Slashdot Mirror
Project OpenSky Takes Off
Jesrad writes "As was reported two years ago on Slashdot, japanese artists, students and engineers under the lead of Kazuhiko Hachiya have taken upon themselves to build a real-size, fully functional Mehve (japanese website), the small jet-powered glider flying wing ridden by anime heroin Nausicaa. They have made a lot of progress, and are now test-flying the full scale, yet unpowered model by tow-launching it along with its thrilled pilot. They're having a lot of fun, too, judging from the movies of the testing sessions."
In think that you may have meant 'heroine' instead of 'heroin'.
You would have to get FAA clearance to fly it if it does not fall under the classification of an ultralight aircraft.
Schrödinger's cat is not amused—maybe.
But would Ohmu's be forced to register with the government ...
Anyone who's seen the opening sequence from "Kaze no Tani no Nausicaa" (Nausicaa of the Valley of the Wind ) can understand the type of flight experience they are trying to produce here.
The freedom with which Nausicaa sails around the skies on a flying machine light enough to carry yet strong enough to carry out some hairy aerobatics has figured in many a daydream. Hayao Miyazaki takes our daydreams and puts them on the big screen.
Of course the reality of FAA regulations and principles of aerodynamics tend to get in the way of truly realizing the dreams but I give kudos to these guys for trying.
If you don't want to repeat the past, stop living in it.
There are lots of glider pilots who use small compressed air or gasoline engines to take off and then switch to glide mode once airborne.
You are so boring that when I see you my feet go to sleep.
Fuel density:
Kerosene (Diesel fuel): 11,000 watt-hours per liter, 13,000 watt-hours per kg
Typical ultralight engine: 30,000 watts
Assuming you are running at full throttle all the time (fairly unlikely):
a 10 liter tank will last you 3-odd hours and weigh right around 12 kg. Most ultralights have a fuel capacity between 8 and 35 liters.
Does the math work out better for you now?
This thing is not that small. According to their website the previous model has a wingspan of 9.6m and this one looks slightly larger.
:)
This is proportionally much larger than what was depicted in the anime.
If we lived in a fantasy world where the atmosphere was denser, then maybe everyone would be flying like this, but in reality things are a bit more difficult.
It just has to be slow (100 mph I believe). . .
.and weigh less than 200 lb (100 kg).
That would kilometers/hour. 55 knots. 63 mph.
. .
155 lbs. for unpowered craft; 255 lbs. empty (maximum fuel load of 5 gal.) for powered craft.
KFG
They're close to skin color, so unfortunately it isn't terribly obvious. This isn't that kind of anime. Sheesh.
FAQ
I give these people full credit for persuing their idea this far. However they're going to have a very difficult time with a design like this as it is inherently unstable. While it may fly fine when straight and level, perhaps doing gentle moves, it'll be very happy to snap back with some very ugly characteristics when pushed outside of its stability envelope.
:D
A full time computer working on the stability will help a lot, however at some points no amount of computer intervention will re-establish stable flight (ie, tumbling).
Then again, similar things were said about the helicopter
Looking forward to seeing what they end up with... especially for the turbine motor.
Sorry... the link is here
The result is that homebuilt aircraft are more likely to have safety features (e.g. modern auto engines,
Gotta stop you right there. Automobile engines and aircraft engines are very different beasts for very good reasons. Automobile engines normally run at 20% of rated power with occasional bursts to 80% rated power and only the rarest burst to 100% rated power. Aircraft engines normally run at 80% rated power and will routinely spend several minutes at 100% power during each flight (takeoff and climbout). That critical "expected normal load" results in a very different engine design.
If you try to put an automobile engine in an airplane without substantial redesign to account for the different expected loads, you're basically guaranteeing premature catastrophic failure.
The result is that homebuilt aircraft have as good a safety record as commercially built designs.
Check your facts. Homebuilts have a much higher accident rate per flight-hour. Still pretty low, though.
Regards,
Ross
Under the FAI definitions paragliders and hang-gliders are both in the same category of foot-launced unpowered aircraft, they both have loosely similar flight-characteristsics, tend to share the same airspace and consequently in many countries they (now) share a regulatory body.
Thus it was I came to be on an instructors' course some years ago when the subject of accident prevention and reporting was being discussed and one thing I remember very distinctly about that was that the same mistakes tend to be made time & time again. I guess this applies to all fields, programming as well, but on this occasion it was pointed out how accident reports of 5 years before looked pretty much like the accident reports currently submitted to the association. I guess the statistics were probably lower than you might think and the majority of incidents involved sprained ankles and broken wrists but the causes were typically pilot error, over-confidence, carelessness &/or neglect - the same reasons hang-glider pilots had been having accidents for 20 years.
Likewise it took a few dead paraglider pilots before the introduction of a certification regimen under which manufacturers of gliders were required to submit new their models for testing - a regimen which 10 years ago had recently matured but which bore remarkable similarities to the certification schemes under which hang-gliders had been regulated since the 1970s. And of course the testing for hang-gliders had been introduced for the same reason - dead pilots, just in the early 1970s they were the result of simple Rogalio hang-gliders entering "luffing-dives" whereas in the early 1990s the cause was paragliders "collapsing" in turbulent air &/or finding themselves stable in flat-spins or spirals.
A previous poster wrote that "the freedom with which Nausicaa sails around the skies on a flying machine light enough to carry yet strong enough to carry out some hairy aerobatics has figured in many a daydream" but wings that achieve this goal, this dream, are already widely available. Just because they don't look quite like the one out of your favorite comic book, I don't think that's a great reason to learn aviation design the hard way.
Aviation design is a really complicated discipline with lots of pitfalls, and mistakes may not show up until a wing has been flown for a number of hours, which is kinda inconvenient if you're flying at a few hundred feet at the time. Tailless aircraft are particularly quirky, and last time I checked (a few years ago, admittedly) there weren't many designs available - a tail is just a really easy way to ensure pitch and yaw stability.
Don't get me wrong - this looks like a really great toy, I'd love to have a play with it and I wish these guys the best, but I hope for their sakes that they've done their homework. The veteran pilots I've known who have lost friends to the sport (and I guess that includes me) haven't really known what they were getting into.
Well - sort of - in the animated movie, the jet is used only occationally (liftoff etc)
and the wing is often used as a glider.
It's impressive that they're doing this. Moewe has rather low wing area for the slow-speed maneuvering it does in Nausicaa, though. It's certainly possible to make a lively little aerobatic monoplane (the Sukhoi S-26 is one of the best modern ones), but those little wings imply a high stall speed. If you want hang-glider type stall speeds, you need more wing area or less weight. The classic solution for slow flight is the biplane. Take a look at this old Sperry Messenger, which has about the same wingspan as Moewe. The Messenger was a very maneuverable little plane. Sperry himself once landed one in front of the U.S. Capitol.
Moewe's tailless design creates a pitch stability problem from hell, but that's what flight-control computers are for. It's interesting to see what changes they made from the R/C model. The R/C model looks more like Moewe, with straight wings and a huge dihedral angle. The bigger towed model has a bent wing. They're trying for something that wants to fly straight and level.
There's much new interest in light aircraft today. The FAA has created a new category of "light sport planes", heavier than ultralights but lighter than general aviation aircraft, with less restrictive licensing. Take a look at this StingSport, which isn't much bigger than Moewe, even though it's a two-seater.
I expect the Open Sky crowd will build something that looks more or less like Moewe and flies reasonably well. And they'll do it long before Moller gets off the ground.
Increased dihedral really doesn't affect pitch stability, only roll stability. Dangling the weight like a pendulum below the aircraft isn't very effective either, you'd end up fighting phugoid oscillations. Normally, the key for pitch stability is to have your center of gravity in front of your center of (wing lift) pressure. Such a configuration would cause the plane to nose dive like a lawn dart if it had no tail or canard. An unswept flying wing avoids this, essentially, by building the tail into the back of the wing, using what's called a reflex airfoil, which is curved up slightly in the back. You can see this in Opensky's pictures. This severely reduces lift compared to a typical airfoil, but unless you have an onboard computer flying the thing, it's the only way to prevent it from flying like this.