Remote control gliders typically fly like their full-size counterparts. Tail and wing rudders control the direction of flight — but what if the wings themselves could twist and change their profile, similar to that of a bird? Well, RC glider manufacturer [Jaro Müller] did just that — and it is pretty cool (You’ll need a translation to read it though).
Called the Mini Ellipse, the RC glider is designed to be able to fly in slow thermals and maneuver even better than previous models. The entire wing profile can be controlled by wing flexion — the wing itself is very flexible. Unfortunately we don’t have any info about how it actually goes about doing that, but it’s probably either servo motors pulling wires, or maybe nitinol memory wire… but we’re just guessing. Regardless — take a look at the following video and let us know what you think!
When it comes to anything glider related, we can’t help but remember the awesome adventure of launching a glider from the edge of space — because, why not?
[Thanks Vilhja!]
The first steerable human-carrying airplanes had similar operation. Wright brothers era stuff.
I was just going to say the same thing. And I’ve seen people do this on small R/C gliders years ago.
Bingo. It’s called ‘wing warping’ actually patented by the Wright brothers.
It’s a glider, its not making break neck turns and needs to be light weight. I’m gonna guess its Nitinol.
Moderators… I accidentally reported your comment (spaz click). Please ignore…
Nitinol is so inefficient that it would eat up your batteries in a hurry, which is why it doesn’t find much actual use anywhere.
It can’t maintain a static force without continous heating of the wire, and when you stop the heating it becomes like a wet noodle because nitinol is superelastic in its relaxed state.
Correction: nitinol isn’t superelastic, it’s pseudoelastic
https://en.wikipedia.org/wiki/Pseudoelasticity
It basically just means that the tradeoff of having a shape-memory effect is that it won’t hold any rigid shape, so for example the wire that isn’t pulling goes completely slack and floppy and stretchy.
I’ve also done some experiments with nitinol wires, and when you pre-tension them in the relaxed state and then cycle them over and over to pull on something, they start to creep. Every time they get hot, they assume a slightly more stretched state, and if you accidentally get them too hot they just go floppy over a small number of cycles.
I may be wrong, but aren’t there two different types of Nitinol? The type that you are explaining, and a second, where there is a primary shape (I.e. A rod, ellipse, spring), which can be modified by applying current? Or is this another SMA?
Generally they work by forcing the SMA into a specific shape and then heating it past a certain temperature, at which point the crystalline structure re-arranges into that shape. Below this forming temperature, it behaves like spring metal down to the critical temperature, where there’s another phase transition to the floppy elastic state, and it’s this lower critical temperature that works the shape memory effect.
Below the critical temperature, the material is floppy and elastic, and above the critical temperature it’s springlike and tries to pull to the shape you’ve set. It doesn’t have anything to do with the electric current per se.
What you’re thinking about is probably piezoelectric materials.
Yeah, made OP without watching the video.
in the first minute you can hear the squealing ‘whee-whee’ of the servos so I must agree with Joey (moderators: I hit the wrong button. why don’t you put ‘reply’ in that location, HIG!!) it isn’t nitinol.
This has been used since the dawn of aviation, from WW1 fighters to model airplanes. It’s called wing warping: https://en.wikipedia.org/wiki/Wing_warping
Very bad article.
1. The glider does not fly by twisting its wings. It only controls itself by twisting the wings without getting any speed from it.
2. It’s clearly a servo which bend the wings, no memory wires used. You only had to watch the video once to notice that.
It’s not twisting the wings, per se (causing them to spiral around an axis), just changing their camber to alter the lift on each wing replacing the aileron. You can hear the servos acting in the fuselage.
There’s no indication if these can be altered together to provide better slow/fast flight characteristics by altering the airfoil camber together on both sides, though this could be done with a yoke linkage/electronic linkage and is done with conventional control surfaces to give “Flaps” for slow flight and “Camber” (slang) where the flaps move slightly upward to flatten the airflow and provide a high speed foil. “Crow”, used as a dive/speed brake would require actual twist which this doesn’t seem to do.
http://www.rc-airplane-world.com/rc-glider-wing-setups.html
Yeah the distinctive sound makes it very clear. Plenty of room under the canopy for a battery, servos, and receiver.
It’s old and well known. My fater actually has a glider whith that sort of system in the basement left from his RC-flight days.
“…launching a glider from the edge of space — because, why not?”
Because, without at least a filed out NOTAM (might not be enough, since after it reaches the peak, it suddenly ceases to be a balloon and is now a UAV), you will break laws as you enter controlled airspace without being permitted to do so…
I did a Masters thesis on the subject, which led to building the following contraption:
https://www.youtube.com/watch?v=sHNcOn2nKZY
In case you’re wondering, yes, that is cardboard…
Very cool.
You got a permit for that?!?!
It sounds like servos are controlling it @19 seconds into the video.
Wingerons?
That was my first thought but studying the video more carefully, this is a different mechanism. As far as I can tell, the front half of the wing doesn’t move. I think the camber of the wing is being changed, rather than the wing being pivoted as would be the case for a wingeron. It’s not even wing warping/twisting a la the brothers Wright.
[Jaro] did a nice job– it looks very clean. But a difficult problem with this approach is getting an aerodynamically clean joint with the fuselage. You are trading a cleaner wing for a less clean wing joint.
Done long ago by talented and generous (they offer lots of plans and instructions for downlaod) jivaro models. In French / so translation required and Metric System (\0/).
Examples : le crobe, http://lecrobe.free.fr/main.htm
the micro-quark (standard or variable incidence) : http://www.jivaro-models.org/quark_micro/page_microquark.html
I should stress that the whole jivaro-models site is worth taking a (lonnnng look) : plenty of nice, creative yet simple or even poetic models !!! Enjoy : http://www.jivaro-models.org
Very cool! Once we can control the whole wing surface (like a seagull) we will truly be flying correctly. Would take an auto stabilize controller that can tweak multiple points in real time and some new mechanisms so we are a long way from really flying like the masters of the skies.
I want to add thin solar panels to the top and a thermal sensor to the front, and program it to autonomously seek out hot spots and pilot itself towards thermals.
fantastic concept, this would be great for delta wings as well as the AOA will not be changed, i would love to see the inner wing panel, is the wing covering lamination or some sort of flexible sheet?
Lenny Hauf of LISF RC Model Group Modified an Airtronics Sagitta 900 in the late 80’s. I also had a 600 and 900 modified this way. They flew well!
Al Schmadtke