Wednesday, 19 July 2017

The Sounds of Nature ‹ snapshotsincursive

The Sounds of Nature - snapshotsincursive.
Thanks for sharing.

“The three great elemental

sounds in nature are

the sound of rain,

the sound of wind

in a primeval wood, and

the sound of outer ocean

on a beach.”  ~ Henry Beston

Saturday, 1 July 2017

F-22 Raptor vertical takeoff

9 Things That Can Be Easily Overlooked During Preflight

9 Things That Can Be Easily Overlooked During Preflight 
(Thanks to Boldmethod for sharing)

1) Mandatory inspections:
It's important to verify that all required inspections are met for the aircraft you're flying. You don't want to compromise the safety of you and your passengers by flying an aircraft outside of its inspection windows, and you don't want to have to explain why you flew an aircraft outside of mandatory inspections to the FAA, either.
2) Required documents:
At the start of each preflight, make sure your aircraft has all the required documents on board. Remember the acronym ARROW which stands for Airworthiness, Registration, Radio Station License, Operating Manual, and Weight and Balance.
3) Fuel quantity:
Never rely solely on the fuel quantity indicators. Make sure you visually check your fuel tanks to make sure you have enough gas for your flight.
4) Pitot tube drain hole
You should always make sure that the pitot tube is open, as well as the drain hole. If you end up flying through precipitation, you want to make sure that your pitot tube is draining properly, so your indicated airspeed isn't affected.
5) Landing gear condition:
Instead of skimming over the tire and saying "It looks good to me!", make sure you actually check that the tire has proper inflation and that the tread isn't worn down. It's also important to make sure that the brake pads are intact, and that there isn't any hydraulic fluid leaking.
6) Bottom of the fuselage:
While it may seem unneeded, it helps you make sure there aren't any dents on the bottom of the aircraft, tail strikes, or debris from prop blast. You also want to make sure there isn't any excessive oil dripping, and that the avionics antennas are still intact before you go.

7) Contaminants on the wings:
When it's below freezing, it can be easy to overlook contaminants on the wing like frost and clear ice, which both have adverse effects to your aircraft's performance.

8) The propeller:
Take your time to do a thorough inspection of the propeller. Make sure that both the leading and trailing edges of the propeller are smooth, and don't have nicks or cracks. In addition to the visual inspection, you can also perform an audible test on composite props. Gently tap on the propeller from the hub to the propeller tip with a metal coin. If the tapping sounds hollow or dead, your prop could be delaminated, and you should have a mechanic check it out.
9) Fuel filler caps:
Double check them before you fly! If they're not properly attached, you could risk fuel leakage from the top of the wing, which could make for a bad day.
What else is easy to miss on preflight? Tell us in the comments below.

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Saturday, 17 June 2017

How A Turboprop Engine Works

Thanks to Boldmethod for sharing...

Turboprop engines combine the reliability of jets, with the efficiency of propeller driven aircraft at low to mid altitudes. Found on anything from a 50+ seat passenger aircraft to a single pilot cropduster, turboprop engines are perfect for safe, efficient regional travel. This is how they work...

Of all turboprop engines, one of the most popular is the Pratt & Whitney PT6. More than 41,000 PT6A engines have been produced since the family entered service in the 1960s, accumulating over 335 million flying hours. The 69 PT6 models range in power from 500 shaft-horsepower (SHP) to over 2,000 SHP. While not all turboprop engines work exactly like the PT6, they all follow the same basic concepts. Because of its widespread popularity, it's a great example to focus on.

Reverse Flow
Unlike turbofan or turbojet aircraft, air moves through turboprops like the PT6 by reverse flow.
Large air intakes underneath or beside the propeller scoop air into the intakes, where it moves backwards towards the engine firewall. Upon reaching the aft limit of the intake, the air makes a 180 degree turn back towards the front of the aircraft.

In addition to that, air reverses direction again when it reaches the combustor, allowing for a shorter, more compact engine.

The first compressor stages, which are 'axial flow', use a series of airfoil shaped spinning blades to speed up and compress the air. It's called axial flow, because the air passes through the engine in a direction parallel to the shaft of the engine. As the air moves through the compressor, each set of blades is slightly smaller, adding more energy and compression to the air.

In between each set of compressor blades are non-moving airfoil shaped blades called 'stators'. These stators (which are also called vanes), increase the pressure of the air by converting the rotational energy into static pressure. The stators also prepare the air for entering the next set of rotating blades. In other words, they straighten and stabilize the flow of air.

After passing the final axial flow compressor stage, the air moves to a centrifugal flow compressor stage. Air is thrown outwards, away from the engine core, and towards the combustion chambers. The air has made another 90 degree turn.

The combustor is where the fire happens. As air exits the compressor and enters the combustor, it is mixed with fuel, and ignited. It sounds simple, but it's actually a very complex process. That's because the combustor needs to maintain a stable, constant combustion of fuel/air mixture, while the air is moving through the combustor at an extremely fast rate.

The diffuser slows down the air from the compressor, making it easier to ignite. The dome and swirler add turbulence to the air so it can more easily mix with fuel. And the fuel injector nozzles, as you probably guessed, spray fuel into the air, creating a fuel/air mixture that can be ignited. From there, the liner is where the actual combustion happens. The liner has several inlets, allowing air to enter at multiple points in the combustion zone.

The igniters are the last parts of the combustion stage; they're very similar to the spark plugs in your car or piston-engine airplane. Once the igniters light the fire, it is self-sustaining, and the igniters are turned off (although it's often used as a back-up in bad weather and icing conditions).
The Turbines

Once the air makes its way through the combustor, it flows through the compressor turbine. The turbine is a series of airfoil shaped blades that are very similar to the blades in the compressor. As the hot, high-speed air flows over the turbine blades, they extract energy from the air, spinning the compressor turbine around in a circle, and turning the engine shaft that it's connected to. This is the same shaft that the compressor section and all engine driven accessories are connected to. It's a self-sustaining cycle of power as long as the flame in the combustion chamber is lit. About 70% of total engine power is dedicated to spinning the compressor section and engine driven accessories in a PT6.

Think you're just re-reading an article about how a turbine engine works? Well here's where things really start to change...

While the compressor turbine may be spinning the aft portion of the engine shaft (compressor section and engine driven accessories) at more than 37,000 RPM, it is NOT spinning the propeller. An entirely separate second engine shaft is located just forward of the compressor turbine.

Airflow moving past the compressor turbine next encounters the engine's power turbines. These power turbines spin just like the compressor turbine, with airfoil shaped blades. This forward engine shaft is directly connected to the propeller, providing the power for it to spin. About 30% of total engine power is dedicated to spinning the propeller in a PT6.

Fun Fact: Because the PT6 is a free-turbine engine, you could, in theory, hold the propeller still in your hand as the engine is started. The only thing spinning the propeller is air passing over the power turbine wheels. Because these turbines are connected to their own engine shaft, separate of the compressor section, it's conceivable that at extremely low power settings the propellor could remain stationary as airflow moves past the turbines... But please, don't try that at home.
Reduction Gearbox

There's no way the propeller on the front of a turboprop could spin at the roughly 33,000 RPM of the power turbines. A series of reduction gears are installed to reduce RPM to a redline of 1900 RPM, as it's limited to in most PT6 engines.

Next? You guessed it...thrust. Now that the propeller shaft is spinning at a reasonable speed, the propeller is able to generate thrust. Read this article to learn how that thrust is created.
There's no practical use for exhaust air once it passes through the power turbines. It's simply diverted away from the engine and out through exhaust pipes. In some aircraft, the POH provides a number that shows the thrust generated directly by exhaust gases. It's usually just a few percent of total generated thrust. The propeller still wins!

Benefits Of A Turboprop
While turboprops generally have lower service ceilings than turbofan or turbojet powered airplanes, they burn significantly less fuel per passenger. Due to the propulsive efficiency curve, they're most efficient at speeds slower than 400 knots. While expensive, they're extremely reliable.
This makes turboprops the perfect engine type for relatively short regional flights. That's why you'll find them on aircraft like the Dash-8-Q400, Cessna Caravan, Pilatus PC-12, and Beechcraft King Air.

Putting It All Together
Equipping an aircraft with a turboprop engine is the best of both worlds for low altitude regional flights. Air is compressed, combusted, and converted into power that spins the propeller. Compared to piston aircraft, they have relatively few moving parts with much less vibration, making them extremely reliable. Better yet...they burn Jet-A, which is more than a dollar cheaper per gallon than AvGas!

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

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.

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.

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.

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)

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 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

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.

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.

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.


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 -

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 

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.