Turboprop Engines

Turboprop Engines
Turboprop Engines

HOW A TURBOPROP ENGINE WORKS

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.

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Flying in Hot Weather

Hot Weather
Hot Weather

3 RULES-OF-THUMB FOR FLYING IN HOT WEATHER

When the weather gets hot, these rules-of-thumb can help.

1) DENSITY ALTITUDE INCREASES OR DECREASES ABOUT 120 FEET FOR EACH 1°C FROM ISA

If the temperature rises 1 degree from ISA (ISA=15°C at sea level), your density altitude goes up about 120 feet. So if it’s 30°C at sea level, your density altitude is going to be about 1,800′. (30°C-15°C = 15°C above ISA, 15 X 120 = 1,800)

But keep in mind, ISA decreases 2°C per thousand feet. This is important for airports that aren’t at sea level.

Let’s take Denver Centennial, for example, at 5,885′ field elevation. To make the math easy, we’ll round up to 6,000′.

At 6,000′, ISA isn’t 15°C, it’s actually 3°C.

So if it’s 30°C at Denver Centennial, you’re 27°C above ISA, and the density altitude is roughly 9,240′. That’s an increase of more than 3,200′ over field elevation.

The higher your airport, the bigger the difference a hot day makes.

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Spin Recovery, Explained

Spin Recovery
Spin Recovery

THE 4 STEPS OF SPIN RECOVERY, EXPLAINED

Have you ever practiced a spin? If you have (and even if you haven’t), you’ve probably heard the recovery acronym “PARE”. But do you know what each step is for?

FIRST OFF, WHAT EXACTLY IS A SPIN?

Before we jump into the spin recovery steps, let’s take a quick look at what’s happening in a spin. The FAA defines a spin as “an aggravated stall that results in an airplane descending in a helical, or corkscrew path.”

Which brings us to spin point number one: both wings are stalled in a spin, but one is more deeply stalled than the other. The “more stalled” wing is on the inside of the spin, it flies at a higher angle-of-attack, and it generates less lift than the outside wing.

Since your high wing generates more lift than the low wing, it rolls your aircraft into the spin.

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How turbofan engine works

Turbofan Engine
Turbofan Engine

HOW DOES A TURBOFAN ENGINE WORK?

When you board an airline flight, you might not spend much time thinking about the engines. But they’re the only reason that 700,000 pounds of aluminum and passengers can hurtle through the air at 80% the speed of sound. So how do they work? Let’s take a look.

THE BASICS

Jet engines, which are also called gas turbines, work by sucking air into the front of the engine using a fan. From there, the engine compresses the air, mixes fuel with it, ignites the fuel/air mixture, and shoots it out the back of the engine, creating thrust.

That’s a pretty basic explanation of how it works, so let’s take a look at each section of a jet engine to see what’s really going on.

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Power-off 180 Landings

Power-off 180 Landings
Power-off 180 Landings

WHY EVERY PILOT SHOULD PRACTICE POWER-OFF 180 LANDINGS

It’s unlikely you’ll ever have an engine failure abeam the aim point markers on downwind…so why are power-off 180s so important to practice?

WHAT EXACTLY IS A ‘POWER-OFF 180?’

Performing a power-off 180 is just what it sounds like. Abeam an aiming point on downwind, engine power is cut to idle (at or below 1000 feet AGL per ACS standards), and you maneuver to land as close to that preselected point as possible. Most pilots pitch for best glide speed, at least initially, to improve chances of making the runway point.

While it’s not usually a required maneuver for private pilots, it’s a great maneuver to practice for any pilot. The ACS has the following standards for maneuver completion: “Touch down within -0/+200 feet from the specified touchdown point with no side drift, minimum float, and with the airplane’s longitudinal axis aligned with and over the runway centerline.”

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