How dynamometers work

Dynamometers or dyno systems seem complicated but once you understand the basics it all becomes clear! A dynamometer is basically just a measuring tool, in the same way as voltmeters, scales or speedometers are. Among force-measuring devices, dynamometers are a flexible metallic ring that bends when a force is applied in such a manner as to tend to collapse it (the amount of bending being a measure of the applied force) and a hydraulic “load cell” that measures compressive loads in terms of fluid pressure. Once you have built your new motor, or fitted any tuning parts, it is very important to visit a good automotive Dynamometer or rolling road. If you don't, then you will never be able to properly set up your engine. A good dynamometer allows you to use a gas analyzer while under load so you can see the real air fuel mixture at all RPM's while driving. Power-measuring dynamometers may be either transmission dynamometers or absorption dynamometers. The former utilize devices that measure torque, in terms of the elastic twist of the shaft or of a special torquemeter inserted between some sections of the shaft. The torque is produced by the useful load that the prime mover, motor, or machine is carrying. Unlike transmission dynos, absorption dynamometers produce the torque that they measure by creating a constant restraint to the turning of a shaft, by applying mechanical friction, fluid friction, or electromagnetic induction. A Prony brake develops mechanical friction on the edges of a rotating pulley by the means of a few brake blocks that are squeezed against the wheel by tightening the bolts until the friction torque FR balances the torque WL. A water brake creates a resistance by circulating the water flow between a rotating impeller and a stationary shell, while an electric dynamometer generates and absorbs direct-current electricity or eddy currents. In each case, the element that exerts the restraining influence is freely cradled so that its tendency to rotate with the rotating body can be restricted and the restricted force is measured at a known distance from the axis of rotation. Torque is the product of the spring load or weight and the distance from the axis of rotation. Dynamometers also measure the torque produced by an engine in order to reveal important information about its performance. A diagnose is then presented in performance graphs, which can be easily printed and interpreted.

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How Does A Turbojet Engine Work?

A turbojet engine is a type of internal combustion engine often used to propel aircraft. Air is drawn into the rotating compressor via the intake and is compressed to a higher pressure before entering the combustion chamber. Fuel is mixed with the compressed air and ignited by a small flame in the eddy of a flame holder. This combustion technique significantly raises the temperature of the gas. Hot combustion chemicals leaving the combustor expand through the turbine, where power is drawn to employ the compressor. Although this expansion process reduces both the gas temperature and pressure at exit from the turbine, both variabels are for the most part still well above ambient conditions. The gas stream exiting the turbine expands to ambient pressure through the propelling nozzle, causing a high velocity jet in the exhaust plume. So if the jet velocity surpasses the aircraft flight speed it amazingly creates a forward thrust. Under normal circumstances, the pumping action of the compressor prevents any backflow, this kindly helps the flow of the jet engine. You can compare the whole method with a four stroke cycle, but with induction, compression, ignition, expansion and exhaust taking place simultaneously. The efficiency of a jet engine is strongly dependent upon the pressure ratio (Combustor Entry Pressure/Intake Delivery Pressure) and the Turbine Inlet Temperature of the cycle. It is also perhaps instructive to compare turbojet engines with propeller engines. Turbojet engines take a rather small mass of air and accelerate it by a large amount, whereas a propeller takes a large mass of air and accelerates it by a small amount. At great speed the exhaust of a jet engine makes it efficient at high speeds (particularly supersonic speeds) and high altitudes. On planes that go slower and fly a shorter range, a gas turbine-powered propeller engine, commonly known as a turboprop, is far more common and also more efficient. Especially small aircraft primarily use conventional piston engines to drive a propeller but small turboprops are getting smaller as technology improves each day. The turbojet mentioned above is a single spool design, where a single shaft connects the compressor to the turbine Higher Overall Pressure Ratio designs often have two concentric shafts, this is to in essence improve the stability of the compressor during engine throttle movements. Basically it's the outer shaft that connects the turbine engine to the high pressure compressor. The combustor together with the high pressure compressor spool forms the core or gas generator of the engine. We must not forget that the inner shaft connects the low pressure compressor to the LP Turbine to create the LP Spool. Either spools are free to operate at their optimum shaft speed.

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How Do They Make Auto Glass Bulletproof?

As you may know bulletproof glass is glass that is capable of stopping all sorts of bullets fired at it. This type of glass is made by using a strong but transparent material such as polycarbonate thermoplastic. Sometimes it’s constructed by using layers of laminated glass. The polycarbonate layer is often put between layers of regular glass. A bullet will probably pierce the exterior glass layer, but will be stopped by the really strong polycarbonate layer before it can pierce the inner layer of glass. There’s also what’s called bullet resistant glass that’s constructed of laminated glass layers. This is built from sheets of glass glued together using some sort of liquid rubber. One-way Bullet Proof Glass As technology advances in the field of bullet resistant glass we now have a new type of bullet proof glass called one-way bulletproof glass. These types of glasses are commonly used by armored cars. The beauty of this glass is that it will resist incoming fire arms striking the outside of the glass, while allowing those on the other side of the glass, such as guards, fire from inside the armored car, through the glass at the exterior threat outside. Usually One-way bulletproof glass is made up of two layers. A brittle layer on the outside and a flexible layer on the inside. If a bullet is fired from the outside it will hit the brittle layer first and will probably shatter an area of it. This shattering of the glass absorbs some of the bullet's energy, and spreads it out on a larger area. When the slowed down bullet hits the flexible layer, it will be stopped. However, when someone fires a bullet from the inside it hits the flexible layer first. The bullet will then go through the flexible layer because its energy is focused on a smaller area. The brittle layer will then shatter outward because the inner layer flexes and doesn’t stop the bullet's progress.

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How Do Hybrid Vehicles Work?

How many times have you pulled up to the pumps lately only to be shocked at the price of gasoline? Suddenly your $25 tank of gas is costing $40. Have you considered trading your vehicle in for something that gets better fuel economy? How about a Hybrid vehicle? If you’ve ever wondered “how do hybrid vehicles work?” read on. Hybrid vehicles address two issues – global warming by reducing emissions and reduced fuel costs. There are lots of different hybrid designs showing up on the market, so understanding how they work is very important to getting the best value for your money. If you have ever owned a moped, you can proudly consider yourself a first generation hybrid owner because they combine pedal power and gasoline. Hybrid vehicles really aren’t that new a concept. You’ll find them all around you in commercial use. Giant mining trucks, submarines, buses, and even train engines all have a fuel source and an electrical source of power. Most of the hybrid vehicles we are seeing on the market are gasoline and electric hybrids. This means they use both gas and electricity to power them. The two power sources can be combined in different ways. The parallel hybrid has a fuel tank which supplies fuel to the engine and a set of batteries which supplies power to the electric motor. Both sources are able to turn the transmission. The series hybrid is a little different. The gasoline engine turns a generator which can either power the electric motor that drives the transmission or charge the batteries. In this type of hybrid the gas engine never directly powers the vehicle. With a hybrid car the gas engine can be a lot smaller than in a conventional car so it can be a lot more efficient. Acceleration requires a larger engine to produce the power needed, but by using a smaller engine and combining it with the assistance of an electrical motor that is operating at peak load the acceleration needs of a vehicle can be met. Hybrid vehicles also capture the energy from the braking system. When the brake is applied, energy is removed from the car and dissipated as heat which is then captured and stored in the batteries for later use. Hybrid cars also have an automatic shutoff, so when the vehicle comes to a stop the engine is shut off and then restarts automatically when the accelerator is touched. This conserves energy that would be wasted when idling. Depending on the manufacture, the technology is used in various forms but the basics remain simple. Hybrid technology in the consumer auto market is still relatively new but will continue to develop and improve. Hybrid vehicles work efficiently to reduce tailpipe emissions and improve mileage. So if you are in the market for a new vehicle you might want to have a look at the hybrids.

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How Can an Engine Produce More Horsepower? Part I The Basics

So you have a lead foot (and the tickets to show for it). You want to put the pedal down and have a little more power to the pavement (don’t we all). Then let’s talk about the basics of how your engine produces power, no matter if it is a 4 cylinder rice burner or a mammoth V-8 brimming out of your hood. Let’s start with the basics. As a Crew Chief in the United States Air Force, jet engine combustion was always taught in the simplest of terms: Suck, Squeeze, Bang, Blow. Yes it sounds like a sultry movie you would watch at a pay by hour motel, but it will all make sense in a second. Let’s start with the first part of our friendly Department of Defense taught equation. Literally your engine “sucks”oxygen. Now follow me on this one Homer, the air from the outside travels through an intake tube to a manifold all the way into the cylinder chamber. So why do we need more oxygen? Good Question. We need the maximum amount of ambient air to fill each cylinder chamber (no matter if you have 4 or 10 of them) on the down stroke of a combustion cycle with one of the magical ingredients that produce horsepower: you guessed it, oxygen . Why? Keep reading. At this point after our “suck” part of the equation is complete, we move on too the “squeeze” part. The valve that allowed the air to enter the cylinder chamber closes and the cylinder moves upwards and squeezes the air that was “sucked” in, at the same time fuel is introduced to the chamber at this point. Now if you where a Boy Scout or had gone through Combat Survival like I did, then you know you need three things to make fire. Air (oxygen), Fuel (gasoline), and Ignition (sparkplugs, more on these later). Now we are condensing the air and the fuel, making a nice packed (and denser) concoction for a nice fire, well really an explosion. How? Keep reading. I like fireworks, and that is what you have for the third part of our equation, “bang”. Now we are cooking, with that oxygen and fuel all compressed and ready to explode. Remember I told you about the ignition, you know the sparkplugs. These little puppies produce a high intensity spark that are going to ignite that condensed concoction we have been talking about. Bang, ignition, an explosion happens and this is really where the horsepower happens. Why? Well at this point the cylinder is pushed down at X amount of force. That X amount of force is dependant on a lot of factors, which when you get right down to it is where horsepower is made. How? Because that little explosion pushes the cylinder down, in turn will push one of your other cylinders up and then that little explosion happens again. It’s a tough vicious cycle, rotating continuously, producing what is better known as horsepower. Let’s move on. So we have sucked, squeezed, banged and now we need to blow (you’re a pervert). The exhaust valve opens up and lets out the carbon dioxide that are left over after our little explosion inside the combustion chamber. Now this little cycle, which happens in milliseconds, is reproduced thousands of times a minute. You know your tachometer, RPM (revolutions per minutes), that is about how many times this cycle of combustion happens in one minute. There you go this is the very basics of how an engine produces power. If this is still a little confusing to you, well try to envision it as much as possible. Now on the next article we will talk about how we can improve this combustion cycle to produce the best possible combustion which in turn produces more horsepower from your engine. Check out: How Can an Engine Produce More Horsepower? Part II The Intake

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Hotels: How to Get Free Gifts

Planning to visit Las Vegas or any other vacational resort where casinos are a major portion of their business? I have just the thing for you. Here, I will show you how to pass off as a High Roller and collect many complimentary items and gifts. What is the Secret? The Secret is that you have to make them believe you are rich and love gambling. In short you have to impersonate a High Roller. Why? Hotels love high rollers because these players leave behind thousands of dollars each visit. And the real cool part about this is that if you act the role, casinos will lavish you with the same gifts and complimentary items that a real High Roller would receive. How ? It is not that difficult to fool the hotel and resorts with some finesse and true self-confidence. It can be done. 1) The Way you Dress: Elegant and smart is the way to go. Opt out of the baseball cap, t-shirt and jeans. Try and wear a suit or at least a regular buttoned shirt with an elegant dark jacket. It was Shakespeare who said that the clothes maketh a man, and so too, when going to a hotel resort. They judge you according to how you dress, so dress according to the role. 2) A Large Pad of Notes: Yes. Just like in the movies. Carry a large bundle of notes with you and keep them in plain sight. You do not have to really take with you that much. Instead, take a few notes and place them at the top and at the bottom of real note-size paper cuttings. Just remember to never expose this while you are in the casino. Use other notes you’re your wallet instead. But do it nonchalantly so that none of the casino personnel will notice. 3) Always Flash Your Notes Around: No matter where you go, whether its to the hotel restaurant for lunch or for to the bar. They will be watching. From time to time, use that money to play at a range of table games or video game and bet some of that money. Remember you must use some of your money to play but just do not use all of it. 4) Play Complicated Games: This is one of the more problematic things to do and requires some training at home. Learn on your own how to lay and how to bet on the high rolling games such as roulette, baccarat and craps. You could also play poker or Texas holdem in one of the larger ante tables, but in any case stick to your plan and you will soon reap the flowers. Conclusion: Above, I have outlined some of the more practical methods by which one can save money by receiving gifts from the casino. These gifts range from casino comps (free money to play), room deals that can get nearly free and many others such as free drinks, clothes, coupon to stores in Las Vegas and many more. Note that what you are doing here is completely legal provided you don't take up a false name or falsify your passport card.

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Hot Weather Affects the London Tube

The soaring temperatures on the London Tube over the summer months have been a problem for some years now. A London Underground team has attempted to come up with some engineering solutions to the problem by creating a groundwater cooling system. The trial, which starts this summer, aims to make it cooler for passengers on platforms and will be tested at Victoria station which is so deep that it is effectively under water and pumps out 35 litres (eight gallons) a second, to stop it coming through the walls. The idea of the new system is to push the water through a network of pipes into heat exchange units on the platforms, which will suck in warm air and pump out cooler air. The heat could be used to power homes and offices above and this way the temperature will be brought down. But this is only a trial to be tested this year and it is far from being put into work as well as new trains with air cooling systems that are promised for Circle, District, Hammersmith and City and Metropolitan lines. Meanwhile the temperatures in the deepest tunnels, reach 30C (86F) in summer. These changes might affect the London Tube in a drastic way. Some of the Tube lines might be closed especially on the hot summer days. London Underground assures that there are no plans to close any Tube Lines during the summer but in the future years it might get to the point "where the underground will become literally intolerable and you could face the prospect of loss of life" as Mr Livingstone from LU advised. About 1,000 London Tube passengers were trapped for nearly two hours when three trains were held up in a tunnel. The Central Line closed after signal failures stopped the trains between Marble Arch and Lancaster Gate. The trains have been evacuated and three people were treated for the effects of heat.

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