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The unstallable plane that stalled

fearoflanding.com

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Re: The unstallable plane that stalled

#41

Post by ketralnis »

hinkley wrote: post #36
jcalvinowens wrote: post #17

It is not necessary to empirically determine a specific airplane's stall speed in order to operate it safely. It's not required in the US, we just use the number the manufacturer publishes. It's normal for airplanes of the same model to fly differently: I fly a little fleet of six Citabrias, and their stall characteristics are radically different. You'd expect more uniformity from a modern aluminum airplane, but stil…

Decreases the stall speed? How does that work?

Things that can influence stall speed include weight, power, center of gravity, flaps/landing gear configuration, and more.

Why? Well, stall speed isn't a real thing. There isn't a speed at which you stall, that's not how it works. It's a convenient short-hand that we use for the more complicated reality. The physical reality is that stalls happen at a particular angle of attack (AOA) into the apparent wind. That is, the angle of your wings relative to the airflow. Up to the critical angle a higher AOA means more lift to counteract gravity. As you slow down you generate less lift because there's less airflow over the wings. So as you slow down, in order to generate a similar amount of lift you have to increase your AOA. If you keep slowing down and adjusting your AOA to compensate, you'll reach a speed that's low enough and therefore AOA high enough that adding more AOA no longer adds more lift (the air no longer flows smoothly over the wing). That's the stall speed, the speed at which more AOA no longer generates more lift. But it's the AOA that's the problem, not the airspeed.

In addition to lower speeds needing more AOA, you also need a higher AOA if you weigh more. A wrong but illustrative way to think about it might be that you need the engine's thrust pointed more towards the ground the more you weigh. That means that as you burn fuel (lose weight) the AOA that will stall you doesn't change, but the excess AOA available due to your weight-change does so in effect the air speed at which you would be near the critical AOA to stay airborn does change.

Stall speed is still a useful concept especially while landing but it's misleading outside of landing and when anything else is remotely unusual like weight or modifications to the plane. For this reason the FAA has been trying to get AOA indicators installed in planes and to train pilots to look at those instead of thinking about stall speeds https://www.faa.gov/sites/faa.gov/files/2022-01/Angle%20of%2...

Re: The unstallable plane that stalled

#42

Post by tomaskafka »

"As a result, the aircraft pitches up unless the pilot controls the flight path using the elevator. If this pitch up is not controlled, the aircraft is at risk of exceeding the stall angle of attack."

This has been happening for me in MSFS, and I considered it a really weird behavior - why can't I take off in a same way as from the runway? Now I know.

Re: The unstallable plane that stalled

#43

Post by VS1999 »

roywiggins wrote: post #33
lettergram wrote: post #10

Earlier quoted context omitted.

My reflex is to never mandate safety procedures. To put it simply, why should the state use force to mandate something like safety. The implication being if someone refuses the force of the state is used on them… which is definitely not good or improving safety. Mandating the seatbelts exist, sure. Mandating people wear them? Idk about that. In the case of tractors for instance, wearing a seatbelt is downright danger…

Everyone ends up paying for that, in the form of insurance rates.

And healthcare insurance if you live in the US, and regardless of where you live it clogs up your entire healthcare system as Jimmy-no-seatbelt flies into the trauma center.

Re: The unstallable plane that stalled

#44

Post by jiveturkey »

ambicapter wrote: post #27

> Cessna aircraft have a hinge line on the upper surface. As a result, turning the aileron down causes a sharp angle on the upper surface. The air is unable to flow around such a sharp edge and stays attached. The result is a sudden right wing tip flow separation. Should this say "The air is unable to flow around such a sharp edge and does not stay attached"?

I also caught this seeming error. It stood out especially since the rest of the article is so well written. I don't know anything about flying so I thought it was perhaps a lay misunderstanding on my part.

Re: The unstallable plane that stalled

#45

Post by daedalus_f »

andrewaylett wrote: post #23
Waterluvian wrote: post #2

Life jackets seem like they’d be problematic in an enclosed cabin where their use is if you’ve crashed and are taking on water. That’s a bit different compared to a pleasure craft or other vessel that has an outside deck and likely more time to react. But I don’t really know things. Perhaps most float plane emergencies that require life jackets don’t suffer from my perception of the issue.

In my vernacular, I distinguish between "life jackets" and "buoyancy aids". Apparently most people don't. A buoyancy aid has a foam core, and always provides buoyancy. It's the sort of thing you'd wear while kayaking, but it's far too bulky to want to wear it unless you expect to go in the water. A life jacket is inflatable, and normally automatic. If you're at risk of falling in, and to do so would be dangerous, you…

I’ve heard that distinction used in the UK.

The other down side of buoyancy aids I was told about is that many (most?) will not turn you face up if you are unconscious. Gives useful extra mobility for sports but can be fatal if the wearer is unconscious.

Re: The unstallable plane that stalled

#46

Post by Waterluvian »

macintux wrote: post #28
artine wrote: post #19

Earlier quoted context omitted.

Mandating the wearing of seatbelts isn’t entirely about protecting the person wearing the seatbelt. An unbelted occupant becomes a projectile in a sufficiently violent collision, and that projectile can cause harm to people outside of the vehicle.

Heck, I recently saw a video (may be an old one) of a driver who fell out of his car while showing off his acceleration. Now the entire car is an uncontrolled projectile.

Interesting that pleasure craft have dead-man switches you can optionally affix. They’re also designed to turn anti-clockwise forever if nobody is at the wheel.

I guess because there aren’t seatbelts and these boats are usually open-top.

Re: The unstallable plane that stalled

#47

Post by Waterluvian »

_trampeltier wrote: post #7
BalinKing wrote: post #4

Earlier quoted context omitted.

Indeed, passengers inflating their life jackets too early directly caused many of the deaths on Ethiopian Airlines Flight 961 [0]. This is why the modern safety briefing includes the bit about waiting until you've exited the cabin to inflate your life jacket. I have no clue how this applies to floatplanes, though—I'm curious for more details about when the article says "there are approved life jackets which could be…

"Many of the passengers survived the initial crash, but they had disregarded, did not understand, or did not hear Leul's warning not to inflate their life jackets inside the aircraft, causing them to be pushed against the ceiling of the fuselage by the inflated life jackets when water flooded in. Unable to escape, they drowned."

Definitely far up the list on horrible ways to die.

Re: The unstallable plane that stalled

#48

Post by Jiro »

VS1999 wrote: post #43
roywiggins wrote: post #33

Earlier quoted context omitted.

Everyone ends up paying for that, in the form of insurance rates.

And healthcare insurance if you live in the US, and regardless of where you live it clogs up your entire healthcare system as Jimmy-no-seatbelt flies into the trauma center.

That's an argument against a state-run healthcare system. It gives the state reason to classify arbitrary things as "increases the cost of insurance" and prohibit them.

Re: The unstallable plane that stalled

#49

Post by LeifCarrotson »

dramm wrote: post #39

What a horrible click-bait title. There is nothing about a C185 or one modified with a STOL kit that is unstallable. A better title would be something like "Clueless pilot stalls aircraft. Which unfortunately is not an uncommon thing.

I wonder if they're practicing modern journalism strategies that are worried about libel suits? Or it's so obviously satire to them that they don't need to clarify? When they write:

> However, the investigation discovered that despite his experience, he had never practised stall recovery on the Cessna 185. The pilot had no knowledge of the aircraft’s stall behaviour at all. His opinion was that the Cessna 185 simply didn’t stall.

In writing targeted at lay readers, I would expect this to be followed with something like "This opinion, of course, is complete lunacy. All aircraft can stall. Practicing stall recovery should be a normal part of pilot training."

Re: The unstallable plane that stalled

#50

Post by [deleted] »

hinkley wrote: post #36
jcalvinowens wrote: post #17

It is not necessary to empirically determine a specific airplane's stall speed in order to operate it safely. It's not required in the US, we just use the number the manufacturer publishes. It's normal for airplanes of the same model to fly differently: I fly a little fleet of six Citabrias, and their stall characteristics are radically different. You'd expect more uniformity from a modern aluminum airplane, but stil…

Decreases the stall speed? How does that work?

[deleted]
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