I'm reading Stick and Rudder by Wolfgang Langewiesche, and in Chapter 7 titled, "What the Airplane Wants to Do" he discusses stability. In discussing it, he says that no plane yet built is completely "well-behaved" and that the plane closest to perfection is Fred E. Weick's Ercoupe.

It's been over 50 years since this book was written. Have aircraft flying characteristics improved? How much have they improved? And what airplanes have we built that have the best flying characteristics (which are the "best-behaved")?

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    $\begingroup$ As stability is always at odds with manoeuvrability, it’s an important design objective to not make the plane too stable... $\endgroup$ – Cpt Reynolds Jun 16 '18 at 15:00
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    $\begingroup$ Yeah I can cut a rock to the shape of a cube and set it down on the prairie, and it ain't goin' nowhere but it's stable as all get out. $\endgroup$ – John K Jun 16 '18 at 17:09
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    $\begingroup$ Is this question talking about flight mechanics isolated stability or are you including in your question also the electronics? Currently, if we consider the full stability of the full airplane, including the electronics, the stability has increase significantly. $\endgroup$ – Trebia Project. Jun 18 '18 at 22:18
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    $\begingroup$ This is a pretty broad and subjective $\endgroup$ – Carlo Felicione Jun 19 '18 at 0:19
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    $\begingroup$ @Carlo, very broad but not entirely subjective. There are control laws that are 'best', i.e. are proven to give best results. The problem is, this highly depends on the task at hand. This is one of the reasons why computer-controlled (and even some older) aircraft have reconfigurable control laws. I don't have the guts to write an elaborate answer, but to the first approximation, we humans control best when there is one integral between the input and output. Typical roll control is the closest to it: the stick input is roll rate, the aim is roll angle. $\endgroup$ – Zeus Jun 19 '18 at 3:17

First, let's get a little perspective

Stick and Rudder was written in the early days of aviation. To a modern reader, things were really weird back in the early days of aviation.

  • For a while, air traffic control was a guy sitting in lawn chair next to the runway waving a big flag that said "GO".
  • Parts on the plane just failed. Planes would crash on their way back from bombing Hitler, a truck full of mechanics would come out to bolt on some (hopefully) new parts, and then they'd take back off in the crashed airplane to go bomb Hitler some more.
  • One time, the Allies bombed Switzerland by mistake. This was a world where more than one airplane could miss not only a target, but the entire country.

The kinds of things that went on in those days as a matter of routine would send any modern-day NTSB investigator into full-blown panic attacks.

What I'm getting at here is that it's a mistake to judge Stick and Rudder by modern standards. This is not the equivalent of brain surgery. You have to think of this as a surgeon just trying to get other surgeons to wash their hands with soap before they operate.

Now on to your questions

Have aircraft flying characteristics improved?

Yes. One example out of many: Cuffed wings.

How much have they improved?

Enough that Wolfgang didn't need to write a second book.

And what airplanes have we built that have the best flying characteristics (which are the "best-behaved")?

An Airbus flying in Normal Law.

There's a section in Stick and Rudder (page 160 in some editions) where Wolfgang says that a "foolproof" airplane is one in which the controls have been restricted so that the pilot is mechanically incapable of pulling the airplane to an angle of attack which will result in a stall. Guess what? A pilot flying in normal law can yank on elevator all day long and not stall that Airbus.

An Airbus in normal law automatically trims itself.

An Airbus in normal law automatically increases power on the engines if a pilot pulls the airplane into a high angle of attack.

Some people might hesitate to put words in a dead man's mouth, but he's not here, so I'll go for it: The best behaved airplane according to Wolfgang would be a modern-day Airbus airliner.

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    $\begingroup$ Thanks! I know this wasn't the most specific or well-informed question, but you still gave me the answers I wanted (and made me laugh). $\endgroup$ – ifandonlyif Jun 19 '18 at 10:13

Flying characterisctics have improved as engineers have learned more about aerodynamics. Like adding wing dihedral to make the plane self centering. Better stall characteristics.

How much? Tons! Enough so so that manufacturers could dream of a plane in every garage for homeowners.

Which best? Cessna Cardinal after getting past the initial year jitters. Sweet handling, pretty fast, good on fuel, easy to land.


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