Posts tagged ‘flight’
Bumblebee Flight is Not Scientifically Impossible
By Terry D. Johnson
The myth that bumblebee flight is scientifically impossible persists today. Even some presidential hopefuls believe it. Don’t be fooled. This tale’s been floating around since the 1930s, back when aerodynamics was emerging from a science.
Various luminaries in the field of fluid dynamics have been accused of popularizing the idea, which seems to have originated in a collaboration between French entomologist Antoine Magnan and his assistant, the mathematician André Sainte-Laguë. Sainte-Laguë had done a primitive calculation on the aerodynamics of bumblebee flight, assuming that the wings we perfectly smooth and flat. They also ignored more complicated aerodynamics in favor of a simpler model.
These assumptions made the calculation easier…and the answer wrong. Magnan himself wrote: “One shouldn’t be surprised that the results of the calculations don’t square with reality.” That didn’t stop the myth from achieving enough lift to take off.
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Image: Wikimedia (gnu)
Why Airplane Shades Must Be Up for Takeoff and Landing
By Chad Upton | Editor
You may not have heard of this, but it’s law in some countries and it’s growing in popularity around the world. The reason is similar to why the airlines dim the interior lights during takeoffs and landings at night.
In short, it’s for safety in the event of an accident. With the window shades up, passengers and crew can spot dangers outside the planes before they open an emergency exit. Dangers like fire, water and running airplane engines can be hazardous if someone opens an emergency exit right into them.
During bright daylight, it also allows your eyes to adjust to the brightness outside, which could be critical during an accident.
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Photo: contraption (cc)
Sources: Airliners.net, Straight Dope
Altitude Does Not Increase the Effect of Alcohol
By Chad Upton | Editor
Whether you’re in a plane, at the top of a ski hill or reading this in the mile high city, your body will metabolize alcohol exactly the same in all cases.
It is a common myth that you get drunk at high altitude much faster than at lower altitudes. In fact, I set out to research why this is the case, only to find out it’s not the truth.
As you can probably imagine, they didn’t have any trouble finding volunteers to help them get to the bottom of this — it has been studied and studied and studied and studied (PDF).
Even without alcohol, high altitudes can induce high-altitude sickness, which happens because there is less oxygen in the air. Because the symptoms are much the same as a hangover (headache, nausea, vomiting…etc), the effects of alcohol are often confused with high-altitude sickness. In fact, there is a study that shows Alcohol can impede the initial stages of adapting to high altitude; therefore, it is recommended that people do not drink for the first couple days while their body acclimatizes to the lower oxygen levels of high altitudes.
A study with alpine skiers in Austria tested blood-alcohol content at sea-level and at 10,000 feet. After drinking a liter of beer, their blood-alcohol levels were the same regardless of altitude.
An FAA study (PDF) found that both alcohol and altitude affect pilot performance, but there was no interaction between the two. Altitude does affect your ability to perform tasks, but that effect is present with or without alcohol. Another US government funded study found the same thing, concluding, “there was no synergistic interactive effect of alcohol and altitude on either breathalyzer readings or performance scores.”
From my observations, college loans are another popular way to get government money to study the effects of alcohol.
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Sources: Pub Med, High Altitude, Annals, FAA (PDF), AHA
Photo: evilmidori (cc)
Relevant:
Professionals should always supervise detox from alcohol and other drugs to prevent any untoward medical mishaps.
How to Get the Best Price When Shopping Online
The internet has completely changed bargain hunting and finding the best price couldn’t be any easier.
I like to use Google products (formerly known as “Froogle”). It compares prices at thousands of retailers and show you the best deals along with ratings for each retailer.
Google products also searches sites like ebay. Although, it’s worthwhile checking ebay independently, there are lots of auctions for new products or if you’re willing to take a used one then you’ll get a great deal. If you’ve looking for something that doesn’t ship well, such as appliances, be sure to check craigslist.org or kijiji.com (owned by ebay). They let you search for products in your area so shipping is not necessary.
Sometimes the best price is at a website you’ve never heard of. This is when customer ratings and common sense are really helpful. If you’ve never heard of the retailer and can’t find a phone number for the office on the site, then I probably wouldn’t order from them. Amazon might be the only exception to this and in fact they’re one of my favorite online retailers, they frequently have the best price and their shipping and customer service are great.
If you’re searching for cameras, be weary of small companies based in New York City. They usually have the best price on camera equipment, but there are lots of online horror stories about some of these companies.
Why do Airplanes Fly at High Altitudes?
A few years ago, I was on a short, low altitude flight on a cold December evening in the Northeast. Because it was a short flight to a tiny airport, the aircraft was a small turboprop plane.
The flight was bumpy from the start. Somewhere in the middle, the flight crew was providing beverage service when the captain turned on the fasten seat belt sign. He instructed the crew to return to their seats and buckle up; before they made it to their seats, we hit a low pressure air pocket and the plane took a sudden drop.
It was just like a roller coaster making its towering first drop. We were in free fall for what felt like a really long time, but was probably only a couple of seconds. A few people flew out of their seats and hit their heads on the overhead bins, the crew was in the isle and did the same. Drinks, books, purses and other personal articles were thrown around the cabin, making a huge mess. (more…)
Why Airplanes Don’t Always Fly in Straight Lines to Their Destination
If you’ve ever been on a flight equipped with a screen that shows the flight path, you might notice some zigs and zags that make your direct flight look like a scenic air tour. There are a number of reasons for this, but most of the time it comes down to Air Traffic Control (ATC).
Some people think that air traffic controllers are the guys that stand on the ground, waving lighted wands to guide the plane up to the gate. Those guys are actually part of the ground crew and they only have control over your flight for the last couple hundred feet before you reach the gate. The rest of the flight is controlled by someone else and it’s not the pilot.
The pilot flies the plane, but his course is being set by somebody on the ground. Those people are known as Air Traffic Controllers.
This system is a lot more complicated than it seems.
At the airport, the air traffic controllers sit up in the control tower. Those guys decide who gets to take off and land, which runways they use and when. They also direct planes that are moving around on the ground between gates and runways on the apron and taxiways. This aims to provide an organized flow of ground traffic and a safe flow of air traffic.
Once your plane has left the immediate area of the airport, the pilot must then communicate with a regional controller at an Area Control Center (ACC). If you’re on a long flight, you may get passed from one ACC to the next multiple times as you fly across the country.
Why? (more…)
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