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# Tag Info

78

The small wings make it fly like a brick. Without the wings it would fly like a stone. Seriously, you are taking the expression too literally. The Space Shuttle is landing like a glider plane with a (not so good) glide ratio of about 4.5:1 (see What was the Space Shuttle's glide ratio?). No brick would be able to achieve that. Designing the Space ...

40

You can get negative load factors (g forces) in different ways than just flying upside down: Change in pitch: When you push on the control column, the pitch will start to decrease. Depending on how fast you do this, the load factor can even become negative from this. Some aircraft do this intentionally to reduce the g force to exactly zero: (image source: ...

37

As everyone has pointed out, it's a joke. Others have answered the lifting-body question (it didn't meet design requirements), so I just wanted to expand some thoughts on the spirit of the "flying brick" nickname. I suspect whoever came up with the term didn't spend a lot of time analyzing it. However, I think it's significant that the nickname is flying ...

21

In addition to its poor glide ratio the shuttles name also stems from the materials its made from as much as it does its poor glide performance. The Space Shuttle's heat shield was made out of LI-900 Silica tiles that strongly resemble bricks and thus the shuttle was sometimes called the "Flying Brickyard". If you would like to know why NASA chose a wing ...

11

The first thing I would do is advance thrust to maximum available thrust, make sure both engines are indeed operating. Next I'd check is if the speedbrake is stowed. I would not consider retracting flaps because when you are too slow to climb you are definitely too slow to retract flaps... could be deadly. Normally this kind of situation can't happen ...

11

"Flies like a brick" is merely a figure of speech. It comes from personal feelings of the pilot when comparing it to an actual plane. It's just like the saying that someone is "dumb as a rock". Obviously, even the most stupid person (or even animal) is much smarter than rock. The saying merely expresses the frustration of the speaker when dealing with a ...

9

Quoting the F/A-18A,B,C,D Flight Manual A1-F18AC-NFM-000, I-2-42 2.8.2.8 Control Augmentation System (CAS) [...] The lateral control system uses ailerons, differential trailing edge flaps, differential leading edge flaps, differential stabilator, and rudders to achieve the desired roll characteristics. Scheduled air data roll rate feedback is used ...

8

@Michael Hall said it best, in the first sentence of item 1 of his answer: There are simply too many variables for a definitive answer. Here are two extremes to illustrate the range of answers insofar as altitude is concerned: Let's say you have a 747 at it's optimum altitude in cruise with all four engines operating, say 37,000 just for the heck of it. ...

8

Five short, generic reasons (i.e., not specific to the Weedhopper): Fatigue reduction: some highly stressed parts of the airframe (particularly mainspars and engine mounts) are susceptible to fatigue failure from cyclic loading. The key word here is 'cyclic'; a spar which is subjected to loads between (say) -5g/+5g will fail faster than one which is ...

7

The change in pitch during the landing is called the flare and it is controlled by the pilot (or autopilot for an autoland) using the elevators (i.e. pulling on the yoke). From the Boeing 737 NG FCTM (6.10 Landing): When the threshold passes under the airplane nose and out of sight, shift the visual sighting point to the far end of the runway. Shifting ...

6

This answer assumes that the wind is uniform in direction and speed, from the balloon all the way down to the ground. The object will impact the ground directly below the balloon, not "upwind" of the balloon. As the falling object accelerates vertically, the trajectory of the falling object as viewed from the ground reference frame continually becomes more ...

5

A "fully-stalled take-off" is an attempted takeoff where the elevator has too much authority. This can cause the aircraft to rotate to an excessive nose up attitude, which can exceed the stall angle of attack, before takeoff speed is attained. Ventral fins were added to some B707s to improve lateral stability, and prevent over-rotation. Over rotation which ...

5

In the most simple model for subsonic aerodynamics, drag is split into two components: Zero-lift drag, that is all the drag created when the airplane produces no net lift. This kind of drag has again two components: Friction and pressure drag, that is the aerodynamic drag parallel and perpendicular to the local surface. This drag would dominate in a ...

4

Laminar flow and turbulent flow are not directly linked to Reynolds number, even though Reynolds number is a heuristic indicator of when the flow may transition from laminar to turbulent. However, the transition is actually not well-understood and is difficult to model/predict. That's why you will see cases where, for the same Reynolds number, one flow is ...

4

The increase in the lift curve slope at low angle of attack is quite normal. At 10° you see the effect of vortex lift kicking in. Yes, that is specific to delta wings. Attached and vortex lift over angle of attack (picture source). This is taken from the excellent Cambridge Core article on vortex lift and these particular diagrams are from E.C. Polhamus: A ...

4

Note that your plots show lift coefficient over angle of attack. This lift coefficient is referenced to a reference area which must be defined somehow. It is customary to use the projection of the clean wing area in the x-y plane for all flap settings in order to keep coefficients comparable. The lift curve slope increases because the real wing area ...

4

Adding to other answers, yes space shuttle is a brick that flying not just a brick. Body-lifting can not be disregarded in hypersonic flight during the reentry, it is not just the wing creating the lift, it is the whole bottom section hitting the atmosphere. Looking at another famous spacecraft, Appollo, it doesn't have any conventional wings but NASA uses ...

3

Bernoulli's equation holds only if there is no energy source in the system. Since the fan adds energy, Bernoulli's does not apply across the fan; in the context of 1-D flow, pressure changes discontinuously across the fan. Due to conservation of mass (no mass source for a simple fan), airspeed cannot change discontinuously across the fan interface. ...

3

When flying at the airspeed that yields the maximum L/D ratio, which is also the airspeed that yields the lowest total drag force, 50% of the total drag is "induced drag", i.e. drag due to the creation of lift. At higher airspeeds, a lower % of the total drag is "induced drag". At lower airspeeds, a higher % of the total drag is "induced drag".

3

You want to move a heavy payload at low speeds. This means that induced drag will dominate the aircraft. If we assume a quadratic polar, the least amount of energy for staying airborne is needed when induced drag is three times higher than friction drag. Assuming a quadratic polar, the optimum lift coefficient at that point is c_L=\sqrt{3\cdot c_{D0}\cdot\...

3

The FDR would show exactly what the control inputs were so they would know from that. It's important to understand that pitch trim effectively controls the airspeed the airplane will seek naturally without any control input (FAR 25 pitch stability requirements specifically require airplanes to effectively seek a trimmed speed within certain parameters ...

3

This sort of scenario happens from time to time. Before a flight the crew will calculate the flap setting and speed at which the aircraft rotates based on aircraft weight, the weather conditions, and runway length. If any of these are entered incorrectly, the aircraft could rotate too soon and not lift off when expected. To decrease wear on the engines, ...

3

I know this was answered a while back but let me give you my two cents. As explained by Peter a combination of the wing swept and low aspect ratio affect the lift production of the wing. But another effect also takes place; vortex lift. aeroalias explains it very nicely on this post: What is vortex lift? In short vortex lift is lift generated by the ...

3

The tail only looks backward when people can usually see it: in the pattern, parked, or flying formation with a photographer in a slower aircraft. Rather than using trim tabs to push control surfaces out of alignment (which adds drag), the entire empennage pivots for pitch trim adjustments. To trim the nose up at low speed, the leading edge of the horizontal ...

3

Most planes fly best without any extra holes, of course! The specific effect of a hole is modifying local airflow, increasing turbulence, and increasing the aircraft's wetted area on the side of the breach. As long as there isn't a matching hole in the back, however, the airflow inside separates (similar to a pickup truck), so most of the airflow is still ...

3

Increasing the flaps does increase the drag, but not by that much initially. For the first stages of flaps you gain more by reducing required takeoff speed. If you would increase the flaps more and more, eventually the drag would become too much and you would lose takeoff distance again. Flap setting has an affect on the wing’s lift coefficient and on the ...

2

The illustrations under the time-invariant, inviscid, irrotational and incompressible (potential) description is a bit misleading, in my opinion. In the real world, assuming the airfoil starts from rest (no flow field) and you start accelerating it to some airspeed, viscosity should start generating vorticity as soon as airspeed becomes non-zero. Therefore, ...

2

Transonic buffet, or Mach induced buffet, or high speed buffet, is a flow separation due to the combined presence of shockwave and "high" angle of attack. The boundary layer separation results in random high frequency vibrations. As the AOA increases, the separation and the associated vibrations worsen, up to the point where the crew can no longer read the ...

2

Newton's first law of motion states: An object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. The instant you let go of the object, it has 50 kt sideways motion, and 0 kt vertical motion. First, let's assume this happens in a vacuum, so only gravity applies. This is essentially a ...

2

You have a very thin book. The answer depends on how you initially drop the book. 1. If you drop it flat about its front It will very closely approximate a flat plate; in this case, the pressure drag will overwhelm the skin friction drag. Hoerner, Fluid Dynamic Drag has some empirical data on the drag coefficient of a bluff body (near 2.0): To retrieve ...

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