AvFacts - Aviation knowledge without limits

The jet engine revolutionized air travel in the 1950s, and since then jet engines have only gotten more reliable, more efficient, and more powerful. This is due in part to the switch from turbojets to turbofans. In this episode, I discuss what turbojets and turbofans are, and the important differences between them.

What was in auto engines 50 years ago, is in piston aircraft engines today. It's not always true but it certainly feels true often. Only in the last 30 years or so has carburetion been supplanted by fuel injection in aircraft engines. In this episode I will introduce you to the purpose of carburetors, what they do and how they work, and talk about a few different types of carburetors.

Flights of military aircraft always fly in formation. Flying in formation offers significant tactical advantages when in a combat area, and helps maintain cohesion of the flight when not. Learn about how military aircraft fly in formation, the different types of formations used, and how they deal with contingencies.

Low-frequency radio ranges are a simple form of instrument navigation that hasn't been around since the 1970s. And while it's comparatively primitive today, it was revolutionary in the 1920s, demonstrating that for the first time airplanes could be navigated by instruments alone. Learn about how LRR stations worked, and how LRR approaches were charted and flown.

Ice is nice in cold drinks but can be a real hazard to airplanes. When supercooled water droplets freeze and create ice on the wings, an aircraft can suffer loss of lift and control. Learn about where and why ice forms, and why it's such a big deal to the pilots who fly through it (and try to avoid it).

Bombing has come a long way from its primitive origins. Today, computers help pilots put bombs exactly where they want them. In this episode I cover some of the different ways that pilots “pickle,” or drop their bombs, and how the HUD and the fire control radar help them, even when dropping dumb bombs.

Aircraft that fly high and fast deal with a whole range of aerodynamic issues that lower and slower planes never see. They stem from the shape of the aircraft, the properties of the air at high altitude, and shockwaves caused by approaching the speed of sound. In this episode, I discuss high-altitude, high-speed aerodynamics, including Mach tuck, coffin corner, and Dutch roll.

In aviation, airspeed is life. But it's also not simple — there are lots of different kinds of airspeed, from indicated airspeed to calibrated airspeed to true airspeed and more. In this episode, I cover the different types of airspeeds, what they all mean, and why they're important.

Bombs are getting smarter every day. In the 1960s, we got the laser-guided bomb, marking the end of the era of indiscriminate bombing of targets. Today we have GPS-guided bombs too, as well as hybrid guidance systems. In this episode, I'll cover some details of laser- and GPS-guided weapons; how they work, tactics, and shortcomings.

This is part 6 of a 6-part series on transoceanic flights. Transoceanic flights date back to Charles Lindbergh's famous Spirit of St. Louis flight in 1927, but today the world is quite different, with numerous procedures and rules to keep us safe as we fly across the ocean. In part 6, I cover gross navigational errors (GNEs), some of the procedures used in the cockpit to mitigate risk, and strategic lateral offsets, or SLOP.

This is part 5 of a 6-part series on transoceanic flights. Transoceanic flights date back to Charles Lindbergh's famous Spirit of St. Louis flight in 1927, but today the world is quite different, with numerous procedures and rules to keep us safe as we fly across the ocean. In part 5, I cover performance-based requirements, including required navigation, communication, and surveillance performance; and some of the technologies we use to achieve those requirements.

This is part 3 of a 6-part series on transoceanic flights. Transoceanic flights date back to Charles Lindbergh's famous Spirit of St. Louis flight in 1927, but today the world is quite different, with numerous procedures and rules to keep us safe as we fly across the ocean. In part 3, I cover organized track systems, including the busiest oceanic airspace in the world, the North Atlantic, and its North Atlantic Tracks (NATs).

This is part 4 of a 6-part series on transoceanic flights. Transoceanic flights date back to Charles Lindbergh's famous Spirit of St. Louis flight in 1927, but today the world is quite different, with numerous procedures and rules to keep us safe as we fly across the ocean. In part 4, I cover extended operations, or ETOPS, and how pilots plan flights with the ability to divert to airports halfway across the ocean.

This is part 2 of a 6-part series on transoceanic flights. Transoceanic flights date back to Charles Lindbergh's famous Spirit of St. Louis flight in 1927, but today the world is quite different, with numerous procedures and rules to keep us safe as we fly across the ocean. In part 2, I cover high-frequency radio, and how it's used to send messages over the horizon, and selective calling, or SELCAL.

This is part 1 of a 6-part series on transoceanic flights. Transoceanic flights date back to Charles Lindbergh's famous Spirit of St. Louis flight in 1927, but today the world is quite different, with numerous procedures and rules to keep us safe as we fly across the ocean. In part 1, I cover oceanic flight plans, including how they're received; and voice position reporting.

The most important number in cross-country gliding is “speed to fly.” Speed to fly is a complex topic, that involves thermals, headwinds and tailwinds, glider performance, and much more. On this episode I cover the basics of cross-country flying and racing in gliders, and introduce you to Paul MacReady's theory of efficient glider flight.

Primitive forms of aerial refueling have been around since the 1920s; since then, it has matured into a complex but effective procedure for getting gas from one aircraft to another. In this episode, I look at the different kinds of aerial refueling, when it's used, and some things pilots have to be aware of to do it successfully.

The US airspace system is undergoing massive changes in the wake of RNAV and GPS. Learn about the high-altitude redesign (HAR), non-restrictive routing (NRR), RNAV routes, and other projects underway to redesign the highways in the sky.

One of the symptoms of hypoxia is decreased judgment and decision-making ability — not good for pilots. It can sneak up on you slowly, and by the time you realize it's happening, you're too impaired to do anything about it. So pilots have a lot of different ways to ensure their brain is getting the oxygen it needs, even at high altitudes. Today I talk about hypoxia, the different types of hypoxia and its signs and symptoms, and the different ways pilots have of receiving supplemental oxygen.

This is the first of a series covering how pilots defend against incoming missiles. In this episode, I will discuss how pilots use geometry and the limitations of radar to defend against radar-guided missiles. In the next part, we'll look at countermeasures (chaff and flares).

Noise is one of the most persistent issues in aviation. People want to fly, but when it comes to noise, they want to pretend flying doesn't exist. I'll be doing multiple episodes on noise abatement in the future, but for starters, in this episode I'm talking noise abatement departure procedures (NADPs): what they are, how they're flown, and how they're used to reduce the environmental impact of airliners on noise-sensitive communities.

There are many technologies pilots and ATC use to locate aircraft and avoid mid-air collisions. The most important is the pilot's own eyeballs. But beyond that, many other technologies work together to keep aircraft separated. Today I'm going to be discussing primary and secondary radar, traffic collision avoidance systems (TCAS), and automatic dependent surveillance-broadcast (ADS-B).

Turn circles are a fundamental concept in basic fighter maneuvers, or BFM -- the skill of dogfighting. In this episode I will cover the mechanics of turn circles, including rate and radius. I'll also cover entry windows, and the basics of the one-circle and two-circle fight.

Altimeters get less accurate the higher you go. For the longest time, the rules required that airplanes flying above 29,000 feet have 2,000 feet of separation between them, instead of the usual 1,000 feet. But with more and more airliners flying, we needed a way to double the capacity of the flight levels. Enter reduced vertical separation minima, or RVSM: The rules and restrictions that allow us to pack them in even in thinner air.

There are multiple ways for Navy and Marine aircraft to launch and recover to an aircraft carrier, and it all depends on the weather and visibility. In this episode, I discuss the different ways that carrier aircraft are launched and recovered.

The private pilot certificate is the first license that many pilots get. It's a handy certificate that allows the pilot to fly their friends and family around, but they can't take money. There are only a few very limited exceptions in which a pilot can take money or other consideration for a flight. In this episode, I'll talk about these exceptions, and why a pilot can't just go on Craigslist looking for a passenger.

Do airlines weigh passengers? Nope. There are no hidden scales on jetways. Instead, airlines must estimate the weight of their precious cargo, to ensure they don't take off overweight or out of balance. In today's episode, I'll talk about how this works, and how it's led to some unfortunate accidents when it isn't done right.

Electronic countermeasures (ECM) includes radio and radar jamming — it's the techniques we use to deny an adversary the use of their electronic equipment. ECM is a cat-and-mouse game. Radar jamming started as simple noise jamming, but as radars became more sophisticated, ECM techniques have had to increase in sophistication too. Learn about the origins of ECM and how modern ECM works.

Angle of attack is the single most important number in aeronautics. It literally means the difference between flying and falling. Let it get too high, and your airplane can enter a stall, where the wings are no longer able to effectively generate lift. In today's episode, I talk about what angle of attack is, why it matters, what a stall is, and how we get into and out of them.

Scotch whisky is an alcoholic drink made from malted barley, aged for at least three years, and produced in Scotland. Scotch whisky is categorized by its origin, one of five regions in Scotland, each of which has its own distinct flavor, primarily due to the water and soil in which the barley is grown. In this episode, I'll walk you through what exactly Scotch whisky is, the different varieties and their flavor profiles, and how best to enjoy it.

Smart bombs, dumb bombs, cluster bombs, laser-guided bombs … what does it all mean? Bombs have come a long way from World War I, where they were just hurled out of airplane cockpits by pilots with an innate sense of timing. In this episode I'll cover the different types of bombs; their different guidance methods, fuzing, and warheads; and what we choose to use when.

Coaxial-rotor helicopters have two rotors mounted on a single vertical mast. The two rotors rotate in opposite directions. These helicopters don't need a tail rotor and have significant maneuverability and power advantages over traditional helicopters. In today's episode, we'll learn about the history of coaxial-rotor helicopters, and their advantages and disadvantages over traditional helicopters.

In this episode, I cover the details of how we start up aircraft, and in particular jet engine-powered aircraft.

Decalage is not often taught to student pilots, but it's a critical component of what makes an aircraft fly. Decalage provides an aircraft with angle of attack stability — in other words, it makes an aircraft that is flying, want to stay flying. In this episode, I'll talk about what decalage is and why it's what makes an airplane an airplane.

In this episode I'll cover the basics of how air-to-air radar works, and some of the different modes that a modern fire control radar (FCR) operates in. I'll talk about the tradeoffs of each of these modes and how they are used in modern air combat.

Flying over the North or South Pole, or even over Northern Canada, presents unique challenges in aviation. In this episode we'll learn about these challenges: navigation, fuel freezing, diversions, communications, and altimetry. The FAA wants to make sure you don't get stuck somewhere in sub-freezing weather, and so they require airlines to undergo unique training and procedures when they conduct high latitude operations.

Surprisingly, pilots actually care about a lot of different altitudes in aviation. There's the obvious ones: altitude above ground level (AGL) and above mean sea level (MSL), but there's also some not-so-obvious ones you might not have heard of, such as pressure altitude and density altitude. In this episode we will learn about how these different altitudes are measured and what their significance to pilots and air traffic controllers are.

Lead pursuit, pure pursuit, and lag pursuit make up part of the bread and butter of basic fighter maneuvers, or dogfighting. In this episode, learn what these are and how they can lead to overshoots and reversals, which can turn the tables of a dogfight.

An engine failure or fire during the takeoff roll is a critical emergency — the pilot has to make a split-second decision whether to “stop,” and abort the takeoff, or “go,” and take the problem into the air. To ensure the pilot makes the right decision, a whole bunch of planning goes into that stop-or-go decision. On today's episode we look at all the planning involved in minimizing the hazards of an emergency on the takeoff roll. Voice acting: Matt Sherman, Ignacio Soto

Gyroscopes have been a critical part of instrument flying in aviation. Without them, aircraft would have no safe way to fly in clouds or poor visibility. Today we learn about the three gyroscopic instruments in an airplane's instrument panel, how they work, and what the future holds for gyroscopes in aviation.