Questions tagged [aircraft]

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

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17 views

How to calculate the electric field strength in between asymmetrical capacitors?

For a school project I am trying to calculate the thrust to power ratio of the electroaerodynamic drive aircraft invented by MIT. See this article on the MIT News web site for details. I need to know ...
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4answers
163 views

Can we make a drone fly on the Moon by using cylinders with compressed air (or cold helium)?

Suppose we want to make a drone fly on the Moon (the gravity on the Moon is 1/6 of that on Earth), only by making use of its rotors and air. The drone is as light as possible ($m_{min}(kg)$, has ...
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1answer
37 views

Wind tunnel experiment that measures lift (not the lift coefficient)?

Does anyone know of a wind tunnel experiment on a wing or airplane that measures the absolute amount of lift (not the lift coefficient); and demonstrates conclusively that the lift generate by a wing ...
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2answers
45 views

Can an airship tack? [closed]

A sail ship leverages the keel’s resistance to turning moments to allow a wind crossing a sail at an angle to tack, achieving a speed greater than the driving wind. But is it possible at all for an ...
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What causes the Coandă effect? [duplicate]

What causes the Coandă effect? Here's my understanding of it: When a fluid flows around a curved surface it has high velocity and so low pressure its pressure will be lower than the atmospheric ...
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1answer
75 views

Effects of altitude on paper airplanes

If one were to fly a paper airplane at the Dead Sea (400 meters below sea level) and another identical paper airplane at the peak of Mount Everest (8800 meters above sea level) would there be any ...
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2answers
58 views

Why do airplane wings have fins?

I was watching this video and it shows that adding fins on the wing helps the air get turbulent on the upper part of the wing, which forces the air to stay longer, and ultimately this helps with lift. ...
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Heat dissipation in space - how do they do that?

Consider a space aircraft. During its propulsion, I believe a lot of heat is transmitted to the aircraft by simple contact with the motor. But in space, there is no air to cool the aircraft. The only ...
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1answer
98 views

Why are turbines more effective than propellers on airplanes? [closed]

I have read this question: Why do turbine engines work? The compressor generates a certain volume of air at a high pressure. In the combustion chamber, this air is heated - this leads to a much ...
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4answers
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Why are aerodynamic / streamlined shapes always stumpy at the front?

I'm building an autonomous boat, to which I now add a keel below it with a weight at the bottom. I was wondering about the shape that weight should get. Most of the time aerodynamic shapes take some ...
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Calculating (transient) rate of cycles of practical thermodynamic engines (turbojet, multi-cylinder car engines etc..)

I tried to make a plan for a turbojet engine with my physics knowledge and I'm stumped in the first step. For any sustained real engine, I need to somehow take a fraction of the energy output and use ...
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1answer
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Induced emf over the cuboidal wing of an air plane due to Earth's magnetic field

If the wing of an air plane is cuboidal in shape, and that the Earth's magnetic field $\bf{B}$ is uniform in the neighbouring volume of the plane, does that mean the induced emf over the entire 'block'...
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Model (or approximate model) of drone take-off forces?

I would like to implement a model of the force/uplift the floor makes in a multicopter take-off, but I don't find any info of this exact dynamic. Is there any paper that tackles this issue? Or any ...
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1answer
38 views

Why is pressure over the wing lesser than the pressure on the bottom? [duplicate]

Why is the flow above the wing faster than the lower one? Most people say it's because the pressure above is lesser than the bottom one But for the pressure to be low... The velocity must be high.So ...
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How are coefficients of equation of sideslip angle in the paper “A general Solution to the Aircraft Trim Problem” calculated?

I am sure many of you guys(Aerospace related) must have read the paper, "A General solution to the Aircraft Trim Problem" by Marco, Duke and Bernt. I am working with the turning of the Aircraft and I ...
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2answers
39 views

How does pressure become velocity in a jet engine axial turbine?

All right. Here's what I understand about axial turbines: It is an axial compressor in reverse. An axial compressor forces air to flow in an increasingly tight space, where there is not enough ...
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2answers
41 views

How can a fighter jet pilot pour water from a bottle to a cup without spilling while doing barrel rolls?

I came to watch two videos related to fighter jets, one in which the pilot pours red bull in a glass and another in which pilot pours water from a bottle to cup while doing rolls and while being ...
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2answers
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How much at least should the Earth be smaller so that we notice these three phenomenons?

The Earth is moving with a speed of about $1670$ $km/h$ around its axis. This speed is more than the sound speed. So the Earth is always breaking the speed of the sound. How much at least should the ...
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1answer
112 views

Why can a helicopter fly upside down?

I saw images and video clips of helicopter flying upside down, so it can't be bernoulli principle or angle of attack of the rotary blades. So how can the upside down helicopter provide lift in this ...
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49 views

Drag and lift as a function of speed

Assuming turbulent flow, the drag force $F_\mathrm d$ and the lift force $F_\mathrm l$ are usually given in terms of the following equations $$ F_d\, =\, \tfrac12\, \rho\, u^2\, c_d\, A $$ $$ F_l\, =\...
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2answers
109 views

Reason for lower air pressure above an airplane wing

I am posing this question from the perspective of a novice. I read an article, from Scientific American, titled "No One Can Explain Why Planes Stay in the Air". The article explains how, while we ...
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1answer
31 views

Fluid Dynamics (Air) Specifically Aeronautics

An airplane lifts off when the pressure of air pushing down on the wing is reduced due to the speed of the vehicle. Would it be possible to construct an airplane so heavy that it would be totally ...
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Problem involving the 4 forces that maintain an airplane in level flight

The 4 forces affecting an airplane in level flight are gravity, lift, thrust, and drag. By altering one, the others are affected. My question is could a wing (retractable) be installed on top of a ...
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2answers
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How can Lift = Weight; if airliners fly with Thrust-to-Weight ratios = 0.3? [closed]

Question: I'd appreciate it a lot if anyone could explain how lift can equal the weight of an airplane in flight (Lift = Weight), if these airplanes have thrust-to-weight ratios of 0.3 (e.g. Boeing ...
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1answer
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Lift => Mass, for a helicopter in a hover; not Lift = Weight? [closed]

Background: According to Newtonian mechanics, a helicopter in a stable hover accelerates ('a') a mass of air ('m') downwards to generate a downward force; according to Newtons 2nd law (Force = ma). ...
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1answer
67 views

An interesting query about gravitation [duplicate]

If a helicopter flies linearly in the upward direction from a point A on the earth stays in the air at the same position for a long time and then linearly comes down , will it land at the same point A ...
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3answers
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If the aircraft has no inertia, how will it move after losing power?

If the aircraft has no inertia, how will it move after losing power? I think because of the aerodynamic force, the aircraft stopped moving immediately. Am I right?
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7answers
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Is the weight of the aircraft flying in the sky transferred to the ground?

Is the weight of the aircraft flying in the sky transferred to the ground? Is the weight of people swimming in the pool also transferred to the ground? How can we prove it?
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speeding up airflow over wings while keeping the propulsive efficiency?

So, let's say we have an aerofoil and we were to apply thrust at where the air speed was the greatest. See figure: Since we apply a thrust to the air it will speed up, thus reducing the pressure even ...
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2answers
524 views

Is a square tube more resistant to bending than a round tube?

In considering tubular forms for aircraft construction, I am reasoning that a square form (or I-beam) would be more resistant to bending (if the load is directly perpendicular and in the plane of the ...
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1answer
141 views

Conservation of angular momentum on a drone

As I understand, a drone turns horizontally using conservation of angular momentum, accelerating rotors going to one side and deaccelerating the others. All the books I have seen about this say the ...
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3answers
246 views

What's 'force per second'?

For example, if a force of 10 N per second (10 N/s) is applied to an object, does this have a name or a definition? I'm not referring to impulse - which is Ns. An airplane's engine thrust is simply ...
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4answers
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Why don’t people on an airplane experience “weightlessness”?

People in the ISS feel weightless because they are in perfect orbit around the Earth, and only gravity is pulling on them. By that logic, why aren’t people in airplanes weightless? A plane stays at a ...
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Why can't we fly aeroplane or shuttle directly into the space (beyond 100 km height above Earth's surface)? [duplicate]

Without rockets can we go beyond Karmans line by shuttle or plane?
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4answers
153 views

Why doesn't my flight aerodynamics maths work? [closed]

Context: For some context, I'm a game developer and I'm building a flight sim game. My goal is to have realistic flight physics -- not arcade physics. I'm having issues with the maths -- it is not ...
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2answers
60 views

Nuclear-powered Ramjet + criticality

I came across this Wikipedia entry about Project Pluto; a nuclear-powered ramjet that the U.S. was developing back in the day. https://en.wikipedia.org/wiki/Project_Pluto This missile would have ...
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1answer
173 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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2answers
148 views

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
497 views

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
56 views

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
134 views

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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4answers
330 views

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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1answer
50 views

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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2answers
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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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1answer
50 views

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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0answers
74 views

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
63 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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