Hey, take a look at this: http://www.youtube.com/watch?v=UY38uho9ZdE
That's about the weirdest thing I've ever seen actually fly!

 

I've seen them before. Old glow powered free flighters. Can't remember what they are called though. That's the first electric one with throttle I've seen.

 

These are called, McCutchen machines. Guess named after the guy who did alot of work with them in the 50's, Doctor Charles W. McCutchen. Here is some info on it: http://geocities.com/CapeCanaveral/Gala ... e_Idea.htm Kind of proves the adage, that nothing is ever new and things get reinvented all the time. Who knows, maybe someone was working on them before him, possibly even in another country. I remember seeing some models of these in the FF forum at rcgroups. Here is one thread: http://www.rcgroups.com/forums/showthread.php?t=99074 In it, is a pretty cool video of some fellow rc hobbiest experiment with the concept. The video was made in the early 90's:

 

Wow! Someone posted this page at rcgroups. There are two youtube videos there. As a student I used to work at one of the labs mentioned, University of Maryland Rotorcraft Center. Mostly built some composite heli rotor blades and helped with testing them. That's the most impressive example I've seen to date, of a McCutchen machine. Would be real curious of the controls.
http://spectrum.ieee.org/blog/robotics/ ... maple-leaf

 

Another interesting one, rocket powered

 

This one is amazing too. I am sure you will agree.

 

Yes, you are right. I've been collection info on them. Since they are school projects, there are usually papers written. The MIT paper is here: http://rimworld.com/pgh/documents/hoburgmcreport.pdf They say "It is anticipated that the best azimuth estimate will be obtained using integrated accelerometer data with a magnetometer removing integration drift, but configurations using only accelerometers or only magnetometers will also be explored." The interesting thing that I didn't know about is the method of using an accelerometer to sense the angle of rotor tilt. I still have to think about that one.

There is actually a thread on rcgroups that use a magnetic compass using a coil as a detector. He hacked a toy called an itop, and found it just used a coil for the magnetic compass sensor. I have one. It's a toy top with a column of 8 leds and it can write out words using the magnetic compass for position info. Here is the thread from rcgroups: http://www.rcgroups.com/forums/showthread.php?t=394375 He's got a led that blinks once per revolution and that represents the tail, I think. And that's how you get your orientation. So basically, when you hit your yaw (rudder) nothing really happens, except that light move to another position on the circumference. Not sure what method they are using for visual ref with the MIT or UMD monocopters. I can't really see anything.

Here is a video of the itop, where it is counting up the # of rotations and I think that other number is the saved high score. It displays different things for different games you can play with it. Like I think rpm for one game. Another is where it writes out the 4 compass directions.

 

Yes, that's right. It's exactly the same as the cyclic control on a helicopter. Except a heli times it mechanically, basically like a cam. Strangely enough, the cyclic input needs to be applied 90 degrees before where you want it to take effect.

-Kwok

 

Yes, it's always 90 degrees. It's called "Gyroscopic Precession". I've never really understood it. Maybe someday. Have is a demo of it:

 

You love this stuff, ha. If you want to study it, its called "engineering mechanics", specifically starting with "Statics" and then "Dynamics" where things are moving. http://en.wikipedia.org/wiki/Applied_mechanics I don't know. I am still waiting to find out if it's useful or not? :?

I think it's the twisting force that is deflected. If you cut both strings, there is no twist. And nothing would happen. We call the twist a torque or a moment: http://en.wikipedia.org/wiki/Torque It is probably easier to see, in the classic demo with someone holding a gyroscope and on some bearing so he is free to rotate. See 1st video, where he is twisting the bicycle wheel side to side. Moving it around doesn't do anything. You have to twist it. That's an interesting idea of using angular momentum to create some form of lift in some way. Try the second video. That seems to some a possible use of that. The weight hasn't been reduced, but the torque is not working against you now making the weight lever out of your hand.

 

Mark, now I know what you are getting at. I actually messed around with this stuff as a teenager and forgot all about it. Cranked up the old scanner, but the light is crapped out; so here are some fuzzy hand held shots.





Attached files

 

Here's another strange flyer, that I've never seen before.

 

The monocopter was inspired by spinning maple seeds. Check this out, the seeds from the Alsomitra Vine. Wonder if they inspired anyone? The video saids they come out of a football sized pod, so they are decent size:
http://news.bbc.co.uk/earth/hi/earth_ne ... 391345.stm

-Kwok