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Why Do Your Wings Have Dihedral? | Boldmethod

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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.
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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:

boeing-777-dihedral

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:

dihedral-stability
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.
dihedral-overhead
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.
dihedral-slip-rear
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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Source: Why Do Your Wings Have Dihedral? | Boldmethod

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

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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

The 7 Hardest Parts About Becoming A Private Pilot 

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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.

The 7 Hardest Parts About Becoming A Private Pilot

By Swayne Martin

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.

Microlight Trikes Active Recreation by GleBB

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Travel and active recreation. Photo outdoors. Series « Travel, nature and active recreation». Landscape. The natural lighting. via 500px http://ift.tt/2jIMd2B

via Popular on 500px : Microlight trikes _ active recreation by GleBB — Photo Snapping

Why Jet Lag Is Worse than You Think

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If you’re traveling cross-country to run a race or participate in a sporting event, you may want to prepare for the time change in advance. A new study of professional baseball players shows that jet lag doesn’t just affect mental performance—it can also affect physical performance, as well. The authors say their findings can have implications for all types of athletes, and they offer strategies for lessening the impact.

The new study, published in Proceedings of the National Academy of Sciences from researchers at Northwestern University, looked at Major League Baseball data from more than 40,000 games spanning 20 years, including teams’ travel schedules and players’ performance in hitting, running, pitching and more.

Traveling two or more time zones before a game affected play in subtle but detectible ways, the authors found. For example, teams from eastern states who had just returned home from a game out west tended to have fewer stolen bases, doubles and triples, and were subject to more double plays, than those who hadn’t traveled as recently.

Pitchers from both home and away teams also gave up more home runs after traveling eastward. The effects are enough to erase a team’s home-field advantage, the authors say. They speculate that jet lag may have even played a role in Game 6 of the 2016 National Championship Series, in which the home-team Chicago Cubs scored five runs off the visiting Los Angeles Dodgers’ ace pitcher, Clayton Kershaw.

The effects of west-to-east travel were stronger than those of east-to-west travel, supporting the argument that they are due to the body’s circadian clock—not just time on an airplane or scheduling issues in general, says Dr. Ravi Allada, associate director of Northwestern’s Center for Sleep and Circadian Biology.

The study isn’t the first to show that jet lag can impact athletic performance. Allada says the new findings add to the evidence that jet lag isn’t just all in one’s head. “We know, based on studies in animals and humans, that when you misalign your internal biological clock with your external environment, there can be a lot of consequences in terms of health,” Allada says. “And the circadian clock is present in muscle cells, too, so it makes sense that one might see an impairment in muscle activity or muscle efficiency, as a result of this misalignment.”

Based on these findings, Allada recommends that baseball teams send their starting pitchers to games across the country a day or two early, when possible, so that their internal clocks can adjust to the local environment.

Similar advice could also apply to anyone traveling for athletic events—especially eastward—he adds, like runners going to a destination marathon or adventure race. That also includes people who have been away and are heading home for an event: an aspect of jet lag that people don’t often think about, says Allada.

“The rule of thumb is that the body clock can shift about one hour a day, so if you’re traveling across three time zones, you’d want to ideally give yourself three days to adjust,” he says.

If your schedule won’t allow for an earlier trip, he recommends faking it for a few days by trying to wake up and go to bed according to the time-zone of your event, even while you’re still at home. If you’re traveling west-to-east, exposing yourself to bright light earlier in the morning can help, as well.

Allada says there’s not yet a lot of research to back up the effectiveness of these strategies, but he believes they could benefit anyone looking to optimize their performance. “That’s something we’d love to study in the future,” he says, “to work with athletes and see if these interventions actually have real impacts.”

via Why Jet Lag Is Worse than You Think — TIME

How To Make A Perfect Crosswind Landing | Boldmethod

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You’re picking up ATIS on your way in to land. The winds are 23 knots, 40 degrees off runway heading. And your passengers are expecting a landing they can walk away from.

Crosswind landings can be one of the most stressful things for pilots, especially if you haven’t practiced them in awhile. And whether you’re a new pilot just learning to fly them, or a 20 year pilot who hasn’t gotten a lot of practice recently, a little review can go a long way.

When it comes to crosswind landings, there are a couple methods you can use: crab, and wing-low. And there are advantages and disadvantages to both.

Flying The Crab Method

With the crab technique, you fly final approach crabbing into the wind to prevent drifting left or right of centerline. You maintain the crab all the way to your flare, and just before touchdown, you step on the rudder to align your nose with the runway, and use ailerons to prevent drifting with the wind.

The crab technique can be an easy way to maintain centerline on final approach, but it requires quite a bit of judgement and timing to “kick out” the crab just before touchdown. This is the same technique that jets use to land. But there’s a big difference between a 737 and a single-engine piston, and that’s inertia. If a 737 isn’t perfectly aligned with the runway on touchdown, it straightens itself out as the wheels touch down, and it keeps rolling smoothly down the runway. But if your 172 isn’t aligned with the runway at touchdown, you’re going to jump and bounce across the pavement until you are aligned with it. So unless you’re out practicing your crab-to-landing a lot, it can be a tough method to perfect in a light plane.

rudder-usecrab

Flying The Wing-Low Method

In most cases in light aircraft, the wing low method is an easier way to accomplish a smooth touchdown in a crosswind landing. To fly the wing-low method, you use your rudder to line your nose up with the runway, and ailerons to correct for left/right drift all the way from final approach to touchdown. Essentially, you’re slipping the plane through the crosswind in order to keep yourself lined up with the runway from final to touchdown…

crosswind-procedurewheel-order

Source: How To Make A Perfect Crosswind Landing | Boldmethod

The Women Pilots History Forgot

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(CNN)More than 100 years after Harriet Quimby broke down barriers as the first woman to earn a pilot certificate, there are still very few women who choose flying as a career. Worldwide, only 3% of airline pilots are women, the Royal Aeronautical Society said earlier this month. Now, there’s a move to change that.  And the obvious place to begin is by highlighting the achievements of the long-forgotten queens of the air — the women who ignored the men who scorned them, broke through the restrictions society placed on them, and paved the way for Amelia Earhart.

Continue to read the full article on here.

Source: The Women Pilots History Forgot

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