An aileron is the hinged surface in the outermost trailing edge of an airplane wing, designed to control the lateral balance of the plane as it cruises through flight, or during its roll. The ailerons and how they function in relation to the aircraft is something that every pilot and/or aircraft enthusiast should know. Read on below for a basic outline of how the ailerons function.

1. Ailerons Cause The Adverse Yaw

When an airplane rolls to the right, the left aileron is tilted down while the right aileron is lifted upwards. This aileron that is in the upward position (the right one) generates less drag (the aerodynamic force that opposes an aircraft's motion through the air) and less lift than the aileron on the opposite side. Meanwhile, the aileron that is angled downward (the left one) creates more drag and more lift, which in turn, yaws the plane in the opposite direction of the roll.

2. Differential Ailerons

Differential ailerons counter adverse yaw. When one aileron is elevated at a greater distance than the other aileron is lowered, the extra skyward movement from the aileron generates more drag difference than the increase on the downward aileron. This difference creates an increase in drag on the descending wing, which reduces adverse yaw.

3. Frise Ailerons

Frise ailerons are the bottom of the up-aileron that pivots into the airstream. The frise ailerons creates a form drag. The aileron being raised pivots on an offset hinge. The leading edge of the aileron is now pushed into the airflow, creating drag and reducing adverse yaw. In this case, frise ailerons are using form drag to counter induced drag.

4. Using Ailerons During A Stall

When you use ailerons during a stall, you can cause the wing to drop. As you deflect the aileron, you can change the angle-of-attack (AOA) on each of the wingtips. Your left wing is now flying at a lower AOA, while the right wing is flying at a higher AOA. If you add enough aileron deflection, you can push the right wing over the critical AOA, abruptly stalling the entire wing, and causing your airplane to suddenly roll to the right.

5. Ailerons Create Induced Drag

Similar to flaps, the aileron, when lowered, can alter the chord line of the wing, thus creating a higher AOA. As the lift and AOA increases, so does the induced drag. this is because the drag created by the aileron being lowered is the induced drag.

6. Neutralize Ailerons During A Spin

Each wing is stalled during a spin. But the low wing is at a higher angle of attack than the high wing. Bringing both ailerons to neutral helps the wings reach the same angle of attack and thus helps them decrease pitch and roll.

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As a natural side-effect of combustion, piston engines generate large amounts of heat that needs to be managed. An engine’s internal components are cooled by the oil system, but the external components, such as the cylinder heads, need to be cooled as well. While some engines feature water cooling systems and radiators, most general aviation aircraft use air cooling introduced by the cowling at the front of the front of the engine compartment, and a system of baffles within the compartment to distribute air.

Cowlings typically feature two cold air inlets at the front of the engine compartment, and larger warm air outlet underneath to vent hot air away. Modern cowlings use ram air pressure so that a small amount of air does the majority of the work via pressure and airspeed. This allows cowling to be sleek and cause minimal amounts of drag. Cowling can be either up-flow or down-flow, which refers to the direction that air ultimately flows through the engine compartment. Most designs feature down-flow configurations, although up-flow is used on some pusher-type engine housings.

A cowling’s inlet is designed to accommodate for factors like air-speed and the engine’s heat, both of which depend on various flight conditions. If the inlet area is too large, it will create too much drag, causing the aircraft to fly too slow, and make the engine run too cool. Once air is past the inlet, a set of baffles inside the engine compartment control and guide air over the engine and its various components. Some aircraft will also include cowl flaps in their design, which allows the pilot to control how much air flows through the cowling.

While efficient, air cooling does have its drawbacks. During a climb, less air than normal enters through the cowling, causing heat to rise. It is also much less effective during high-power, low-speed operations such as takeoff, landing, and taxiing. On the other hand, high-speed descents can cause too much air to flow into the engine compartment, causing the engine to drop in temperature and the cylinder heads to crack. Therefore, pilots are trained to carefully manage their cooling needs, and never run their engines too close to the red line.

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With every component that comes together to create an aircraft, it is actually one of the smallest components, the fastener, that remains one of the most important parts to the entirety of the structure. A Boeing 747-800, for example, is comprised of 6 million parts, half of them being fasteners. Much like a fastener that one may find at a hardware store, the part’s functionality at its most basic is to join or affix two or more components together in a non-permanent fashion so that the objects could be later separated. Unlike their hardware store counterparts, however, aviation fasteners are held to a much higher standard, and are specifically engineered with precise specifications to ensure they withstand the demands of high altitude flight. Fasteners are important beyond holding components together, also providing the benefit of taking on and redistributing structural loads.

Aviation fasteners come in many types, common examples being screws, bolts, nuts, washers, rivets, and more. They are most often manufactured using metal, namely steel, titanium, aluminum, and alloys depending on the application and conditions they will undertake. Fasteners also are specifically designed with various shapes and heads depending on the utilization as well, and qualities such as the head decides what type of installation is required. Some heads and applications allow for simple hand tools such as a wrench to install correctly, while others may be precisely installed using machines.

With a plethora of fasteners that are being manufactured and entering the commercial market every year, it becomes difficult for the FAA to administer and approve all of them for qualifications such as being a standard part. To remedy this, as well as still maintain quality control of new fasteners, the Fastener Quality Act (FQA) was enacted in 1999. The FQA ensures that manufactured fasteners adhere to precise specifications, laboratories that test fasteners are properly accredited, as well as requiring inspection, testing, and certification for standardization of parts.

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The United States military is a massive purchaser of goods. Tanks, jets, and weapons of war are the most obvious things the Department of Defense requires, but the military is also a leading purchaser for things like storage solutions, electronics, hardware of all shapes and kinds, service and repair tools, and more. But in the military, everything must be standardized for the sake of reliability, commonality, and compatibility between various systems, allowing maintenance crews to swap out components at a moment’s notice. MIL-SPEC is the set of specifications that the military has set for a particular component, with most of the component’s design rights owned by the government. MIL-SPEC certified equipment is manufactured by various companies to the specifications needed to sell to the Department of Defense and its various contractors.

When a manufacturer uses the term “MIL-SPEC,” they are stating that the component will meet the military standards for that component. For example, MIL-STD-810G is a standard for a broad range of environmental conditions, and is used when selecting hardware for military applications, including marine vessels, ground vehicles, and aircraft. 810 covers the different effects a component may experience, such as shock, sudden drops, fog, humidity, sand, vibrations, leakage, explosions, and more. A MIL-SPEC qualifying product doesn’t necessarily need to test for all these variables, just the ones that are relevant. Part one of STD-810 talks about the process of tailoring the device’s capabilities based on how it will be used. A component meant for use by infantry, for example, is much more likely to suffer from handling shock (dropped, jostled, thrown, etc.) than something mounted in a ship, which will face much more danger from wave-induced vibrations and saltwater fog.

MIL-SPEC is often used as a guideline or advertising feature for civilian sporting and outdoor goods, as well as consumer electronics like smartphones and tablets. Rugged mobile computers are the largest segment within the rugged devices market, like the Panasonic Toughbook, the first commercially available computer rated to military specifications and able to meet MIL-STD-461F, MIl-STD810G, and IP65 prerequisites. The rugged devices market is expected to steadily grow at 7 percent annually from 2019 to 2023.

In theory, any product can claim to be designed to MIL-SPEC if it satisfies at least one of the tests from MIL-STD-810 during its design process. Outside of being used by the DOD, there is no certificate of MIL-SPEC compliance.

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All modern computers, from business servers to personal laptops to high-end gaming PCs, depend on microprocessors to function. Also known as a CPU or central processing unit, a microprocessor is a complete computation engine that has been fabricated onto a single chip.

The first microprocessor was Intel’s 4004, invented in 1971. The 4004 could only add and subtract numbers, and could only work with four bits of memory at a time, but it was an enormous technological leap. Before the 4004, engineers had to build computers from collections of chips, or discrete components of transistors wired one at a time. The first microprocessor to be used in a home computer was Intel’s 8080, an 8-bit computer chip, introduced in 1974.

Also referred to as integrated circuits, microprocessor chips are small, thin pieces of silicon onto which transistors making up the microprocessor are etched. A chip can be as large as an inch, and can contain tens of millions of transistors. A microprocessor executes a collection of machine instructions that tell a processor what to do. Based on instructions, a microprocessor can do three basic things:

  • Use its ALU (Arithmetic/Logic Unit) to perform mathematical operations like addition, subtraction, multiplication, and division. Modern microprocessors contain floating point processors that can perform sophisticated operations on floating point numbers.
  • Make decisions and jump to a new set of instructions based on those decisions.
  •  Move data from one memory location to another.

A microprocessor has:

  • An address bus (8, 16, or 32 bits wide) that sends an address to memory.
  • A data bus (8, 16, or 32 bits wide) that sends data to memory, or receives data from memory.
  • An RD (read) and WR (write) line that tells memory whether it wants to set or get the addressed location.
  •  A clock line that lets a clock pulse sequence the processor.
  • A reset line that resets the program counter to zero and restarts extraction.

Microprocessors will contain either RAM or ROM. RAM, random access memory, contains bytes of information that can be read or written, and are what allows a computer to write, save, and edit data on the fly. However, all data on RAM is lost when power is cut off, either on purpose or by accident. Therefore, ROM, Read Only Memory, is used to store critical data for the computer. ROM contains the BIOS, Basic Input/Output System. The BIOS consists of the basic instructions for the computer’s functioning, and is read by the computer during the boot-up sequence. However, ROM cannot be edited, so it cannot be used for frequently used and edited programs. 

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Like all complex machinery, aircraft design is highly iterative. Blueprints will be drawn and redrawn dozens of times over the course of an aircraft’s development, and this holds true for an aircraft’s pylons as well. The pylon, the structure that attaches the aircraft’s engines to its wings, is a critically important part of the fuselage, and so goes through multiple iterations.

The process begins with the aerodynamicists designing the master surfaces of the aircraft’s master surfaces, i.e. the general shape of the aircraft. Structure designers must then work around the space requirements imposed by this design, but compromises between the two design teams will often be needed as the aircraft is designed.

There are multiple factors that go into designing the pylons. The first and most major factor is the operating envelope, the aircraft’s performance characteristics such as top speed and service ceiling that dictate the aerodynamic loads on the pylon. Performance numbers such as thrust and weight can be obtained from the engine, and design load factors such as crash and emergency features must be accounted for as well.

The exact design of the pylon will depend on these figures. Pylon design uses similar structures of cable OEM (original equipment manufacturer) based on that company’s experience, expected mathematical models, and flight test data. Most pylons are based on proprietary structural arrangements used in previous designs. Boeing, for instance, has a proprietary design they do not share with the general public. From this basic design, the unique loads and configuration of the assemblies going into the pylon will be calculated by a stress engineering group into sizing for the geometry of the assemblies. This first pass at the assembly design will be done by the pylon group, then used as a basis of stress for sizing, going through an iterative process that will be repeated until an acceptable design solution is found.

Ground tests and test flights will be the ultimate proof of design. Afterwards, the manufacturer will finish with a weight reduction process to reduce part geometries of excess material once the actual flight loads have been verified.

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Given how complex modern aircraft are, it’s only appropriate that  inspections and maintenance procedures  are exhaustive. With so many pieces of equipment, safety requires persistent vigilance from both the pilot and the technician. Routine check-ups can also ensure a properly functioning aircraft—avoiding costly repairs down the line.

The majority of an aircraft’s maintenance and inspections will revolve around the standards set by Title 14 in the Code of Federal Regulations, or 14 CFR. According to 14 CFR, there are three primary types of inspections: annual, 100-hour, and progressive. An annual inspection must occur once every year. 100-hour inspections are required of all aircraft that carry non-crew passengers. A progressive inspection is a special program where the requirements of the 100-hour inspection is broken up into multiple phases. For example, instead of one inspection every 100 hours, you could have five inspections over the same period of time, each one covering a portion of the 100-hour inspection. These progressive inspection plans require a special application and are typically utilized by owners of high-use aircraft fleets. 

Components frequently inspected by the FAA in annual or 100-hour inspections include the altimeter, transponder, emergency locator transmitter, as well as the angle fuselage, engines, and propellers. Inspectors search for signs of wear and tear, malfunctioning components, and damage. This includes deterioration and loose fittings in the fuselage and wings, cracks and failed sealing in the windows, and any leakage in hydraulic lines for brakes and landing gear

Before every flight, the pilot has to make a preflight inspection to ensure their aircraft’s integrity. This includes a cabin inspection, to make sure that the necessary paperwork is on hand (including airworthiness and registration certificates, operating handbook, weight and balance data, etc.), and ensuring that all electric switches and toggles are in the right position.  It’s also important to clear the cockpit of loose trash and tools. Next is the exterior inspection, a walk-around where the pilot checks for loose rivets and bolts in the fuselage, making sure there are no leaks in the fuel reserves, checking the tires for wear and flats, and clean the windows. These tasks may seem minor, but each one is vital for a safe flight. 

When it comes to maintenance there are two categories: preventative and progressive. Preventative maintenance  involves tasks that don’t require a great deal of disassembly or complex repairs; small, easy procedures that a pilot or mechanic can perform to keep the aircraft working properly such as cleaning, replenishing engine fluids and sealing, or replacing small pieces of hardware. Under 14 CFR Part 61, these tasks can be performed by anyone holding a pilot certificate, as long as the aircraft is not used to carry non-crew passengers. Otherwise, a mechanic certified by the FAA must perform them.

The FAA classifies all repairs as minor or major. Which category a repair falls under depends on its complexity and how important it is to the aircraft’s critical systems. Both types must be performed by an FAA-approved mechanic; however,  after minor maintenance an aircraft can return to the air with the approval of the mechanic or repair facility. Major maintenance requires inspection by a mechanic with an Inspection Authorization, or by a representative of the FAA.

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A deicing boot is an important component involved in removing ice from the exterior of an aircraft. It is a type of ice deterrent system that enables mechanical deicing while an aircraft is in flight. Deicing boots are typically installed on the outer edge of a wing, where the likelihood to accumulate ice is much greater. A buildup of ice can significantly impair the aerodynamics of an aircraft, leading to safety risks.

Its design consists of a thick rubber surface that is then installed over a specific area of the wing, similar to a rubber membrane. As ice accrues, compressed air fills the boot, dislodging ice that has accumulated. From there, the air travels through a pressure regulator followed by a flow control valve. The ice is then blown away naturally and the boots are deflated to their normal shape. Deicing boots are operated manually or by a timer that is controlled by the pilot of the aircraft.

Deicing boots require routine inspection and maintenance. A regular engine cleaning schedule is not only beneficial to the appearance of the aircraft, but also aids in detecting problematic equipment early on. The general condition of the boots should be analyzed during inspection and any damaged area should be repaired immediately. Small cuts are common in deicing boots and tend to enlarge during flight. This damage poses the risk of water entering the boot and subsequently freezing, preventing it from operating properly.

Patching the deicing boot is a relatively easy procedure that can save on costs in the future. Thoroughly clean the area that is scuffed, then apply the repair patch. Patches are designed with a pressure-sensitive adhesive on its backside. Gone are the days of having to apply glue to the boot and the patch. In areas of excessive damage, it may be better to replace the boot entirely.

Replacing an old boot isn’t as difficult as it may seem. Line up the centerline of the new boot with the centerline of the old boot. Once the old boot has been removed, the old adhesive needs to be removed as well. Inspect the surface for any damaged areas or visible corrosion. Damaged areas need to be repaired before installing the new boot. All corrosion element, no matter the severity, should be repaired. Minor corrosion can escalate into major structural rework.

Once the surface is prepped, apply the adhesive in two layers. Let the first layer dry before applying the second one. When the adhesives polyureth have dried, the boot is ready for installation. The first area that needs to be glued down is the two ends of the boot, followed up by the centerline. If you are patient during the installation process, you will end up with a nice, smooth, finished deicing boot.

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Marine propellers operate, essentially, the same way that aircraft propellers do: the propellers generate forward thrust by pushing the fluid back, and the resulting force moves the object forward. This is due to Newton’s third law of motion— for every action, there is an equal and opposite reaction. The propellers are connected to a rotary shaft that is powered by an engine. But marine propellers come in many different specs, all classified and sorted by the number of attached blades and the blade pitch.

An engine may have two to five propeller blades. They have a minimum of two blades for optimal efficiency, and more are added if they have to support heavier loads. A three blade propeller costs less to manufacture, has good high-speed performance, and solid acceleration characteristics. However, these propellers are not efficient for low-speed handling. A four blade propeller costs more to manufacture than the three blade propellers but have better strength and durability, give good low-speed handling and performance, have better holding power in rough seas, and has better fuel economy than other types. Five and six-blade propellers are also more expensive, but they have better holding power in rough seas and support heavier loads. They are often used for heavy container ships.

Propellers may be fixed pitch or controllable pitch. The blades on a fixed pitch propeller cannot be altered because they are permanently fixed to the hub. They do not have great maneuverability compared to a controllable pitch propeller, but they are less complicated and cost less to manufacture. Controllable pitch propellers, also known as variable pitch propellers, can be altered during operation to accommodate various operating requirements. Therefore, they have increased maneuverability and improve engine efficiency. However, due to the mechanical and hydraulic arrangements that allow them to move, they are more expensive to manufacture. 

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“It’s all part of the genie gig—phenomenal cosmic power... itty bitty living space.” In terms of this itty-bitty electrical component, the Genie in Disney’s Aladdin had it right. Capacitors provide a large amount of power in a compact vessel and are used in a wide range of electronics. They are a passive electrical mechanism charged by a current, with the ability to store energy within an electric field. This capability can be utilized to power a camera flash, remote signal, or even switch AC current to DC smoothly.

 So how do these things work? Imagine a bar of chocolate covered Oreo on a stick. Though not edible and probably not nearly as delicious, a capacitor consists of two metal plates that act as conductors (the cookies), and dielectric material in their middle (the cream). These components are then dipped in a resin (the chocolate). This assembly is also attached to two electrical terminals that connect it to power and ground sources (the stick).

Now that we can imagine the structure, let’s look at how the capacitor holds its charge. An electrical current enters the capacitor and reacts with a metal plate, causing negative electrons to get trapped. The insulator material, or dielectric component, is non-conductive, and as one metal plate gathers electrons, the second plate becomes positively charged. With this interaction, an electrical field is formed, allowing the capacitor to hold a charge or a constant feed of tension between the negative and positive plates.

The versatility of these components has led to the development of the three most common variations: ceramic capacitor, the electrolytic capacitor, and the supercapacitor. Each of these works similarly to standard capacitor operations but vary in their level of charge and vulnerability to current leakage.

A ceramic capacitor is most often used on a breadboard or circuit board. They are the most rudimentary, the cheapest to acquire, and they leak the least amount of current. Despite these benefits, ceramic caps hold only a small charge and are not powerful enough for applications requiring higher voltage and/or higher electrical storage.

An electrolytic capacitor is most often seen on a circuit board. Capacitors of this category hold and generate a massive electrical charge while maintaining a compact design. Uniquely, these devices are also polarized. Due to this, they require specific wiring systems to function properly and are equipped with anode (+) and cathode (-) pins. Anodes connect to higher voltages and cathodes connect to lower voltages. These capacitors have the least current leak efficiency and are not best for storing energy.

Last, but certainly not least in energy storage, are supercapacitors. Energy storage and discharge capabilities of the supercapacitor rank the highest among these units. They release their charge all at once, resulting in a shorter lifespan and vulnerability to high voltage situations.

If you are considering the use of a capacitor, there are a few variables to keep in mind. Size, max voltage, and current leakage are all elements that you will want to check with any capacitor. Overall, capacitors are small electrical units capable of high energy storage and discharge. The itty-bitty battery like structures can benefit any project needing a smoother current, capacitor coupling, tuning, or energy storage. 

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