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Myth Bustng - The advantages of low Wing Loading | Forums - Page 4The factors on which aerodynamic lift is dependent are,
1. Wing reference (or planform) area
2. Number of the wings
3. Vertical position relative to the fuselage (high, mid, or low wing)
4. Horizontal position relative to the fuselage
5. Cross section (or airfoil)
6. Aspect ratio (AR)
7. Taper ratio
8. Tip chord (Ct)
9. Root chord (Cr)
10. Mean Aerodynamic Chord (MAC or C)
11. Span (b)
12. Twist angle (or washout)
13. Sweep angle
14. Dihedral angle
15. Incidence
16. High lifting devices such as flap
17. Aileron
18. Other wing accessories
The total Lift of an aircraft is further dependent on a combination of aerodynamic thrust and engine thrust.
these equations need no explanation as you your self has said that you are very talented in maths and physics.The lower the wingloading, the lower the angle of attack you have to pull to carry out the same manoeuvre (other things being equal)
If you look at the lift and drag equations, you can see why that's so important.
Lift (N) = CL * area (sq m) * .5 * pressure (kg/cubic m) * velocity (m/s) squared
Coefficient induced drag (CDi) = (CL^2) / (pi * aspect ratio * Oswald efficiency)
Drag = coefficient * area * density *.5 * velocity squared
If you look at the equations, induced drag increases with the square of CL, and proportionately with the increase in wing area. So double wing area = a quarter the CL = half the induced drag.
To plug some figures in, an example aircraft with weight 3000 kg and wing area of 10 m^2, then the same aircraft with 20 m^2 wings. (this assumes weight doesn't increase with the larger wings, of course)
Assuming lift = 4 times weight, sea level density, speed = 400 km/h
117,600 = CL * 10 * .5 * 1.225 * 111^2
CL = 1.56
CDi = (1.56^)/(pi*6*.8) = 0.16
Induced drag = 0.16 * 10 * 1.225 * .5 * 111^2
Induced drag = 12,074 N
Now the same thing but with double the wing area
117,600 = CL * 20 * .5 * 1.225 * 111^2
CL = 0.78
CDi = (0.78^)/(pi*6*.8) = 0.04 (note how doubling the wing area results in a quarter of the CDi, because CL is squared)
Induced drag = 0.04 * 20 * 1.225 * .5 * 111^2
Induced drag = 6,037 N
Of course, parasitic drag increases with a larger wing area, but basically lower wingloading = an increasing advantage the tighter the turn, and the lower the IAS you fly (and IAS of course is lower at high altitudes)
Even though the weight increase due to larger wing is not factored in this formulae, the general directions of calculations are valid forever.
For your kind info tejas too has three sections slats, flaps, dihedral, twist angle all employed in the air frame.
So, lower wing loading gives,
Lower stall speed, tighter turns (in general).
Usually wings will stall at the same angle of attack, however planes with low wingloading will reach this angle of attack at a lower speed.
huge wing and a low weight aircraft you will get a very very low stall speed,
for example and probably a pretty good turner.
Another quote below,
In general, aircraft with higher wing loadings tend to be faster but less manoeuvrable. Since speed is life, this has historically been a good betting proposition. However, once top speeds become supersonic the trend can break down due to the operational, aerodynamic and thermodynamic issues associated with supersonic flight.
As a result of this, current fighters are no faster than 1960s fighters, but generally have lower wing loadings, since if you can't go faster the next best thing is to turn harder (apart from which, low wing loadings are necessary for high supersonic L/D and therefore help towards supercruise). As such, wingloadings are likely to stay roughly constant or possibly even decrease in future designs until such time as the upward trend in speed reasserts itself.
An aircraft's lift capabilities can be measured from the following formula:
L = (1/2) d v2 s CL
* L = Lift, which must equal the airplane's weight in pounds
* d = density of the air. This will change due to altitude. These values can be found in a I.C.A.O. Standard Atmosphere Table.
* v = velocity of an aircraft expressed in feet per second
* s = the wing area of an aircraft in square feet
* CL = Coefficient of lift , which is determined by the type of airfoil and angle of attack.
The lower your wingloading, the less AOA you have to pull to get the same lift vector.
It is you lift vector that turns the plane as well as allows it to climb and fly.
For turning I would rather have a wing that needs less AOA than one that allows me to use more
but really needs it. The latter will have worse drag.
Of course, parasitic drag increases with a larger wing area, but basically lower wingloading = an increasing advantage the tighter the turn, and the lower the IAS you fly (and IAS of course is lower at high altitudes)
these equations need no explanation as you your self has said that you are very talented in maths and physics.
Even though the weight increase due to larger wing is not factored in this formulae, the general directions of calculations are valid forever.
So, lower wing loading gives,
Lower stall speed, tighter turns (in general).
Usually wings will stall at the same angle of attack, however planes with low wingloading will reach this angle of attack at a lower speed.
huge wing and a low weight aircraft you will get a very very low stall speed,
for example and probably a pretty good turner.
An aircraft's lift capabilities can be measured from the following formula:
L = (1/2) d v2 s CL
* L = Lift, which must equal the airplane's weight in pounds
* d = density of the air. This will change due to altitude. These values can be found in a I.C.A.O. Standard Atmosphere Table.
* v = velocity of an aircraft expressed in feet per second
* s = the wing area of an aircraft in square feet
* CL = Coefficient of lift , which is determined by the type of airfoil and angle of attack.
The lower your wingloading, the less AOA you have to pull to get the same lift vector.
It is you lift vector that turns the plane as well as allows it to climb and fly.
For turning I would rather have a wing that needs less AOA than one that allows me to use more
but really needs it. The latter will have worse drag.
There are some counter arguments too,
but these arguments dont stand the test of questions,Basically wingloading usually defines the aircraft's stall speed (a least in combat, without lift assisting devices such as slats and flaps), and through it, how slow the aircraft can get in turn, and thus the turning circle.
Simply to put, planes with low wingloading are usually having smaller turning circles.
Low wingloading on the other hand is not so pronounced as far as turn rate, or in other words, turn times go. Turn times are basically defined by how high G the aircraft can hold up in a sustained manner. That is basically speaking a race between the thrust of the propeller vs. the drag of the aircraft in turn. Here low wingloading doesn't give much of an advantage, as - all things equal - you will have a larger area wing, and thus higher drag to achieve lower wingloading. You will need more thrust to overcome the greater drag, if you're pulling the same Gs, or rate of turn.
The effect of increasing thrust (ie. engine output, 'boosting') on turn is interesting. Even huge increases in excess thrust (either by increasing engine power or doing a descending turn - tactics, tactics!) have very small effect on turn radii, since the aircraft just can't go below it's given stall speed at a given G-loading. However, increasing excess thrust can have a VERY pronounced effect on turn times.
Simply to put, low wingloading planes don't neccesarily beat high wingloading planes in turn times.
Best examples are the Yakovlevs vs. Spitfires. Spitfires have very low wingloading, and high thrust, high drag; the Yakovlevs have a fairly high wingloading, low thrust (poor engines), and very low drag. Comparing their real life turn radii and time values reveals the Yakovlevs have larger turn radius (by about 50m - about as much as the 109G, differences in turn radii were not as pronounced as some may think), but at the same time they beat the Spits in turn time by about 2 secs for a 360 degree turn.
It's classic example of how drag, thrust and wingloading effects turn time and radii. Turn time is IMHO more important, not to mention the other benefits of high wingloading being still there - lower drag, effecting level speed, zoom climb, dive performance etc.
The lower the wingloading, the lower the angle of attack you have to pull to carry out the same manoeuvre (other things being equal)
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