Questions tagged [flight-dynamics]

Flight dynamics is the study of the physics driving the performance, stability, and control of aircraft. It is concerned with how forces acting on the aircraft influence its speed, altitude and attitude with respect to time.

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Yawing during turns

This is a question about aeronautics. Does an airplane yaw while it is turning?
BomberJoe's user avatar
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1 answer
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Entry to back-side of power curve

When entering slow flight, when do we enter the back side of the power curve? Is it when we reduce the throttle or when the airspeed decreases to just above 5 knots from the stall speed?
zZZz's user avatar
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4 votes
2 answers
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Why does the turn tighten in a Spiral Dive as it progresses? Even without applying any elevator control?

Why does the turn keeps getting tighter as the spiral dive develops? Use of elevator control makes sense as it would increase the horizontal lift vector inside the turn. But even without any elevator ...
Nish's user avatar
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3 votes
3 answers
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Taxiing with a crosswind

Let us say we have a right quartering headwind, we should “fly into the wind” so yoke to the right then that our right aileron will deflect up and left aileron down. How does this avoid the chances of ...
AerospaceX's user avatar
3 votes
7 answers
593 views

If in a coordinated turn, the horizontal lift vector is equal to the Centrifugal force. Then how is the aircraft still turning?

Image source How does the Aircraft continue to turn when the both the Horizontal component of lift and the centrifugal force are equal?
Nish's user avatar
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What are the effects of whiteout (snow) and brownout (sand/dust) on helos?

Is there any other effect besides low visibility? Both seem to show very similar conditions.
BanzaiFighterbomber's user avatar
1 vote
2 answers
141 views

What differences would a helicopter designed to withstand many negative Gs have compared with a normal one?

There are a few helicopters that are able to take negative G's, and to this day only one can actually perform aerobatics (ie. Chuck Aaron's BO-105). The BO 105 is a rigid rotor helicopter that has ...
BanzaiFighterbomber's user avatar
6 votes
2 answers
3k views

Why is a flat turn less efficient than a coordinated turn?

How I understand a flat (rudder-only) turn: AOA between relative wind and the fuselage of the airplane causes a sideslip in the direction of yaw. Vertical stabilizer weathervanes into the relative ...
astroball's user avatar
3 votes
1 answer
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What is the theoretical justification for "proportional navigation (PN)" guidance law?

In missile guidance theory, one of the fundamental guidance algorithms is the so-called "Proportional navigation", which directs a constant-speed missile into a collision course with the ...
user2554's user avatar
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What would happen to the aircraft and its control surfaces immediately after the loss of all hydraulics?

In cases like the DHL shoot-down in 2003 or the Sioux City crash, both aircraft lost all of their hydraulics because of a catastrophic failure of aircraft structure. What would happen if the aircraft ...
Faito Dayo's user avatar
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3 answers
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Does AOA become 0 after the aircraft flies in a particular attitude for sometime as the relative airflow has changed and how does it affect Stall AOA?

As AOA is the angle between relative airflow and Chord Line. Then after you increase the angle of attack and fly at that angle of attack for some amount of time and the relative airflow changes ...
Nish's user avatar
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why lift coefficient decreases at supersonic flow?

In Anderson's performance book, he wrote that the higher the speed, the greater the pressure difference between two points, and as a result, the lift coefficient is greater. But when we reach the ...
alireza's user avatar
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1 answer
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Could you use the flaps to recover from a flat spin

If the plane is in a flat spin, what would happen if you put the flaps down to cause the backward turning wing to be pushed down, and the forward turning wing up, to tip it out of the spin.
Peter R. McMahon's user avatar
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Maximise Range Vs Pitching Down while flying a Glider in a Downward Air Mass

While flying a glider, if I encounter a downward moving air mass (i.e. sink) while on final, should I fly to maximise range (best lift to drag ratio) or should I pitch downward in order to exit the ...
JF0001's user avatar
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What can cause an unstable phugoid mode?

For clarity, I am wondering about how aircraft design can lead to the phugoid poles becoming complex with a positive real part, so an oscillation with increasing amplitudes. My understanding of the ...
Grumpy's user avatar
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3 answers
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Can the use of wide-chord supercritical airfoil blades in a helicopter with coaxial counter-rotating rotors solve retreating blade stall?

The problem with retreating blade stall is that it limits the VNE and the overall top speed of helicopters. Retreating blade stall is basically the tip of the retreating blade having too much AoA at a ...
BanzaiFighterbomber's user avatar
1 vote
1 answer
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Wing incidence angle of tandem wing aircraft

I'm trying to design a tandem wing model aircraft with both wings with the same wingspan. The front wing will have 2 and the rear will have 1 deg of incidence angle, also the front wing will have ...
Kozakov's user avatar
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4 answers
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If I am at absolute ceiling, can I climb further by trading airspeed for altitude?

If I am flying at absolute ceiling, can I still climb by trading airspeed for altitude?
Hitomhi's user avatar
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8 votes
3 answers
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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 ...
Mark's user avatar
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0 answers
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How elevator and ailerons affect attack and roll angles?

I was trying to model the flight of an aircraft and i need some function that expresses the change of attack and roll angle in function of the elevator and ailerons (respectively). Does anyone have an ...
yo yo's user avatar
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2 votes
2 answers
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Longitudinal/Lateral CG envelope for hoist operations

Does a Rotorcraft hoisting CG chart show what the CG will be as the load is hoisted from top to bottom or vice versa?
Wes's user avatar
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4 votes
2 answers
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What open-loop control inputs can guarantee non-divergent descents in fixed-wing aircraft?

(Inspired by What's the best way to get through clouds when not instrument rated? which has at its heart a good question, but isn't getting good answers because everyone is jumping on the "...
Kenn Sebesta's user avatar
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5 votes
6 answers
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How to slow down while maintaining altitude

Is reducing throttle/power already enough? Or do I have to adjust the pitch as well? If so, I suppose pitching up as well? If pitching up is needed as well, is it because as speed decrease, there is ...
Hitomhi's user avatar
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3 answers
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Simultaneous yaw damping and sideslip control of aircraft with rudder?

Yaw damping is achieved by using the rudder to generate a yawing moment that opposes any yawing motion. Also, rudder is used to correct sideslip by applying a rudder input in the opposite direction of ...
hereyougo there's user avatar
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4 answers
595 views

How does increasing the angle of attack increase the lift?

When the pitch of a plane increases (facing upwards), it has a positive angle of attack, and when it decreases to face downwards, it has a negative angle of attack. Increasing the angle of attack ...
planes's user avatar
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3 votes
8 answers
741 views

How does the lift force stop increasing itself after a certain point?

I am currently trying to create a basic flight simulator and am very confused by the concept of lift. This is the equation of lift shown below that I found on the internet. $$ F_l = \frac{1}{2} \rho v^...
planes's user avatar
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3 votes
1 answer
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Why does the maximum allowable load factor vary with airspeed in some aircraft?

In this ASE answer What is the maximum safe bank angle of a 747?, the author writes: If we stay with stationary turns (without the "falling out of the sky" part), the maximum bank angle is ...
quiet flyer's user avatar
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8 votes
3 answers
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Why does a sudden tailwind/headwind change IAS?

I read the following statement: “tailwind quickly changing to a headwind causes an increase in airspeed and performance. Conversely, a headwind changing to a tailwind causes a decrease in airspeed and ...
Breaach's user avatar
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-1 votes
4 answers
268 views

How is Vx speed and Vy affected when climbing?

If my speed for best angle of climb is 60 and rate is 79, if I kept a 500 fpm climb to my cruise altitude of let’s say 4500, would those speed change? The flights are being done on separate occasions.
youngpilot's user avatar
4 votes
4 answers
830 views

Why the heavier the aircraft is, the higher the airspeed must be to obtain the same glide ratio?

I know weight does not affect glide ratio. But why does higher weight need higher gliding speed?
Hitomhi's user avatar
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1 answer
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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 ...
Oleg's user avatar
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1 answer
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FAA's Airplane Flying Handbook says more lift is necessary during a climb. Isn't it the opposite? [duplicate]

"If a climb is started from cruise flight, the airspeed gradually decreases is the airplane enters a stabilized climb attitude. The thrust required to maintain straight-and-leve flight at a given ...
Hitomhi's user avatar
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9 votes
1 answer
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Did the dog-tooth notches in the wing of the F-8 Crusader really have anything to do with "yaw stability"?

What was the real function of the "dog-tooth" notches in the leading edge of the wing of the Vought F8U crusader? Wikipedia says:1 Vought's design team... produced... a relatively ...
quiet flyer's user avatar
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1 vote
1 answer
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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 ...
astroball's user avatar
26 votes
5 answers
5k views

Why a kite flying at 1000 feet in "figure-of-eight loops" serves to "multiply the pulling effect of the airflow" on the ship to which it is attached?

In CNN's June 30, 2023 Giant kites could pull cargo ships across the ocean – and slash their carbon emissions “What differentiates it from other wind solutions,” says Bernatets1, “is that the wing is ...
uhoh's user avatar
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0 votes
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Can engines with a fixed nozzle in the angle of attack have the same effect as the thrust vectoring?

If the figure above represents a missile at the angle of attack and we vector resolution the thrust output from the nozzle, we can see that the thrust is divided into sine and cosine parts. Does the ...
alireza's user avatar
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9 votes
6 answers
1k views

What is the load factor in a descending turn?

Possibly related to How does the load factor vary when the aircraft pitches up/down? Could you help to settle a debate? I have recently flown a dead-stick approach with a CFI in the right seat. ...
ExternalUse's user avatar
1 vote
2 answers
110 views

How to prevent altitude loss or keep flight path angle constant while doing aileron maneuver?

I am trying to perform an aileron roll maneuver for an un-manned aircraft in a simulation. The lateral control architecture is that I am controlling roll rate (stability) with aileron stick and side-...
aerovague's user avatar
2 votes
3 answers
222 views

Does CG change airspeed in a descent or glide?

If the CG of an airplane moves forward, would it fly a faster or slower airspeed in a descent? Usually during a descent or landing, you'd use pitch to change airspeed and power to control descent rate....
thunderstormies's user avatar
0 votes
1 answer
172 views

effect of wing chord length on lift coefficient

In the bertin's Aerodynamics book It is written that reducing the wing chord increases the lift coefficient( decreases stall angle) and as a result, the wingtip stalls earlier than the wing root how ?
alireza's user avatar
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0 votes
0 answers
76 views

why induced drag decreases in supersonic speed?

In John Bertin's book Aerodynamics, it is written that the induced drag at subsonic speed decreases with the increase in wing aspect ratio but the opposite happens at supersonic speed so that in ...
alireza's user avatar
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0 votes
1 answer
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How to convert body frame-relative aerodynamic coefficients to wind frame-relative aerodynamic coefficients

I have a rocket flight simulator that takes in aerodynamic coefficients defined relative to the vehicle body frame axes (Cx, Cy, Cz). These are in a lookup table based on mach. I have some aerodynamic ...
Tombombadilly's user avatar
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1 answer
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wingtip vortex in negative angle of attack

If a wing is at a positive angle of attack, then the vortices produced at the wingtip will generate downwash and induced drag but on the contrary, if the wing is at a negative angle of attack, then ...
alireza's user avatar
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1 vote
1 answer
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Why do dihedral wings increase induced drag?

I read somewhere before that the effect of the dihedral wing is similar to the swept wing so dihedral wing increase wingtip loading and increase induced drag Can anyone tell me how physically this is ...
alireza's user avatar
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2 votes
3 answers
647 views

Airplane speed retention question? [closed]

Imagine the scenario when a plane is flying, then it turns off its engine and nose dives. After gaining a lot of speed, if the pilot pulls the stick back and the plane now points upwards again, will ...
user avatar
0 votes
2 answers
406 views

How does a zero g aircraft work?

In upward motion, drag and gravity is in the same direction (both in downward direction). So in this situation G is negative or less than 1 or something else? In downward motion with thrust greater ...
alireza's user avatar
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4 votes
2 answers
238 views

How does conical camber decrease roll due to sideslip?

I was reading Ray Whitford's Design for Air combat and came upon a passage that said that on the SR-71 conical camber "gives a useful reduction in the otherwise very high rolling moment due to ...
Battery's user avatar
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10 votes
3 answers
4k views

Can we see evidence of "crabbing" when viewing contrails?

Can we see evidence of "crabbing" when viewing an aircraft leaving a contrail? Such as, in the form of an angular misalignment between the longitudinal axis of the aircraft (i.e. the ...
quiet flyer's user avatar
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3 votes
1 answer
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Why would a ram air parachute need less brake input to stall at a higher altitude?

I have some anecdotal evidence that a ram air sport parachute requires less toggle input to stall at higher altitudes. A pilot needed one wrap of the brake lines around the hands to quickly, ...
Oleg's user avatar
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0 votes
1 answer
79 views

How do hybrid control surfaces work?

I am trying to build a self-stabilized model rocket with actuated fins. Suppose the rocket has 4 fins. The diagonal fins must rotate together to control the yaw/pitch motion, and all the fins are ...
Leo Liu's user avatar
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