Airships aren't the only aircraft to use V tails. Early Beech Bonanzas[1] and the Robin ATL[2] both have "ruddervators" - a V tail which combines the function of elevator and rudder into two control surfaces.
They also both use mechanical control mixers. This is a diagram of the Robin mixer - http://i.imgur.com/yVLQA.jpg
The Bonanza was first flown in the late forties.
I'd imagine that the choice to use fly by wire on the Zeppelin NT was more to do with the logistics of routing control cables to the fins, rather than because of complexities in manual control. On that sort of scale, a fly by wire system is going to save you a fair amount of weight in control wiring and brackets, and makes the gondola system far more flexible.
> However, unlike the four fin system, three fins cannot be controlled by a human. To turn left, the top fin needs to be deflected, while the two angled fins need to be deflected by an amount which can only be computed by the sine and cosine of 2π/3 radians times the deflection of the top fin. Turning while climbing becomes even more complicated.
This is like saying that no human could hope to catch a ball flying through the air because it would require doing ballistic calculations in one's head.
I think the author should investigate the combination of control surface manipulations needed to make a coordinated turn in an aircraft, or doing a crosswind landing.
Or if he really wants to have is mind blown: how helicopters are flown.
While the brain is able to combine a lot of sources of perception and create complicated control outputs there are limits to this process. Coordinated turns and crosswind landings are mostly about matching the quite straightforward controls with the external situation and are not comparable to the three surface control problem.
The author spent some effort to build a joystick to demonstrate to us how the problem could be solved. I would think it appropriate you spend some time researching your point of view, maybe with a quick model in X-Plane. We will all be richer for what you find.
I think we'll have to disagree that maintaining coordinated flight is "straightforward." Or especially performing a crosswind landing, which is the controlled de-coordination of an aircraft so that it can hit the ground at exactly the right orientation.
If someone insists that it is 'straightforward' I'm left to conclude that either they're a very experienced pilot who has been doing it for so long that it's difficult for them to remember what it was like to learn, or they don't have an understanding of what's involved.
Consider this: You're flying an airplane. The elevators are trimmed to maintain level flight. Now you turn the yolk to deflect the ailerons, and the aircraft rolls. In this rolled state--say we're rolled 20 degrees from vertical--the elevators are no longer horizontal. They're 20 degrees off the horizontal meaning their force is no longer 100% pitch. It's now a combination of pitch and yaw. Firstly this means that they're no longer trimmed properly to maintain level flight and the aircraft will begin to pitch, secondly they are now causing the plane to yaw into the turn. So now you have to bring the rudder into the equation to compensate for the elevators, but it's also no longer a 100% yaw control surface, it now affects both pitch and yaw and you are left with a situation which should look very similar to that in the Zeppelin NT.
Describing the problem of coordinated flight, you end up with calculations which would be quite difficult to do by hand, and one might conclude that "no human" could hope to pull it off while sitting in a cockpit. Yet it is something humans can not only do, but with a bit of practice can do without even having to try very hard, by learning to "feel" the aircraft.
I think the author's joystick is neat and I congratulate him for making it. My only point is that the author errs in saying that "no human" could directly handle the Zeppelin NT's control surfaces. I think is error is not in overestimating the complexity of the problem but in underestimating the human ability to handle such problems.
I wish it was legal for me to put something like that joystick he devised on to a car. Then, at 29 I could finally learn to drive, which is something I repeatedly failed at; I can't map a wheel, a stick and three pedals (automatic is even more `magic`) to 'forward', 'back', and 'take this turn' in my head for the life of me.
I think you're probably suffering from the same problem I had when learning languages: you're being taught by someone whose teaching technique is optimised for "normal" people.
In my case, I was being taught by people who taught using techniques appropriate for an audience who thought in similar ways to them. I don't. When I finally found a technique that suited the way I think, and the things I already can do, suddenly I found I wasn't bad at languages - I was actually pretty good! But it was too late to gain real proficiency, and I no longer have the time I had in school to work on it. So I get by, rueing the lost opportunity.
But I've since honed my ideas into ways of teaching other stuff to people who think similarly to me, and who want to learn something quickly. I can teach you to juggle in 2 hours. Or teach you to unicycle in 2 hours. I wonder if I could teach you (the underlying rudamentary requirements of) how to drive in 2 hours.
Probably not - driving is more complex than either unicycling or juggling - but I bet the same ideas would work. Wish there was a way to test this.
I think the distinction was that it was a zeppelin, not a blimp. Google does not seem to be involved in its development, you can just pay to take a ride in it.
Zeppelin is just a brand (at this point, anyway). While the Zeppelin NT isn't a blimp, it's not a rigid airship either, but rather a hybrid of the two with an internal frame. Better than a blimp at high speeds and in bad weather, but I doubt the design would scale to the size of the 1930s behemoths.
Well the maker of the Zeppelin NT is the original Eckener entity that created the Zeppelins, so to the extent that a "Zeppelin" is an airship built by Luftschiffbau Zeppelin GmbH, the Zeppelin NT is a real Zeppelin.
But I think it's not accurate to think of the Zeppelin NT as a blimp with some rigid parts. The original Zeppelins had non-rigid fabric gas chambers as well, hung from a duralumin frame which also supported the airfoils and helped the fuselage maintain shape.
The gas chambers of a Zeppelin NT support their own shape through positive pressure, as in a blimp. But they don't have to also support the airfoils, etc. For that, the vessel has a rigid composite structure.
So I think it's more accurate to describe the Zeppelin NT as "a rigid airship with self-supporting gas chambers." And I see no reason why the design could not be scaled up to Graf Zeppelin or Hindenburg size if economics permitted it.
>Well the maker of the Zeppelin NT is the original Eckener entity that created the Zeppelins, so to the extent that a "Zeppelin" is an airship built by Luftschiffbau Zeppelin GmbH, the Zeppelin NT is a real Zeppelin.
Well, yes. He said "this is a Zeppelin, not a blimp", which is a lot like saying "this is a Chevy, not a butterfly". A blimp built by Zeppelin would still be a Zeppelin, and Zeppelin builds all sorts of things that aren't related to airships.
The reason I don't think it will scale well is, like a blimp, pressurization of the gas bag is what keeps a hybrid in the proper shape. This means as the size of the airship increases the envelop pressure must also increase to deal with greater external forces, making the lifting gas heavier and therefor less efficient.
The US navy fielded blimps larger than the Hindenburg until the early '60s, but they were never able to get more than about half the Hindenburg's lift capability for this reason.
With a hybrid you still get the benefit of placing engine pods more efficiently and you don't have to worry about the nose collapsing if you go too fast. However, if you were going to go through the trouble and expense of building an 800 ft airship there's no reason to sacrifice that much lift.
Yes and ironically the First NT Ship was built in the UK at Cardington - I rember seeing it and its predecessors from airship industrys flying over bedfordshire.
Quite a shock to see one of the Airship Industry Airships parked at Cranfield when I got to work one morning
Yes seeing cool planes was a big bonus working on campus at Cranfield University - One time another company there had a IX Spit that they where rebuilding it was refueled about 50 yards from my office we all went out and watched as it put on a display.
As well as being an uber-geek who was head-hunted by Google, Neil is a bit of a Meccano guru. Here is his blog post about building a 3G centrifuge to see if lava lamps would work on Jupiter:
[1]: http://en.wikipedia.org/wiki/Beechcraft_Bonanza [2]: http://en.wikipedia.org/wiki/Robin_ATL
They also both use mechanical control mixers. This is a diagram of the Robin mixer - http://i.imgur.com/yVLQA.jpg
The Bonanza was first flown in the late forties.
I'd imagine that the choice to use fly by wire on the Zeppelin NT was more to do with the logistics of routing control cables to the fins, rather than because of complexities in manual control. On that sort of scale, a fly by wire system is going to save you a fair amount of weight in control wiring and brackets, and makes the gondola system far more flexible.