41
Their primary wing feathers have an unusual structure incorporating a fringed, comblike leading-edge, which reduces wind noise. The wing feathers also have an overall softness or flexibility. The trailing-edge of the wing is also dominated by soft, fringed edges. Even the underwing lining (covert) feathers have an unusual softness that plays a role in ...
36
In addition to quiet flyer's excellent answer:
Owls have large wings in relation to their body size and weight. One might think that no, their bodies are quite large, but actually owls are kind of fluffy flying feather balls: what you percieve as their bodies, is mostly air.
This leads to two things:
Low wing loading. Their large wings do not need to ...
29
Stealth aircraft are built to reduce their observability in 3 main areas, with the goal of reducing the warning time an enemy has:
radar
optical and IR
sound
This is in order of detection range: Radar can find an aircraft potentially at hundreds of km, optical systems go to a few tens of km, and sound becomes a factor only when the aircraft is very near (...
22
To add to the other answer...
The Pilatus PC-24 is billed as a business jet that can operate out of rough airfields. Comparing the pictures of the PC-24 to the Phenom 300 or CJ4, you can see that there is quite a bit of extra ground clearance. You can also see that the rear landing gear on the PC-24 are much more robust (dual wheels, longer travel length) ...
15
The huge support, or bulge, is a fairing, designed for reduction of wing root drag. So many people talk about wing tip vortex drag, but much more is created at the wing/fuselage interface, especially in uncoordinated flight. This improvement, first seen in 1930s vintage gliders (where else!), improves the airflow around the aircraft, resulting in ...
12
The flaps and ailerons are "reflexed" on this glider. They have been raised to a setting above the normal zero position, above the airfoil's normal chord line. A number of flapped gliders have this feature.
Two main benefits are a reduction in pitching moment as the pressure distribution on the wing is moved forward, so less downforce work for the tail, ...
7
The answer of ymb1 already gives you some good answer, but you marked in the comments, that you are also interested in the process of attaching. Therefore I'd like to provide you some more information and did some sketches number I) to III) for the Wing Root (at the end of the section) and another sketch for the horizontal stabilizer installation.
1) Wing ...
6
Flapped airfoils will have a suction peak once the flap is deflected away from its zero deflection position. This means more load on the boundary layer and earlier flow separation at the same lift coefficient. In order to avoid this suction peak over a range of flap angles, the airfoil contour is optimized on the top side for a small positive deflection and ...
6
You can position the flaps/ailerons on the ASG 29 not only downwards but also upwards. The flap/aileron is triangle shaped as you can (barely) see on this photo of an ASG 29 wing joint:
Basically you can reduce the lift (and therefore drag) of the wing by moving the flaps/ailerons upwards, extracting better speed from the wing.
6
On lighter aircraft, the wings are sometimes designed to be detachable for ease of transport:
To achieve this, the wing spar has a stump at the inboard edge that is inserted into a hole in the either the fuselage or the next inner wing section.
Once inserted, they are locked to the fuselage (and often to the wing on the other side) using large metal pins. ...
6
Owls' bodies are optimised for silent unpowered flight; even when owl flight is powered flight, it's powered by wing flapping (rather than jet engines or turboprops). At most I suspect you'll be able to help silence the noise from a body passing through the air; as gliders are rather quieter than light aircraft, I suspect this is the minority of the sound, ...
5
I'm no expert on the plane, but wikipedia claims the Mig-21 has separate flaps and ailerons.
On the trailing edge there are ailerons with an area of 1.18 m², and
flaps with an area of 1.87 m².
The common reasons for not combining flaps and ailerons are that it reduces aileron response and increases the chance of stalling the wing tip (which results in ...
3
I’m a retired FAA licensed A&P mechanic. The wings on the B727 are held on, in part by so called “bottle pins” if memories serves there are two on each wing roughly the dimensions of old fashioned glass quart milk bottles. I’m only “assuming” there are similarities to how the B737max wings are also held in place. Again I’m assuming that the “pickle fork” ...
3
If the other excellent answers roll off you like water off a duck's back, this may convince you:
What owls had to give up in exchange for quieter (not silent!) flight, is fast flying and flying on rainy days. Their feathers miss (most of) the oils that make other flying birds able to take quite a drenching without much trouble (and water birds even more so)....
3
At the same angle of attack, a cambered airfoil has a larger suction peak on the upper side (toward the leading edge), and a larger associated pressure recovery (toward the trailing edge).
Larger pressure recovery is equivalent to larger adverse pressure gradient, which leads to easier onset of boundary layer separation and stall.
2
The reason to use ailerons as flaperons on delta wings is twofold:
Delta wings reach maximum lift at a much higher angle of attack, which entails high pitch angle on landing, which is impractical. A way to generate enough lift at a reasonable angle is required.
With low aspect ratio, space on the trailing edge is very limited, so there is a desire to use ...
2
Vortex generators re-energize the boundary layer and can slightly postpone flow separation at high angles of attack. Therefore, adding them in front of a control surface is a realistic way of retaining authority. In fact there are real life examples:
[picture by Peter Kämpf]
That being said, these devices are a crutch that is best avoided on clean-sheet ...
1
Effectively the raised flap lowers the angle of attack by virtue of the variation of the chord line.
Less drag, higher speeds for, as has been said, penetration.
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