At some point, Ray Harryhausen’s Earth vs The Flying Saucers was broadcast into space. Likely the aliens took one look, said “Cool!” and immediately revampted their interstellar fleet style. But after *Bullitt * was broadcast, they no doubt would have adopted a style reminiscent of the Mustang Shelby GT.
So - given that the maximum sphere for the Harryhausen Effect is roughly 40 light years in diameter, the saucers must emanate from a relatively nearby source. But if we start seeing Shelbys, they are from much closer.
a.) If you don’t think about the saucer as being flat on the bottom and instead go with an oblate spheroid then yes, it is good for that. Sure there’s lots of area, but it’s scattering the beam all over the place. Angle of reflection is equal to the angle of attack, and all.
b.) From Wikipedia: "The possibility of designing aircraft in such a manner as to reduce their radar cross-section was recognized in the late 1930s, when the first radar tracking systems were employed, and it has been known since at least the 1960s that aircraft shape makes a very significant difference in how well an aircraft can be detected by a radar. " Then there were materials. In WWII the primarily-plywood deHavilland Mosquito was known for its relatively small signature.
Your stealth c.) It’s simply easier to balance the the various masses in a vehicle around a center point if it is circular. Aerodynamic forces are also easier to balance when the edges are all the same distance from the thrustline. If the vehicle is expected to maneuver quickly and in all directions, it’s easy to do by tipping the vehicle so the thrust is (roughly, taking gravity into account if needed) opposite the direction you want to travel in. That’s how helicopters do it–think of the rotor as creating a virtual disk as it turns and understand that its swept area is so much larger than the area of the fuselage that the disk is the important part and the fuselage is just there as a power pod. Sure, you can do it with other shapes, but it’s easier with a disk–Harriers go faster forward both because they are designed to but also because they present much less area from the front than the side. A disk presents the same amount of area from any direction.
Then if you imagine the rim of the disk turning as part of the means of producing lift and stability, like the German experimental saucers or, for that matter, a Frisbee, you can see why a circular format is required.
To further muddy the waters, there were proposals for Lenticular Reentry Vehicles, which would have been a subclass of lifting body. AFAIK, none were ever actually built.
This is absurd. You’re just extemporizing, like the people I mentioned in my first post.
1.) There’s nothing special about the shape of the saucer for minimizing radar reflection. If there were, our stealth ships would be saucers. What’s mainly needed is to avoid corner cubes for retroreflection, and flat surfaces likely to be normal to the radar emitter. There’s an infinite variety of shapes that do that.
2.) The optimum shape depends on the engineering requirements, as I said at first. You can certainly make up situations that fit that requirement, but as long as they’re not practical (and if they were, we’d have actual flying saucers), it’s just an exercise in pointless speculation.
3.) The Osprey has no problem with VTOL, and it’s not a saucer.
The saucer shape would be ideal if you don’t need any idea of a “front” (e.g., a UAV with cameras all over) and your engines can take you in any direction you wish (which is what’s claimed of UFOs). By being radially symmetric, you can ‘turn’ without having to ‘turn’, which is quicker and more efficient. Being flat is obviously better for drag.
Lovely. You use the Osprey as an example of an aircraft that flies well. :rolleyes:
I won’t continue to argue with you, especially with this “You’re wrong!” “No, YOU are!” back and forth we’ve found ourselves in stopped going anywhere hours ago. And especially since I’m not arguing from my own understanding of engineering principles studies alone, but also Hill’s, and we all know that, though he was a professional engineer who spent his career solving real-life attitude control of real-life spacecraft, his attempts to explain the mechanics of UFOs are worthless because UFOs are completely imaginary and not worthy of study, and trying to understand the imaginary can have no engineering value. And because you cannot accept that one solution to an engineering problem should be thrown out because it does not obviously pertain to a specific application.
I know that this sounds like the old “you scientists cannot see beyond your own preconceptions” thing of the crackpots, but everybody can get stuck in a rut sometimes and I find Hill’s book to be a takeoff point for interesting “what if?” thoughts. However, if the “stick in the mud” shoe fits…
How the hell did you guys do that? How do you take a subject so naturally given to whimsey and spitball fun as flying saucer design, and manage to find something to get pissed off about? Whatzamatta you?
Moi? I am not pissed off. This is the thrust-parry of the SDMB, and I am currently thinking (and I have the OCD (“At least you chose the right career”) diagnosis to go with it, that I, for the moment, have the upper hand, and Silent, but not enough, Cal has taken the other side. You have mixed this sort of thing with political discussions, where people are arguing Truths, not Possibilities. I know I get weary arguing the Engineering Process, which involves a LOT of “‘You are totally wrong!’ ‘No, I am not, and here’s why!’” back and forth, but that is part of the process. It’s just usually not in public.
I’m a lot more worried about the much-more-widespread propensity on this board to take subjects that deserve to get taken seriously, and get pissed off about, and instead be whimsical and throw spitballs about them instead. Better to err on the side of seriousness, I say.
To the OP, the best shape for such craft would be derived from the requirements of their FTL/jump drive and on the physiological (if any) nature of their occupants. Tell us what those are and we can make some headway.
On one of the myriad shows on the History Channel they presented the idea that some of the aliens (that may or may not be) visiting us may be doing it just for kicks, and the “saucer shaped” craft are more like the sports cars of the spacecraft world and aren’t meant to serve the most practical purpose, wheras other shaped crafts (i.e. cigar, boomerang, whatever) would be used for important things such as military, science, or exploration.
Of course all of this is a big load of “what if,” but it’s an interesting idea and as good a way to dance around them not being the best design plan as any.
You’re missing one of the the main purposes of alien space exploration. The point is not just to travel vast distances clandestinely, get blurrily photographed and take the occasional peek up our butts (I’m betting one of us – and I have my suspicions – has something truly amazing up there that neither they nor we have discovered yet), it’s to scare the hell out of the local rubes in Roswell, or Dimbulb, Iowa, or wherever, just to keep us off balance enough so we all don’t start thinking rationally and solve interstellar travel problems our ownselves. I’m assuming, therefore, that ships due for arrival over North America, for example, are currently shaped like gay weddings, burning flags, and evolutionary biologists.
Fleeemnt: It’s totally impractical
Bob: yeah, but nice lines
Fleeemnt: It doesn’t even handle that well, but what we’re really talking about here is pussy
Bob: I’ll take it.
“What about this pretty blue and white planet? We went to a red one last time…”
“Well, lets see…‘mostly harmless’…good, good…‘no known source for dilithium crystals’…mmm, not so hot, ours are gonna buckle one of these days…‘natives strangely fond of having foreign objects thrust into their cloaca…’ How very odd…”
“Oooh, that sounds exciting! Just thinking about it makes me want hronk your sznargle!”
“Why, Mbl! You dirty little sthondat, you! Well, OK, but lets take our own food, I don’t want the Kessel runs for twelve parsecs like last time…”
Any kind of craft that relies on interaction with the atmosphere for lift generation, and is designed to be longitudinally stable is going to favour flying in one direction. Stability is dependent on the centre of mass and centre of pressure, and without some kind of horizontal surface other than the main lifting surface such as a traditional tail-plane or a canard, the aircraft will have a tendency to tumble unless the CoM and CoP are in the exact same place. CoP is dependent on angle of attack, airspeed and other factors, so it’s easiest to add a horizontal tail to an aircraft than to move the CoM to keep it stable.
If we assume a saucer shaped aircraft is designed to operate efficiently in all directions, yet relies on its body for lift, it would require constant thrust vectoring/augmentation to keep it level. Such an aircraft would be hideously unstable, beyond the level that would be desirable in manoeuvrable aircraft. But who’s to say that extraterrestrial intelligence hasn’t managed just this.
If the aircraft has some non-aerodynamic means of attitude and position control, however, then you can make it any shape you want.
