For good reason. They invented the 3rd axis of control that prevented exactly that from happening.
But a hang glider is different in this respect. Directional stability is maintained by shifting weight below the lifting surface. or put another way, the lifting surface is manipulated a single unit instead of controlling it through manipulation of the 3 axis.
Yes - sort of.
A big issue is that the inevitable error phases can easily wind up with the experimenter dead - as indeed happened multiple times. This fundamental problem tends to put a premium on accompanying trials with careful development of theory.
It also means that you could have had individual successful flights long before the bugs were worked out, if the pilot was lucky enough that where the uncontrolled glider wanted to go happened to coincide with where the pilot wanted to go. Hence, perhaps, those semi-legendary flights CalMeacham mentioned.
Possible, but unlikely.
Using basic materials, we now know enough to build a glider capable of flight, strong enough to stay together and stable enough to fly for a reasonable time without active control by its pilot. But this is way beyond what was known at the time those legendary flights were said to have been made.
Lilienthal’s efforts were state of the art for his time - indeed, they significantly extended the state of the art. His gliders were the most efficient yet made, and were controllable by the operator (using weight shift). And his longest flights were a few hundred feet.
Certainly unlikely for any given flight. But human history has had no shortage of stupid daredevils, and people have been attempting flight for a very long time. I wouldn’t have a hard time believing that a few of those many daredevils managed to draw the royal flush of a survivable landing.
Heck, there was a case in modern history where a jet lost control, the pilot ejected, and the unpiloted jet subsequently managed to get back under control and landed itself. Something similar could have happened with a glider with a pilot who couldn’t actually do anything.
Right. This is quite a useful technique to gather information about such things as the L/D (= glide ratio) of a prototype.
But a tethered flying machine exhibits few control issues compared to a free-flying one. And that’s where much of the challenge (and danger) lies: controllability.
I strongly question whether it was really a matter of early windmill builders simply not noticing the shape of naturally occurring non-rectangular airfoils like maple seeds. Rather, I suspect that the flat rectangular shape was simply far easier to construct with the materials and techniques available at the time.
I would agree. It took a manned glider for the Wright Brothers to figure out the need for a 3rd axis of control. Keep in mind they didn’t launch it off the top of the Eiffel Tower. They flew it down gently sloping hills so their height over the terrain remained low.
And speaking of how birds misled human gliding attempts, how do birds do without any sort of vertical stabilizer?
Exactly - if the usual wind was sufficient to turn the millstone or water pump, no need to get more efficient.
They can manipulate their wings and (nominally) horizontal tail in complex ways that have thus far proved impractical on aircraft.
Some tail-less aircraft have been produced (Northrop YB-35, Northrop-Grumman B-2) but they present various problems and are far from common.
Humans can build aircraft that are substantially more efficient than any bird. But we lag pitifully behind birds in active re-configuration of aerodynamic surfaces.
Interesting note: when Stringfellow built his unmanned steam-powered propeller-driven monoplane in the 1850s it had no vertical stabilizer. It flew really well in the absence of cross-breezes So he flew it in long buildings and tents, so he wouldn’t have to deal with them. I always wondered why he didn’t use a vertical stabilizer – you’d think it would be an obvious innovation, inspired by the rudder on a boat.
Perhaps he’s one of those mislead by vertical stabilizer-less bird design. But you’d think that he’d add that vertical tail when his planes started veering left and right.
But they do have a vertical stabilizer. It’s on-demand and combined with the horizontal stabilizer.
Think in terms of a V-tail Bonanza.
