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.
270 questions
5 votes
2 answers
472 views
Why doesn't an aircraft turn when rolling on a point?
During flight training rolling on a point aka dutch rolls are an exercise to develop coordination of aileron and rudder to avoid slipping or skidding turns. Why doesn't the heading of the aircraft ...
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0 votes
0 answers
41 views
Relating component CL, CD, CS, CMm, CMl, CMn to total CL, CD, CS, .. etc through .LOD and .STAB file outputted from VSPAero
My question is as the subject conveys, how do I transform between the results? I have tried the obvious way of summing them, but I get a significant discrepancy (~10 %) which I can't overlook without ...
3 votes
3 answers
328 views
How to predict rate of roll for an aircraft at various airspeeds using only aerodynamic data
I'm trying to create a spreadsheet/calculator that can predict/calculate rate of roll at a range of airspeeds between 0.01 and 0.99 Mach. The goal is to be able to predict an aircraft's roll behavior ...
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2 votes
0 answers
153 views
Does proportional navigation transform closed-loop missile control system into a PD controller?
[This question was inspired by a discussion in chatGPT. ChatGPT is excellent at making cohesive summeries, but from my experience is not so good at explaining/clarifying deep "core issues". ...
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1 vote
2 answers
271 views
What would be the most efficient wing span for single aisle?
Longer wing allows more efficient planes hence the use of foldable wings. If airport gate dimensions and manufacturing costs were out of the question, what is the most efficient wing length for an ...
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4 votes
2 answers
279 views
How does the apparent speed stability of the Airbus A220 FBW work?
The Airbus A220/Bombardier C-series utilizes the C*U fly-by-wire flight control law, which is similar to the ones used in the 777/787. Now, I don't understand much about the C*U flight control laws, ...
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2 votes
1 answer
217 views
Why does the Embraer E2 have a manual pitch trim if the FBW system trims the plane?
A quick Google search says that the Embraer E2 uses C* for their fly-by-wire control law. Now as far as I understand, C* longitudinal control law commands tracking. So, a neutral stick would command ...
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8 votes
2 answers
2k views
Is it possible for a small plane to form vapor from aggressive maneuvering?
It's well known that fighter jets can produce vapor condensation when maneuvering aggressively, especially in high-humidity conditions. My question is, can this also happen with smaller aircraft? Is ...
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1 vote
0 answers
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How can aircraft accelerate while maintaining level flight? [duplicate]
My understanding is that lift is approximately proportional to speed, how can planes increase their forward velocity without causing lift?
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1 vote
1 answer
340 views
When reporting roll attitude, is that relative to the horizon or relative to the Earth frame?
I'm trying to figure out if what I've always thought of as roll from the cockpit is not in fact roll at all. The Tait-Bryan convention defines RPY (roll, pitch, and yaw) as the Euler angles from the ...
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13 votes
1 answer
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What happens when a helicopter loses the engine and autorotation is not initiated?
I am thinking of a very basic main and tail rotor configuration helicopter, without any aerodynamic surfaces like vertical or horizontal stabilizer, in a steady state horizontal forward flight at ...
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1 vote
1 answer
216 views
Climb angle relationship to excess thrust
In the PHAK, Chapter 5 Aerodynamics, the following statement is made regarding forces in a climb: The thrust required for a stabilized climb equals drag plus a percentage of weight dependent on the ...
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1 vote
2 answers
174 views
References for lift and drag coeficient formula/values
I'm looking for references for values/formula for lift and drag coenficients. In this paper https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6244461 it is said that $C_L(α)$ and $C_D(α)$ ...
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6 votes
4 answers
3k views
What is a "rapid changes in gravitational force"
I've been reading an article on the BBC Website about the 21/May/2024 incident on Singapore Airlines. According to this article: "The rapid changes in G over the 4.6 seconds duration resulted in ...
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-4 votes
2 answers
283 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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