# Tag Info

33

It appears to be a Rolls Royce Viper turbo jet engine made in 1966. The maker's mark (BSB) derives from Bristol Siddeley, formed from Armstrong Siddeley (the company that originally developed the engine) and Bristol Aero-engines. Bristol Siddeley were later taken over by Rolls Royce. Source: Wikipedia

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Turbojets and turbofans are very similar indeed: both are turbine engines; both create thrust from jet exhaust; and both have a rotating implement in front that can be called a fan. Although in the case of the turbojet, it isn't called a fan but the compressor first stage. $\$ Junkers Jumo 109-004 So what is the difference? There are five types of ...

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In a turbojet, all the air goes through the engine proper, through the combustion chamber and all the stages of compressor and post-combustion turbine blades. In a turbofan, some of the air is just pushed by a fan around the rest of the engine. This is the "bypass". As Harper points out, it's not fundamentally different from a turboprop or extracting ...

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"Glide performance" is measured by "Lift-to-drag ratio": In aerodynamics, the lift-to-drag ratio (or L/D ratio) is the amount of lift generated by a wing or vehicle, divided by the aerodynamic drag it creates by moving through air When you look for examples you'll see that for the most part larger airliners do indeed have a more ...

15

Completely different design philosophies They are both turbine engines, and that is where the similarity ends. In a turbojet, the compressor-burner-turbine package is optimized to make thrust. A turbofan engine is a type of turboshaft engine. These use a compressor-burner-turbine core, but use a secondary set of turbine blades to convert its thrust ...

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A few reasons: if we're talking glide range from altitude, then jets certainly can glide longer! They fly MUCH higher than most props do, even turboprops! Second, propellers are draggy when they're at idle- you effectively have a big speedbrake on the nose of your plane. This is the reason a lot of planes have featherable props- they can be turned into the ...

3

After reading all the answers I felt that none of them really explained the answer in a way understandable to a layperson, so I will attempt to do so. First of all, both types of engines will burn fuel to generate energy, which is ultimately used to accelerate a stream of air towards the rear of the aircraft to create thrust. They differ in the method by ...

3

A burning turbine consists of compressor stage, burning stage and gas turbine stage. Both compressor and turbine stages consist of sets of stator and rotor blades and the rotors are connected via shaft so part of the work the turbine generates can be used to compress the intake air. The output from the turbine stage is a high-velocity jet of hot air-fuel-...

3

Assuming that the net thrust of a turbojet is constant is not correct. It is assumed to be constant (for simplicity by the aircraft performance engineers and usually valid for low subsonic speeds), but in reality, the performance is not constant, and it also varies with altitude. This is best shown by a simple simulation of a turbojet engine. The following ...

3

Question 1: Can the LOC-D be flown with the tower closed at all? (The Alternate Minimums clearly state Circling is NA with the tower closed and LOC-D is a circling only approach. But aircraft are commonly cleared LOC-D approach with tower closed...) Ans: The restriction eliminating the option of flying the LOC-D with the tower closed only applies when ...

3

Thrust is created by accelerating a working mass in opposite direction. Net thrust is the difference between the impulse of the air flowing towards the engine and the combined impulse of burnt fuel and the air exiting the engine (and propeller, if one is fitted), derived by time. That impulse is the product of mass and speed. When flying faster, the entry ...

3

There's absolutely no difference as such between the two. If you removed the engines from both, there's no inherent difference. Note that, naturally, modern airliners (which are all jet) are incredibly better and more sophisticated than old-fashioned historic prop aircraft in every way. So, totally unrelated to the engines, of course they have incredibly ...

2

To talk about maximizing glide ratio is the same as talking of maximizing Lift/Drag (derivation can be given, "exercise for the reader"). Since lift is a given when gliding (we don't typically lose weight when engines are inoperative - and we consider a steady symmetric flight). To maximize L/D we minimize the drag. For a car, or other land based ...

2

Jet-propelled planes are often aerodynamically 'cleaner' than propeller planes. Hence, drag is smaller and L/D is higher. So they glide much better...

2

Power consumption=Kinetic energy=$1/2mv^2$. Thrust=momentum change=$mv$. This is only true if the engine is perfectly efficient internally and the air is still relative to the aircraft. If the air is moving relative to the aircraft (and the engine is still perfectly efficient internally) then. Power consumption=Kinetic energy=\$\frac{1}{2}mv_e^2 - \frac{...

2

It is simply the rate at which fuel can be burned. For instance, the Saturn V's first stage carried 1.37 million kg of liquid oxygen (along with the kerosene fuel), which it burned in about 165 seconds. Imagine the size of the jet intake you'd need for a comparable amount of air.

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You need to obtain the specific fuel consumption (SFC) for the particular dash number of PT6 (scroll down to the bottom for the chart with the data). For example, the -67A turboshaft is down around .47 lb/hp/hr, close to piston engine territory, but most are between .5 and .6 lb/hp/hr. So pick the dash number of engine applicable to the airplane you want to ...

1

First, thrust = ma = mv/s Next, what type of engine are you referring to? Throw out the first graph, it's all about propulsive efficiency vs speed (props, fans, etc.), not about engine efficiency. Considering exhaust only, the engine has to work to push out the exhaust. This is why rockets have more thrust in space. Also known as "backpressure". ...

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There are several effects which in combination make constant thrust a good approximation at subsonic speed. Thrust is created by accelerating a working mass in opposite direction. Net thrust is the difference between the impulse of the air flowing towards the engine and the combined impulse of burnt fuel and the air exiting the engine (and propeller, if one ...

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This cannot be answered specifically, the stoichiometric fuel/air ratio (FAR) is based on burning all oxygen, while for cooling purposes the airflow is generally much higher; therefore the FAR will be lower than the stoichiometric FAR. Note that you do not want to burn fuel at stoichiometric conditions as this produces the most nitrogen oxides. Fuel is being ...

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It is because in a turboprop, almost all of the energy extracted by the engine turbines is used to run a propeller. So, it is all about how much power that is required to turn the propeller. To measure the amount of force required to rotate the propeller, we use a sensor to measure the amount of twisting force acting on the propeller shaft. This sensor is ...

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