Studies In Ornithopters

Wrong branch by benj_e · 2003-09-01 01:55 · Score: 4, Informative

It's the Marines that use the Osprey, not the Army.

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Re:Wrong branch by HerrKobes · 2003-09-01 06:26 · Score: 2, Informative

Actually, the USAF and USN will use them as well.

MV-22 is slated for Marine usage, the CV-22 is for the USAF, and the USN is looking at an HV-22 variant for Combat Search and Rescue (CSAR).

The USAF version, the CV-22, will be operated by the USAF under US Special Operations Command.

The V22? by Realistic_Dragon · 2003-09-01 01:57 · Score: 5, Informative

No need for the V22? Hardly.

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 :oD

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Re:The V22? by bbaskin · 2003-09-01 02:29 · Score: 5, Informative

The cause of the Arizona accident that killed 19 Marines was a form of vortex ring state that formed around one proprotor that caused an imbalance of lift from one side to the other. The ship rolled sharply and nosed in. All helos are susceptible to VRS and it forms when you are travelling down too fast in combination with low forward airspeed. At the time, the Osprey had a vertical descent rate limit of 800 ft/min at low forward airspeeds. The ship in question was descending at ~2100 ft/min, almost three times the recommended rate. Pilot error. The other crash later that year was due to a combination of hydraulic and software failures that reduced the redundancy of some control systems.

The VRS has now been shown to not be a symptom of tiltrotors only, its boundaries have been mapped out, warning sensors have been installed, and VRS exit strategies developed. In a helo, you just gain some forward speed or sideward speed. In a tiltrotor you have the additional option of tilting the nacelles a few degrees. In addition, plenty of improvements have been made to all sorts of subsystems and the computers have been through the cleaners to check for more bugs.

The commuter ship, the BA609, will also benefit from these studies. It's target certification date is late 2007. That date is so distance for a variety of reasons, most of them non-technical.

Tiltrotors are complicated, but I've flown the BA609 sim, and it's by far the easiest VTOL aircraft I've flown and the capabilities are impressive.
Re:The V22? by Martin+Blank · 2003-09-01 02:58 · Score: 4, Informative

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).

First point correct, second point misses the mark. The C-5 (and the C-17 and C-141) are entirely different classes of aircraft than the V-22. The V-22 is designed more to set troops into action like a conventional helicopter such as the Black Hawk does, though I believe it's possible to parachute from them. The other three are primarily cargo aircraft with secondary airborne capacity. Their ranges also beat out the Osprey's.

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

That's also going to require putting a lot of armor onto an Osprey, and I don't know if it can handle that. Your performance statistics seem to be off of the real mark, judging by the Navy's version of things. With a max speed of only 275mph, and what looks to be a fairly small difference between the empty and various max-takeoff weights, I don't see this becoming a challenge to the A-10 anytime soon, since that plane not only carries the GAU-8/A (with its weight of 281kg plus a kilo for every round), but also up to 7250kg of payload underneath it. I've seen pictures of them with a bevy of Mavericks slung underneath, and it's a menacing sight.

Getting back to the original story topic, though, I can't see yet how this idea would translate into a usable large aircraft as the submitter is hoping. The forces are significantly higher at the wingtip than at the root which is going to stress the wings in an increasing fashion the longer they are, not to mention the material fatigue from a material that is constantly changing directions. I can see this used as they envision now, with small drones or perhaps as a new ultralight, but I can't see how the increased lift would be generated efficiently for a replacement to even a small troop transport like the Osprey.

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Re:No pictures?? by Anonymous Coward · 2003-09-01 02:00 · Score: 5, Informative

Click a bit further ;-) home page and movie can be found here.

related article with picture by BoosterToad · 2003-09-01 02:03 · Score: 5, Informative

This article has a picture of the ornithopter:

Mentor Micro-Air Vehicle

Wow, it looks weird.

V-22 by Ribald · 2003-09-01 02:09 · Score: 5, Informative

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.

with pictures - I got pictures by wadiwood · 2003-09-01 02:11 · Score: 2, Informative

story with pictures
This thing seems to go back to at least July.
The picture looks like something we could build with alfoil from the kitchen, a broken umbrella and a toy aeroplane engine. Maybe we need video too. Anyone got Video?

And just because you can't think of a good use (non military) doesn't mean there isn't one. Mark Twain had trouble imagining what use a telephone would get, and Bill Gates didn't believe in the internet for a long time.

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-- it must be true, it's on the internet.

Compare apples with apples ... by slb · 2003-09-01 02:16 · Score: 3, Informative

> the V-22 Osprey really HAS no reason to exist

Ridiculous comparison, this technology is designed to build micro-drones while the Osprey is supposed to lift tons of armament and passengers !

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now with video, if you are patient by wadiwood · 2003-09-01 02:18 · Score: 2, Informative

A picture of what they're aiming for and a video of what they've got I think we're perfectly safe for a while from these things. Of Course Aussies can handle a fly swat or rolled newspaper with ease, so they're not safe from us, or our blue heelers.

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-- it must be true, it's on the internet.

Absurd by SuperBanana · 2003-09-01 02:29 · Score: 4, Informative

No need for the V22? Hardly. 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.

Your argument is all and well, except that aircraft ARE virtually perfect- it's the ones that are NOT perfect that we hear about. Second, when an aircraft is NOT perfect, you're supposed to fix it. The contractor involved and the armed forces instead outright lied through their teeth and ignored the problems while soldiers continued to die. Lastly, the problems were far more extensive than just one issue with ground effect.

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

One of the warthog's best features is its heavy armour- some jokingly call it the 'flying bathtub' because of the cockpit reenforcement. I believe most hydraulic and electrical systems are also heavily armoured. It takes more than just a plane to make an effective way to shoot at people. Nevermind that the V22 looks to be completely intolerant of failure in either engine- and as any pilot knows, twin engined planes have twice as many engine failures because, surprise, you've got two of 'em :-) I'd be curious to hear your thoughts on how someone would eject from the V22 without standing a good chance of being sliced to pieces.

As for the original poster's comment that this will replace the V22- I hardly see how. Ever notice that 'Ornithopters' in nature don't really exist above a dozen pounds or so? Sure, we had some big flying dinosaurs a while back, but even those weren't nearly big enough to weigh as much as a small plane.

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Re:Absurd by bbaskin · 2003-09-01 02:40 · Score: 5, Informative

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.

CarterCopter a more likely V-22 replacement by ehintz · 2003-09-01 02:33 · Score: 2, Informative

CarterCopter

I don't believe it will go quite as fast as the V-22, but mechanically it's a much simpler design, more of a morph between a gyrocopter and fixed wing. In the 2-engine variety it will do a true hover, and they expect it to scale up into the C-130 size range or so. And manned experimental versions have been flying for a year or two now, even at Oshkosh.

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ehintz

Re:Here's the URL by Baron_Yam · 2003-09-01 02:42 · Score: 3, Informative

A certain idiot who shall remain nameless left this out of his post...

Ornithopter.Net

I think these are the same UofT guys who built the smaller model mentioned in the article.

More Ornithopter info... by c_king · 2003-09-01 02:51 · Score: 4, Informative

ornithopter.org

Re:Assumption is the mother of all f**k-ups... by weileong · 2003-09-01 02:59 · Score: 2, Informative

44 accidents in its first five years compared to just two in the Osprey's first five years

There was (is?) a scandal about how a lot of the personnel who were involved in the Osprey project have systematically been fudging reports to make things look better than they really are. This makes evaluating its performance hard because you can no longer trust any "good" reports.

When you say accidents, what are we talking about exactly? The kind of thing where nobody walks away from, or? (i.e. are we comparing apples to oranges, with the Ospreys crashes involving quite a lot of fatalities).

VTOL planes always seem to be plenty risky - the Harriers are also quite widely known for killing their pilots, aren't they?

Picture link, for those 2 lazy to google by Anonymous Coward · 2003-09-01 03:09 · Score: 1, Informative

http://mi.wizards.com/global/images/magic/general/ ornithopter.jpg

you're friggin welcome

Re:Assumption is the mother of all f**k-ups... by WIAKywbfatw · 2003-09-01 03:14 · Score: 4, Informative

VTOL planes always seem to be plenty risky - the Harriers are also quite widely known for killing their pilots, aren't they?

Err, no. Harriers have an excellent safety record and an even better combat one. During the Falklands War, British pilots of the Royal Air Force and Royal Navy lost none of their Harriers to enemy aircraft (one was shot down by ground-based anti-aircraft fire) whilst managing to shoot down twenty Argentine aircraft - this despite the fact that the subsonic Harriers were matched up against supersonic opponents.

VIFFing (vectoring in forward flight), a strategy limited to the Harrier and other VTOL aircraft capable of redirecting their thrust mid-flight, is a favourite dog fight strategy of Harrier pilots. One minute you're on his tail, lining him up for a shot, then next minute the Harrier's no longer in front of you because its pilot has "jumped" vertically. And, by the time you've worked it all out, he's dropped back down behind you and is about to missile lock your aircraft.

Next time, do your research.

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"Accept that some days you are the pigeon, and some days you are the statue." - David Brent, Wernham Hogg

Flight control using insect vision by Anonymous Coward · 2003-09-01 03:37 · Score: 2, Informative

Some experimental aircraft and rotorcraft use insect vision for flight control

minor point by lone_marauder · 2003-09-01 04:10 · Score: 1, Informative

(and all the army personnel at risk of dying in one should rejoice)

Which would be zero, since the V-22 is used by the Marines.

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Re:Assumption is the mother of all f**k-ups... by bluntmanspam · 2003-09-01 04:33 · Score: 4, Informative

OK, how bout next time you do your research, too. A quick google search turned up this story from the LA Times (mirror here)

Quote from the story:

The lifetime accident rate for the Marines' AV-8B is 11.44 per 100,000 hours of flight, well over the combined rates for other attack and fighter planes flown during those years by the Marines, the Navy and the Air Force.

And before you go off about untrained or unskilled American pilots again, check the author's Q&A here, where he points out this:

The AV-8B had 12 major accidents per 100,000 hours flown during the decade. The three similar Harrier models flown by the Royal Air Force during that time had accident rates ranging from 12 to 19 when the U.S military standard is applied.

and this:

Because there are fewer Harriers in Great Britain, and they fly fewer hours, they've had fewer crashes and fatalities.

The Harrier is not a safe aircraft. The RAF knows it, that is why they are part of the Joint Strike Fighter program. That program aims to create a VTOL aircraft without the problems of the Harrier.

Re:Assumption is the mother of all f**k-ups... by weileong · 2003-09-01 04:35 · Score: 4, Informative

Hi, read this article some time back:

Harriers - the Widowmaker (from the LA Times)

Some excerpts:

Far From Battlefield, Marines Lose One-Third of Harrier Fleet
The corps, pursuing its long-held dream of a unique flying force, pays a heavy price: 45 of its elite officers killed.

Many of the Harrier's ailments can be traced directly to its innovative vertical-thrust technology. But despite the investment of tax dollars, aircraft and pilots' lives, there is little evidence that the Harrier's noncombat deaths have been redeemed in any significant way on the battlefield

In the Persian Gulf War in 1991, the hot thrust-producing nozzles in the heart of the fuselage -- the devices that allow the Harrier to rise and balance in the air -- made the plane a magnet for heat-seeking missiles. Its loss rate was more than double that of the war's other leading U.S. combat jets. Five Harriers were shot down and two pilots died.

"It's the most vulnerable plane that's in service now," said Franklin C. "Chuck" Spinney, who evaluates tactical aircraft for the Pentagon.

Next time, do your research

I actually did, you'd be pleased to know.

Re:Material Fatigue ? by G4from128k · 2003-09-01 04:47 · Score: 5, Informative

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.

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Two wrongs don't make a right, but three lefts do.

Re:WTF's up with all the talk of carrying PASSENGE by R2.0 · 2003-09-01 08:09 · Score: 3, Informative

Yeah - and the fact that "army personnel" could care less: the V-22 is flown by the Marines exclusively. And if one doesn't think there's a difference, head off to the bar nearest the local Marine base. I'm sure someone will provide enlightenment.

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"As God is my witness, I thought turkeys could fly." A. Carlson

Re:Assumption is the mother of all f**k-ups... by Thomas+A.+Anderson · 2003-09-01 08:36 · Score: 2, Informative

There's no need to be rude in your post - so what if you disagree with what the person said. Now, lets talk about research....

VIFFing (vectoring in forward flight), a strategy limited to the Harrier and other VTOL aircraft capable of redirecting their thrust mid-flight, is a favourite dog fight strategy of Harrier pilots. One minute you're on his tail, lining him up for a shot, then next minute the Harrier's no longer in front of you because its pilot has "jumped" vertically. And, by the time you've worked it all out, he's dropped back down behind you and is about to missile lock your aircraft.

There's been quite a bit of speculation about the usefulness of this trick in combat (for both the harrier and the "cobra"-capable Russian fighters) and the general concensus is that it's a sure-fire way to be missle-bait. Speed is you friend in air-air combat!

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Re:Assumption is the mother of all f**k-ups... by mamahuhu · 2003-09-01 18:57 · Score: 2, Informative

in fact Argentina put Skyhawks up against the Sea Harriers in the Falklands war and they're not supersonic.

Here are the Skyhawk Tech Specs - top speed 675 mph - and to jog you memory the Speed of Sound is 761 mph (1,223 km/h).

Here is a link to Skyhawks in Argentina and in the Argentine Forces during the Falklands war.

They did field four Super Etendard Fighters which are supersonic - but not against the Sea Harriers. The Sea Harriers were lost mainly through accidents, SAMs and small arms fire! British Aircraft Lost.

Here's a breakdown of Argentine Aircraft Lost - you'll see they were shot down mainly by missiles - some from ships others by Sea Harriers. The Sea Harrier can thus be seen as a platform for missiles - and can not really be lauded as a performance aircraft - though the VTOL ability is amazing.

I'm no war or fighter nut - these links above were found on Google over a 10 minute period - it's called research - something I don't think you actually did :) No hard feelings just do a Google and show us the links if you feel strongly enough about your position.

Just the facts Man!

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