting the rudder for left or right yaw could knock your nose up into a stall or down into the ground.
Apr
9
revised Whats the anti-torque mechanism in horizontal take-off aircraft?
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Apr
9
answered Whats the anti-torque mechanism in horizontal take-off aircraft?
Apr
9
comment Why water in the sink follow a curved path?
@Jim: I wouldn't have paid much attention to the sink's floor and wall, but yeah, I think that's right. You always get a vortex, but its size depends on how much angular momentum is in the water. If the water is really really still, then the vortex is really thin, but it's there.
Apr
9
comment Why water in the sink follow a curved path?
@Jim: It's almost impossible for it to have absolutely zero rotation. At the very least, it's turning with the earth at about 1/4 degree per minute. If you put in a drop of ink, of course it spreads out, but does the center of the ink blob stay in exactly one place? You can make the drain swirl clockwise or counterclockwise by just slightly stirring it with a spoon before hand, or by putting in some kind of baffle so that as it flows toward the center it is nudged in one direction or the other. You can perceive that the water has no rotation, but it only needs a tiny tiny bit.
Apr
8
revised Why does the wave description say that probability oscillates, while the phase interpretation says constant amplitude?
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Apr
8
revised Why does the wave description say that probability oscillates, while the phase interpretation says constant amplitude?
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