40

The wing was swept to move the center of lift back, closer to the center of gravity. When the design of the DC-1 was advanced to a point where the center of gravity became clear, a redesign of the wing-fuselage intersection would had been more effort, so the outer wing panels were swept back a little. From this website by Jeff Lucker: the unique and ...


24

Sweeping a wing costs weight, for several reasons. Therefore, if the goal is to fly high and achieve long range, an unswept wing is the better choice. Only when transport performance needs to be maximized will a moderately swept wing look better. Why is a swept wing heavier? Sweep reduces aerodynamic efficiency, so a larger wing is needed to create the ...


19

The tail sweep helps to extend its range of angles of attack. For both stability and control, it is very important that the tail doesn't stall before the wing in any circumstances (for a classic design; for canards it may be beneficial). Generally, for high positive angles of attack, the horizontal tail already has an edge because it is set at a lower angle ...


17

Disadvantages of wing sweep Lift curve slope is reduced by the cosine of the quarter chord sweep angle. This means more angle of attack for takeoff, which requires a longer take-off run and a longer landing gear to avoid a tail strike on rotation. If you rotate the airplane, the tips of backward swept wings come down when the aircraft rotates for take-off. ...


17

It was obvious to the design team that conventional aircraft could not satisfy the required specification; knowing little about high-speed flight and unable to glean much from the Royal Aircraft Establishment or the US, the team at Avro investigated German Second World War swept wing research. The team estimated that an otherwise conventional aircraft, ...


15

MiG-23 For the MiG-23, it was manual. [The] MiG-23 had a completely manual wing sweep control. But there was no gauge to indicate optimum wing position for the surrounding conditions. "You had to manually put the wings into position to safely fly the airplane," (...) "They had a very nice gauge that showed where the wings were commanded to, where the ...


12

Wing sweep improves the performance by delaying the shock waves and accompanying aerodynamic drag rise caused by fluid compressibility at high (near sonic) speeds. However, there are some disadvantages associated with the wing sweep like: Wing sweep reduces the slope of the lift curve and the maximum lift coefficient of the wing. This means that the swept ...


10

I finally found several arguments to answer this question from different sources. Sweep and Mach Number from Airbus This argument is developed in an Airbus magazine from 1985. To grasp it it is important to understand the purpose of swept wing. By sweeping the main wings one introduces an angle between the leading edge of the wing and a line perpendicular ...


10

The oblique wing and the swing wing aim to reduce the drag over a wide range of speeds by changing the wing sweep. While the swing wing rotates a part of the wing to achieve this, the oblique wing rotates the whole wing. The first production aircraft with variable sweep wings was the F111 Aardvark, while the most famous one is the F-14 Tomcat. "F-14 Tomcat ...


8

Basically, because of its mission requirements. It wasn't intended to fly fast, and because it didn't need to go particularly fast, there was no need to sweep the wing. Instead, it was supposed to provide a massive amount of data (by 20th century standards) along its flight path, which necessitated long flight times: thus the long, straight wings providing a ...


8

Advantages of an oblique wing over swing wings: Low wave drag due to favorable volume distribution over length. Lower structural mass. The hinge of a swing wing is heavy! No shift in the center of lift (if the sweep angle is higher than the Mach angle). A swing wing experiences a severe shift in the center of lift. Disadvantages of an oblique wing over a ...


8

I would not say that no other bomber ever had delta wings. Convair B-58 Hustler and Mirage IV both have delta wings. They are both supersonic though. The B-52 did not have to worry too much about MTOW and empty weight since SAC already had bases with long runways capable of really heavy aircraft. That's thanks to B-52's predecessor B-36. The B-36 was the ...


8

Mark is right when he says that there is no induced drag at supersonic speeds, but it is an invitation for misunderstandings. Induced drag is replaced by lift wave drag, and all what happens is that aerodynamicists choose to use two different names for basically the same effect: Air gets pushed down. As usual when I post a long answer, I was not quite happy ...


6

Yes it could, but don't hold your breath. Forward sweep means that the aeroelastic forces will twist the wing at high lift into an increased angle of attack, so such a wing needs to be stiff in order to avoid divergence (PDF!). Also, aileron effectiveness is excellent, so a forward-swept configuration is a good choice for dogfighting. Since backward sweep ...


5

The two pictures in the question only show how to decompose the speed vector into the normal and parallel components. They are nowhere near "real" flow vectors. First I recommend to read this answer so you get an idea how air is accelerated and decelerated when flowing around an airfoil. Note that the low pressure area over the wing will suck in more air. ...


5

A swept wing has less torsional strength than a straight wing, ie there's less structure at 90d to the root supporting the tip of a swept wing. Thus a swept wing twists when it's loaded, which unloads the tips and thus generates less lift at higher weights.


5

There is no magical switch that gets flipped once you cross a specific sweep angle. Things are gradually changing with the cosine of the local sweep angle. Now let's look at your questions one by one: What happens to the wingtip wake on a forward-swept wing? Nothing special. It is part of the full wake system and behaves like in any other aircraft of ...


5

In supplement to @Dave's answer and as he said depending on the airplane, the complexity of calculating the c.g. can vary greatly. The manufacturer of every large aircraft I've programmed weight & balance for has had tables for each tank. In Boeing's case for the 747-400, each table line is a tank volume in gallons and the tank c.g. at that volume in ...


4

Yes. Variable sweep airplanes exist and it shouldn't be a problem to design a system able to sweep the wings forward and rearwards. However, the few aerodynamic advantages of the forward swept wing at low speeds doesn't justify the added complexity, weight and loss of space inside the fuselage.


4

The pivot wing, also called oblique wing is a type of wing design that tries to minimize the drag over the entire speed range of the aircraft. At low speeds, the main concern is the induced drag, which can be reduced by increasing the aspect ratio. That is why low speed aircrafts like gliders have very long slender wings. As the speed increases, the ...


4

Sweep is not strictly required, but helpful to increase supersonic L/D. Just witness the length to which aircraft manufacturers went to sweep wings for Mach 2+ flight. However, sweep comes with its own set of problems.


4

One aerodynamic behavior appears at high angle of attack : dihedral or anhedral wake, which affects (in some weird mixture) both roll and yaw stability. Forward swept trailing edge is much more stable than backward swept trailing edge. Some jet fighters (let's say F-22) and most aerobatic airplanes (let's say SU-31) adopted forward swept trailing edges in ...


4

The tail is swept to move the aerodynamic center aft to provide more "leverage" for the tail in generating down force. Same as sweeping the fin, although that is also for looks. If the airplane had a straight fin and straight horizontal tail, the tail surfaces would have to be larger to have the same tail "volume" (area x moment arm) or the fuselage itself ...


4

They simply have enough thrust to do so with their given wing. There is no rule that high speeds are associated with variable sweep wings or that you need such a wing to go fast. As a matter of fact many of the testbed super sonic aircraft as well as the really high speed stuff dont have swept wings. Wing design can effect efficiency (which may or may not ...


4

You will need to consult the POH for the airframe in question and see what it says in regards to fuel burn from tanks at different moment arms. Ultimately you will need to program in the variable factor of fuel burn. It sounds like the program will have more inputs than just the weight of the passengers, fuel, and cargo. The end user will also need to input ...


3

A swept wing would most likely adversely affect the handling of a U2 during a typical mission profile, and would adversely affect the structure required (weight) of the aircraft. A swept wing adversely impacts the stall characteristics and stability when flying near a stall. It should be noted that while a swept wing helps manage effects due to the ...


3

The aim of parallel isobars on the wing is to generate quasi two-dimensional flow. Let's say, the layout is set. You shaped the wing in a way to 'force' the isobars to be parallel with the sweep - the entire span. You now (should) have the same pressure distribution in every single profile of your wing. This eases your calculations extremely!


3

The easiest way to sweep a wing is an oblique flying wing. This is essentially a straight wing with pivoting rudders and engine pylons which flies at an increasing angle of sideslip where a swing wing aircraft would fold its wings back. Oblique flying wing (picture source) If you want to know more, I suggest to read this website. Excerpt: Although the ...


3

Most twin engine jets have one very long tank in each wing for each engine and often a center tank that feeds both. The fuel shifts forward as fuel is consumed from the wings (dihedral plus sweep), and aft as fuel is consumed from the center tank, if installed (always before the wings, so if there is a center tank the C of G moves aft until the tank is dry ...


2

For a given lift coefficient, boundary layer drag is smaller for the straight wing configuration, and lift-induced drag is larger for straight wing. These conflicting effects may give an advantage to straight wing at low subsonic speeds. At speeds of about Mach 0.8 you begin to get wave drag because the flow over the wing is not uniform, and in some ...


Only top voted, non community-wiki answers of a minimum length are eligible