36
Why no flaps?
Flaps change the pitching moment of a wing. After all, they add lift over the full chord, so the sum of the increased lift attacks at about mid-chord, which is a quarter chord aft of the regular lift. If there is no separate tail surface to compensate for the pitching moment caused by that extra lift, the aircraft will quickly pitch nose-down ...
14
Assuming maximum altitude for the highest blimp is 74,000 feet, and the rail to be angled at 15 degrees, it gives us a rail length of 285,000 feet. The HiSentinel stratospheric airship flew that high, and was able to carry only 36 kg.
The steel rail/rope would weigh roughly 5.5 million kg. Based on steel density and a good sized rope, to withstand the ...
11
Normally, one degree of flaps in fact only translates to an extension of the leading edge devices (e.g. slats), trailing edge flaps remain fully retracted.
On some aircraft this configuration can be used for take-off.
Combination of flaps and spoiler is for example used in slow flight on steep descends. The flaps ensure that the wing doesn't stall, the ...
10
The idea is to generate a vortex near the fuselage. In most cases we do not want any vortexes, as the unnecessary air movement always causes an increase in drag. In this case however, you need them.
As the air flow separates from this small triangle wing while at large angles of attack, it gains a rotary motion (if you look at the left wing standing in ...
10
The area, or as originally written, length and width*, are but two of many parameters that define the flaps and slats.
The final parameters are a result of an iterative process, as shown above. You try a set of parameters, if they don't work, you go back one step, or even two steps (redesigning the wing).
For example when the A320 was stretched to become ...
8
Unless something broke mid-flight -- which you would have probably been told about as a passenger because of the faster landing speed -- leading edge devices (slats) are used for takeoff, approach, and landing on the A320-family.
For takeoff the slats are put in position 18 or 22, and for landing in position 22 or 27, as the table below from an A320-family ...
8
This might be a bit late but the short answer is, again, no.
Check NACA report 427 and Experimental investigation of a Handley Page 44f wing. Slots at locations other than the vicinity of the leading edge are shown to be rather useless.
In addition, there seems to be no correlation between the "rounding" of the channel inlet and a better performance. The ...
8
No, it will not work in the way you plotted it.
First, the corners of the duct should be nicely rounded. With the sharp corners you will get a lot of vorticity, but little lift increase. Actually, lift will drop and drag will go up.
Next, a gap works best when connected with a contour break, such as that of a slat or a flap. If you round the corners and ...
7
It works but your description is not so clear about the real size of the gap.
Gliders sometimes have little holes along the wing on the upper side where air from beneath is provided to them by a little duct.
The reason is to keep the linear air flow straight a little longer at low speeds.
I have not found a live picture. For this I'll have to visit the ...
7
Similar to a leading edge flap, fixed in the extended position with no gaps: The nose is lowered, so at high angles of attack the flow still has its stagnation point at the round nose where on an un-drooped nose it would had slipped below the nose section.
This reduces the suction peak near the nose of the upper surface pressure distribution and ...
7
@DamalaniSingh: I wonder why you see the need for a bounty when web pages such as this give a good explanation already. In order to avoid a link-only answer, I will summarize the LEX-related gist here (LEX = leading edge extension).
You may know that a delta wing forms a powerful vortex on its suction side at high angle of attack which allows it to work ...
7
Leading edge extensions like slats are used in airliners. Most of these are controlled ones, so as to improve low speed characteristics.
By Adrian Pingstone (Arpingstone) - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4761104
The dog tooth extensions were used in some older airliners like the Ilyushin Il-62 and the Vickers ...
6
In modern gliders, active tripping of the laminar boundary layer helps to reduce or avoid a laminar separation bubble. There are three ways of doing this:
Noppenband (dimple tape):
Close-up picture of a spool of Noppenband (picture source)
Zig-Zag-tape:
Spool of zig-zag tape (picture source)
Blowhole tripping: a line of tiny holes (0.8 mm diameter, ...
6
The strakes function as giant vortex generators. They generate vortices at high AOAs to improve airflow over the rudder at low speeds. During the Q400 test program it was found that there was some local flow separation at the lower area of the rudder (reducing rudder power and possibly creating unpleasant vibration) and this is a classic, relatively hassle-...
5
Yes leading edge devices indeed postpone stall to a higher Angle of Attack. They are particularly useful for:
Airfoils which are prone to leading edge stall. Deflection of the trailing edge flap creates upwash at the wing nose, which reduces stall AoA mainly on thinner wing profiles.
Aeroplanes which use lift dumpers as speed brakes. Deflection of the ...
5
Most modern airliners have some form or other of mechanism that does exactly that, mostly for the slats (which are more important in stall prevention, anyway).
E.g. on modern Airbusses, there is a Slat Alpha Lock function which prevents slat retraction at high angles of attack, on the Boeings there is a Slat Auto-Gap function extending slats from mid to ...
4
Definitely use the local Reynolds number on each of the flaps! The flap will only work properly if it is allowed to produce its own, fresh boundary layer. If instead it inherits the slow, thick boundary layer of the wing or flap ahead of it, the flow would soon separate and the flap would loose most of its effectiveness.
Note that a Reynolds number is ...
4
Because with a delta wing the trailing edge has the elevators and it's too far aft to have a flap. They depend on wing area and the ability to operate at much higher AOAs than straight wings to get the speeds down.
As for slats, they don't increase Clmax all that much, only a little bit from the increase in chord in drooping the leading edge. The main ...
4
The beauty of the pure delta configuration was you could get a reasonably low supersonic drag configuration in a planform with a lot of wing area, essential for really high altitude cruise and for reasonable landing speeds without high lift devices. It was a good overall compromise for Concorde's mission.
The Avro Arrow, produced then scrapped in Canada ...
4
It did not need them. Concorde could operate from most commercial airports and did not need especially long runways. Retractable canards add drag and the mechanism is a point of failure.
I fail to see how Tu-144 canards is a “superior” feature as they were added to support a less effective wing.
Very much related: Why is the Tu-144 the only commercial ...
3
The suction peak is the point of lowest pressure on an airfoil, in other words the highest point on a typical pressure or Cp graph of an airfoil. On an airfoil it's typically located just after the leading edge on the upper surface, take a look at this image for instance. In that image you can also see that as you increase the angle of attack of the ...
3
The aspect ratio of a wing is defined as:
$$ \text{AR} \equiv \frac{s^2}{A} , $$
where $s$ is the wingspan and $A$ is the total wing area.
Some types of flaps are not only increasing wing camber, but also the wing area:
The Fowler, Fairey-Youngman and Gouge types of flap increase the wing area in addition to changing the camber.
(Wikipedia)
Since the ...
2
A basic problem you have with this design is weather - what do you do when a storm passes through? Due to their large surface area, your blimps at lower altitudes are going to be pushed around a lot by high winds, probably to destruction.
Storms, and the associated high winds, can extend upwards of 40k feet, in extreme cases.
You might think about ...
2
They are vortices coming from the flap panel, same as the vortices coming from the wing tip, but much more intense because the angle to the flow is so high. Because of this, the pressure drop in the core of the flap vortice much more than pressure drop in the flow off the wing tip. This means the temperature drop is also much more, enough to condense the ...
2
Some of the gliders I fly do the same: They do not droop ailerons in full landing configuration but do in intermediate settings. There the reason is aileron effectiveness at high angle of attack and prevention of a tip stall.
If you droop the ailerons it yields more lift but the angle of attack at which the airfoil stalls is decreased, which might give you ...
2
Design is compromise
Would a tailplane+flaps have avoided the risk of high-speed tire failures? Quite possibly, but tire failures can still happen and the debris will still hit the underwing where the fuel tanks are.
The solution to that would be a swing wing, which was studied and rejected because of the added weight and complexity.
Ground studies, ...
2
Most Airlines have slats, as a matter of fact, even smaller jets have them. Slats have to do with swept wings which allow to fly faster.
Manufacturers use this method to delay the onset of relative wind on the upper side becoming supersonic. The trade off for this is (amongst other things)a higher stall speed and a higher angle of attack required at ...
1
They are typically called "strakes" are there to improve handling by minimizing unwanted rolling tendencies. I think the plane is an Bombadier Dash-8
Wikipedia article with more pictures: https://en.wikipedia.org/wiki/Bombardier_Dash_8
You can see them on this Q400 planform
1
As mentioned in other answer, you use the flaps to put the wings in a configuration where, at the cost of more drag, they increase lift; this allows the aircraft to fly a bit slower.
The spoilers, on the other hand, are used as a temporary measure to decrease lift and increase descent. So, basically, in approach you would have your flaps in a fixed ...
Only top voted, non community-wiki answers of a minimum length are eligible
