# Questions tagged [aircraft-physics]

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

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### How a flying saucer could fly [closed]

Just to know if there is interest about Flying Saucer or circular/anular wing shaped aircraft and how they can designed and build with the state of the art tecnology. I have hypothesised the ...
106 views

### Have elephants ever been parachuted out of aircraft? [closed]

my previous question's answers (link here) helped me confirm that elephants had indeed been transported by aircraft for various different reasons on multiple occasions. One of the answers is about ...
132 views

### Formula relating propeller torque to lift

I'm trying to find a formulas that relates lift to torque on the rotor shaft. Torque, angular velocity and power are related by the following relationship: $P=\tau \omega$. I am especially interested ...
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### Has there ever been a case where elephants are carried by aircraft?

I know that today's aircraft can carry very large amounts of cargo, and some (presumably military heavy transport aircraft) can even carry tanks. However, I've been thinking, has there ever been an ...
454 views

### Can any aircraft beat this car's 0-400-0 km/h record of 28 seconds?

In 2024, the KOENIGSEGG Jesko Absolut set a new world record for 0-400-0 km/h. That's starting from 0 km/h, accelerating to 400 km/h and then decelerating to 0 km/h again. Without such easy rolling ...
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### How do aeroplane wings work? [duplicate]

I wonder why this question has not been posed on this forum. Is it such a dumb question that nobody needs to ask because the answer is obvious? A search on the internet for "How do wings work&...
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1 vote
240 views

### Does a longer wing produce same lift as a wider wing with the same total area?

Considering the image below, as shown, both wings have the same total area but with different different measures. Do they produce the same lift, or which wing produces more lift and which one makes ...
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### Can someone explain the damage distribution on this aircraft that flew through a hailstorm?

An A320 flew into a hailstorm 20mins from landing. I’m intrigued by the damage distribution. Seems like everywhere else wasn't touched at all. Why?
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### What's gonna be the physics behind building 'futuristic' airplanes? Use physics formulas or even theories to answer this question [closed]

After thinking about these 'futuristic' airplanes, I wonder if there's any special physics theory or law behind them. I wonder how faster they can be, persevere more and fulfill the aviation's lover ...
115 views

### In a straight and level flight if thrust is equal to drag how is aircraft moving forward?

If two forces are equal and acting in opposite direction should not the object remain stationary. Is there an excess thrust which actually pushes the aircraft forward ?
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### induced drag at supersonic speed [duplicate]

for a delta wing with supersonic leading edge at small angle of attack there is no stagnation point on leading edge so There is no connection between the top and bottom of the wing. Therefore, the air ...
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### In a hot air balloon what proportion of the lift comes from the heated air compared to that from the combustion products?

A hot air balloon is heated with propane or similar hydrocarbon. One of the products of combustion is H2O with molar mass 18 so it is substantially less dense than air (78% nitrogen, molar mass 28 and ...
39 views

### Does partial flow separation due to toggle input affect the physics of paraglider/ canopy controls?

A skydiving canopy designer said the following: Airflow is separated even before stall on a big portion of the canopy.... It's specific to [the] way toggle[s] distort the trailing edge. Is this true,...
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### How does ground effect work with a banked wing?

How would an explanation of ground effect such as this one from Peter Kämpf be modified to account for a highly banked wing? A paraglider and HP canopy pilot told me that when he banks a wing to touch ...
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1 vote
52 views

### Does ground effect affect a paraglider/ canopy?

I've heard that ground effect is only significant if the wing is closer to the ground than its span, and I've never seen a canopy/ paraglider that would qualify for that. Is that true or would there ...
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### Is the thrust/lift trade-off for powered lift linear?

On the wikipedia page Powered lift there is this graph of thrust vs lift: (public domain) This graph shows a roughly constant (not exactly constant but that's not the point) sum of thrust and lift. ...
132 views

### How to maximize L/D ratio by design in a high altitude glider? [closed]

EDIT: Some initial confusion with TAS and IAS confused me, I now understand this better, thanks for everyone who helped. I'm designing a high-altitude glider, and I'm wondering how the angle of attack ...
91 views

### Doubt in the Coriolis component of the net force acting on the aircraft

I dig a little and got to know that the force equation in 6DOF are nothing but a mathematical depiction of the fact that for a translating & Rotating body in 3D,The net force is the Translational ...
1 vote
30 views

### Intersecting Boundary Layers in XFLR5

I am analyzing an airfoil called RevE-HC. While doing a type-1 analysis, I encountered that the BL is intersecting towards the trailing edge. The panels are refined and the geometry is also smooth. ...
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### Does a carbon fiber fuselage suffer wear from pressurization/depressurization?

I've heard many times that one of the factors that causes wear and tear to the fuselage of airliners is the pressurization and depressurization from each flight. From what I recall these were ...
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677 views

### What are the correct Cd0 and Cdi values for a NACA 2412 airfoil?

According to an answer to this question, at best L/D the the drag coefficient is evenly split between Cd0 and Cdi. I'm going to limit the question to the Cessna 172 and its NACA 2412 wing with an ...
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### why does the rotor could head (Nr) "overspeed" if the collective is lowered suddenly, what is the Physics behind it

I know that in helicopters the N2 and Nr are coupled. I would appreciate a physical explanation leading to the cause of how the rotor blades could overspeed if collective (power) is lowered suddenly I ...
429 views

### Would it be practical to have missiles that can aim forward and backwards?

I have been researching recent air-to-air combat kills in some recent wars and in every case it seemed that the pilot who was in the back won. So I was wondering why they don't just design a missile ...
152 views

### What's the efficiency between the duct and the fan blade?

I've heard many times that the smaller the gap between the fan blade and the duct, the better the efficiency/thrust is. Is there a formula or graph available to see how much efficiency is lost as you ...
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1 vote
191 views

### Could an passenger jet perform a complete power down & up IN FLIGHT? [duplicate]

I've read various references that it is not uncommon that modern passenger jets' computer systems need an occasional reboot to fix some erratic state. Of course, that is done on the ground and ...
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### If a Cessna 172 is dropped from the sky, what minimum altitude is needed to safely land?

If an aircraft like a Cessna 172 is dropped from a helicopter, what absolute minimum altitude above the ground will be required to safely land the aircraft? CONDITIONS: Weather: Perfect conditions, ...
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### Gyroscopic Precession in Coaxial Helicopters

I'm trying to understand gyroscopic Precession in the case of coaxial helicopters. Obviously the effect still exists. But if gyroscopic Precession is a result of counter torque. Shouldn't the effect ...
1 vote
906 views

### What causes magnetic compass turning errors?

What exactly causes magnetic compass turning errors? I found two completely different and contrasting explanations online and I'm confused as to which one is correct. Explanation 1: Reference: ...
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### What causes magnetic compass acceleration errors?

I was trying to find out what exactly causes magnetic compass acceleration errors, and I found two completely different and contrasting explanations online (both are supported by an equal amount of ...
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### How do you calculate the theoretical vertical speed of an aircraft? [duplicate]

I'm doing this for a High School research paper, so it would be preferable if little calculus is used for any calculations (up to Calculus I is probably okay). This should be based off of the flight ...
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### Does the “Torque-Induced Precession” of the two rotor blades cause the V-22 Osprey to tear itself apart

Concerning Bell Boeing V-22 Osprey Aircraft: Does the “Torque-Induced Precession” of the two rotor -- 3-blade, propellers cause the V-22 Osprey to become unstable. In the case of a helicopter the ...
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### What is the speed and temperature profile of the boundary layer at the stagnation point?

At the statgnation point where the air velocity is zero, what is the shape of the velocity and temperature profile of the boundary layer? Is the velocity profile of the boundary layer in the form of a ...
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185 views

### Exhaust temperature of CFM56 engines range (Nozzle downstream temp)?

EGT is available but not the temp of the exhaust nozzle in the CFM56 series.
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### Why isn't the rudder below the tail?

Most airplanes have a rudder on top of the tail. When it is turned to the left, it causes the plane to yaw to the left. But it also puts a roll force to the right, because it is usually above the ...
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### Yawing during turns

This is a question about aeronautics. Does an airplane yaw while it is turning?
181 views

### Why does the F/A-18 use external aileron and flap hinges?

As seen in the picture, the legacy Hornet uses ailerons and flaps with external hinges, and I was wondering what were the advantages of external hinges compared to flush hinges in the land-based ...
114 views

### Deriving Accurate Exit air velocity of rotor

My goal is to derive the equation for exit air velocity as a function of: Pitch angle RPM Rotor Radius Constants like ρ Assumptions: Vc is relative velocity of air upstream, and is = 0 Inflow is ...
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### Is the Lift required for a steady-state climb and descent equal for the same absolute value of the kinematic climb angle? [duplicate]

Here is my confusion : I found in my lecture script the following equation for the steady-state climb and descent (wings level) ...
1 vote
268 views

### Is the Reference Speed (Vref) the same as the speed at which the aircraft cross the runway threshold in landing phase?

Just a little confuse when I learned about the aircraft classification based on approach speed. Can anyone help me to have an accuracy look about this question?
211 views

### Does pilot need to increase thrust when gust hit him at landing and where is axis of rotation?

Let's say a plane is flying above a runway in straight line, and gust of wind hits the plane from side. Do pilot need increase thrust to stay above runway and where is axis of rotation ? It often said ...
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### Do airliners respond to mild turbulence in real time?

I've always been fascinated with the impact of ailerons on an aircraft's trajectory; from what I have seen sitting by a wing is that the slightest movement can bank the aircraft quite significantly. ...
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Every treatise I read about propellers/fan blades/wings states that long, thin wings are more efficient than wide stubby ones. So why is it that the blades in high-bypass turbofan engines fitted to ...
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### Flying upside down without feeling it

A friend of mine told me that several years ago she flew on a two-seats general aviation aircraft. She does not remember the exact model, but she remembers well that the pilot flew upside down for a ...
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### Do fuel tanks need to be pressurized?

Do fuel tanks need to be pressurized? It's my understanding that the pressure difference between the outside air and the inside fuel would force the kerosene out of the fuel tank. What stops this from ...
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235 views

### How does elevator control effectiveness change with altitude/ air density?

Suppose an unpowered, rigid, mechanical, lightweight aircraft (e.g. sport glider) is descending at a steady glide in a constant trim (hands off) configuration in a standard atmosphere. The pilot ...
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147 views

### Why will all air slow down by the same amount in an adverse pressure gradient?

Boundary layer separation is caused by air slowing down to zero and reversing before reaching the end of the body. This is due to friction (viscous effects) + adverse pressure gradient. The formation ...
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### How does momentum thrust mechanically act on combustion chambers and nozzles in a jet propulsion?

I'm asking this question since I can't intuitively understand how the acceleration of mass flow and therefore the increase of its momentum can actually mechanically act on the combustion chamber ...
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### Why does bank angle have no effect on pivotal altitude?

Pivotal altitude is the height for a given ground speed at which the line of sight from the cockpit directly parallel to the lateral axis of the aircraft will remain stationary on an object on the ...
286 views

### Does the cross-sectional shape of a fuselage affect drag?

Comparing two bodies with the same streamlined longitudinal shape, and the same cross-sectional area, one with a circular cross-sectional shape, the other with a quadratic cross-sectional shape, ...
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