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Questions tagged [aerodynamics]

Aerodynamics is the study of how air moves and interacts with solid objects. It is an essential part of aircraft design.

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Why isn't the bell distribution used? [on hold]

Why has the bell distribution not become widely used? Is the bell distribution only ideal in inviscid flow scenarios or is there another reason for the lack of use?
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2answers
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What helicopter has the most rotor blades?

I have seen 2 rotor blades up to many and wonder when does having more rotor blades become less efficient? What helicopter has the most rotor blades? Related: Why don't helicopters prefer shorter ...
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3answers
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Why is airspeed different in climbs and descents although the AoA doesn't change?

Here are the background facts: This excercise has the objective to familiarise the student with the slow flight characteristics. The steps are: 1)Establish straight and level, 90% RPM, 15 units ...
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0answers
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Are any commercial airliners other than the Boeing 737 MAX dynamically unstable? [duplicate]

There are many reports online that the 737 MAX is dynamically unstable. Is this unprecedented in modern commercial aviation? References: https://spectrum.ieee.org/aerospace/aviation/how-the-boeing-...
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0answers
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Drag Coefficient of a rounded nose cylinders [on hold]

According to this pages: http://www.aerospaceweb.org/question/aerodynamics/q0231.shtml The drag coefficient of a rounded cylindrical bodies is given by this graph :http://www.aerospaceweb.org/...
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3answers
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Why in helicopter autorotation phase the opposing torque is eliminated?

As you many know, according to Newton's 3rd law for every action there is an equal and opposite reaction, as the main rotor of a helicopter turns in one direction, the fuselage tends to rotate in ...
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6answers
359 views

How does the engine produce aerodynamic lift at high angle of attack?

This answer asserts that "at high angle of attack the engine is producing aerodynamic lift". In the context of that answer, we are concerned about the increased torque that raises the nose of the ...
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0answers
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What is the difference between flutter and vortex induced vibration?

During flutter, the airfoil oscillates with a large amplitude, which generates vortices at the wake. In vortex induced vibration (VIV) the oscillations of the airfoil are caused by the shedding of ...
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6answers
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Is there an aerofoil that gives reasonably good lift for both air flow directions: forward and backward?

Could an aerofoil be designed to give reasonably good lift for both flow directions? I was motivated by this related question on Aviation SE: Can a plane fly backward if its propeller is in reverse? ...
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11answers
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How do wings generate lift?

Just the basic question that every aviation enthusiast must be curious about: exactly how does a wing generate lift?
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2answers
151 views

How to calculate the amount of weight my plane can takeoff with?

This is how I approached this problem- My takeoff run is limited. So, depending on my configuration I calculated the maximum possible velocity I can attain in my groundroll. I assumed that at the end ...
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2answers
1k views

How does the line of thrust affect longitudinal stability?

I’ve been studying Pilots Handbook of Aeronautical Knowledge FAA-H-8083-25B and on p 5-17 they talk about thrust line and stability. Can someone explain why the moment changes when thrust is applied? ...
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4answers
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How does aileron reversal work?

I want to know how aileron reversal takes place when control reversal velocity is higher than divergence speed and operating speed is in between them (for conventional wing)
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1answer
585 views

Is drag coefficient lowest at zero angle of attack?

The drag coefficient of a symmetric airfoil is lowest when its angle of attack is zero. I'm not sure if this is true in general.
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2answers
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In the gyroscopic precession left turning tendency, why does a pitch down cause a forward force at the top of the propeller?

I'm a student pilot, and all the textbooks and online resources I'm reading show a pitch down as a forward force acting on the top of the propeller (causing the resulting forward force on the right ...
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4answers
2k views

How can we recover from a tailplane stall?

I was studying for icing and a tailplane stall. I have looked up some internet pages and instrument flying handbook, and found the procedure below. raise flaps to the previous setting. (To reduce ...
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2answers
1k views

What is the maximum theoretical lift of a plane as a function of engine power and surface of the wings?

Maximum theoretical lift of a plane as a function of engine power and surface of the wings? I know that the maximum static thrust of a propeller turned by an engine of power $P$ can not be greater ...
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2answers
304 views

Why doesn't Stratolaunch have connected tailplanes like it has connected wings?

As a complete layman, the design of the Stratolaunch airplane, especially when reminding myself of its size, seems too flimsy, in that the only connection between the two fuselages is the center wing. ...
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7answers
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Why are adjustable area jet engine nozzles mostly limited to military use?

It seems that only jet engines with afterburners use adjustable area nozzles (this means adjusting the area of the nozzle but not necessarily the direction). This includes most fighter jets, as well ...
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2answers
8k views

What is the typical temperature of an airliner's hull during flight?

Some high-speed military aircraft like the SR-71 had real heating problems, but airliners also travel almost at the speed of sound, use most of their fuel to make up for frictional losses, so I would ...
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2answers
516 views

How does having a bigger engine placed slightly more forward and higher impact the plane in pitch?

I'm asking about general aerodynamics for under-wing twin-jets – I'm not after information/speculation on the Max 8 crashes/systems, but I mention the crash below because of what I see as an unclear (...
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2answers
136 views

Pressure Distribution Pattern around Wing

it is clear that the overall integrated pressure on the top of the wing is less than the overall pressure at the bottom of a wing in order to produce a net nonzero lift force. Based on the attached ...
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2answers
101 views

Does load factor affect roll rate?

To be clear I am referring to a given aircraft at a given weight, speed, attitude, etc everything else the same except one is at say 0.5g and the other at 2.5g will there be a difference in roll rate ...
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2answers
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What is the difference between centre of pressure, aerodynamic centre and neutral point?

I have just started learning some aerospace concepts, and I am not able to understand the difference between the three terms centre of pressure, aerodynamic centre and neutral point. What are their ...
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1answer
522 views

How does the LIP package which is standard on the A320NEO enable to approach at a slower speed?

Could someone kindly explain as to how the lift improvement package on the A320NEO enable it to approach at a slower speed compared to the IAE CEO. I have the list of the modifications which is done ...
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1answer
109 views

How to calculate the power required during transition from VTOL to fixed wing?

In a VTOL, I have calculated the power required for take off and cruise which was not difficult at all. Between take off and cruise, there is a phase where the VTOL has to transition by tilting the ...
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4answers
171 views

Does Buoyant Lift Force scale with Load Factor?

Let's say I am flying an airplane that has a weight of 100,000 kg with a 1G load factor at normal steady flight. I have helium lift assist that is providing 50,000 kg (50%) worth of buoyant lift force ...
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2answers
101 views

How does engine geometry affect flight stability?

News items around the recent aviation accidents involving Boing 737 MAX 8 aircraft suggest, that bigger engine diameter demanded for a different (longer) nacelle strut for proper ground clearance ...
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4answers
318 views

Why does elevator input move the turn coordinator ball in steep turns?

When practicing steep turns, I'm running into an unusual phenomenon. If the airplane is losing altitude in coordinated flight and I apply aft stick pressure to pitch up and correct, I notice that the ...
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2answers
57 views

How does the advancing wing in a flat spin create nose thrust?

Peter's answer to this question leads me to another question. How does the advancing wing in a flat spin create nose thrust? I imagine this like some object spinning in a liquid. I would think ...
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2answers
180 views

Does lift generation create a vacuum over an airfoil? [duplicate]

According to Bernoulli’s principle, airflow speeds up over an airfoil which decreases the pressure, and I read somewhere that when airflow speeds up over an airfoil, this creates a vacuum. Is this ...
2
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1answer
107 views

Does speed or angle of attack generally have the greatest impact on total induced drag?

I know induced drag varies with speed and angle of attack in straight and level flight. Which factor primarily determines the amount of induced drag? The speed of the airfoil through the air, or the ...
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2answers
2k views

Do negative angles-of-attack create lift?

(wikimedia.org) A typical curve showing section lift coefficient versus angle of attack for a cambered airfoil. Based on the graph above, do negative angle-of-attack values create lift? How?
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4answers
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How do conventional missiles fly?

With the exception of cruise missiles, most missiles don't have any obvious lifting device. If you watch a missile being fired, prior to its rocket firing it does exactly what you'd expect: ...
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0answers
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Is there a relationship between 2D airfoil aerodynamic results and a revolution body from that airfoil?

The airfoil would be symmetric and the axis of revolution would be its chord line. Edit1: To clarify the question, suppose we have a NACA 0010. Then, using for example XFoil, I'm able to get, for ...
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1answer
74 views

Is there a way to calculate the perfect angle of incidence of a horizontal stab for a given airspeed?

I have a Grumman AA1. It’s been modified several times through stc’s to increase power and speed. The aircraft requires full nose down trim to fly level in cruise. Is there a way to calculate the ...
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1answer
368 views

What’s this vortex generator like thing below the wing?

In Barcelona’s El Prat Airport I saw some ceiling fans and noticed that they have on the lower part of the wings something that looks like a wingtip device or vortex generator. As far as I understand ...
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1answer
242 views

Could Falcon 9 fairing become glidable / flyable?

Reading and thinking about this and this questions on space exploration stackexchange, I was wondering if the fairing could shape itself, so that it becomes one stable and steerable gliding element ...
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1answer
411 views

Is there a way to avoid fuel loss caused by vaporization from engine heat?

Concorde had engines directly attached to the wings, close to the fuel tanks. Some fuel was evaporated due to heat. What were the reasons to not use pylons or some cooling system to limit this effect?
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1answer
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Airplane gently rocking its wings during whole flight

I was on a flight with a regional airline a while ago in a Bombardier airplane (if I recall correctly) where the airplane would slowly and gently rock its wings just a little bit on the whole flight. ...
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8answers
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How does stall depend on angle of attack but not speed?

Everyone says that the angle of attack is what determines a stall, not the speed. I understand the theory and understand that it is separation of the airflow that matters for stalling. However, I don’...
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4answers
95 views

Aerodynamics of lift [duplicate]

How can lift on a canvas covered airplane wing in level cruising flight be explained without introducing Bernoulli ? Both upper and lower surfaces are bulged out,which indicates lower than ambient ...
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2answers
77 views

Can I use the load factor to estimate the lift?

If I have a fixed aircraft as the baseline, then I am not sure the specific flight condition, can I use the load factor to estimate the lift on the wing?
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1answer
45 views

Why are some dynamic derivatives not included in DATCOM file? [closed]

I am trying to understand Flight dynamics, particularly I am using Missile Datcom to get aerodynamic parameters of a missile, then use MATLAB, simulink to simulate its trajectory. It seems there are a ...
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2answers
3k views

Why is the empennage of some aircraft not placed on the centerline?

Check the MD80's empennage below. Can easily tell it's not built on exactly centerline by naked eyes. Is that because aluminum joint or consider aerodynamics? I don't think it is manufacturing ...
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2answers
153 views

What is the difference between static and dynamic stall?

What are the static and dynamic stalls on the aircrafts wing? When would we encounter static and when dynamic one? What is the difference between them?
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7answers
5k views

Can aircraft other than rockets go to space?

I always wondered if it was possible for planes and other aircraft to leave the Earth's atmosphere. Normal commercial transport airplanes can fly pretty high, but then they need air to get the speed ...
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2answers
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Is the physical MAX8 design bad because software is required for the aircraft to stay airborne? [closed]

I'm not an aviator by any means, but one thing that has come up in recent conversations with friends is that the MAX8 is inherently unsafe because alone, unpowered, the craft is not 'aerodynamically ...
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3answers
2k views

Would a slotted “wing” work?

The early history of aviation is full of crazy designs, so please allow me this one: A span wise narrow gap in the wing halfway between the leading edge and the trailing edge. The door to the gap ...
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1answer
2k views

How do ground effect vehicles perform turns?

Considering that Wing-In-Ground-Effect (WIGE) vehicles fly with a rather low ground clearance, there is not much room for banking. How do WIGE vehicles turn? Do they turn just very slow with a low ...