Questions tagged [aircraft-physics]

Physics as they apply to aircraft. Including aerodynamics, flight dynamics, stability and control, aircraft hydraulic and electric systems, engine thermodynamics.

Filter by
Sorted by
Tagged with
2 votes
3 answers
286 views

Is there a standard word or phrase in the English-speaking world to describe the angle between the fuselage and the flight path / relative wind?

Is there a standard word or phrase, or several alternative commonly-used words or phrases, in the English-speaking aviation world to describe the angle between the longitudinal axis of the fuselage, ...
quiet flyer's user avatar
  • 22.2k
3 votes
1 answer
148 views

How common is it in current British usage for the angle between the chord line of a wing and the flight path to be called the "angle of incidence"?

In American usage, the angle between the chord line of a wing and the flight path is called the "angle of attack". The angle of attack is also represented by the greek letter "alpha". However, some ...
quiet flyer's user avatar
  • 22.2k
4 votes
1 answer
822 views

Why do all fifth generation fighters (J20, F22, SU57) put their wing above the fuselage?

I heard that upper wing could increase stability, but why do fighters need it? Or are there some other reasons? Please specify.
zyx's user avatar
  • 93
3 votes
2 answers
457 views

What is the average pitch of a plane?

I'm looking for the average pitch of big planes like an Airbus A300. For horizontal travel, is the plane horizontal or does it have a pitch like 1 or 2° (or more)? If the plane does not accelerate ...
Mailou75's user avatar
2 votes
4 answers
2k views

How do single engine airplanes handle changes in torque?

In multirotors, there is a regulation of torque from the rotors which keeps it stable. However, in single engine airplanes, there is only one engine with one propeller. How is the aircraft able to ...
Skyspy's user avatar
  • 87
0 votes
1 answer
2k views

Helicopter or Airplane, which is the most difficult to fly? [duplicate]

I know it varies from aircraft to aircraft, but I want to know in general, which would be the most difficult aircraft to fly even after years of experience. Helicopter or Airplane ? I tried to fly a ...
JeanExtreme002's user avatar
18 votes
2 answers
5k views

Why does an airliner have a shallow descent when heavier, opposite to gliders with ballast?

Gliders utilize water ballast to, among other things, descend faster: But sometimes you need to get down fast: This is when water ballast is added. In airliners however, the heavier the plane, the ...
user avatar
4 votes
4 answers
3k views

Can a fixed-wing plane jump up by blowing air over its wings? [duplicate]

NASA's X-57 electric plane has 12 wing-mounted propellors which drive air past the wing. This video describes how the resulting increased air velocity causes an increase in the amount of lift the ...
mherzl's user avatar
  • 149
0 votes
1 answer
169 views

Wing flex physics?

What physics is involved with wing flex when in air? A simplified answer will suffice. I can understand when on the ground that a heavier wing makes it bend more down. My feeble understanding: When ...
Invariant's user avatar
  • 1,731
18 votes
2 answers
6k views

Why does each fan blade have a different mass and frequency?

From a documentary (at 16:39) on building a Rolls-Royce jet engine: ... no two finished blades are exactly alike, and with twenty in each fan, it will only spin smoothly if the blades are perfectly ...
Auberron's user avatar
  • 1,567
3 votes
2 answers
434 views

How do turbofan internals handle the load from the thrust?

To my understanding, turbofan engines get the majority of their thrust from the fan in front of the engine, up to around 70-80% while the core flow generates around 20-30%. Forward movement is ...
Erik's user avatar
  • 433
3 votes
3 answers
3k views

What is physics explanation for minimum sink rate airspeed?

I did some research on Minimum Sink Rate, and saw much information defining it, (such as it is the speed at which the aircraft will remain in the air for the longest time, etc.) and how it is ...
Charles Bretana's user avatar
2 votes
2 answers
216 views

XFY-1 Vertical take-off mechanics

Hi I saw this video the other day of an XFY-1 doing a vertical take-off and landing and moving left to right while hovering. See the video Here. After watching this I had a few questions on how ...
FutureCake's user avatar
5 votes
3 answers
348 views

How changes in Air masses, Air flow direction and intensity affect lift?

I have a question regarding the airflow an aircraft experiences during 3 distinct scenarios: An aircraft during landing, experiencing a sudden gust of 40 knots from the tail. What would be the ...
Stan's user avatar
  • 443
10 votes
8 answers
23k views

Can passenger airliners hover completely motionless in the air?

I've seen many stories of this occuring on r/glitch_in_the_matrix (a popular Reddit). People have been seeing big airliners just paused in the air, not moving. Some of them stopped their car and saw ...
Lars Knowles's user avatar
1 vote
4 answers
1k views

Why do gusts change the airspeed during landing, but turning (which changes where the wind is coming from) does not?

As we know it, aircraft are extremely sensitive to gust during its final landing stage. They can lose airspeed if the wind changes to tail, ad thus loose lift or need to adjust their thrust in order o ...
Stan's user avatar
  • 443
3 votes
4 answers
864 views

Aerodynamics of Flight Control Surfaces

From what it appears to me, flight control surfaces seem to be taken for granted. In terms of how they actually work and what kind of physical outputs they give in terms of forces and such. Take for ...
Kiyo's user avatar
  • 55
8 votes
5 answers
3k views

What factors influence the maximum speed of an airship?

I'm interested in learning about the physics of airships; in particular, how you determine an airships maximum speed. For example, the Hindenburg topped out at about 80 mph. The ship itself weighed ...
RetailPleb's user avatar
8 votes
1 answer
331 views

Since shock waves have non-negligible viscosity, why do the normal shock relations ignore friction/viscosity?

The normal shock relations (seen below) are derived by using steady, 1D, neglect potential, no shaft work, adiabatic and zero viscosity assumption. However, since shock waves are "thin regions of high ...
Nick Hill's user avatar
  • 606
-2 votes
2 answers
188 views

Can planes go to space? [duplicate]

What are the reasons why planes can't go into space? https://thehumble.co.uk/aircraft-with-forward-swept-wings/
Dilshan Hiruna's user avatar
6 votes
3 answers
735 views

Why does the faster-moving air over the static port not result in a lower static pressure?

I understand the concept that the static port is measuring "static" pressure, meaning the pressure the air is exerting on its surroundings. However, there is also Bernoulli's principle, which, put ...
bcf's user avatar
  • 807
4 votes
5 answers
3k views

Does the power behind the engine make any difference to how strong the thrust is? [duplicate]

What difference does horsepower make? If the engine can spin the propeller fast enough, why does it need power behind it?
qwertyuiop's user avatar
1 vote
1 answer
401 views

Can accelerations be used to calculate load factors?

Can I use the z accelerations to calculate the load factor in that axis? Please explain how or why not.
Ryan Hirani's user avatar
7 votes
2 answers
557 views

What is the aerodynamic reason that the An-225's vertical stabilizers are not simply vertical?

I am trying to understand the aerodynamic consideration that the two vertical stabilizers of this gigantic Antonov An-225 are not simply made vertical and are slightly pointing in. Then my questions ...
AirCraft Lover's user avatar
5 votes
7 answers
1k views

How much of an airplane's forward energy is lost to lift?

An airplane needs to move forward to generate lift, and because energy isn't created from nothing, all the kinetic energy of lift comes in the form of drag, where air (air resistance) turns forward ...
Tal's user avatar
  • 201
1 vote
1 answer
1k views

Which type of fan is better for wind tunnel testing?

I would like to build a small wind tunnel to test a miniaturized wing/airplane. I have two options, using axial blower (picture 1) or using centrifugal blower (picture 2). The first will be the wind ...
AirCraft Lover's user avatar
4 votes
1 answer
575 views

Why are the Phugoid and Short period approximated instead of calculated exactly?

We can calculate the period and half-amplitude time for phugoid and short period using equations of motion. We will get an exact answer. Then why is there a need for doing approximations to ...
Pavan's user avatar
  • 461
0 votes
3 answers
197 views

What kind of motion will an airplane enter into when disturbed?

When an airplane is disturbed from a longitudinal equilibrium position, what sort of motion will the aircraft experience? Will it be a phugoid or a short period motion? Or will it be both?
Pavan's user avatar
  • 461
42 votes
6 answers
17k views

Do airplanes need brakes in the air?

A few days ago I flew on a Boeing 737-900ER. Luckily I was sitting just beside the left wing, seat 26B. I observed that the spoilers were activated (opened) just after the pilot spoke on the Passenger ...
AirCraft Lover's user avatar
4 votes
1 answer
1k views

Why does lift curve slope increase when Fowler Flaps are deployed?

Below is an image for a Fowler Flap: Notice that as the flap is deployed, both the camber and the area increase. This change in wing shape modifies the lift curve as follows: (source: Development of ...
Nick Hill's user avatar
  • 606
-1 votes
1 answer
248 views

How is the impact force on the landing gear distributed in fighters?

Upon landing, what percentage of weight is distributed on the main and the nose landing gears of fighters? Upon landing of a fighter aircraft, what would be the approximate time of transfer of the ...
jack's user avatar
  • 17
2 votes
2 answers
2k views

Why does the Biot-Savart law give the induced velocity of a infinitesimal segment of a vortex filament at point P?

My question is about the proof of how the Biot-Savart law can be used for vortex filaments. This is what I have in my textbook: However, I'm not certain how it was derived - I understand that the ...
Andrew Xie's user avatar
3 votes
1 answer
519 views

Does the aerodynamic center always have to lie on the chord line?

A lot of resources online state that the aerodynamic center is the "point on the body of an airfoil with respect to which the moment coefficient does not change with angle of attack." However, does ...
Nick Hill's user avatar
  • 606
1 vote
3 answers
1k views

Is there a method for calculating change in V-speeds with a change in weight for a Cessna 172?

For example, what would the rotation speed (Vr) and stall speed (Vs) be at maximum takeoff weight versus flying with a single occupant? (2297 lb vs 1807 lb)
flextempers's user avatar
1 vote
3 answers
766 views

Why is the stagnation point on the upper surface before the start of circulation?

In many textbooks, such as Anderson (Fundamentals of Aerodynamics), Bertin (Aerodynamics for Engineers), and Houghton (Aerodynamics for Engineering Students), the authors present the idea that there ...
Nick Hill's user avatar
  • 606
2 votes
1 answer
694 views

Why does IAS decrease with lower air density if power is constant?

TAS increases with less dense air, which is intuitive. What I don't understand is why IAS decreases. This is assuming sub-transonic speeds where compressibility effects are negligible. To phrase ...
John's user avatar
  • 218
3 votes
2 answers
572 views

What is the explanation of this airfoil phenomenon? Why the air from below the leading edge's tip deflected up?

I have difficulties to understand this air phenomenon, why the air from below the leading edge's tip (from below the horizontal line) is deflected up and not just follow the bottom wing's surface? ...
AirCraft Lover's user avatar
2 votes
0 answers
363 views

Does the angular momentum of a jet engine affect aircraft performance?

I am interested, do jet engines have angular momentum? And how does such momentum affect airplane stability?
Ali's user avatar
  • 21
1 vote
3 answers
7k views

How do I calculate the center of lift?

See my other question here for the background context. Consider this simple plane. I have applied the 4 basic forces: lift, drag, weight, and thrust. My question is, where, precisely, do I apply the ...
mr-matt's user avatar
  • 447
1 vote
1 answer
2k views

How much force is produced by control surfaces?

Context: For some context, I'm a game developer and I'm building a flight sim game. My goal is to have realistic -- not arcade -- physics. The game is in Unity. Unity handles the actual application ...
mr-matt's user avatar
  • 447
5 votes
1 answer
829 views

How do I obtain the max endurance altitude?

There are excellent explanations of the physics that determine maximum endurance speed here, here, and here. I was thinking of aircraft that have to be "on station" without an indicated altitude and ...
feetwet's user avatar
  • 2,274
1 vote
1 answer
233 views

What is an example of a quantitative analysis for the lift using Newtonian mechanics?

There are several different ways of explaining how an airplane generates lift. The simpler qualitative explanation uses Newtonian mechanics (the third law is invoked to explain how the wing pushes air ...
Pancake_Senpai's user avatar
0 votes
1 answer
421 views

How to calculate on ground aircraft yaw rate knowing the longitudinal speed and inferred yaw angle

Please consider the following scenario: a generic aircraft is on-ground taxing at 50 feet per second (~15.25 m/s, ~29.5 knots) The pilot inferred 20 degrees of yaw How can I calculate the yaw rate ...
Alex Mcfly's user avatar
9 votes
2 answers
378 views

What is the "compression ratio" of air hitting the nose?

Sorry but I don't know how to accurately phrase this question. I want to know how much compression results from air hitting the nose of an aircraft. I'm interested in the traditional airliners (Mach ...
DrZ214's user avatar
  • 17.7k
8 votes
3 answers
665 views

What are accurate flight simulation models called? Is there a standard model?

I'm risking a question that might be "opinion based", but I hope it will not be seen as that. This question is touched upon in the following questions: What are the differences between PC and ...
AlphaCentauri's user avatar
10 votes
1 answer
3k views

If the efficiency of a turbofan engine is 35%, where does the rest of the fuel energy go?

There have been a couple of questions on this site about the efficiency and propulsive power of turbine engines (here, here, here). In a high bypass turbofan engine, what are the losses in the ...
Koyovis's user avatar
  • 61.6k
0 votes
1 answer
324 views

At what angle-of-attack (sideslip angle) would a symmetrical vertical fin stop "helping" a deflected rudder produce sideforce? [duplicate]

For rudder deflection angles of 5, 10, 20, 30, and 45 degrees, at what (negative) angle-of-attack does a fin-rudder combination (including dorsal fin if present) create exactly the same amount of ...
quiet flyer's user avatar
  • 22.2k
5 votes
1 answer
293 views

Would all these three things have the exact same effect on the flight duration of a glider?

Consider a glider trimmed to fly at some given angle-of-attack, gliding in smooth air (no thermal convection, ridge lift, wave lift, etc.). If air density is somehow kept exactly constant in all ...
quiet flyer's user avatar
  • 22.2k
3 votes
1 answer
601 views

What does a higher pitching moment mean? (ie -0.095 vs -0.0022)

I've found that as the angle of attack increases, the moment becomes more negative. I wanted to know what does that negative value say about the characteristics of the airfoil, and what is its ...
Kino's user avatar
  • 43
0 votes
0 answers
41 views

Two aircraft with same air speed, blank angle, but different mass, are the radius of turn the same? [duplicate]

Two aircraft with same airspeed, blank angle, but different mass, are the radius of turn the same?
Flying777's user avatar

1
3 4
5
6 7
9