Dragonfly V1 Alpha Launch

[FoamyDM]

I have always been fascinated Hayao Miyazaki, whose love and fascination with flight and flying show through in his many inspiring works.

I've been interested in building a flying platform similar to dragonfly or this Dragonfly-winged chariot-style craft. With research it seem possible. Someone in Japan has managed it.

honestly, he has done nearly everything I'm looking to improve upon.

So I've been looking in detail at
slow motion dragonfly video and http://rstb.royalsocietypublishing.org/content/371/1704/20150389 for better source material.

Now I know there are other Toys designed, but I wanted something closer to the real deal.

So, let get into the Project mission statement and Design parameters.

MISSION STATEMENT:
Build a stable hovering dragonfly model. where FPV can get an agile yet steady shot without a gimbal.

Design parameters:
Glide as default @ 0 vertical throttle
Hover capabilities
Tail used as a rudder
Steady body for FPV

I'll start with Replicating the Wings then, Planning the gears and Mock up with Plastic bag and BBQ skewers.

Away we GO!

As always, Ideas, comments, and criticisms are welcome.
Feedback is a Gift.

 

[FoamyDM]

Wing build

This will be brief.
I have cut out two front and rear wing shapes from poster board stock and used the shading and the scan from the British national academy article to score and bend the wings. to shape. It is awesome how strong the wing becomes (yet flexible). It bends a lot on the outer half on the upstroke but remains rigid on the downstroke. I've used BBQ skewers for the wing spars. The real wings have a verticals membrane to create a strong 3d shape front wing spar. For the alpha, I'm skewering it. The rear spar of the wing will be used to control wing pitch. Here's the pics.



I'd love to hear your thoughts.

 

[FoamyDM]

It has been a long time and my planes ago since I last uncovered this thread. It is not forgotten. I was looking around for a graceful, contoured beauty to hone Master Series style building - design technique. (Many thanks to @Niez13, listen here if you want to try your hand; ) The Quickie; A Burt Rutan designed homebuild kit. Whose sister plane (the curves) to one called the dragonfly.

I am at the servo electronic stage of that project, looking up the dragonfly and seeing the wing configuration of the Quickie /Q2 in the search engine, brings up dragonfly wings. Leading me back to check if I still have the cad files for the wings...

Turns out is did. So I scaled them up. Each pair to a sheet of foam. Here is the Top View:

Here is the Bottom - Note that the underside is a different pattern of cuts and grooves:

Hopefully, I will get to show you the reason, later today.
Then on to design a Flapping Mechanism.
My plan is build the center to be powered much like the creature. with partial energy cover through elastic properties.

 

[FoamyDM]

Some of Dr. Kazuhiko Kakuta's Latest Dragonfly work:

He has pulled away from using Small Powerful motors, but has been experimenting with using lightweight fast and strong 5g Servos. while not as powerful it lightens the structure His is close to 32g. He has developed an interesting new method of translating stick movements to flight controls that yield desired results.

my wings shown above are nearly 140g... I will stick with motors for now.

This is a great deal of research to sift through. Things that hold nuggets like this:

Very useful when trying to fold this origami construction properly. Deep corrugations, then it flattens out.
and, "pleated airfoils have higher lift and moderate drag results compared to profiled airfoil." except at AoA = 0

 

[FoamyDM]

Found this Image very descriptive of the statement above

 

[FoamyDM]

Below are some of the work completed tonight on the rear wing pleats.
I think I need to make a wing jig

Front wings are next while I figure out how to get these flapping.

 

[JetCrafts]

wow

 

[Scotto]

@TFerenc posted this a while back. I need a 3d printer to try it myself. Before I found flitetest I was a little obsessed with ornithopters but I couldnt fly anything yet figured id better start with planes lol.

 

[Baron VonHelton]

The dragonfly needs that long skinny tail for balance, I suspect.......

 

[Baron VonHelton]

"pleated airfoils have higher lift and moderate drag results compared to profiled airfoil."

How can something with pleats in it have LESS drag? That makes no sense! But it DOES explain why they are so fast & maneuverable!!

 

[Scotto]

"pleated airfoils have higher lift and moderate drag results compared to profiled airfoil."

How can something with pleats in it have LESS drag? That makes no sense! But it DOES explain why they are so fast & maneuverable!!

I think by moderate they mean not as much more drag as youd expect. Its like nature's Kline-Fogleman wing. (This is the kind of details I see in nature that make me think "no way that happens on accident. That takes too much thought to all work perfectly and if anything changes it doesnt work at all." Not trying to start that debate- just my opinion.)

This is a very cool and challenging project! Id love to see a video of it flapping with the camera on the stick so you can see how it changes between up and down strokes.

 

[Baron VonHelton]

I think by moderate they mean not as much more drag as youd expect. Its like nature's Kline-Fogleman wing. (This is the kind of details I see in nature that make me think "no way that happens on accident. That takes too much thought to all work perfectly and if anything changes it doesnt work at all." Not trying to start that debate- just my opinion.)

This is a very cool and challenging project! Id love to see a video of it flapping with the camera on the stick so you can see how it changes between up and down strokes.

AH! I saw such a video! Lemme see if I can find it.

 

[Baron VonHelton]

I think by moderate they mean not as much more drag as youd expect. Its like nature's Kline-Fogleman wing. (This is the kind of details I see in nature that make me think "no way that happens on accident. That takes too much thought to all work perfectly and if anything changes it doesnt work at all." Not trying to start that debate- just my opinion.)

This is a very cool and challenging project! Id love to see a video of it flapping with the camera on the stick so you can see how it changes between up and down strokes.

Try this.......

 

[Piotrsko]

I think by moderate they mean not as much more drag as youd expect. Its like nature's Kline-Fogleman wing. (This is the kind of details I see in nature that make me think "no way that happens on accident. That takes too much thought to all work perfectly and if anything changes it doesnt work at all." Not trying to start that debate- just my opinion.)

In nature if something doesn't provide beneficial results it tends to go extinct somewhat fast.

 

[FoamyDM]

If you see the cross section pic above, it creates vortices in the troughs giving a low friction "surface" for laminar flow to pass over. Like the Kline-fogleman profile. There are a number of white papers studying these things. There is even on studying why the "filled" section 3/4 along the leading edge.

I need to learn some 3D modeling to finished this. Proper. But I make mock some of it in foam.

 

[FoamyDM]

Try this.......

Watched that before.... There are a lot of cool ideas there

 

[FoamyDM]

What I would love to do would be vacu-forming these from thin sheet plastic. Likey CF and mylar will be lighter though.

 

[Scotto]

Try this.......

Wow that thing is awesome! Its not made how Id expect, probly because the way I would do it would never fly haha. Its flapping mechanism is different. What I pictured is more like this-

Which is why I posted the video of the gears. I didnt explain myself at all there. With that gear my thought is you could have this arrangement with a higher speed motor, but this may not lend itself to a quad'thopter.
What kind of mechanism arrangement were you thinking FoamyDM? Have you seen these? Aliexpress $12 probly too small and heavy but the price is right.

It is awesome how strong the wing becomes (yet flexible). It bends a lot on the outer half on the upstroke but remains rigid on the downstroke

This is the video I was saying Id like to see btw.

 

[Baron VonHelton]

The downstroke must be rigid to create lift, and the upstroke must be flexible to create turbulence. I bet it's unstable on all it's axis' as well.....