Slashdot Mirror
Studies In Ornithopters
weileong writes "This should be of especial interest to fans of Frank Herbert's Dune (or maybe only those who preferred House Atreides) - a genuine, flexible, flapping-capable winged aircraft (by which I don't mean passenger-carrying. Yet.) has been produced by the University of Toronto's Institute for Aerospace Studies and SRI International (Washington Post article, free reg required). Advantages include everything from low speed control to efficiency. Once these things really hit "real world" usage, the V-22 Osprey really HAS no reason to exist (and all the army personnel at risk of dying in one should rejoice)."
No need for the V22? Hardly.
:oD
The V22 is _finally_ getting to the mature design stage. They removed the problems that killed people (mostly, no a/c is perfect) like the inability to handle the loss of ground effect under one rotor.
Now they have an a/c which can not only take off vertically (or very sharply with high load), fly at 400mph and carry a ton of stuff. For it's role it beats the shit out of any helicopter (fast enough to do the job more fuel efficient, heavier loads,) and and cargo plane (no need for a JATO unit, can't run a C5 off a carrier).
This new technology is (like the tilt rotor concept was) unproven, and requires a complex set of engineering decisions to be made to get it to fly safley (like the tilt rotor). In 20 years, with a few deaths, it might be great - but the tilt rotor is here now.
FWIW there is now a commercial version of the V22 in prototype, the BA commuter aircraft. Small enough to land on helipads, but fast enough for intercity (and in Europe) international work. There have also been plans for a gunship version of the V22, with a massive rotary cannon and the ability to fly very slow it's even going to make the A-10 look a bit lightweight
Beep beep.
Click a bit further ;-) home page and movie can be found here.
This article has a picture of the ornithopter:
Mentor Micro-Air Vehicle
Wow, it looks weird.
"centuries of evolution have produced structures and systems that work very well." Centuries of evolution on Earth have produced structures and systems that work very well on Earth. People have spent decades, possibly centuries, developing flapping-wing vehicles that, even now, barely fly on Earth, and someone wants to send them to Mars in 6 years (2009)? I think a sailplane-like vehicle would still be much more effective.
10 Bits= $.25
100 Bits= $.50
110 Bits= $.75
1000 Bits= 1 byte
he might have noted that there are no plans to build larger versions of these things. The entire point is small "insect sized" spy drones.
Various small ornithopers have been built. You can even buy toy windup versions. In small sizes they work.
They do not scale. There is no known way to make them scale. Neither the physics nor the engineering support the idea of producing large amounts of lift be rapidly anad violently flapping around large inertial masses.
Not to mention the fact that in the large scale the problem has been solved already with the rotating wing.
I haven't a clue how thousands of pounds of rapidly flapping metal could be deemed to be potentially safer than the Osprey, particulary given the sorts of mechanisms that would be required to drive them.
KFG
An excellent Magic card, too! 0/2 flying artifact creature for 0.
As a blocker, it can't be beat.
The Osprey's had trouble for a reason--it's horribly complex, and there's never been an aircraft like it before (outside the X-planes, that is). An aircraft that transitions from a conventional airplane to a would-be helicopter has a lot of control issues to work out.
The poster's theory that the ornithopter will somehow make this superfluous is a bit ludicrous. An ornithopter large enough to carry troops will likely be even more complex. Taking the output from a turbine engine and gearing it down to spin a prop is trivial--we've been doing it for decades. Even with the complicated transmissions and crosslinks and control systems on the V-22, it's still basically just a combinatinon and evolution of previous aircraft.
Taking output from a turbine and translating it to drive a piston is another matter. It can be done, of course, but entails much higher losses. The researcher says enormous amounts of energy are required for the small one, and it's, um, small.
The strength of the parts is another issue. Making wings and linkages that will drive them is going to be a challenge. As will performance after an engine failure.
Don't get me wrong, this is quite an achievement. For the unmanned aerial vehicle trade. I don't think we'll have the technology to make a troop transport, or even a one-man aircraft, out of an ornithopter for a long time.
Trying to foist this as a replacement for the Osprey is a bit ludicrous. Replacing a complicated aircraft with a more complicated one does not lend itself to safety or reliability, right out of the box.
And the ornithopter, being a different design, clearly will not have this fault.
The V-22 or any other Bell twin engined tiltrotor to date can fly on one engine. The two rotors are cross shafted together so that both rotors remain in synch and powered at all times. A quad tiltrotor has been considered and that aircraft (C-130 sized) would have all four engines and rotors cross-shafted so that several engines could be lost without losing the aircraft.
That said, the V-22 will not be a A-10 replacement. That simply makes no sense. A gunship version has been proposed but it's more along the lines of an AC-130 gunship. Orbit higher and a little futher away from the targets. More of an area weapon for softer targets not getting down and dirty with heavy armor. The 'Hog is tops for that.
Early test V-22s did have ejection seats. The rotors do not pass above the cockpit so there is a small path in VTOL mode and obviously a larger path in airplane mode for a safe ejection. Current production ships no longer carry this feature and like any other cargo ship, there were never plans to eject all the passengers.
Yes and no. Fatigue WAS a major issue in the early years of aviation, but now it is well understood. As long as you have a proper understanding of the material's properties and the stresses induced by the application, then you can design to forestall or eliminate fatigue cracking. Some materials (certain types of steel) actually have infinite fatigue resistance as long as the stresses are below a critical threshold. Stress cracks are not an issue where one can employ a combination of good design, good "life" testing, good operator training, and good inspection/maintenance procedures. I'm not saying that bad things can't happen, just that they are preventable.
Two wrongs don't make a right, but three lefts do.