Questions tagged [aircraft]
Aircraft are man-made vehicles intended to operate while flying through Earth's atmosphere.
195
questions
0
votes
1answer
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 ...
0
votes
0answers
17 views
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?
2
votes
2answers
91 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 ...
0
votes
2answers
77 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 ...
19
votes
4answers
3k views
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 ...
-1
votes
1answer
46 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 ...
3
votes
1answer
86 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 ...
0
votes
4answers
213 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 ...
0
votes
1answer
45 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?
1
vote
2answers
35 views
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 ...
0
votes
1answer
48 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 ...
5
votes
2answers
104 views
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 ...
1
vote
0answers
22 views
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 ...
0
votes
0answers
63 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 ...
1
vote
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 ...
3
votes
0answers
97 views
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 ...
2
votes
1answer
139 views
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 ...
1
vote
2answers
106 views
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 ...
0
votes
0answers
24 views
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 ...
0
votes
2answers
55 views
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 ...
2
votes
1answer
96 views
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 ...
0
votes
1answer
92 views
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 ...
0
votes
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?
1
vote
0answers
63 views
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 ...
3
votes
3answers
93 views
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. ...
2
votes
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, ...
0
votes
1answer
39 views
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 ...
-2
votes
1answer
27 views
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 ...
-1
votes
1answer
73 views
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, ...
0
votes
1answer
77 views
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-...
4
votes
2answers
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.
...
1
vote
1answer
55 views
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, ...
0
votes
4answers
201 views
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 ...
3
votes
4answers
655 views
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 ...
-1
votes
2answers
80 views
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 ...
-1
votes
2answers
79 views
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) ...
0
votes
1answer
70 views
Lightning strike on aircraft
Is an electromagnetic pulse sufficient to account for the complete dscharge of an aircraft struck by lightning?
1
vote
1answer
35 views
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 ...
2
votes
1answer
152 views
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 ...
0
votes
1answer
110 views
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, ...
-2
votes
2answers
1k views
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 ...
0
votes
1answer
70 views
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 ...
-2
votes
2answers
87 views
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 ...
15
votes
4answers
774 views
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 ...
0
votes
1answer
211 views
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 ...
-2
votes
1answer
54 views
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 ...
1
vote
0answers
24 views
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 "...
0
votes
1answer
24 views
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. ...
1
vote
0answers
73 views
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 ...
-2
votes
1answer
153 views
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 ...
