Airtimes

In the United States there are many experienced skydivers with hundreds or thousands of jumps. Usually, an experienced skydiver owns his gear and his parachute and prepares his gear on his own for the jumps. The enthusiasts jump every weekend and whenever they have spare time. Here is what jumping is like:

* The first thing to do is packing the parachute and checking it.

* This is followed by the AAD (automatic activation device) set and check.

* The skydiver puts on his jumping gear and his parachute and is checked by another skydiver for the straps and rig to be well set.

* The skydivers embark on the plane. The number of the skydivers that can jump at the same time depends on the size of the airplane.

* The jump altitude is reached. The most common jump altitude is 10 000 feet and gives the skydivers a 45 seconds free fall before opening the parachute. The altitude varies and can go as high as 16 000 feet providing 75 seconds of free fall. Above this altitude, the skydivers would need supplemental oxygen.

* After reaching the jump altitude, the plane lines up with the jump site and the skydivers take the leap.

* In the first ten seconds, the jumper accelerates and reaches the speed of 120 mph. after this point of terminal velocity, he is in free fall.

* The parachute is deployed at around 2500 feet by a drogue parachute.

* The parachute is than steered to line up with the landing site and the skydiver lands.

The tandem jump

For the first timers, the best and most popular way to take a leap is the tandem jump. This procedure requires for the student to leap from the plane strapped to his instructor and fall with the instructor’s parachute (which is big enough to carry both your and the instructor’s weight and is controlled by the instructor).

Dalvin Rumsey
http://www.articlesbase.com/sports-and-fitness-articles/the-skydive-in-words-108564.html

Technorati Tags: airplane, Altitude, Drogue Parachute, Enthusiasts, Feet, First Timers, Fitness Articles, Jumper, Leap, Packing, Rig, Skydive, Skydiver, Skydivers, Spare Time, Supplemental Oxygen, Tandem Jump, Ten Seconds, Terminal Velocity, United States

i’ve taken airplanes while traveling but i never understood how airplanes get from point A to B in the sky?

There are several methods to get to where you want to go in an airplane.

The first and most basic is navigation by land marks, lakes, roads, other airports, mountains…. the list goes on.

Next comes radio navigation, there are things called VOR’s all over the country and with the proper equipment you can fly to or from a near by one and a lot of them are at or near airports.

Next if you plane is equiped with GPS it is a no brainier, just punch in the airport code and it will guide you right to it.

Lastly all big planes and some small plane that are flying IFR under control of Air Traffic control. ATC tells you what direction, speed and altitude to fly to get to your destination.

Technorati Tags: Air Traffic Control, airplane, airplanes, Airports, Altitude, ATC, Fly, Gps, Mountains, Planes, Punch, Radio Navigation, sky, Traveling

we are riding a boeing 777. i heard that a boeing 777 once crash landed because there was ice build up in the engines. we’re flying over canada and greenland and those are cold places! will we be safe? what if the same problem happened!?

Jason, don’t be worried. The temperature at the altitude where you will be flying has nothing to do with the temperature on the ground. You will be safe. Every day there are jetliners that fly over Canada and Greenland on their way to Europe and the Far East. If it were not safe, the airlines would not allow it and the pilots would not do it.

Regards,
Dan

Technorati Tags: airlines, airplane, Altitude, boeing, Boeing 777, canada, Cold Places, crash, Europe, Fly, Greenland, Jetliners, Temperature

An airplane is flying at an altitude of 5 miles and passes directly over a radar antenna. When the plane is 10 miles away (s=10), the radar detects that the distance is changing at a rate of 240 miles per hour. What is the speed of the plane?

let d = the distance between the radar antenna and the plane. let x = the horizontal distance between the radar antenna and the plane with the radar station being located at x =0. let y = the altitude of the plane with the radar station being at y =0.

d^2 = x^2 + y^2

take the derivative

dd’ = xx’ + yy’

From the problem
d = 10 mi
d’ = 240 mph
x = sqrt( 10^2 – 5^2) mi
y = 5mi
y’ = 0 (constant altitude)

solve for x’

Technorati Tags: airplane, Altitude, Dd, Miles Per Hour, Radar Antenna, Radar Station, Related Rates, Xx Yy

If you’re flying in a commercial airliner and the engines cut out will the plane fall out of the sky or will there be time to land safely on the ground? (I’m scared out of my mind every time I fly)

Commercial airliners are good gliders and the "Glimli Glider" is a great example of how it can be put to good use.

At altitude you have substantial amount of potential energy by virtue of its position. This can be converted into kinetic energy, which means forward air speed. The airliner doesnt care if it is powered or not, all it needs is forward air speed. A good pilot can maintain the airspeed and glide to a safe landing.

Technorati Tags: Air Speed, airplane crash, Airplane Engines, Airspeed, Altitude, Commercial Airliner, Commercial Airliners, Fly, Forward Air, glider, Gliders, Kinetic Energy, pilot, Potential Energy, Quot, sky, Virtue

Do airplanes crash more on takeoff or on landing ?

There’s a saying in aviation community, "don’t worry about the runway behind you and the altitude above." An airplane is more likely to suffer a crash from mechanical failure during take off. Imagine you just took off and climbing with maximum power and one of your engine failed. Depending on what type of aircraft you are flying, most likely, you don’t have enough altitude and speed to turn around, and all the runway is already behind you. At this point you have a full load of fuel and your aircraft is in takeoff configuration (flaps up, landing gears were coming up or already up, etc.). Even if you can manage to get your aircraft to the landing configuration, you will not have any runway to land right front of you. If you turn around, you can’t lower the flaps to increase lift which results in soft landing. You can’t lower the flaps because at this slow speed they will produce more drag then lift. On the other hand, when you are landing, if anything goes wrong, you have runway front of you and altitude below you to maneuver, and most importantly, you are already prepared for landing- your land gears were down, flaps extended and you were in a mindset to touch down anyway. Planes glide to landing anyway after an engine failure. They don’t glide to altitude after an engine failure during takeoff.

Technorati Tags: airplane, airplanes, Altitude, Aviation Community, crash, Engine Failure, Gears, Landing Gears, Maximum Power, Mechanical Failure, Mindset, Planes, Quot, Slow Speed, Takeoff, Worry

An airplane flying at an altitude of 12000 feet passes directly over a fixed object on the ground. One minute later, the angle of depression of the object is 40 . Approximate the speed of the airplane to the nearest mile per hour.

The only way to do this problem is to assume the plane is flying parallel to the ground, so that is what we shall assume.

From the object to the plane is 12000 ft, or 200/43 miles. That is one side of a right triangle. The other side is equal to x / 60 miles, x being the speed (mph) of the airplane. It is x / 60 because the plane has flown for one minute, or 1 / 60 of an hour. 1 / 60 * x (mph) = x / 60 miles

The hypotenuse then drops from where the plane is at after one minute to the object on the ground. We don’t really care about the length of the hypotenuse. We now have our right triangle. We know that the angle of depression is 40 degrees, so the remaining angle, on the ground between the vertical and the hypotenuse, is 180 – 40 – 90 = 50 degrees.

We know that in a right triangle, the tangent of an angle is equal to opposite / adjacent side lengths. Therefore, tan 50 = ( x / 60 ) / ( 200 / 43 )

Solve for x:
tan 50 = ( x / 60 ) / ( 200 / 43 )
(200 / 43) * tan 50 = x / 60
60 * ( 200 / 43 ) * tan 50 = x

So x is approximately 332.582397933

The speed of the airplane is 333 mph

Technorati Tags: airplane, Altitude, Angle Of Depression, Feet, Hypotenuse, Side Of A Right Triangle, Tangent Of An Angle

An airplane flying at an altitude of 11000 feet passes directly over a fixed object on the ground. One minute later, the angle of depression of the object is 38 . Approximate the speed of the airplane to the nearest mile per hour.

Well, in knots ( not miles per hour ) that would be about 250kts.
Hope that helped.

Technorati Tags: airplane, Altitude, Angle Of Depression, Feet, Knots, Miles Per Hour

This a thermodynamic question from a chapter on specific heats, entropy & adaibatic-processes: "Commerical jet aircraft fly at cruising altitudes between 30,000 & 40,000 ft. Yet such aircraft carry heat exchangers to cool cabin air while flying at these altitudes. (a) Estimate the air temperature at which jet aircraft fly. (b) Explain why it is necessary to cool cabin air at cruising altitudes. Hint: The ratio of the heat capacities of air at constant pressure and volume is about 1.4." I alrealy have the answer to (a). It’s 181 Kelvins. I need help with (b). Even if you could just give me a verbal answer for why airplanes have to cool their cabins and hence pressurize them would be helpful. Thanks.

Pressurization is required for physiological reasons. Some of the answers above say that the plane’s fuselage will crush. This isn’t true because the same pressures would exist on both the inside and outside of the airplane just like it is on the ground with the aircraft doors open. Furthermore, following the same logic, if this were true then a rapid decompression would mean the aircraft fuselage would collapse and that also isn’t true. Anyway, the atmosphere has constant percentages of nitrogen, oxygen, and other trace gases, regardless of altitude. However, the distance between molecules increases the higher up you go in altitude. This is what causes atmospheric pressure to decrease with an increase in altitude. As such, with each constant volumetric breath, you would have fewer oxygen molecules in your lungs. You reach a point where you aren’t getting enough oxygen to survive. Interestingly, at altitudes above 25,000 you can be oxygen deprived even if you are breathing 100% oxygen. People that climb Mount Everist are frequently hypoxic even if they are breathing 100% oxyen.

As for your other question. air for pressurization is taken from the compressor. The air is very hot so it has to be cooled. That’s the down and dirty answer!

As for further information, as far as outside temperature is concerned, a standard atmospheric day starts off at 15 degrees celcius at 0 feet MSL. The temperature cools at the rate of 1.5 degrees celcius with each one thousand feet of altitude all the way up until reaching the tropopause.

The efficiency of an internal combustion engine is directly proportional to the temperature difference of the "hot sink" and "cold sink". In this case, the hot sink is the combustion chamber and the cold sink is the outside air. This is one of the reasons why it is more efficient to fly higher. Furthermore, at any constant fan or compressor RPM, a specific ratio of fuel to air must be introduced into the combustion chamber. The higher the airplane is, the less air there is and as such, the less the amount of fuel that must be sequenced into the combustion chamber. This is the second reason why it is more efficient to fly higher.

Technorati Tags: Air Temperature, Aircraft Fuselage, airplanes, Altitude, Altitudes, Atmospheric Pressure, Dirty Answer, Heat Capacities, Heat Exchangers, Jet Aircraft, Mount Everist, Nitrogen, Oxyen, Oxygen Molecules, Percentages, Physiological Reasons, Pressure And Volume, Question Air, Rapid Decompression, Trace Gases

First, no windows on modern jets are made to open. Some airliners, mostly older I think, have side windows on the windshield that slide open. If a door is made to open to the inside of the aircraft, the cabin pressure will prevent it from being opened at altitude. If it opens to the outside, you could still open it, but would be "blown" out of the aircraft in the process. Planes can be pressurized on the ground for maintenance reasons, but it must be within the allowable pressure differential in the aircrafts limitations. That would be the difference between the outside air pressure and cabin pressure.

Technorati Tags: Air Pressure, Airliners, airplane, Altitude, Cabin Pressure, Differential, jets, Maintenance Reasons, Planes, Side Windows, Windshield