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 do newer engines have such wide fan blades?
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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Can vortex ring state (VRS) be solved by shaping the blades so that the vortexes they produce are weak enough not to form a vortex ring?
Vortex Ring State is one of the hazardous states a helicopter can find itself into. VRS happens when a helicopter has low airspeed (and usually hovering OGE) and is descending. If the helicpoter is ...
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Can the S-64 Skycrane really power itself out of vortex ring state?
It's claimed (all over the web too) that the Skycrane is the only helicopter to be able to power itself out of vortex ring state. The claims says that it is possible to power out of vortex ring state, ...
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Would a winglet be able to work in supersonic airflow?
Of course, there is a reason why existing supersonic airplane designs do not use winglets in the same way that an airliner wing uses winglets. I imagine the parasite/wave drag penalty from a winglet ...
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Are there fixed wing planes that have a Vne above their terminal velocity with the nose pointed straight down?
Are there any fixed wing aircraft that will not exceed Vne if they are taken to their ceiling, engine is pulled to idle or shut down, and then the nose is pointed straight down? Lets assume they are ...
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Why does Vx have a relationship with thrust but Vy has a relationship with power?
https://www.boldmethod.com/learn-to-fly/performance/vx-vy-altitude-and-where-they-meet/
After I watch this article, now I understand the relationship between altitude and the rate of climbs.
But I ...
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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 ...
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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 ...
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Delta wing RC aircraft unstable
I've been building and testing an tailed delta wing'd RC aircraft, but it has seemed that the plane is extremely pitch happy and tends to somersault when at high speed, is there some type of easy fix? ...
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If you could put multiple smaller ejector pumps in the same space, would it work better than one larger ejector pump?
I saw somewhere how, for Dyson bladeless fan systems to work for hovering, you'd need an entire grate of ejectors rather than a single ring. However, if you had five ejectors in the same space, each a ...
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Why is more angle of bank (AOB) at the best gliding speed giving less altitude loss?
Reading the manual for the T6b (turboprop aircraft single engine), it says different altitude losses during a 360 degree turn, holding 125 kts (the best glide for range speed), power is either dead, ...
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Can the use of flaps reduce the steady-state turn radius at a given airspeed and angle of bank?
Note that for the purposes of this question, I am only interested in the scenario described below. By 'steady-state' I mean to exclude from consideration the short-term effects of changing the flap ...
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By aircraft design, excluding engine power, how do you make planes that have a tight turn radius while maintaining speed?
What are all factors in design, excluding engine power and acceleration, thrust vectoring and flight computers, that makes a plane that have a real tight turning radius while maintaining speed? Like ...
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How to calculate angular velocity and radius of a turn?
How can I calculate with known tangents of different angles and by rules of thumb?
Which formulae should I use for fps and NM?
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Oswalds efficiency factor for trapezoidal wing
For a part of my university project we have to approximate 2d to 3d data ideally using oswalds efficiency factor, the equations given to us are for either rectangular or swept wings however the wing I ...
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Is it feasible for an individual with limited current knowledge to undertake the development of an aircraft from scratch? [closed]
The world of aircraft engineering is truly remarkable, and even the smallest components involve a wealth of knowledge. I'm eager to explore this field and embark on the journey of building an aircraft....
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How do uncoordinated turns (skid, slip) affect a helicopter's turn radius?
Is a helicopter's flight path (track made good) an arc of constant radius regardless if it's a coordinated or uncoordinated turn? (Assume nil wind conditions and that the pilot maintains the angle of ...
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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 ...
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How deliberately stall fixed wing reduce drag if stall decrease static pressue? [closed]
In this VIDEO at 5:40 we can see how stall decrease pressure at upper wing surface.
If stall/flow separation reduce static pressure how in this VIDEO they reduce drag when stalling the wing?
Here is ...
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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 "...
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How to calculate lift and drag coefficients of an airfoil with slotted flaps?
I am doing a project attempting to determine the increase in lift and drag coefficients of an airfoil as the angle of its flap increases. In my research, I have found the thin airfoil with flap ...
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How do swept back wings delay shock wave
Swept back wings can delay the formation of shock wave and increase the aircraft critical mach number of the aircraft, right? But how
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General Thin Airfoil Theory
I can't understand where the equation in the blue circle comes from or is derived from, I know it says the sum of the perpendecular components should be zero, but can you explain visually? and what ...
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Why does a rectangular wing stall at the root first?
Study of countless aerodynamic questions and answers on this site has reshaped my understanding of both lift and and induced drag.
Questions like this: How does an aircraft form wake turbulence? have ...
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Why does a flat plate create less lift than an airfoil at the same AoA?
This picture of the lift curve slopes for four-digit NACA airfoils and a flat plate is from another question on this topic. It shows that at the same positive AoA, a flat plate generates less lift ...
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Why do airplanes usually pitch nose-down in a stall?
Why do airplanes usually pitch nose-down in a fully-developed stall?
I've seen this seemingly-simple question discussed on other aviation forums, but there doesn't seem to be a single agreed-upon ...
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Confusion about center-of-lift vs center-of-gravity [duplicate]
As usually depicted, in a small aircraft (maybe larger commercial ones too), the lift due to the main wing (excluding the elevator) is depicted as on average aft of the center of gravity, with the ...
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Do airliners stall first at the wing tip?
One of the disadvantages of the sweepback aircraft is the tendency of a stall to occur at the wingtip first. Various high lift devices are added by design to the wings of the sweepback aircraft like ...
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Ram Rise and Total Air Temperature explantation [duplicate]
Since ram rise is the same as total air temperature, why does Total Air Temperature minus Static Air Temperature give ram rise? What is really the meaning of ram rise: is it the kinetic components ...
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Spanwise location of mean aerodynamic chord for Swept Wing
How would I calculate the spanwise location of the mean aerodynamic chord for a swept wing?
I see a general formula for an elliptical planform wing, but having trouble finding anything on swept wings.
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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....
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Should I advance my propeller lever forward during a glide?
I am reading the FAA Airplane Flying Handbook, chapter 3. It says:
To enter a glide, the pilot should close the throttle and, if equipped, advance the propeller lever forward. (...)
Why do we ...
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Is more rudder pressure needed in gliding turns than normal turns
The FAA Airplane Flying Handbook says
the rudder compensates for yawing tendencies when rolling in or out of a gliding turn; however, the required rudder pedal pressures are reduced as a result of ...
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Do you pitch the nose up or down when flying at best glide speed during a glide
So in a glide, flying at the best glide speed, will you be pitching the nose up (nose points above the horizon) or pitching the nose down (nose points below the horizon) or does it depend?
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Cause of Drag From Windmilling
I know that when a propeller is windmilling it creates drag, I assume this is from the propeller being flat against the air causes drag, but propellers are designed to essentially pull an airplane ...
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How attitude, speed, and altitude vary when increasing pitch?
I have been struggling with the following question for a while, would greatly appreciate some help and explanation why.
Scenario:
I'm cruising in my Cessna- cruise attitude 2300 RPM trimmed for 95.
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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.
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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?
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Why do airplanes lift up their nose to climb?
Is it right that basically an airplane just needs to accelerate to climb?
Greater velocity of an airplane leads to greater lift - and since its weight remains constant (or even decreases) - a greater ...
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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 ...
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Can I climb with no excess thrust [duplicate]
I've been searching on the internet about this question and all say you are not able to climb with no excess thrust. But I am wondering that if I have no excess thrust, can I still climb in exchange ...
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Is more lift needed for a stabilized climb [duplicate]
First, the photo depicts a vector diagram during a climb. L means Lift. Lv means the vertical component of lift. Lh means the horizontal component of lift. T means Thrust. D means drag. W means weight....
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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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Why does a turbulent boundary layer cause more friction drag than a laminar boundary layer?
From what I understand, friction is caused by viscosity and a bigger Reynolds number signifies lower viscosity.
Thus, a higher Reynolds number(i.e. turbulent flow) results in lower friction.
But, ...
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Circulation around an airfoil at negative α
I was recently reading this very helpful string What is the physical meaning of circulation found in Kutta condition? and it explained very nicely potential flow around an airfoil. My question then is ...
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What are some of the advantages of inverse-tapered wings?
Inverse tapered wings are rarely used in aviation. The only legitimate plane I know about with inverse-tapered wings is the XF-91 Thunderceptor. So why aren't they used. What are the disadvantages of ...
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Does the X-59 comply with the "area rule"?
The Lockheed Martin X-59 was rolled out yesterday :-)
Brett Tingley, Watch NASA's sci-fi-looking X-59 'quiet' supersonic jet roll out of the hangar, August 2023.
I am no expert here (and no English ...
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In a plane with airbrakes, such as a glider, how do slips and airbrakes interact?
While adding a slip to enhance my descent rate, I got to thinking that the airbrakes might be losing effectiveness as the slip twists them out of the relative wind. This thought arose because I did ...
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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 ...
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Is this method to calculate a biplane's center of gravity using 57% of the biplane's gap and 23% of each wing's MAC correct?
Once you have the MAC for both wings and the CG balance point as a percentage of the MAC. connect the two CG positions with a line. Measure up between the wing Gap distance and place your center of ...
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