Purchasing Efficiency Blog

Obstruction lighting is an important aid in ensuring the safe flight of aviators around the world. You’ve almost certainly noticed it before, but you may not have given it a second thought. Obstruction lighting refers to the lighting atop tall buildings and structures that allows operators to see them from a distance. They are used at night and serve as an important collision avoidance measure. Towers, skyscrapers, bridges, hills, and even chimneys or antennas are all objects that could be considered aviation obstruction. Obstruction lighting is critical in illuminating these objects and creating a safe environment for flight.
 
Because obstruction needs to be visible from a radius of miles away, there are varying types and intensities of obstruction lighting. The three levels of intensity are low, medium, and high. Low-intensity lights are applied to objects no higher than 45-meters. Medium lights appear on taller buildings, structures, or natural objects like a hill. Lastly, skyscrapers, highrises, and other extremely tall constructions are equipped with high-intensity lights. In addition to the varying intensities, obstruction lights also have 4 types - A, B, C, and D. Type A lighting is a steady, read light with an output of up to ten candelas (units of measurement to describe a light’s power). Type B lights are also a steady, red light, but their power output is no less than 32 candelas. Type C lights are flashing, yellow or blue, and have at least 40 candelas. Type D, by far the most powerful, is a flashing yellow light with a candela output of 200 or greater.
 
Obstruction lights of both Type A and B are used with low-intensity lighting. As Type B is more powerful, it is preferential, but Type A is used in cases where Type B lighting could compromise a pilot’s visibility or blind them altogether. For medium intensity lights, types A, B, and C are all used. Objects taller than 150 meters require high-intensity lighting during both day and night. At night, a power output of approximately 2000 candelas is used. At dusk, that number increases tenfold to 20,000 candelas and in broad daylight, 27,000 candelas is required to properly light a structure.
 
Historically, beacons or aircraft warning lights have been made with incandescent filament bulbs. To improve the otherwise unimpressive lifespan, obstruction lights are made with a rugged design and run below their maximum operating power. Developments such as the use of high-power LED lights have solved both of the problems experienced by incandescent filament bulbs. LEDs are not only more energy efficient but also have longer lifespans, both reducing maintenance costs and supplementing reliability.
 
Lighting is also an important factor in safe airport runway management. Airport beacons are large, rotating lights that are highly visible from miles away. Pilots can easily find an airport at night thanks to these beacons, making it one of the easiest checkpoints for pilots navigating a nighttime flight. In addition to obstruction lights and airport beacons, taxiway lights and runway lights are also very important in creating a safe and efficient flight environment.
 
At Purchasing Efficiency, owned and operated by ASAP Semiconductor, we can help you find all the LED obstruction light parts for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. As the only independent distributor with a no China sourcing policy, we can guarantee that all obstruction light parts we sell will come from a trusted manufacturer and function reliably. For a quick and competitive quote, email us at sales@purchasingefficiency.com or call us at 1-469-319-8300.

Before we can dive into how turbofan engines work, we need to first look at the core functionality of a turbojet engine. This is because the only difference between the two is an added fan placed in front of a turbojet’s core engine. This fan is encased in its own inlet and increases airspeed and thus pressure, ultimately resulting in an increase in overall exit thrust. This enhancement occurs without the need of additional fuel, making turbofans the engine standard for airliners because of their fuel efficiency. There are four main parts of a jet engine that air flow passes through that need to be explained to understand just how thrust is produced. These parts are where air enters an engine inlet and meets the compressor to, when it passes through the combustor, turbine, and exits out the nozzle.
 
Air that enters a core compressor is squeezed into smaller areas creating air pressure. This air pressure is then forced into the combustor or combustion chamber where it is mixed with fuel and then ignited. This produces hot expanding gases (up to 2,700 degrees F) that then make their way to the core turbine. These gases cause the fan turbine blades to rotate and spin around thousands of times, pushing hot air into the last part of a turbojet engine, the nozzle or exhaust duct. In the nozzle, hot air combines with cold air that bypassed the engine core processes explained above and these temperature differences expel an exhaust force that causes forward thrust.
 
Jet engines are also called gas turbines and produce tremendous thrust and very high speeds during flight. The concept for these engines were first theorized by Sir Isaac Newton in the third law of motion (cause and effect). If a rearward-channelled explosion could be attached to a machine, this theory could project an aircraft forward at very high speeds equal to the force of the backward explosion. Types of jet engines include ramjet engines, turboshaft engines, turbojet and turbofan engines as explained above, and turboprop engines. 
 
At Purchasing Efficiency, owned and operated by ASAP Semiconductor, we can help you find all the unique parts for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@purchasingefficiency.com or call us at +1-469-319-8300.

Aircraft spacers are used to guide wires, keep conflicting wires separated and hold wiring bundles in place. Wire organization is key in aircraft assembly to avoid electrical system malfunction and ensure the longevity of installed wiring. These spacers can be tubing, shafts, piping, or part fitters and come in a wide variety of shapes, sizes, and materials. Their shape can be hinged, hexagonal, cylindrical or flat and some materials used in their manufacturing include steel, aluminum, brass and synthetic materials such as nylon, rubber and plastic. 
 
A one-piece spacer has the strength and lightness of forged aluminum and self-locking stainless steel inserts that, when attached to an aircraft’s structure, counteract vibratory loosening. Two-piece spacers do not have self-locking inserts but instead utilize self-locking nuts in conjunction with mating. Clip-on spacers do just that, they clip on and attach wiring harnesses to aircraft stringers. The easiest spacer application is the adhesive mount spacer, made up of a thin aluminum plate and nylon that sticks to a wide variety of surface textures and materials. One and two-piece spacers can either be threaded or unthreaded depending on the nature of the attached components. Threaded spacers are referred to as standoffs and unthreaded spacers are known as clearance spacers. Both of these spacer ends have a male and female thread combination.
 
Devices like shims and washers can also be considered spacers because of their similar functionality of providing assistance between various fasteners and system components. The designs of these closely related devices can be notched or waffle and cupped to fit and attach to complex custom aircraft structural shapes, accomplishing the same goals of a spacer. The aerospace industry has no shortage of small yet useful parts and components, the spacer is no exception.
           
At Purchasing Efficiency, owned and operated by ASAP Semiconductor, we can help you find the aircraft spacers you need, new or obsolete. As a premier supplier of parts for the aerospace, civil aviation, and defense industries, we're always available and ready to help you find all the parts and equipment you need, 24/7x365. For a quick and competitive quote, email us at sales@purchasingefficiency.com or call us at +1-469-319-8300.

Within aircraft, there are a multitude of systems that utilize hoses. Hoses can be installed for fuel lines, hydraulic systems, brakes, oil coolers, and more. Flexible aircraft hoses in particular are important in situations where parts may be subjected to vibration or the hose system needs a lot of flexibility. In this blog, we will discuss some of the important considerations and steps that should be taken into account when purchasing and installing a flexible aircraft hose.
 
When considering purchasing flexible hoses for your aircraft, it is important to decide whether you should purchase new, used, or surplus. When getting either used or surplus, buyers may find that they are much cheaper than new hoses. While this may make a great difference in their decision, some may be more wary of the shelf life of the hose. Shelf life, however, is often decided by the manufacturer based on their best guess, and commonly does not account for the actual life of the hose once it is installed and utilized in the aircraft. Nevertheless, ensuring that the hose is still flexible is important.
 
Before purchasing your hose, it is paramount that it is engineered to be capable for the application that you intend to use it for. Aircraft fuel and oil hoses need to be able to withstand the temperatures that they may be subjected to during use, and hoses for a hydraulic system need to meet needed operating pressures.
 
Ensuring the correct size of the hose is also always crucial for any system. Hoses are measured by their internal diameter, while a tube on the other hand may be measured from its external diameter. Sizes are also measured in 16ths of an inch, which is important to remember when finding the right fit. If you are cutting your own hose for installation, be sure that the cuts are clean so that they can be fitted properly. Also keeping extra length than what may be needed can allow for the tube to bend and flex.

At Purchasing Efficiency, owned and operated by ASAP Semiconductor, we can help you find the aircraft parts and flexible hose assemblies you need, new or obsolete. As a premier supplier of parts for the aerospace, civil aviation, and defense industries, we're always available and ready to help you find all the parts and equipment you need, 24/7x365. For a quick and competitive quote, email us at sales@purchasingefficiency.com or call us at +1-469-319-8300.

Hydraulic systems are a widely used, reliable, and cost effective method of creating motion and actuation for various components. They can be utilized for car braking systems, aircraft flight control systems, industrial machinery, and much more. Simply put, hydraulic systems work by pressurizing liquid in an enclosed space, which in turn transfers that pressure equally through the system which can be used to perform various tasks. With hydraulics, it is important that that pressure remains equal and there is a backup in case of leakage or failure. To prevent and solve this problem, many hydraulic systems utilize hydraulic bypass valves.
 
Hydraulic bypass valves work to maintain equal amounts of pressure within the hydraulic system. This is achieved through the use of a piston and spring that work together to divert or bypass fluid when needed. Normally, the piston remains closed and the fluid flows normally while there is equal pressure in the inlet and outlet of the spring. When one side begins to build up a great amount of unequal pressure, the spring begins to compress, pushing the piston which creates an opening. Fluid is then diverted into this new opening and typically is moved pack to a reservoir or another area of the system.

For example, in the case of a car braking system, the hydraulic bypass valve works to ensure the braking system does not fail in case of leaking or damage. Cars often rely on their front brakes for stopping power, and leakage can cause them to fail through a loss of fluid pressure. Hydraulic pressure in this case becomes uneven and the bypass valve redirects brake fluid to the back brakes to allow for safe stopping. Hydraulic bypass valves are seen in many other systems in which water and oil is utilized for actuation and creating motion, as well as they are always useful for maintaining safe and equal pressurization.

When you’re dealing with complex, highly-engineered, and expensive aircraft, it is important that every single piece does its job. From the engine down to the smallest fastener, each part has an important role to play. Bolts, a small but critical fastener in the construction of any aircraft, are no different. The stress of flight means that non-aviation grade hardware simply doesn’t do the trick. It has neither the strength nor the corrosion resistance to work effectively in flight. This has required aviation authorities to develop strenuous standards for aircraft bolts, as well as an exhaustive description and coding system.
 
Bolts used for aviation purposes are manufactured to AN (Army/Navy) standards. AN bolts are used for either tensile or load-bearing applications. They are made from a variety of different materials including cadmium-plated nickel alloy steel, corrosion resistant steel, or aluminum alloy. Their comprehensive coding system seems daunting but, once you break it down, is easy to follow. For example, a typical bolt coding will look something like this:
 
AN4-(H)10A
 
“AN” is a common prefix simply standing for Army Navy, the two authorities from which this coding system came. The number 4 denotes that the bolt has a diameter of 4/16th of an inch. If the bolt was 3/16th of an inch it would be AN3. The dash following AN4 seems like nothing, but actually signifies that the bolt is constructed of cadmium-plated steel. (H) designates that the bolt has a drilled head bolt and is left off the code in the event that no drilling in the head is necessary. The fourth section, the number 10, indicates that the bolt is ten inches in length. Much like the diameter, this number changes with the length of the part. The final character, the letter A, is used to show that a cotter pin hole is not required.
 
As you would expect, the bolt codes can differ drastically based on a number of factors and specifications. This standardized coding system is a convenient identification tool and can save operators a lot of headaches during their search for proper bolts.

The O-ring is a manufacturing component that has been around for over a century. Thanks to their design simplicity and practical nature, O-rings remain in widespread use to this day. Their function is as simple as their design, which serves to create a tight, leak-proof seal between two components. They are very similar to gaskets, although O-rings are normally used in higher-pressure environments where other seals parts would fail. O-rings work by sitting between two other pieces that will be connected. The O-ring lies in the connective joint between the two parts where, once under pressure, will shift around causing it to more tightly hold onto the inner and outer walls of the pieces it’s connecting.
 
Despite being a very simple part, O-rings come in a variety of types and materials. Some of the materials they’re made from include rubber, nitrile, silicone, fluorocarbon elastomer, metal, stainless steel, and NBR, a type of elastomer part. O-ring uses are as varied as the materials they come from. Here are just a few of them:

Although O-rings are an incredibly basic piece of technology, they are a vital component of many manufactured goods.

Bearings are used in many of the machines we use on a daily basis. If bearings didn’t exist, we would be constantly replacing parts, which would inevitably slow down productivity. The bearing parts were designed with a simple concept in mind— objects can roll better than they can slide. Bearing design is based on the magnitude and direction of the load that they are intended to support.
 
The beauty in the simplistic design of bearings is something to be admired. Ball bearings are essentially made up of a ball and a dual sided surface for dissipating stress that is applied to it. The ball carries the load of the weight while the force associated is what enables rotation. The method in which the force is absorbed depends on two factors: thrust load and radial load. Radial loads apply tension to the bearing which causes it to rotate. Thrust loads put stress directly on the bearing from an angled position. A deep groove ball bearing and tapered roller bearing can facilitate both loads. The load type and capacity to support weight are factors to consider when choosing the proper bearing for a job.
 
The ball bearing is the most common type on the market and can handle both thrust and radial loads. There are also roller bearings, ball thrust bearings, roller thrust bearings, tapered roller bearings, and magnetic bearings. Each one supports a different function. Roller bearings are used in objects such as conveyor belt rollers and are capable of holding heavy radial loads. The roller is constructed as a cylinder meaning the contact between the inner and outer race is a line. Ball thrust bearings are used in instances where low speed is key, and a radial load can’t fully be handled.
 
Roller thrust bearings are constructed to support large thrust loads. These bearings are commonly found in vehicle transmissions and are used to separate the gears. Tapered roller bearings have the ability to support both large thrust loads and large radial loads. Magnetic bearings contribute to the functionality of high-speed devices. This includes advanced flywheel energy storage systems. Bearings with rollers or balls can’t withstand the high-speed temperatures and would ultimately melt.

Bevel gears are gears where the axes of two shafts intersect, and the tooth-bearing faces of the gears themselves are conically shaped. Bevel gears are typically mounted on shafts that are 90 degrees apart but can be designed to function at other angles as well. One of the most common use of bevel gears is in the differential of a vehicle, where it transmits power generated by the power engine to the vehicle’s wheels.
 
The two most important concepts in gearing are pitch surface and pitch angle. The pitch surface of a gear is the imaginary toothless surface that one would have by averaging out the peaks and valleys of the individual teeth. The pitch surface of an ordinary gear is in the shape of a cylinder. The pitch angle of a gear is the angle between the face of the pitch surface and the axis. Most kinds of bevel gears have pitch angles of less than 90 degrees and are therefore cone shaped. These are called external bevel gears, because their gear teeth point outwards. Internal bevel gears, meanwhile, have pitch angles of greater than ninety degrees, and have teeth that point inward. Bevel gears with pitch angles of exactly 90 degrees are known as crown gears.
 
Bevel gears can be classified into several different types, based on their geometry. Straight bevel gears have a conical pitch surface and teeth that are straight and tapering towards the apex. Straight bevel gears have a conical pitch surface and teeth that are straight and taper towards the apex. Spiral bevel gears have teeth that curve at an angle, which allows contact to be gradual and smooth. Zerol bevel gears are technically spiral bevel gears but have a spiral angle of zero at the middle of the face width, effectively combining the strengths of both straight and spiral bevel gears. Lastly, hypoid bevel gears are similar to spiral level, but the pitch surfaces are hyperbolic and not conical. A hypoid pinion is also larger in diameter than an equivalent bevel pinion. Lastly, mitre gears are a type of bevel gear with equal numbers of teeth and are primarily used to transmit rotational motion at a 1:1 ratio.

To understand how an airplane’s wings keep it in the sky, we first have to understand the forces influencing all aircraft - thrust, drag, lift, and weight. Thrust is the force that propels the aircraft forward provided by its engines, both piston and jet turbine. Drag is the force trying to pull the aircraft back, generated as the aircraft displaces the air in front and around it. Lift is the force generated by the airplane’s wings and the flow of air over and below them, while finally weight is the force of the Earth’s gravity trying to pull the plane back to the ground. 
               
 An airplane’s wings generate lift as they move through the air, but how exactly? They do so for two reasons: Bernoulli’s principle, and the shape of the wing itself, also known as the airfoil.  Bernoulli’s principle, named after the Swiss mathematician that discovered and described the phenomenon in 1738, states that as air speeds up, its pressure drops. An aircraft airfoil is shaped deliberately so that air going over the wing will be going faster than the air going under it. This means that the faster air going over the airfoil exerts less pressure than the high-pressure, slower-moving air going underneath it.  This results in lift that pushes the airfoil, and the rest of the airplane, up. 
               
Typically, a plane’s airfoil will be designed to provide enough lift to keep the plane level while flying at its cruising speed. But what about when a plane is taking off and landing? In those situations, the plane’s flaps and slats come into play to alter its airfoil and generate more lift.  
               
During takeoff and landing, the flaps located on the back of the wing extend downward from the trailing edge, altering the shape of the wing’s airfoil and generating more lift. This altered shape also generates more drag; this is useful for slowing down during landing, but it also means takeoff requires more thrust than normal. Slats also work on the same principle of altering the wing’s shape but are located on the leading edge of the aircraft. They are also used during takeoff and landing.