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38

Something should be pointed out here. Fume events are not related to Phosphate Ester hydraulic fluid and there is nearly zero risk of Skydrol or Hyjet getting into an air conditioning system (if there are airliners out there that use air conditioning source bleed, to pressurize accumulators or reservoirs, with an open return path back through the bleed ...


23

Skydrol was developed to provide a hydraulic fluid that does not catch fire when a fine mist of particles under pressure is released, upon a leak in the hydraulic system. Of the two evils, poisoning or burning, a case can be made to avoid the latter when considering aeroplanes. For ground based systems like full flight simulators, hydraulic systems are on ...


19

The main gear sits between the wings and retracts inwards, such that the wheels will rest in the lower fuselage. Lengthening the main gear would either require to shift the gear attachment points outward or to retract one leg a bit forward and the other a bit backwards, such that both wheels will sit behind each other instead of side-by-side, as they do now -...


10

The Concorde flew above 15,000m. At this altitude a sudden reduction in cabin pressure would prove hazardous to crew and passengers with most falling unconscious within a few seconds. The low air-pressure would also render the oxygen supply system inefficient and most passengers would suffer from hypoxia. Thus we have the reason for the smaller windows, ...


9

The problem is that there is no redundancy in the sensor input. The quote from the article is: This original version of MCAS, according to two people familiar with the details, was activated only if two distinct sensors indicated such an extreme maneuver: a high angle of attack and a high G-force. So on the original design, MCAS activation required two ...


7

I'll do this without most of the math since your target audience won't want to read equations in your story. In the simplest terms, the maximum speed of an airship occurs when the maximum thrust generated by its engines is equal to the drag it experiences while being pushed through the air at that speed. That drag depends on the diameter and length of the ...


6

Because lengthening the main gear struts constitutes an almost complete structural re-design of the main wing structure, with dramatic consequences on cost, lead time, re-certification, weight increase etc. The main landing gear of most swept back winged aeroplanes retract behind the rear spars, in the kinked section close to the fuselage. Picture above is ...


6

Of course the airlines knew about MCAS. Do you think the maintenance manuals, maintenance program documents, tech training, wiring diagrams, and all that stuff was left out so it was totally top secret? There would be a controller, wiring and software on board even though there were no cockpit indications or controls, so certainly the techs who might have ...


5

Areas on the airplane with ice protection have it for important reasons: Ice on the wing/empennage disrupts airflow, adding drag and making it more susceptible to stalling. Ice on an engine cowl lip can disrupt flow into the engine, causing stability issues. If it dislodges it can damage the engine. Ice in the pitot/static system prevents the air data ...


4

For the A320, this can be found in the CCOM (Cabin Crew Operation Manual)... So the A320 is a 5.5 meter (17.04 foot) knotted rope stored above the side cockpit windows. There are 2 ropes in the cockpit (one on each side). I can't find the CCOM for the A330 but it should be a similar size.


4

It was due to flow issues. Here's an excerpt form Air & Space Magazine We discovered a few things that would need to change before the aircraft entered production. On the X-35B’s STOVL variant, the doors above the lift fan had a bi-fold arrangement: They folded and slid outward, creating an opening for air to enter the fan. However, when the ...


4

The top speed depends on the type of the airship. While the first designs were non-rigid, it became soon obvious that useable speeds could best be achieved with rigid designs because the higher dynamic pressure at higher speeds required more internal pressure to maintain the hull's shape. Given the low strength of early hull materials, the internal pressure ...


3

Source: nap.edu Not really no. The velocity off a propeller does not shoot straight back, rather in circular motion (shown above and below). Source: High-Lift Propeller System Configuration Selection for NASA's SCEPTOR Distributed Electric Propulsion Flight Demonstrator, NASA From the conclusion of that NASA report on span-wise propellers generating lift: ...


3

I drew in the approximate location of the screws used to hold a level while leveling the Cessna Cardinal for weighing. When my plane was weighed, they had to lower the nose by deflating the nose strut some, and raise the main gear, to get the aircraft to the level position indicated by the manual, with a level across the leveling screws on the side of the ...


3

Because the wing has less torsional stiffness for a given area. This lets lower torsion moments overpower the ability of the wing to resist that torsion. The torsional stiffness is proportional to the skin thickness and the cross sectional area of the airfoil. For a given wing area and lifting potential, a higher aspect ratio will reduce that cross section, ...


3

If the airfoil profile does not change along the span, then we can expect the entire wing to enter a stall condition at the same time. This means the stall break will be sudden and sharp. If instead we transition between several different airfoil profiles along the span of the wing, we can get different portions of the wing to stall at different airspeeds/...


3

Comparison of two giants from the golden age of airships LZ 127 Graf Zeppelin and LZ 129 Hindenburg provides some useful information on your proposed scaling. Both airships were around 800 feet long and cruised at 80 - 85 mph. Hindenburg was 35 feet wider, with more than double the lifting capacity, but required 4 x 1200 hp compared with 5 x 550 hp of the ...


3

A winglet makes lift like a wing. That's why it's called a wing...let. It's basically a sail (originally they were called "tip sails") designed to exploit the otherwise wasted circulation of air from bottom to top around the tip, placed so that the local flow curling around the tip strikes it at a positive angle of attack. It makes lift/thrust and, being a ...


3

No, there isn't any single rule of thumb for airframe shape. Just look at the huge variety of airframes that have been built and flown over the years. One way to scratch-build is to start with a cardboard glider that's roughly the shape you want. Tape the wings and tail to the fuselage in different places, tape on some noseweight, give it a toss, deflect ...


3

That's a completely incorrect understanding of the article. The summary should be: MCAS activates if: a) Sensor detects a high angle of attack and b) Sensor detects a high normal G load If one sensor is erroneous and and the other one isn't, then MCAS would not erroneously activate.


3

You have a problem because you would have to know where the vertical center of gravity is to be able to mathematically calculate a correction factor to apply to the weighing points. The higher the vertical C of G is, the more rear weight bias you will get if the plane is nose-high from level, or front weight bias if nose-low. How much to allow for? You ...


3

That's because Bernoulli's principle breaks down at and above supersonic velocities. In the subsonic realm, when an atom is sped up, it doesn't have much time to spend pushing around a fixed place (it passes by that place quickly). In doing so, the static pressure drops as the speed increases. And in doing so, the neighboring atoms, who are also not doing ...


2

There is a limit to what can change on an air-frame before being considered a new aircraft. I mean new as in a whole new designation. That means a whole new approval cycle that may or may not be approved by the FAA or international organizations. Moving a pivot point is not a simple task, there is a lot of structure to move. If you move structure there is ...


2

Yes, of course this is possible. The main factor taken into account is pilot training. Mid-air refuelling puts the receiving aircraft into an unstable position which needs to be held manually for the duration of the operation. Without proper training, the refuelling operation will carry a high risk of being unsuccessful. Mechanically the modification is ...


2

As for the weight vs. speed: a rigid or semirigid airship has a max takeoff weight, which depends on it's size (because the size pretty much determines the max lift). If this airship was to fly, say, only half of the max weight, it would not go any faster, as the drag would be the same because the size does not change. An airship may lift a load heavier ...


2

Unfortunately the short and simple answer is money. They weren't prepared to spend the money on a costly redesign of the already proven 737NG fuselage. The best in depth explanation I've seen of the whole issue with the MAX is: "How the Boeing 737 MAX disaster looks to a software developer".


2

The technical answers above are fairly good, but probably the biggest answer is that Boeing corporate out in Chicago was simply too miserly to invest in a clean sheet airplane (which it could have EASILY done) and demanded that Boeing Commercial Airplane develop this new medium range airliner on a limited budget within a limited time span. The 737 MAX ...


2

Just to put it into perspective: $Sine$ 4 degrees × 100 = 7 % grade $Cosine$ 4 degrees x 100 = 99.75 % of perfectly levelled scale. So unless your scale is on a fairly steep mountain grade, your main concern, if any, is to level the plane. It would seem to be much easier to use a block and a bubble, with an appreciation of the fact that the "ball" ...


2

As Crossroads shows, the data provided for W&B calcs is based on a level fuselage. If the fuselage is not level, you would need to do some math to calculate adjustment factors for the wheel weight values, and to do that you would also need to know where the vertical C of G is. Good luck with that. So there's no work around that I've ever heard of, and ...


2

The fuselage is a pressure tank, the window is a hole in the construction of the pressure tank. Adding windows also adds weight: the pressure vessel construction must be reinforced around the hole. The window glass is obviously airtight, but does not contribute in absorbing any of the stresses of the pressure differential. The window size is a function of: ...


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