Has anyone ever built a glider based on frisbees?

No, it will glide for a much shorter distance because it will only be oriented properly in relation to the airflow for a tiny fraction of the time that it would if it were spinning. It it happened to be traveling horizontally, and there was a strong enough updraft, it would gain altitude whether or not it was spinning. With a REALLY strong updraft, it would gain altitude no matter what the orientation, like a car that gets thrown up into a tree during a tornado. :stuck_out_tongue:

I see your point, but I meant giving it enough thrust to experience sustained lift under normal conditions. But reading that got me thinking on whats behind all that spinning, what are the possibilities of exploiting purely the precision (or the gyroscopic principle that keeps the torque created by the airflow from flipping the Frisbee over, like the way a leaf or piece of paper falls in one direction, and then sways to another) aspect for use in an aircraft?

Gyroscopes are used pretty extensively in spacecraft to orient them in the optimum direction. Is that the kind of thing you’re thinking of? Also, there is at least one aircraft (and nautical too, I think) instrument, called a gyrocompass, that uses a gyroscope for navigation.

The rotation of a frisbee is more or less incidental to the thrust. Like a baseball, you can propel a frisbee without rotation, but the natural motion of your arm and hand tend to impart rotation. The designer of the frisbee surely understood this.

Yeah, I get the sense that the weight of the plastic makes any sort of lift that might be being generated, moot.

That depends on the glider: The Space Shuttle only gets 1:1.

That must be why it has such a high landing speed – more than 200 mph. Here is a description of the landing from NASA.

In light of what we’ve learned about Frisbees, designing a glider you could ride based on them is nearly impossible, not very probable, and hardly practical. But just for fun someone did take take the liberty to go ahead and sketch it out. The designer would face many challenges, don’t ask me how it is supposed to work, cause I don’t think it will. The fun part would be naming the contraptions, like “Flyder”? and “The Grisbee”?
The crude drawing shows a stationary bicycle/spinning Frisbee propelled unlikely candidate, an air splitting Frisbee covered rocket, and a “traditional” hang glider with a Frisbee top, instead of wings. Here it is on flickr.

I’m home now and I looked at that Skyak page and video.

I got the sense that you could throw a spear of the same size farther than you could throw that thing.

It looks to me like it generates a net lift of nearly 0. Any point on the “wing” generating positive lift has a point on the opposite side of the circle generating about the same amount of negative lift. So you’re left with about the same amount of lift as you would have with his “first glider” – the strip of wood with two loops of paper stuck to either end. I’m not even sure you would call that lift – it’s more like drag – just a greater resistance to falling through the air. More like a parachute than a wing.

Then again, I’m not an aerodynamicist, so what do I know?

Luckily, we can learn about ring wings from The Hummingbird Project. A jet with a ring for wings? How does it work? Well these guys think they can do it. Plus there’s the ultra cool seabird Bleriot III. For all kinds of wacky flying machines that never hit big check here at wright-bothers.org which includes some rings and even flapping wings.

Ok. Picture a giant frisbee, and some kind of centrifuge like thing to throw it. You need to design a release mechanism so it kind of rolls out of the centrifuge thing, which will impart the spin. Dead center of the giant frisbee you have the passenger seat. I won’t use the term pilot because I can’t imagine any actual control mechanism for a pilot to use. Seatbelt, at the least, would be mandatory.

Now you have a flyable system. Granted, one with an excellent chance to kill the passenger. If the stall and landing don’t kill you, maybe the rotation itself will like, snap your neck or something.

So let’s throw on some other stuff that may increase the odds of survival, but also increase the weight and shorten the flight. Some kind of transparent fairing/bubble over the passenger would smooth the airflow and possibly save the passenger from being crushed if it flipped over in flight.

Maybe an ejection seat and a parachute, or maybe a big ballistic parashute for the whole contraption that could be triggered by the passenger.

Personally I wouldn’t touch this thing if I were going to be spinning like a top for the whole flight, so I suggest a system to stop or minimize the rotation of the passenter while the rest of the thing spins like a mofo.

So, the passenger seat is bolted to a hub in the center of the frisbee. The frisbee rotates around the hub like a wheel around an axle, with lots of bearings so the two rotate more or less independently. Built into the hub and/or the the passenger seat are some hefty gyroscopes, oriented and spun up to whatever speed is needed to counter the spin of the hub. In other words, as the whole contraption is being spun off the launching centrifuge, the hub will naturally begin to spin along with the rim. The gyroscopes can be used as a brake on the hub rotation.

Actually, you can but the gyrocontrol mechanism in the hands of the passenger, and then decide if controlling the spin rate of your seat, and nothing else, is enough to grant the title of “pilot” to the passenger. WTF, why not?

But something has to power the gyroscopes. So maybe you put some decent size flywheels on them, and have them mechanically spun up by a link to the centrifuge, or you put motors and batteries onboard in the hub or seat. Either way, quite a lot of weight.

And that’s about it. How big would this thing have to be? It has to support several hundred pounds at the center of mass. I don’t know enough math to calculate it all out. 50 feet? A hundred feet in diameter? Plus you’d have to have a really massive launching instrument.

This, plus also you have to keep the disc spinning. It isn’t important when you throw a frisbee because you give it the spin when you throw and the flight is over before it stops spinning.

For any decent full size flight you are not going to be able to impart all the spin you need for an hour (or whatever) long flight so you are going to have to have something to make you keep spinning. That is going to take energy which is inevitably (if it is a true glider) going to come from gravitational potential, and that is going to detract still further from glide ratio.

I’d add to **Boyo Jim’s **excellent post that this massive launching instrument is going to have to be several thousand feet in the air that being where gliders are launched from.