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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12
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3answers
6k views

Why does the Cessna 172S Skyhawk use only two blade fixed pitched prop?

Surely it would get more thrust from a three blade variable pitch propeller. From what I've read it's all about the area swept and also should be far enough apart to not cause too much interference. ...
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Why do many ram air inlets have this shape?

I often see this particular shape for ram air inlets. Here on an older 737 It's stretched on the newer 737's but still the same basic shape A also see it a lot on cars. 1979 Camaro Z28 ...
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1answer
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Why do some commercial aircraft have no landing gear cover? [duplicate]

The B737 has no cover on its landing gear, as may be seen in this picture. Doesn't this increase the air drag? Almost all other airliners have doors that close off the rubber of the wheels, for ...
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Thought experiment: can an aircraft that is dropped from the sky get into gliding? [duplicate]

Here's a totally hypothetical question that came up in a discussion with friends: If a commercial aircraft (say, an Airbus A320) was "dropped" from a typical cruising altitude (say, 35,000ft) with a ...
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Any info on very strange wing endings on this Stemme glider?

Do you have any info on this strange wing endings used on Stemme glider? Source
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What causes hunting movement in helicopter rotors?

The blade of an helicopter rotor can have three hinges: pitch hinge, flapping hinge and lead-lag hinge. Lead-lag (dragging): movement of a blade forward or aft in the plane rotation. Lead lag is ...
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1answer
484 views

How do aerodynamic loads explain the Spaceship2 accident?

From the NTSB's preliminary report, we read in the "Findings" section: Although the copilot made the required 0.8 Mach callout at the correct point in the flight, he incorrectly unlocked the ...
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What are lateral, longitudinal and directional stability? [duplicate]

When we talk about aircraft having a stable configuration, it refers to lateral, longitudinal and directional stability. Can someone give a practical explanation of what those are and how they work?
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Stalls: which flight control surface is effective last?

In an aerodynamic stall, which flight control surface (limited to ailerons, elevators and rudder) remains effective for the longest period of time during the stalling condition? In other words, which ...
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1answer
252 views

what would happen if we use needle shaped nose in blended wing?

We are using blunt shaped nose in blended wing,instead of blunt,if we use needle shaped nose what would happen ,it reduce shockwave or it produce bow shock?
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1answer
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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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Why aren't thin, delta-shaped wings used for fighter aircraft?

In the past, we used thin, delta-shaped wings (ogival wings) such as those on the Concorde. These wings can be used up to mach 2.2. Due to high fuel consumption, these wings are no longer used ...
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How is pitch controlled in a flying wing?

How do delta wing or flying wing aircraft maintain their pitch attitude in the absence of an elevator? I understand that the ailerons on the wings do control the banking/roll, but they are ...
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What is (theoretically) the most efficient shape for an aircraft, assuming you don't have to carry any cargo?

Assuming that you don't need to have any large piece on the underside dedicated to storage area/people (as all planes do) and you don't care about stability, what is the most energy efficient form for ...
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Why does the yoke “stick” in a turning position?

As you make a turn, an airplane does not naturally straighten itself out (like a car does to some extent). Are ailerons engineered to stay in whatever position they are placed, or is this simply a ...
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What is the typical fatigue life of a helicopter airframe? [duplicate]

For military helicopters such as the Sikorsky UH-60 Black Hawk, what is the typical fatigue life of a helicopter airframe (in cycles and hours) ?
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How does a 'Highly Swept leading-edge' delta wing reduces fuel burn and increases range? [duplicate]

Spike Aerospace claims to have designed an aircraft called S-512, with maximum speed of 1.8 mach and cruise speed of 1.6 mach, speaking about the notable changes in the aircraft, Spike Aerospace says:...
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What are the vertical pieces of metal on the Slingsby Swallow wing for?

I was watching James May's Toy Stories, particularly the one where they try to fly a glider across the English Channel. In the middle of the episode they mention a glider that was used for training ...
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Is the commonly assumed UFO (flying saucer) design aerodynamically efficient? [closed]

Is this design, a circular disc (or flying saucer) slightly humped on the top and bottom aerodynamically efficient? And if, we are able to use it for commercial purposes , would they give a better ...
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3answers
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Why couldn't my aircraft depart fully fueled on a 44C day?

My flight from Abudhabi to SFO was postponed. Official reason given to us was outside temperatures were too high - around 44+ degree Celsius and aircraft can not take off with full fuel loads at such ...
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1answer
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What is the difference between types of propeller? [closed]

I have been noticing almost every Multirotor vehicle uses a single thin double-bladed propellor on each axis. And yet clearly, there are some that do not fit the norm. Can someone explain what the ...
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1answer
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Why most of the supersonic or fighter aircraft use all-moving control surfaces?

What are the advantages of using all-moving control surfaces? can someone give explanations based on aerodynamics?
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Why does a missile have small wings but better agility than a plane?

An anti air missile has often very small wings but out performs a fighter aircraft, e.g. much higher g-load, since g-load comes from lift which is the area of wing. Why not designing an aircraft like ...
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Can airliners benefit from vertical take-off and landing?

A vertical take-off and landing (VTOL) aircraft is one that can hover, take off, and land vertically. We have several military fighter jets, which can takeoff and land vertically (like the Harrier ...
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How is the area rule applied on airliners like the A380?

Wikipedia says that because of the area rule's impact on wave drag: aircraft have to be carefully arranged so that at the location of the wing, the fuselage is narrowed or "waisted", so that the ...
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Would solar panels on the wing of an aircraft increase drag?

If a small scale UAV (wingspan <2 metres) was to be fitted with solar panels on its wings to have more power available, would the addition of these panels cause an increase in the drag coefficient, ...
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1answer
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How does a wing mounted jet engine on a supersonic airplane prevent the interference in the flow due to Shock? [duplicate]

Wing mounted jet engines face the free stream at Mach number 1 or above, and they work perfectly for Mach numbers below 1 as well, even though the free stream characteristics change a lot after Mach 1....
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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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How do modern helicopters tackle Vortex Ring State?

According to the wikipedia page : Air vortices can form around the main rotor of a helicopter, causing a dangerous condition known as vortex ring state (VRS) or "settling with power". In this ...
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1answer
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How to calculate the fuselage geometrical parameters?

How I can calculate the fuselage midsection having a constraint length? Also, if I want a cross section shaped like an Antonov that on top of it have a lower ratio than the bottom, as that is part or ...
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Is it possible for an airliner to safely fly with doors open?

From another question asks about the possibility of dropping bombs from converted airliners. My question: is it possible to safely fly aircraft with a door open for the whole flight envelope? Would ...
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What is P-Factor in Propeller Aerodynamics? [duplicate]

What is the P-Factor when we're talking about a Propeller Aerodynamics ? Thanks
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Why do the missiles on an F-16 point slightly down?

I've been wondering this for quite a while: Why do the missiles on the F-16 point down a little bit? I went and did a little searching and found out that the F-16 isn't the only plane that has this ...
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What is the working principle of trim tabs on the elevators?

Trim tabs are used on the tail's horizontal elevators to adjust its neutral position. What is the working principle behind this? How does this affect the sensitivity (the feel) of the pitch to the ...
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Can a plane with 2 sets of shorter wings fly?

I am proposing a plane that has 2 short wings of the same size on either side of the fuselage (two in the front and two in the back). Rather than using the horizontal stabilizer to destroy lift, the ...
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How does take off mass impact induced drag?

In this answer to another question, it was stated that: Take-off mass: If you take no payload, the aircraft will produce less induced drag and reach a slightly higher range How does a change of ...
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Why don't all wind tunnels use magnets to suspend models?

NASA and the French aerospace agency have conducted research into magnetic suspension and balancing systems (MSBS) to suspend models during wind tunnel tests, like this system in South Korea. Where ...
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Where does ice collect first on a wing in flight and why?

I've seen some reports that say ice forms on the back half of the wing and on the outside edge of the wing (the part furthest from the body) before it will form anywhere else. I'm wondering if this ...
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How can opening of a door on small plane cause a drop in altitude?

Last week in Ecuador I was on a flight in a small plane (twin engine prop, full with pilot and 5 passengers). The passenger door opened in flight. I was in a position to grab the door and pull it back ...
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1answer
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What are the opimum values of Cl during descent?

Statistical Analysis of A320 aircraft shows the Cl values to be as under: cl_value. L is assumed to be 0.5*MaximumLandingWeight of A320 as the Aircraft is about to land. The Units used are: Flight ...
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Will wind tunnel modelling ever be completely replaced by computer models? [closed]

With computer-based fluid simulation already being extremely realistic (and likely faster and cheaper than physical wind tunnels), are they, anywhere, completely replacing physical wind tunnels? If ...
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1answer
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What are the pros and cons of having canard control surfaces versus a horizontal tail control surface?

For a normal civil aviation aircraft, what are the pros and cons of having Canard control surfaces or horizontal tail control surface?
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What happens after a rudder hardover?

I'm sure many of you are familiar with "rudder hardover", where an aeroplane's rudder deflects to an extreme position - full left or full right. Many of you will be aware that such an event, caused by ...
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Is excess lift or excess power needed for a climb?

As answered in this question, aircraft need excess power - not excess lift - to climb. This is plausible when the aircraft's thrust vector has a vertical component (its nose and engine points upwards),...
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Why isn't the V flight formation being used for commercial purposes?

The V Flight Formationhas been found to be helpful in achieving greater fuel efficiency and range. Though it is currently used mostly for military purposes, what restricts it from being used for ...
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What is the working principle of a Gurney Flap?

Recently I came across a airfoil improvement called a 'Gurney flap', see image. I don't really understand the working principle of a Gurney. Wikipedia states: The Gurney flap increases lift by ...
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Why is stall speed listed in a POH?

In this comment on this question about stall warning systems, it was stated that: You can stall at any airspeed (see this question and this one) and in any attitude, only the AoA is important ...
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What is the function of the tail section on a fixed-wing aircraft? [duplicate]

In a generic fixed-wing aircraft like a Cessna, what is the function of the tail section, i.e. the rudder and elevators?
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1answer
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Where does the flat plate theory in this paper come from?

The aerodynamic model cited in this paper (pdf) as "flat plate theory" was a good first-order approximation of the aerodynamics of a perching glider. I immediately saw the similarity with the ...
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1answer
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How did flight 2574 break up?

My understanding of Continental Express flight 2574 is that a de-icing boot on the horizontal stabilizer of the EMB120 was missing screws and therefore detached, leading to the tail separating. I ...