Questions tagged [aircraft]

Aircraft are man-made vehicles intended to operate while flying through Earth's atmosphere.

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58 views

How much kinetic energy does a helicopter use in a hover? [duplicate]

A helicopter just circulates air in a hover and maintains a stable altitude. So, how much energy is used to do this? Using the standard equation $KE = \frac12 mv^2$; then the kinetic energy used would ...
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Center of lift in an aircraft

what is center of lift in an aircraft? How is it different from aerodynamic center and center of pressure? Why is COL important?
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Is the physics behind planetary travel simpler than atmospheric travel?

I've been watching a bunch of documentaries lately and had a question that I couldn't really figure out the answer to online. When spacecraft travel through space, are the equations and physics used ...
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2answers
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Calculate work done by a hovering helicopter over time

This is likely to be very simple, but... How does one calculate work done by a hovering unmoving aircraft over time? As in work in Joules. In this scenario, to remain hovering the aircraft has to ...
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Why do jet engines sound louder on the ground than inside the aircraft?

Everyone is familiar with the whirring sound of jet engines when seeing an aircraft taking off from a nearby airport. It is distinctly very loud on the ground and one can hear it even when the ...
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1answer
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Drawbacks of a Tip jet helicopter [closed]

A Tip Jet helicopter offers some advantages, i.e. eliminates transmission, torque is lower, etc. Engineers experimented with this design in 1950s, but remains marginal at best. What are the ...
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1answer
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Why is it a sonic “boom” and not a sonic “boooooooooooooooo…m”?

As I understand it, when an object pushes past the sound barrier, a sonic boom doesn't happen just once, but rather, continually (correct me if I'm wrong). So why is it that there seems to be only a ...
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The physics of airplane flight [closed]

Physics in schools teaches two contradictory and mutually exclusive things: (1) That the upward lift force on an airplane in flight equal its weight (Lift = Weight = mass x gravity). This is based on ...
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Why an aircraft or a ship produce pressure waves both in front and behind them?

I think it is obvious why a pressure wave is produced in front of a moving object but why the rear of it should produce a wave?
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Is plane altitude limited by engine power and if so does air density cause this?

I notice that, for example, human-powered flight operates at low altitudes. This might of course be due to safety but I wonder if in fact the delta in air pressure is greater at lower altitudes and ...
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Why do planes use 1-2 propellers in the front, but drones have 4 on top? [closed]

Planes with propellers normally have one or two propellers in front, facing forward, helicopters have one on top facing up and one facing the side, and drones have four on top facing up. How do the ...
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Do planes have to be noisy?

I tend to think of noise as an undesirable waste of energy because the generator was not designed for that purpose. But that doesnt mean this waste can be avoided. So I wonder how much of this noise ...
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Is there a physical limit to silent quadcopters, and what are the parameters?

Quadcopters can now navigate fairly well indoors. One could imagine many possible uses, including telepresence and security, but which are limited because of the loud noise. Assuming zero 'motor ...
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Thrust needed from an engine to reach orbit

Assume you had an airplane with magical engines that didn't need fuel, air or power, to operate. What thrust to ground weight ratio would the airplane need to reach orbit? By ground weight I mean mass ...
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1answer
39 views

Derivation of the expression of a propeller pitch distance

The pitch distance of a propeller is given by: $$p = 2\pi r \tan{\beta}$$ where $\beta$ is the pitch angle and $r$ is the radius. I cannot find how this expression was derived. Could you please ...
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Lighting an Electric Bulb with Earth's Magnetic Field

Yesterday, I was solving some problems of Electromagnetic Induction. Suddenly a thought struck my mind. Earth has its own magnetic Field.If an aircraft of metallic body is flying in the air then ...
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1answer
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Why wasn't the Stipa-Caproni plane efficient in its flight?

The Stipa-Caproni was an experimental italian plane design. Though it has a very peculiar shape, it seems at first glance like it would have pretty good aerodynamic profile since its reference area ...
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2answers
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Horizontal component of Coriolis force in an aircraft: compensating force with its wings angle

I have the following problem: "An aircraft is flying at 800 km/h in latitude 55◦ N. Find the angle through which it must tilt its wings to compensate for the horizontal component of the Coriolis ...
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Inverted flight [duplicate]

I've read the answers provided but I'm still confused that if an aerofoil is designed so that air flows faster over the upper surface for the purpose of providing lower pressure and hence lift why in ...
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Is lift force proportional to size?

I'm trying to calculate lift force of a particular object I'm working with. However, I can't find much information on how much force is required for an object to stay in flight though. My questions ...
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1answer
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Principle of Lifting of an Aircraft [duplicate]

While using the Bernoulli's equation to deduce the upthrust on an aircraft , a statement is always made that The air particles going above th wing have to cover a greater distance in same time than ...
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Why dont we account the rotation of the earth in aircrafts? Is it just because of the air or is there more to it? [duplicate]

Today there was a seminar regarding modern air crafts held in my school. At the starting of the lecture, we were asked a question which I found quite intriguing. "Why does a helicopter or a fixed ...
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1answer
43 views

Motion of a contrail “vortex”

I want to understand what causes this motion on contrails (Cirricular motion) and it’s name if possible. What effects it? How and why is it formed?
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Rate of change of heading in terms of normal acceleration and air speed

Let's say an aircraft is traveling with speed $|\mathbf v|$ with respect to an inertial frame. The aircraft is able to execute turns by producing an acceleration $\mathbf a$ that is normal to $\mathbf ...
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Strange optical distortion in a video recorded from an airplane window

I recorded this video from an airplane window while it was decreasing its elevation. What is the explanation for this optical distortion? This distortion appeared only in a certain range of elevation. ...
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1answer
166 views

How do you explain the formation of shockwave on the wing surface during near sonic flight?

Explanations of shockwave for the common folks (youtube videos, googling) all tend to focus on successive sound waves generated by the air craft traveling outward in circles (sphere). That to me, ...
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Defining the change in direction due to wind

My question: Which force vector (A, B, C, or D) represents the APPROXIMATE direction in which the boat is travelling as a consequence of the wind? My approach: I looked for which vector combination ...
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Effect of Bodyform on Air Resistance [duplicate]

Visualize those little pictures as the front of vehicles like airplanes and trains. I wonder if I am right about my speculation below, and if so, if somebody could explain the exact reason. Sources ...
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How does gravity effect to aircraft in sky?

Aside aerodynamics and buoyancy, Is there a simple way to explain how gravity is negligible in flight paths using free falling body diagram? In a parabolic trajectory,we know that at max height, ...
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Why is the polar diagram of an airplane depended on weight?

Can anybody answer this question? Although aviation-related, it is in fact a fluid mechanics problem: https://aviation.stackexchange.com/questions/54192/why-is-polar-curve-of-a-glider-dependent-on-...
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169 views

Sonic Boom in Aircraft and Spacecraft

I would like to know why aircraft, and spacecraft produce a double sonic boom on breaking the sound barrier. A while ago, I thought I got it, as there’s a start and finish point to every vehicle. ...
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what would a “ceiling effect” (the converse of ground effect planes experience) entail?

Wikipedia describes ground effect as "the increased lift (force) and decreased aerodynamic drag that an aircraft's wings generate when they are close to a fixed surface." That's all fair and good, ...
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Effect of tailwind on aircraft speed

I have been spending some time in analyzing the impact of tailwind on the ground speed of the aircraft. My analysis is based around the following equation : VAW = VAG - VWG ; where VAW is the velocity ...
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What causes the air speed difference above and below the wing of a plane?

I am studying about the lift generated by a fluid flowing on a surface. In the case of an airfoil I have seen that there are various ways to explain it, you can use for example: the third law of ...
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When plane crashes

Could it be true that when the plane is falling to crash, one should start to jump. If the moment the plane crashes, you are in the air then, you are not affected by the momentum. That is very ...
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How powerful can the vacuum from an open aircraft window be?

It has been an item of folklore that a "pressurized" aircraft cabin, if punctured will force people through the aperture, a la Goldfinger. However, obviously the pressures inside the cabin (12 PSI) ...
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Lightning strike on aircraft

Is an electromagnetic pulse sufficient to account for the complete dscharge of an aircraft struck by lightning?
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How would I calculate the speed passengers 'jump' based on the speed and displacement of a plane during turbulence?

I read recently that if I'm in a plane that hits turbulence, the plane might only move 1 to 20ft. However, due to the speed that plane is travelling at (say cruising at 550mph). The passengers in the ...
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1answer
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What does it mean that the weight is negative?

In a recent question on the Aviation Stack Exchange, one explained that would cause an autogyro's crash. Basically, it says that the one thing that would make the gyro crash is to unload the motor too ...
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Airplane trails

Some airplanes leave a trail through some regions of sky. This post explains why it is so, but it seems not enough. The trail is said to be made mostly of water which, on a specific altitude, ...
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Flying with or against rotation of a planet

So, I've read a bunch of articles about how, somewhat contrary to intuition, it's usually faster to fly with the rotation of the earth versus against it. All the answers have to do with wind and ...
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Would a plane get lighter if dry ice is inside and it sublimes during the flight?

During a series of comments here, it was suggested that taking dry ice into an airplane, the airplane gets lighter as the ice sublimes. This was supported by the idea that when the dry-ice sublimes ...
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Flow over Airplane Wings

I recently read this from Wikipedia in an article discussing lift. A fluid flowing over the surface of a body exerts a force on it. It makes no difference whether the fluid is flowing past a ...
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Can you “rewind” sound messages by going supersonic? [duplicate]

I was having a discussion with a friend about supersonic flights. It was then when he proposed an idea on an interesting experiment that can be done during a supersonic flight. The experiment goes ...
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I'm confused about the aerodynamics of a gas turbine compressor blade of a jet engine?

I have a few questions here- Why do you need an increase in static pressure, why not total pressure? The rotor vane increase total energy, is this energy converted into kinetic energy or total ...
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Could you build a “space tunnel system”? [closed]

With the limitation of fuel that can be taken on a space craft, would it make sense to build a propulsion system in space instead? For example via rings that are aligned very well and are positioned ...
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Cold airplane window frame

I was flying from Asia to Europe and noticed that the bottom of the window frame was ice cold while the top was warm. Why? My theory: The sunlight warming the air between the "inner window" and the "...
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Is Gyroscopic precession relative to the object in precessions axis of movement when there is drag imposed on the disc?

Does my question make sense? I am referring to the disc of an AutoGyro aircraft. Though the fuselage of a modern pusher AutoGyro will weather vane into the wind, the disc that provides lift does not. ...
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Why does a car need so much power to get to a given speed compared to an aircraft?

This question has been bothering me for a long time because it seems like it should be obvious, but I can't figure it out. Excuse me if I'm being dumb. Why does a car require so much more power then ...
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If Earth is curve and spinning, why plane flying in high altitude does not delayed?

If earth is spinning globe then the layer of athmosphere have a different tangential velocity for different altitude. For near the ground (solid surface of the earth) then the velocity of the air just ...