# Questions tagged [aircraft]

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

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1 vote
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### Mechanics of the "airplane" thrown at angle to the horizon

Good day! I am interested in the solution of the following problem, could you please help me. Suppose that we have some solid airplane. We throw this airplane at some angle $\theta$ to the horizon ...
75 views

### Why is there sound aboard Concorde after it goes supersonic?

I recently saw a video from a passenger of Concorde after it goes supersonic. Inside the aircraft, there is still a loud roar similar to what we hear in aircraft today. However, since the aircraft is ...
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### Why doesn't a Hang-glider Stop Moving Forward, Stall and Fall?

Why doesn't a hang-glider stop moving forward (because of air resistance), stall and fall?
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### What's the reason an airplane turning 180° from strong headwinds causing it to have no ground speed does not stall?

I saw a video of a small propeller plane hovering over the ground due to strong headwinds but then turns 180 degrees and flys away. I was trying to figure out if the plane shouldn't be stalling ...
24 views

### If a spacesuit cracks open, does the astronaut blow up due to difference of pressure? [duplicate]

Me and my friends had a discussion on emergencies in outer space. One questioned what would happen if a spacesuit ruptured and exposed an astronaut to vaccuum. One claimed that since there is no ...
1 vote
33 views

### Airflow on wing, simple force analysis

(Look at the picture) Let's assume there is an horizontal plane impacted by diagonal airflow with components from coming downwards and ahead. If we say that the airflow is fully deviated by the ...
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### What is responsible for an airplane's sound?

Airplanes traveling at supersonic speeds produce sonic booms because the pressure waves they create converge to produce an extra high intensity wave. But what about planes traveling at slower speeds? ...
42 views

### Rocket flying around earth at constant speed and constant altitude

I am trying to make a rocket move around the earth at constant speed and constant altitude on a WGS84 earth within a python simulation (right now the output is a pandas dataframe). I start with the ...
1 vote
21 views

### Buoyant Air Kinetic Energy in a Lagrangian Approach to Derive Airship Equation of Motion

I am currently working on deriving airship equations of motion, in a fluid in motion (unsteady and non-uniform wind). The article cited in most sources is Equations of Motion of a Vehicle in a Moving ...
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1 vote
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### In an aeroplane's jet engine, where is the forward force applied to the mass of the plane?

In a standard jet engine on a standard aeroplane, is the majority of forward force received by the aeroplane (which causes it to be propelled forwards) applied on the compressor blades, the rotor ...
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### Goniometer stages/positioners stacking

I am working on a project related to calculation of roll/pitch/yaw misalignment. I am new to the field and trying to understand. I more or less understand math behind this - order of rotations is very ...
37 views

### The relationship of yaw and roll on a spacecraft using Trust Vector Control

I’ve previously asked the question how does applying rudder (yaw) on aircraft also cause roll. Turns out it’s caused by both the rudder usually being above or below the center of mass and the ...
1 vote
94 views

### How does the newton's third law generate enough lift to make the airplanes fly? [closed]

How does the newton's 3rd law generate enough reaction so as to make the airplanes fly to great heights? The airplanes push air downwards but really is that enough to make the airplanes fly to great ...
3k views

### Is it possible to statically generate lift with the difference in pressure like wings?

If I understood it correctly, the shape of the wings and/or propellers generates lift/thrust with the difference in pressure in both sides of the wings/propellers; where the lower side has higher ...
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1 vote
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### PI controller - output calculation [closed]

The propeller of an airship is connected to a DC motor. The motor is being controlled using a PI controller. The PI controller has a proportional gain of Kp = 2, and an integral gain of Ki = 0.5, and ...
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### Why are the blades of a pedestal fan so different from the blades on an aircraft propeller?

Both fans and propellers move a quantity of air. In the former, that is the end goal. In the latter, this movement of air creates a force in the direction opposite to the airflow. So, why are the ...
249 views

### Would Aeroplanes or Helicopters work on our Moon?

Would Aeroplanes or Helicopters work on our Moon? In general , I think , in Aeroplane Case: (1) Air is required for Aeroplanes to float : Would Moon have enough air? (2) High speed is required for ...
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### Any skilled pilots? Explain how a craft flies over the curve of the earth [closed]

So, flat earthers believe that there are no adjustments, whether in manual or autopilot, to maintain level flight over curved surface such as earth. But, altitude is determined by barometric pressure (...
138 views

### Windspeed and Aeroplanes

Say we had an airplane cruising at velocity $V$ and the airplane was going from point $A$ to $B$. If the wind was also blowing in the same direction from $A$ to $B$, at a velocity $U$, could we say ...
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### Why are the vectors for the pressure above the airfoil bigger when pressure is actually lower?

This image displays "Pressure vectors and flow over cambered section". As far as I understood fluid dynamics, the static pressure is lower in areas where the fluid flows at a higher speed. ...
• 11
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### Energy balance in fixed wing flight, action/reaction

When an airplane is in flight the engine of the plane overcomes drag until the plane is moving forward fast enough to balance drag. In a stable configuration the air moving over the wings creates lift ...
53 views

### The suction and thrust of an aircraft engine

Does only the air sucked in (not the air that is ejected at the back of the engine) by an airliner engine (turbofan engine) causes a thrust forward or in other words pull the engine forward? and why ? ...
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### What is the useful limit for ground effect on an object? [closed]

What the maximum size an object can benefit from ground effect? Also known as riding a cushion of air created from flying close to the ground, some birds can use this effect to fly with less energy ...
29 views

### Sonic boom mitigation by leading low pressure via intake?

As a thought experiment to try to illustrate my question below: If a fan was moving forward at the speed of sound but was rotating such that the low pressure created by the fan's rotation was equal to ...
1 vote
56 views

### Aircraft turn displacement from non-linear turn rate (instantaneous roll rate)

I've been trying to figure out an aircraft kinematics problem to estimate the x and y offset relative to current position after completing a turn. The turn is a specific change in heading, finishing ...
1 vote
1k views

### Convert BLDC motor thrust in grams ($\rm g$) to Newton ($\rm N$)

I am making a quadcopter with takeoff weight equal to 2 Kg. Using thrust to weight ratio of 3:1 the required thrust per motor is 1500g. (No experimental thrust has been obtained for thrust.) Now I am ...
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### Battery efficiency [closed]

I have 4000 mah 4 cell and a 5000 mah 3 cell Which battery is more efficient. Higher mah or more number of cell. I am selecting batteries for rc plane
30 views

### Calculating kwh required to get an aircraft to 1000' based on climb rate

I'll start with the question and then provide context: to get an aircraft to 1000', does a steeper climb angle consume more energy? Assume the flying speed and angle of attack stay constant. This ...
1k views

### Origin of the thrust force in jet engine

I am reading a lot about the jet engine operation and I meet mostly explenation that the thrust is generated thanks to the exhaust nozzle that "accelerates" the air. However the nozzle ...
1 vote
182 views

### Which direction will a truncated cone be pushed by airflow?

Consider the shape below, with the bottom and top faces being holes. Imagine we hold the shape in place and blow a wind into the big hole. The air will exit the small end at a higher velocity due to ...
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### Does general relativity predict different forces on aircraft than Newtonian mechanics?

When taught how airplanes fly, we are probably always given the Newtonian mechanism: that four forces act on an airplane; lift and weight on the vertical axis, and thrust and drag on the horizontal ...
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### Relative efficiency of airplanes and helicopters, why is this argument wrong?

I'm trying to better understand why helicopters are less fuel efficient per unit distance than airplanes. One argument I keep seeing in other questions on the topic is that helicopters actively ...
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### How are shockwaves created if no particle goes around the wings at supersonic speed?

so,the title could be a bit misleading, let me elaborate: whenever studying aerodynamics, the explanation starts with considering the wing of a plane still, and the flow of air arriving from either ...
239 views

### Is the downforce of rain on airplanes negligible?

Is the downward pressure exerted by raindrops in even a strong storm on a lightweight aircraft negligible? Someone better informed may likely improve the following reasoning, cobbled together from ...
1 vote
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### Finding windspeed gave me negative time value

This is a homework question, I will make it as concise as possible: A 1-way plane trip is 2800km and the plane's airspeed is 790km/h. The plane flies with the wind on the way there, and against it on ...
1 vote
87 views

### Newtonian mechanics vs. Pressure in Flight [duplicate]

Which one is better to describe lift of a plane wing: Newton's third law of motion: (The wing applies a force on air and the air applies an equal and opposite force on wing - which causes lift.) OR ...
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### Why is an airfoil shaped like a teardrop?

I understand the reason airfoils are cambered on the top: to create lift. But one would assume this would result in aircraft wings having a semicircle-shaped design. Why is the cross-section of an ...
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### The lift of an airplane is similar to that of a balloon. It uses the density difference of air, right?

The lift of an airplane is similar to that of a balloon. It uses the density difference of air, right? The air density on the top surface of the balloon is low and the air pressure is small. The air ...
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### Impact of the location of the aircraft propeller on yawing moment

we know that the effect of P-factor on puller propellers is the yawing moment in the opposite direcrion. i mean if we had a load(thrust or lift) on the right side of propeller , then airplane will yaw ...
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### How can we calculate $g$ force in this maneuver?

How can we calculate $g$ force in this maneuver? We are not dealing with conventional maneuvers like level turn or loop so what equation used to calculate g force in this maneuver? What about other ...
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1 vote
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### Would helium-3 be a better lifting gas than normal helium?

Buoyant force is proportional to the mass of the fluid displaced minus the mass of the volume doing the displacing. Thus the best choices of lifting gas are nothing(vacuum), hydrogen, and then helium ...
1 vote
18 views

### Subsonic flight in saturated steam vs. air

I am wondering whether differences in density, temperature, viscosity, drag coefficient, or lift coefficient between steam and air might affect subsonic flight through these media. Let's assume ...
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### How much energy does a bird use gliding, vs how much energy is there to capture in the moving air?

So I have this image in my head of a robotic pigeon with a wind turbine strapped to it. For the purpose of this mental image, imagine the robotic pigeon is in every relevant way just like an actual ...
241 views

### Why does a fluid follow the wing?

When air is moving above and under a wing that is curved, why does the air at the top of the wing follow the wings shape and go downwards when it could just go in a straight line? It doesn't make ...
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### What direction is aerodynamic lift in?

So I was researching about aerodynamic lift, in all the research I read it says lift is perpendicular to the flow direction. But in 3d space there isn't only one perpendicular vector to a given vector....
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### Converting heat to mechanical energy

Could an object convert heat in the air around it to mechanical energy in order to accelerate itself? In other words, the craft would take in surrounding air composed of random-velocity molecules and ...
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### The effect of velocity on the $g$-force applied to the pilot [closed]

In a level flight (not maneuvering), if an aircraft increases its velocity from Mach 0 to Mach 10, how much $g$-force is applied to the pilot? Is that any equation for it?
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1 vote