# Questions tagged [wing-sweep]

Angle of a line from root to tip, 25% of the way back from the leading edge, measured from the perpendicular to the longitudinal axis of the aircraft.

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### Why does F-18 have low wing sweep?

Compared to most other fighters, the f-18 has a low sweep angle on its wing; 20 degrees compared to the f-16s 40 degree sweep and f-15s 45 degree sweep. Additionally the wing has a relatively high ...
6k views

### How I determine numerically the roll rate of an aircraft?

I'm a Spanish student of aerospace engineering and I'm doing my final bachelor work that consists in designing an unlimited aerobatic plane, and I wonder if it is possible to calculate an ...
74 views

### Lift distribution of a swept wing with twist, dihedral, taper

I am trying to get the lift distribution of a swept wing with taper (in chord and thickness along the span), twist, and dihedral. I know that Kuchemann Index method is used for swept wings but I am ...
1 vote
240 views

### Why did the F-14 sweep wing control have a cover?

I learned from Top Gun maverick that the F-14 had what seemed to be a metal cover in front of the wing sweep adjustment cursor. Maverick modifies the sweep angle twice, and twice needs to first lift ...
844 views

### Swept outer section of the wing on turboprops

It's quite common to see turboprops having a wing with the outer part of the wing with a small sweep (around 3 deg at 1/4 of the chord). What's the reason? It's usually stated that wing taper is used ...
219 views

### What are the effects of a corrugated surface on spanwise flow deviation, for a swept back flying wing?

Considering a Ju-52 wing in some hypothetical swept back flying wing configuration using the same strucural design as the Ju-52. What would be the effects of that corrugated skin, regarding spanwise ...
246 views

### 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....
695 views

### 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
1k views

### 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. ...
69 views

### How does wing sweep impact lift? [duplicate]

Given that swept wings (according to a google search) decrease lift, how much is lift affected? Why are they so commonly used in aircraft nowadays, like the SU-27, and subsonic aircraft like the ...
6k views

### Why is the coefficient of drag for straight wings at supersonic speeds lower than for swept wings?

Why is the coefficient of drag of a straight wing lower than the coefficient of drag of a swept back wing at higher supersonic speeds (above, say, Mach 2)?
53 views

### Literature request for effect of Aspect Ratio and Wing Sweep on critical angle of attack?

So I'm trying to find academic literature detailing how both aspect ratio and taper ratio affect the critical angle attack of an aerofoil - namely for a v. low AR wing (AR<1), and high sweep (~75 ...
21k views

### Where is the spanwise flow? How does the span wise flow point the air towards the wingtip?

If you search Google for span wise flow, the first result under the pictures tab is a image of a wing with the span wise flow at the trailing edge: (Source) If you look at some other photos you ...
168 views

### Impact to lift curve slope for a tapered wing with only trailing edge sweep?

I'd like to use a tapered wing with 0 deg leading edge sweep and 12 deg trailing edge sweep as shown below for my RC model. I understand that lift curve slope, a, is reduced for wings with leading-...
3k views

### How does a variable-sweep-wing aircraft keep wing-mounted payloads straight?

So, a variable-sweep wing is an interesting design, but I am wondering: if the aircraft wing moves back or forward, then the payload's angle will also change. Is there a another rotating mechanism in ...
885 views

### If sweep delays compressibility, why does 747 cruise slower than A380?

B747 has a sweep angle of 37 deg and A380 has a sweep angle of 33 deg. If the main reason for sweep is to delay compressibility effects and increase operating Mach number, why does B747 cruise at a ...
701 views

### Comparisons between the A340 and 747-200 wing: sweep angle and span

Here is a picture of the wings of the A340 (launched in the late 1980s) and the Boeing 747-200/400 (launched in the early 1970s / 80s) superimposed upon each other (source: https://www.amazon.com/...
2k views

### For aircraft with variable-sweep wings, how unstable is it to have each wing in a different position?

Wikipedia presents this photograph of an F-14 Tomcat, with one variable-sweep wing swept forward and the other back: I was surprised to see that this configuration was possible; much less feasible or ...
1 vote
390 views

### Why do most canards have swept wings?

So most canards have swept back wings. Now I have been told that it is that way to ensure yaw stability (for example in a crosswind) - not sure though. But then I look at the new Lilium jet, which is ...
811 views

### How do the orientation of spars and ribs affect the aerodynamic efficiency of wing?

There are various ways the ribs and spars can be oriented in the swept wing. Do the placement of ribs and spars affect the aerodynamics? And, what are the structural advantages of both orientations ...
128 views

### How would I draw the Max Thickness Sweep Angle on a wing from a Top View?

I have the Max Thickness Sweep Angle, Wing Tip and Root Chord Length, and Max Thickness to Chord Ratio defined. However, I am having trouble drawing the Max Thickness Sweep Angle on the wing because I'...
4k views

### What is the aerodynamic benefit of trailing edge sweep?

Sweep will allow flight at higher speed because the perpendicular air flow speed (over wing) is less. But why is there trailing edge sweep? We can have a swept leading edge and unswept trailing edge ...
2k views

### Taper sweep angle

Is the Taper sweep angle the same as the sweep angle? So I know that the sweep angle is the angle from the vertical line from the leading edge to leading edge wing line.
189 views

### How does forward sweep of a wing affect the formation of shock waves?

I understand that sweeping a wing back reduces the component of velocity perpendicular to the wing and can allow it to travel at subsonic conditions, and reduce the formation of shock waves, even if ...
394 views

### Jettisonable wingspan for early long-range airplanes

Reading this question, I was wondering if, at some point early in aviation history there may have been designs or concepts anticipating variable swept wing by "expendable wingspan wing"? For ...
1 vote
427 views

### Does the quarter-chord-angle rule still hold for wings with very long chords or large differences between leading- and trailing-edge sweep angles?

For most fixed-wing aircraft, the effective wing-sweep angle (i.e., the angle that the aircraft aerodynamically behaves like its wings are swept at) is equal to the angle of the quarter-chord line (...
1k views

### Why is sweep angle measured at the 25% chord?

If you look at wing planforms of e.g. the Spitfire, you can see that the sweep measured at the 25% chord line is 0°. However, the leading edge is rounded/slightly swept and therefore induces spanwise ...
629 views

### Swept back wing theory

I'm a beginner in airfoil design. I just came across swept-back wings. There is a point that I couldn't understand that theory. Why is the only perpendicular component of the airflow to the wing(...
1 vote
315 views

### Why doesn't a wing in supersonic flow produce a shock that results in flow parallel to the leading edge?

When we look at a wedge in supersonic flow, a shock emanates from the leading edge such that the flow after the shock is turned and is parallel to the airfoil surface. The shock angle is based on the ...
2k views

### Why are Vertical tails generally tapered?

I'm just intrigued to know why the vertical tail of a majority of aircraft is tapered? Is it due to aerodynamics, structural design or due to some instrumentation or multiple other reasons?
288 views

### What is the purpose of the fin sweep on small piston airplanes? [duplicate]

Why some small piston airplanes, like Cessna 152/172, Tecnam P2008 and many more, have the vertical stabilizer with a sweepback? I don't think that those airplanes may encounter compressibility ...
91 views

### What characteristic my canard needs to have when the canard also carries a pair of engine?

I am in 3rd year Aerospace Engineering and trying to do a preliminary design of an airplane. My design has a front wing that also has an engine at its root on both side of the fuselage. There is ...
630 views

### Could an arrow planform be better for a supersonic aircraft than a delta? Why?

From this review paper Page 11: Strut-bracing for the SST allows very significant reductions in both vortex and wave DDL via an extreme arrow configuration and could be favourable to LFC via reduced ...
2k views

### How does one calculate the Mean Geometric Chord in extended Trapezoid Wing?

The general formula to calulate MGC of a wing is given for a trapezoid in many books but there isn't an example showing how to calculate it for a wing shaped like the one below. I tried to solve ...
1 vote
821 views

### Difference in lift generation for a swept wing and straight wing in subsonic condition

Would there be any differences in lift for a straight wing and swept wing (front or back) with the same airfoil cross section, same chord length, same wing span, and same area when flying in subsonic ...
602 views

### Can wing sweep decrease total drag force at low-subsonic speeds?

From experience everybody knows if you put your arm out of car window at high speed(150km/h), it's a lot easier to hold arm angled backward then hold arm straight out(prependicular to airlfow).So ...
200 views

### Why do semitailless swept-winged aircraft, but not delta-winged aircraft, suffer from (primarily) pitch oscillations at high mach?

Semitailless1 swept-wing aircraft without active stability enhancement2 generally3 have extremely poor handling characteristics, most notably a tendency towards violent pitch oscillations at high ...
904 views

### How ribs angle change wing overall shape? [closed]

How ribs angle change wing overall shape?
3k views

### Why does the U-2 Dragon Lady not have swept wings?

Swept wings increase the critical mach number for aircraft with otherwise identical wings (Source 1). The U-2 Dragon Lady is limited in altitude by its critical mach number, as it needs more speed in ...
3k views

### Does an increase in lift always cause an increase in lift-induced drag?

An increase in lift causes an increase in drag. Is it always true? I am confused with two points. Lift increases with an increase in airspeed but induced drag reduces with an increase in airspeed. ...
1 vote
462 views

### Tapered Wing Providing low Coefficient of Lift

Hi I am currently analyzing different wing designs using ANSYS Fluent. One of my designs has a straight leading edge but a swept trailing edge thus it is tapered with wing root chord at 50mm and wing ...
2k views

### Why do swept wings decrease the drag increase that occurs in transonic flows?

Swept wings are used in aircraft that fly in the transonic regime because they 1) delay the critical Mach number 2) reduce the drag increase that occurs (smaller drag divergence). I am trying to ...
935 views

### Is airflow deflected inwards or outwards by wing sweep?

We are often told that wing sweep causes the airflow to be deflected outwards. I can understand this for the underside, but for the upper surface it seems inconsistent with other effects. For example ...
18k views

### What is the reason for the poor low-speed characteristics of sweptback wings?

I know there are advantages of swept-back wings delaying shock-wave allowing a aircraft to fly faster. However, what are the disadvantages. I know one of them is that they have very poor low speed ...
1 vote
793 views

### Why don't commercial airliners use variable sweep wings? [duplicate]

I know they're not used in military aircraft because it decreases the stealth factor, but why don't commercial plane manufacturers make variable sweep planes?
2k views

### How do I factor sweep and dihedral in the lift equation?

I'm guessing that you add cos(angle of dihedral) to calculate lift loss by dihedral, but I'm not sure how to factor in the lift loss by the wing swept. Could someone help me include lift loss due to ...
1 vote
225 views

### How do I choose the correct params?

I am very new to airplane design. I am working on this project to design a flying wing glider (no propeller) that would glide in a circular pattern with a fixed radius of 250 m after being released at ...
111 views

### Why don't commercial aircraft have variable sweep wings? [duplicate]

I was wondering why commercial aircraft don't have variable sweep wings just like the Bell X-5 did? By sweeping the wing further at high altitude it helps the aircraft move faster and also it helps ...