why are oval windows used in aircrafts?
916646
Physical stress.\n\nThe first commercial jet airliner (the British-made Comet) had some accidents that were traced to the larger square/rectangular windows that were used...this forced a redesign - which other manufacturers copied for safety reasons.
1025416
because it is eisier to break through it.  if people go through smaller windows, then they might hit the frame and get a seriouse injury.
592588
They're like the wings on a '52 Studebaker. They serve no purpose but they sure look cool.
587814
The rear window of a car is made of tempered glass -- the glass is heated approximately to its softening temperature and then cooled abruptly to put its surface under compression, leaving its inside material under tension. That tempering process makes the glass extremely strong because its compressed surface is hard to tear. But once a tear does manage to propagate through the compressed surface layer into the tense heart of the glass, the entire window shreds itself in a process called dicing fracture -- it tears itself into countless little cubes.\n\nThe stresses frozen into the tempered glass affect its polarizability and give it strange characteristics when exposed to the electromagnetic fields in light. This stressed glass tends to rotate polarizations of the light passing through it. As a result, you see odd reflections of the sky (skylight is polarized to some extent). Those polarization effects become immediately apparent when you wear polarizing sunglasses.
48985
airplane wings work because of their curvature - the upper surface of the wing is more curved than the lower surface, so air moving over the top of the wing has to take a longer path.  \n\nthis longer path causes the air to thin out over the top surface of the wing, and this leads to a lower pressure on the top surface.  the higher-pressure air on the underside of the wing pushes the wing upwards into the lower-pressure region, just like the higher pressure inside a balloon pushes the balloon outwards into the lower-pressure atmosphere.\n\nanyway, i think you can think about a leaf on a windshield as acting like a wing of sorts.  air will flow faster over the upper surface of the leaf but stay trapped underneath.  if the leaf is solid, then the pressure differential pushes outward on the leaf, away from the windshield.  \n\non the other hand, if there is a slit in the leaf, then the higher-pressure air underneath can move through the slit and equalize the pressures, so there is less force on the leaf pushing it away from the windshield.\n\nas for holes, perhaps if the holes were big enough, you would no longer have the smooth ("laminar") flow over the surface, and instead get turbulent air that causes a vortex to form.  \n\nvortices are lower pressure areas so that might suck the leaf off.  or, a big hole might cause an edge of the leaf to flip up into the airstream and catch some of the air, forcing it down under the leaf and pushing it off the windshield - whereas a slit might still allow the air to flow smoothly over the leaf yet still equalize the pressure.\n\ni'm totally guessing, but i guess it's a reasonable theory.
1068651
White reflects light at *visible* wavelengths better.\n\nHowever, the designers were not trying to reflect visible light.  I would guess they designed the coating to emit thermal radiation as efficiently as possible - approaching 'black-body'.  The coating color would probably be secondary to that consideration.\n\n****\nSide Note\n*****\nDue to it's tremendous speed, the orbiter shock-heats air at it's leading surfaces during reentry. (the orbiter's underbelly is exposed directly to the 'wind stream', if you will, due to the orbiter's initial high-angle of attack)\n\nThe temperatures of the thermal protective surfaces rise primarily in response to thermal radiation from the incandescent shockwave.  NOT FROM FRICTION.
863935
Yes, they absolutely are.  An air pocket is better called a vertical draft, or an updraft or a downdraft, depending on which direction is is moving.  The reason they are sometimes called air pockets, even though everything around it is also air, is that the vertical draft is typically a pocket of air at a different temperature than the surrounding air, which causes the vertical displacemet of air.\n\nVertical drafts are dangerous because they can lead to overcompensation by inexperienced pilots.  This is most commonly seen during landing, if the air pocket takes the form of a downburst.  The air spreads in all directions after hitting the ground, creating a headwind that causes a false indication of increased speed.  The pilot might then slow the forward speed, if he is not familiar with this phenomenon.  Once the headwind is cleared, the plane is no longer moving fast enough to provide lift force in the still air, and the plane can plummet to a crash.
423448
Usually they are there to improve the visibility of the wire and grab your attention.  You don't want a tall sailboat going under low wires do you?
1084157
They found that the second wing (bi-wing planes) was not helping the planes lift, but rather was just adding unnecessary weight to the plane.  Therefore it was inefficient.\n\nSome planes today actually have a smaller wing in the front and a larger wings in the back.   Also, some one plane known as the flying wing did not have a wing in the back.  In fact this is basically the design of our new stealth fighters and bombers.   \n\nSo new designs are coming forward all the time that find new design concepts in flying.
908073
Ummmm... Are you talking about sprint cars? They have aluminum "wings" on top. They contribute to the aerodynamics of the car. They also allow for additional handling adjustments. The position of the wing determines air flow which can either loosen or tighten the handling of a car. :) If you want to see a picture check out http://www.billthomasracing.com/ or http://www.rtschassis.com/.
61716
The air inside the vehicle is moving the same speed as the vehicle. To the fly it's still air, unless a window is open, then the fly may not be able to fly normally.
614744
The curved surface on top of an airplane wing causes air to travel faster over the top of the wing then the bottom.  This causes a decrease in the air pressure above the wing and a net force upward (called lift) that is equal to the air pressure below the wing minus the air pressure above the wing times the area of the wing.
941103
Because round covers don't fall in.  They are the same distance across, any way you turn them.  They always stay on top.\n\nIf it was square, it could fall in if placed at an angle or carelessly dropped by a worker.
285215
If you are in an airplane they are circular.  We usually can't see the bottom because there is no rain to reflect the colors in the earth.
718609
Wind Sock. Purpose\n\n1) Airports : Big planes don't need it but small aircraft need to know wind direction when landing or taking off\n\n2) Petrochemical Complexes and Refineries : in such places, there is always a (hopefully low) risk of a release of a toxic or highly flammable gas. If an alarm goes off indicating that this has happened staff need to know which way the wind is blowing such that they can go to a safe area without passing through the gas cloud and emergency response teams need to know which direction to approach the point of the leak from, always upwind.
752359
The f-22 raptor is still a highly secretive plane. as for the missles im sure it uses the standard aim 9 side winder. how it works is by locking on th ir trail of a plane. as for the skin of the air crat all i know is that it has r.a.m. on it (radar absorbing material) thats about it
990419
To look like it is flying.