All Questions
306 questions
-1
votes
1
answer
64
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Does flying an airplane opposite to the Earth's rotation direction save fuel & time? [duplicate]
The Earth rotates in an eastward direction, known as prograde rotation. If you
were looking down on the Earth from above the North Pole, it would appear to be
spinning counterclockwise. Therefore, if ...
3
votes
3
answers
2k
views
Why do race cars accelerate faster than jets?
In a Top Gear video, the race car has an advantage during the first few seconds of the race. The car accelerates faster, leaving the military jet behind. My question is, why does this happen? Is this ...
- 69
0
votes
2
answers
93
views
How much energy per second would a nuclear reactor need to power a fighter jet?
Fighter jets typically require high amounts of thrust compared to other aircraft. Lets take the F-22 for example, and lets assume the F-22 powered by a nuclear reactor and the F-22 powered by a ...
0
votes
1
answer
95
views
Calculating aerodynamic forces on a random object
I've set out to designing a game that would let the user design a vehicle/plane and then fly it around and I'm interested in what would be the best way to go about the physics aspect of it.
The 3d ...
- 1
0
votes
1
answer
39
views
Spinning top stabilisation for a type of aircraft/drone
Spinning tops use gyroscopic precession to be able to stay upright whilst spinning.
Would it be possible to use this phenomena to create a flying craft that would be stabilised by gravity and the ...
- 1
1
vote
0
answers
27
views
Is there a minimum power required to keep a drone or helicopter in the air - and if so, what is it? [duplicate]
Assuming a mass M and horizontal projection of area A for a hovering object (no wind) like a drone or helicopter, what's the minimum power required to keep it hovering? Let's assume no ground effects....
- 228
1
vote
0
answers
138
views
In gyroscopic effect of a quadcopter, why does precession cause torque, not vice versa?
I don't know if the header corresponds to my actual quest but i will explain.
In quadcopter dynamic equations of Newton-Euler formation that I have encountered in all academic publications, torque ...
- 21
0
votes
1
answer
63
views
Does a helicopter fly because air is forced downwards, or because each rotor acts as an aerofoil to generate lift? [duplicate]
The answer may be a combination of the two.
Does a helicopter fly because air is caught by the rotor and thrown downwards, which causes an equal reaction in the opposite direction and 'throws' the ...
- 101
1
vote
2
answers
279
views
Why is accelerating more air slower more efficient than less air faster?
According to this answer on Aviation Stack Exchange, when propelling an airplane it is more efficient to accelerate a bigger amount of air a little than to accelerate a small amount of air a lot. Why ...
- 355
20
votes
7
answers
6k
views
Why aren't helicopter blades tapered?
From my understanding helicopter blades work similar to a planes wings, ie the air going over is faster due to the shape. So my question is why then are the blades rectangular? ie they are the same ...
- 973
0
votes
0
answers
48
views
Lift generated by airfoil and why does a flow with a positive angle of attack around a flat plate curve upwards instead of downwards?
I've recently been reading about what really causes lift on an airfoil and the article linked mentions that even a symmetric airfoil or even a flat plate generates lift as long as the angle of attack ...
- 531
0
votes
2
answers
66
views
Do airfoils need narrowing tails to create a forward force?
All airfoils I have seen become narrow towards the trailing edge.
Is it still possible to create a forward vector force if the shape becomes wider again after a narrow middle section?
I read that the ...
- 31
0
votes
0
answers
75
views
Calculate wind speed on aircraft given measurements of speed and heading
I have X amount of speed measurements of an aircraft, each measurement includes a heading and a forward ground speed.
What I want to do is to calculate the wind speed affecting the craft.
For example:
...
- 1
0
votes
1
answer
39
views
Is the wing drag of induced drag + 2d drag at 0lift still accurate for cambered airfoils?
I have some work at uni that requires some aerofoil analysis to create a wing, but from the polar plots its clear that the cambered aeros have lower total 2d viscous drag (from xfoil) at the cl its ...
- 113
1
vote
1
answer
127
views
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 ...
2
votes
2
answers
130
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 ...
- 205
0
votes
1
answer
54
views
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?
0
votes
1
answer
68
views
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 ...
- 1
1
vote
0
answers
46
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 ...
- 19
0
votes
1
answer
74
views
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? ...
0
votes
1
answer
88
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
0
answers
26
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 ...
- 33
1
vote
3
answers
104
views
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 ...
- 181
0
votes
1
answer
51
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
1
answer
245
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 ...
10
votes
5
answers
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 ...
- 275
1
vote
0
answers
35
views
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 ...
- 31
0
votes
2
answers
72
views
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 ...
- 51
0
votes
3
answers
583
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 ...
- 548
-2
votes
1
answer
101
views
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 (...
0
votes
2
answers
168
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 ...
- 195
0
votes
2
answers
309
views
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. ...
- 21
0
votes
1
answer
50
views
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 ...
0
votes
1
answer
84
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 ?
...
-1
votes
1
answer
113
views
What is the main role of the Angle of Attack of an airplane, as in mainstream explanation of lift? [duplicate]
The question is conceptual and simple, it needs no more information to answer it. And I wish not to influence the answerer.
- 5
2
votes
2
answers
59
views
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 ...
user265090
0
votes
1
answer
47
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
1
vote
2
answers
60
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 ...
- 21
1
vote
1
answer
2k
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 ...
- 13
-1
votes
1
answer
36
views
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
- 21
0
votes
0
answers
33
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 ...
4
votes
6
answers
2k
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
1
answer
353
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 ...
- 107
0
votes
2
answers
98
views
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 ...
- 303
5
votes
2
answers
392
views
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 ...
- 2,744
0
votes
2
answers
276
views
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 ...
- 9
6
votes
1
answer
270
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
2
answers
49
views
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
2
answers
151
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
...
- 268
19
votes
1
answer
4k
views
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 ...
- 307