Friday, 19 May 2017

Why Do Your Wings Have Dihedral

Why Do Your Wings Have Dihedral? - Bothmethod

If you look closely at the wings on most aircraft, they're tilted up slightly. Why would they ever do that? It's not because you pulled too many Gs on your last flight. It's because of a design feature called dihedral.



First Off, What's Dihedral?
Dihedral sounds like one of those words you cringed at in math class, but it's actually pretty simple. Dihedral is the upward angle your aircraft's wings. Here's a great example of wing dihedral on a Boeing 777:



Why Do You Need Dihedral?
It all comes down to stability. If you didn't have dihedral, you'd spend more time keeping your wings level. Here's why:



When you bank an airplane, the lift vector tilts in the same direction as the bank. And when that happens, your airplane starts slipping in the same direction, in this case, to the right.

The problem is, if you have a straight-wing aircraft, there's no force that will bring the airplane back to wings-level flight without you intervening. And while that may be good for an aerobatic aircraft or fighter jet, it's not something you want in your general aviation aircraft or airliner.
How Dihedral Fixes The Problem

When you add dihedral, you add lateral stability when your aircraft rolls left or right. Here's how it works: let's say you're flying along and you accidentally bump your controls, rolling your plane to the right. When your wings have dihedral, two things happen:

1) First, your airplane starts slipping to the right. That means the relative wind is no longer approaching directly head-on to the aircraft, and instead is approaching slightly from the right. This means that there is a component of the relative wind that is acting inboard against the right wing.



2) Second, because the relative wind has the inboard component, and because the wings are tilted up slightly, a portion of the the relative wind strikes the underside of the low wing, pushing it back up toward wings level. What's really happening here is the low wing is flying at a higher AOA, and producing slightly more lift.



The more dihedral your aircraft has, the more pronounced the effect becomes. But for most aircraft, they only have a few degrees of dihedral, which is just enough to return your wings to level during small disturbances, like turbulence, or bumping your flight controls in the cockpit.
It's Not All Good News: Dihedral Comes At A Cost

Dihedral isn't always good, and like almost every design factor, it comes with a cost. In this case, there are two costs: increased drag, and decreased roll rate....

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Saturday, 15 April 2017

The Thunderstorm Threat

The Thunderstorm Threat — General Aviation News
By ED BROTAK


With the onset of warmer weather, pilots face the increased risk of encountering thunderstorms.


Although more common in the warmer months, thunderstorms can occur even in the winter, especially in the southern states. It’s estimated that 100,000 thunderstorms occur in the U.S. each year. Some locations in southwest Florida have 100 storms a year, but thunderstorms do occur in all 50 states.
Thunderstorms are most common in the late afternoon, but can occur at any time of the day.
Technically called convective cells, a thunderstorm can cover an area from 200 to 1,000 square miles. Storms can range in height from 10,000 feet to over 60,000 feet. Individual cells can last from less than a half hour to many hours.

THE DIFFERENT TYPES OF THUNDERSTORMS
There are different types of thunderstorms that develop under different conditions. “Air mass thunderstorms” typically develop in the late afternoon and evening due to the heat of the day. Development tends to be random, but they are more numerous over mountainous terrain. Although relatively weak, they can still pose problems and should be avoided. Fortunately, air mass thunderstorms tend to be slow moving.

A greater threat is posed by organized convection. These are stronger storms that often move quickly, up to 60 mph. They are often associated with fronts, especially ahead of cold fronts.
“Squall lines” form when convective cells develop in a line in response to prevailing atmospheric conditions. The line can extend for tens or even hundreds of miles. Although there are breaks between the cells, circumnavigation or remaining on the ground until the line passes is strongly recommended. Individual storms will die out only to be replaced by new cells, with the whole system lasting for hours.

MINIMIZING THE DANGER
It’s a good time to review the risks thunderstorms pose to aviators and what you can do to minimize the danger.
Many things are happening inside a thunderstorm cloud (cumulonimbus) that they pose a wide variety of threats to aircraft.
Lightning can certainly do some structural damage and affect electrical equipment inside a plane.
Hail, which can grow to the size of softballs, can damage windshields and the exterior of the aircraft. The occurrence of hail indicates sub-freezing temperatures at some height in the cloud.
Even with the warmth of summer, towering thunderstorm clouds easily reach and exceed the freezing level. This also means super-cooled water and the risk of icing is present.
One of the more subtle threats thunderstorms produce is erroneous aneroid altimeter readings due to the rapid pressure changes the storm induces. Readings may be off by 100 feet.
But by far the greatest risk is turbulence. Updrafts and downdrafts within the storm can easily reach 50 mph (73.3 feet per second) and can reach 100 mph (146.6 feet per second). Planes can literally be torn to pieces by the turbulence generated between the up drafts and down drafts.

Even if there is no structural damage to the aircraft, loss of control is a distinct possibility.

And obviously within the cloud, IMC exist and the risk of Controlled Flight into Terrain (CFIT), especially in uneven terrain, is great.

Movement and turbulence of a maturing thunderstorm (FAA graphic).

And keep in mind that convection can develop very quickly. What was VMC everywhere can quickly contain areas of IMC.

TROUBLE ALL AROUND
Dangerous weather conditions are not limited to within the storm cloud itself.
Turbulence above the cloud top can extend upwards for thousands of feet.
Interestingly, the massive core of the storm can actually act as a solid impediment to the prevailing winds, almost like a mountain. Clear Air Turbulence (CAT) can be produced in the air flow downwind of the storm and extend tens of miles.
Beneath the storm cloud base, conditions can also be treacherous. Blinding rain and even hail can extend to the ground. IMC conditions are common.

Extreme downdrafts, called downbursts or microbursts, can occur even without precipitation. Once these downdrafts hit the ground, they can spread out, sometimes for tens of miles, producing strong, shifting winds that can exceed 100 mph, and the dreaded wind shear.

Microbusts can product destructive winds greater than 100 kts. (FAA graphic)
BE PREPARED

Before you start your flight, your preflight weather check, including TAFs and FAs, should highlight any convective problems.
Particularly note any CONVECTIVE SIGMETS, forecasts that warn of dangerous flying conditions due to convection in the next two hours.
But keep in mind, it is impossible to predict exactly when and where thunderstorms will develop in advance. And convection can develop rapidly, sometimes in a matter of minutes.
Closer to takeoff, you can check the latest METARs and PIREPS to see if convection has been reported.
Weather radar is the best tool for locating and tracking thunderstorms. The heavy rainfall rates associated with convection are well depicted as areas of yellow, red, or even purple if hail is present.
Movement and changes in intensity can be determined by tracking storms over time.
Major terminals are well covered by land-based radar. Terminal Doppler Weather Radar can detect thunderstorms and even wind shear near an airport. Larger airports also have specialized wind shear monitoring equipment for the runways. Smaller GA airports are often not as well equipped.

IT’S UP TO YOU
It’s up to the pilot to determine thunderstorm risk. Fortunately with today’s technology, a variety of weather radar products are readily available over the Internet and there are even apps for smartphones.
Always check the time on any radar display you’re checking. Delays due to processing are common. The radar image you’re looking at could be up to 20 minutes old. In fast developing convective situations, that could be crucial.
If your aircraft is equipped with radar, it can be extremely helpful in convective situations. Current radar data is always available, allowing you to detect significant convection 300 nm away.

Monday, 20 March 2017

When Is a Non Precision Approach a Better Choice Than a Precision Approach

When Is a Non-Precision Approach a Better Choice Than a Precision Approach? | Boldmethod
primary

When you're picking an approach at your destination, you usually go for the precision approaches first. But is there ever a time when shooting a non-precision is better?

There can be, depending the ceiling, visibility, turbulence, ice, and how soon you want to get out of the clouds. But any time you choose a non-precision approach over a precision, you're also taking on more workload, and opening yourself up to the possibility of a mistake while descending on the approach.

Seeing The Runway Sooner
Let's look at this example in Olympia, WA. Runway 17 is in use. The visibility is 10SM, and the ceilings are overcast at 700'.

Looking at available approaches, the ILS to 17 is your first pick. But like most ILS approaches, you can also shoot a localizer only approach to runway 17 using this chart.

olm-ils
What's the difference? The ILS gets you down to 218' above touchdown, and the LOC, which is a non-precision approach, gets you down to 433' above touchdown.

Since the ceiling is 700' overcast, both approaches with get you out of the clouds with no problem. But if you fly a localizer only approach, it can get you out of the clouds sooner, depending on your descent rate. Why would you want to do that? It can give you more time to visually orient yourself with the runway and surrounding area. And if you're getting beat up by turbulence or picking up ice, it can give you, and your passengers, some added relief.

How Much Time Will You Spend In The Soup?
Let's start with the ILS to 17. If you're flying a 90 knot approach speed on a 3 degree glideslope, you'll need to descend at roughly 450 feet-per-minute (FPM) to maintain the glideslope.

There's a pretty easy rule-of-thumb to figure that descent rate out. Divide your ground speed by 2, then add a 0 to the end. So if you take 90 knots / 2, you get 45. Add a zero to the end, and you get 450 FPM.

On this approach, glide slope intercept is at 2400' MSL. Since TDZE is 207' MSL, that means you're roughly 2200' above the touchdown zone when you intercept glideslope. And since the ceilings are 700' overcast, you'll need to descend roughly 1500' before you break out of the clouds.
That means if you're descending at 450 FPM on the ILS, it will take you roughly 3 minutes and 20 seconds before you break out of the clouds.

What If You Fly The LOC Only?
Now lets look at the LOC only approach. You know that the MDA of 640' MSL (433' above TDZE) is still easily going to get you out of the clouds. And if you increase your descent rate even slightly, it can get you out of the clouds sooner.

When you cross the FAF, if you start a descent at 600 FPM, which is still a very reasonable descent rate, it will take you about 2 minutes and 30 seconds before you break out of the clouds. That's 50 seconds sooner than shooting the ILS.
precision-vs-nonprecision-chart

non-precision
Making The Best Choice For Your Approach
In almost all cases, using a precision approach is the best choice. That's especially true in low visibility. Following the glideslope on a precision approach means you know you're at the right place, at the right time, all the way to DA/DH.

But if you want to get yourself out of the clouds to get oriented with the runway and surrounding area a little early, or if you're trying to get yourself out of the clouds when there's turbulence or ice, using a non-precision can do that for you. Just make sure you're flying a stable descent, you're ready to level off at MDA, and you're prepared to make a stable descent from MDA to touchdown.

ALL THANKS TO BOTDMETHOD FOR SHARING THIS WITH US

Irresistible Why We Can’t Stop Checking Scrolling Clicking and Watching

Irresistible: Why We Can’t Stop Checking, Scrolling, Clicking and Watching

Online world: it can be hard to tell where the internet ends and the real world begins. Photograph: Natthawat Jamnapa/Moment Mobile/Getty

To call the plethora of addiction-themed popular psychology books a cottage industry would be an error of scale. It’s more like a factory operation.

One feature of this literature is a mutually congenial tendency to medicalise eccentric behaviour: the lustre of science lends moral authority to the quack author and a plaintive urgency to the reader’s perceived woes, driving each into the arms of the other.

But supposing the malady under discussion is so widespread that almost everybody has it? This is the dilemma highlighted in Irresistible: Why We Can’t Stop Checking, Scrolling, Clicking and Watching.

The online world is so intimately bound up in our daily lives that it can be hard to tell where the internet ends and the real world begins. Whereas junkies or winos wear their condition visibly, and invariably succumb to it in some calamitous life-affecting way, internet addicts are often inconspicuous, their habit humdrum and their social existence high functioning. As a patient at an internet-addiction clinic in Beijing tells Adam Alter, “It’s not a real disease. It’s a social phenomenon.”

According to some surveys about 40 per cent of Americans suffer from a form of internet addiction. If you’ve ever felt a Pavlovian glow at the “ding” of your inbox filling up, or if you happen to compulsively check your messages late at night, when you should be sleeping, you too might be hooked.

We have a problem, then, of definition: either the world is in the grip of a silent and dangerous epidemic or the parameters of normality, and of how we understand consciousness in general, are shifting ineluctably and forever...

Saturday, 4 March 2017

Ice cream laws face revamp in the battle against obesity in Ireland

Ireland's ice cream laws face revamp in the battle against obesity - Independent.ie

Change in recipe for ice cream? Stock photo

Irish ice cream laws dating back to 1952 are being revised in an effort to fight national obesity levels.

Health Promotion Minister Marcella Corcoran Kennedy has proposed to revoke the current Food Standards (Ice Cream) Regulations dating from 1952.

The planned changes will revise the content of milk-fat, milk solids and sugar content in ice cream. One of the stipulations in the 1952 regulations states that ice cream must contain at least 10pc by weight of sugar.  This obviously presents problems for any company wishing to reduce the sugar content of its ice cream products, according to the FSAI.

It says the purpose of the proposed regulations is to revoke these compositional standards as soon as possible.  Having consulted other relevant Government departments and official agencies, it is considered that it is no longer fit for purpose and has largely been superseded by EU legislation, Ms Corcoran Kennedy said.  Recent research found that Ireland has the third highest consumption of ice cream per capita in Europe...

Sunday, 12 February 2017

The 7 Hardest Parts About Becoming A Private Pilot

The 7 Hardest Parts About Becoming A Private Pilot 
Boldmethod

Everyone knows that crosswind landings are usually challenging for student pilots. But beyond landings (and money!), there's a lot about learning to fly that can be pretty tough. Here's what you should be ready for...

1) Aircraft Systems
One of the toughest topics for private pilot students is aircraft systems. As less and less people grow up working on cars or around machinery, there's diminishing knowledge behind what makes that engine turn.

Want to know more about the systems and equipment in your aircraft? Dig into your POH and read section 7. Better yet, find a local A&P at your airport and have them walk you through a few systems with the cowling off. Getting hands-on with the equipment behind closed panels is a great way to learn how your airplane flies.



2) The National Airspace System

It's more than identifying lines of airspace on a sectional chart. You'll need to know what weather minimums exist at different altitudes (day and night), what your equipment requirements are, and what your communication requirements are.

We can help - give our National Airspace System course a try.




3) Learning Regulations

There are hundreds of FAA Regulations that govern how, where, and when you can fly. Some of them can be pretty confusing. As a student pilot, you're just as responsible for adhering to the FARs as any fully certificated pilot. Keep yourself out of trouble and learn those regs!



4) Aerodynamics

A huge part of learning to fly is understanding the physics behind how it all works. But how can a strong foundation of aerodynamics save your life? One simple example is the lift to drag ratio for your airplane. At L/D max, or the best lift to drag ratio, you'll find an approximate best glide speed.



5) Decoding Textual Weather

Whether it's a METAR or PIREP, it's your responsibility as a pilot to maintain your skills for decoding textual weather.

Need a refresher? Give our Aviation Weather Products course a try.



6) "Radio Talk"

Learning how to actively listen for your callsign in busy airspace with dozens of airplanes on-frequency is tough. Adding that to learning the correct verbiage provides quite the task for brand new student pilots. Here are some things you shouldn't say over the radio.



7) Getting Into "School Mode"

First and foremost, getting your brain into a "school mode" can be tough, especially if you haven't sat in a formal classroom setting in years. Learning to fly is undoubtedly fun, but there's also a lot of work outside the cockpit.


Wednesday, 8 February 2017

Smartphones, tablets and internet killing Irish marriages and family life

Smartphones, tablets and internet killing Irish marriages and family life, warns expert - Irish Mirror Online

Couple annoyed at each other after argumentCouple fighting
Forget affairs or simply falling out of love, technology is the biggest factor in the breakdown of Irish marriages, it's claimed.

Family psychologist and UCD lecturer, Dr John Sharry, maintains the overuse of smartphones, tablets and the internet is having a devastating impact on relationships - and our sex lives.

Worryingly, our must-have gadgets are also ruining family life and the bonds between parents and their children.

Dr Sharry's warnings are supported by counselling body Relationships Ireland, which claims 90% of couples seeking its help say technology is a big factor in their marriage troubles.

Read more: Four things that spell relationship trouble - and how you can avoid heading for the divorce courts.

Tuesday, 31 January 2017

'Fake news' inquiry launched

'Fake news' inquiry launched - News from Parliament - UK Parliament



The Culture, Media and Sport Committee launches an inquiry into 'fake news': the growing phenomenon of widespread dissemination, through social media and the internet, and acceptance as fact of stories of uncertain provenance or accuracy.

Call for written submissions

The Culture, Media and Sport Committee are looking at ways to respond to the phenomenon of fake news, focusing in particular on the following questions:
What is 'fake news'? Where does biased but legitimate commentary shade into propaganda and lies?
What impact has fake news on public understanding of the world, and also on the public response to traditional journalism? If all views are equally valid, does objectivity and balance lose all value?
Is there any difference in the way people of different ages, social backgrounds, genders etc use and respond to fake news?
Have changes in the selling and placing of advertising encouraged the growth of fake news, for example by making it profitable to use fake news to attract more hits to websites, and thus more income from advertisers?
What responsibilities do search engines and social media platforms have, particularly those which are accessible to young people? Is it viable to use computer-generated algorithms to root out 'fake news' from genuine reporting?
How can we educate people in how to assess and use different sources of news?
Are there differences between the UK and other countries in the degree to which people accept 'fake news', given our tradition of public service broadcasting and newspaper readership?
How have other governments responded to fake news?

Submit your views through the Fake news inquiry page.

Deadline for written submissions is Friday 3 March 2017.

How Stall Strips Keep Your Plane Under Control

How Stall Strips Keep Your Plane Under Control | Boldmethod



Stall strips create a more controlled stall across the wing, and they also increase wing buffeting before a full stall happens. So how do they work? It starts with something called the stagnation point.



How Stall Strips Help.

Stall strips start working when your wing is at a high angle-of-attack. Because the stagnation point is on the underside of the wing at a high AOA, air flows up and around the leading edge, making its way over the top of the wing. With no stall strip, airflow can stay attached to the wing when this happens...



....
By Colin Cutler   01/31/2017

Sunday, 29 January 2017

Motorized deltaplanes by GleBB

Popular on 500px : Motorized deltaplanes _ Earth farewell _ Good luck! by GleBB ‹ Photo Snapping ‹ Reader — WordPress.com







An ultralight trike is a type of powered hang glider where flight control is by weight-shift. These aircraft have a fabric flex-wing from which is suspended a tricycle fuselage pod driven by a pusher propeller. The pod accommodates either a solo pilot, or a pilot and a single passenger.
Trikes are referred to as “microlights” in Europe. Such aircraft are also known as 2-axis microlights, flex-wing trikes, weight-shift-control aircraft, microlight trikes, deltatrikes or motorized deltaplanes.
The history of the trike is traced back to the invention by Francis Rogallo’s flexible wing and subsequent development by the Paresev engineering team’s innovations and then others. On 1948, engineer Francis Rogallo invented a self-inflating wing which he patented on March 20, 1951, as the Flexible wing...

Monday, 9 January 2017

Drive to bring more international students to Ireland

Drive to bring more international students here - Independent.ie
Fee-paying schools are expected to enjoy a Brexit bounce, as well as benefit from a new drive to recruit international second-level students to Ireland.

Major financial corporations, such as banks and insurance companies, are turning their eyes to Dublin as an EU base in anticipation of the UK's departure from the EU.

Children's education is high on the list of priorities for executives who are being asked to relocate with their families, with school fees a typical part of the remuneration package.

"This is happening anyway, but a lot more is expected post-Brexit," said one source in the financial world who is already dealing with such queries.

Typically, HR personnel from the companies involved come to check out what's available, with a focus on the fee-paying sector.

Meanwhile, there is a growing international market in second-level students, similar to what happens at third-level, from families in central and south-east Asia who want an English-speaking education for their children...

Thursday, 5 January 2017

Sugar is the ‘alcohol of the child’, yet we let it dominate the breakfast table | Robert Lustig | Opinion | The Guardian

Sugar is the ‘alcohol of the child’, yet we let it dominate the breakfast table 

Breakfast is considered by most nutrition experts, including Public Health England, to be the most important meal of the day. It gets your brain and your metabolism going, and it suppresses the hunger hormone in your stomach so you won’t overeat at lunch. But in our busy lives, it’s easy to turn to what is quick, cheap, or what you can eat on the go. Cold cereal. Instant oatmeal. For those die-hard “I’m gonna serve something hot for breakfast” types, it’s microwaveable breakfast sandwiches. Gotta get out the door now? Granola bars. Protein bars. Yoghurt smoothies.



Children consume half of daily sugar quota at breakfast – study

Read more

Sadly, as the National Diet and Nutrition Survey found, what you’re really doing is giving your children a huge sugar load while sending them on their way: half of their daily intake on average. There’s a reason that the World Health Organisationand the United States Department of Agriculture have provided upper limits of sugar – because dietary sugar fries your kids’ liver and brain; just like alcohol.

Alcohol provides calories (7kcal/g), but not nutrition. There’s no biochemical reaction that requires it. When consumed chronically and in high dose, alcohol is toxic, unrelated to its calories or effects on weight. Not everyone who is exposed gets addicted, but enough do to warrant taxation and restriction of access, especially to children. Clearly, alcohol is not a food – it’s a dangerous drug, because it’s both toxic and abused.

Dietary sugar is composed of two molecules: glucose and fructose. Fructose, while an energy source (4kcal/g), is otherwise vestigial to humans; again, there is no biochemical reaction that requires it. But fructose is metabolised in the liver in exactly the same way as alcohol. And that’s why, when consumed chronically and at a high dose, fructose is similarly toxic and abused, unrelated to its calories or effects on weight. And that’s why our children now get the diseases of alcohol (type 2 diabetes, fatty liver disease), without alcohol. Because sugar is the “alcohol of the child”. Also similar to alcohol, sugared beverages are linked to behavioural problems in children...