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        Discussion Japanes Ball Drone.

#1 Tuner Jun 11, 2011 03:28 PM

Japanes Ball Drone.
 
http://www.engadget.com/2011/06/10/j...ntrance-video/

Every Since seeing the ATMOPOD I thought I would love to see about 100 of these with transparent construction materials and LED lighting do a choreographed dance to music at night.

I also wanted to make a bigger one of these out of Kite Construction techniques and make it a flying toy that can run into things and bounce off without breaking the prop.

Just thought Id share.

#2 TheNiceGuy Jun 14, 2011 08:52 PM

Lol, me too! I posted earlier in the fpv forum, but no one seems able to detail a model.

#3 TheNiceGuy Jun 17, 2011 04:58 PM

Any basic VTOL principles to keep in mind? I'm particularly interested in length of fuselage for stability, and size and shape of control surfaces.
I'm thinking to make a round version of this encased in a rod sphere:
ElectriFly VFO EP ARF - Setup Techniques & Flying Tips (8 min 4 sec)

The ball would be shorter/wider, with rounded control surfaces, and the cage would raise teh CoG. I'm worried about stability.
I hope to use a blue wonder setup, 8040 prop, 3s, 9g servos.
Would it work???

#4 Brandano Jun 18, 2011 08:26 AM

with a fixed pitch prop it does not really matter where the CoG is in relation to the prop as far as stability in the hover is concerned. the thrust vector tilts with the airframe, so there's no way to obtain a self-righting setup. what matters is the distance between the control surfaces and the CoG, or, if you want to see it this way, between the vector of thrust and the CoG. Any tilting moments in a hover, for a single rotor platform, are a function of the moment arm between the global thrust vector and the CoG.

P.S.: Rockets are perfectly stable with their thrust applied at the tail. As long as the CoG is ahead of the center of pressure, the design is stable. Hover will be always unstable, you can only mitigate it with stabilization devices like gyros or flybars. they won't prevent the plane from tipping over, but they will slow it down enough that the pilot will manage to keep it upright

#5 derk Jun 19, 2011 11:58 PM

anyone else notice the perimeter thrust directing plates? that would need 4 or 8 servos by itself. looks like it limits the tip thrust of the prop and they move down to allow the tip thrust to move it in the desired direction. while the gentleman had it sitting on the table near him, all 8 plates were down, so i think it has to have 8 separate servos for each one of them. it really does have some intriguing features...

#6 TheNiceGuy Jun 20, 2011 02:06 AM

I noticed those as well. I wondered if they were free-floating dampers of some kind?

#7 RCvertt Jun 20, 2011 03:34 AM

Quote:

Originally Posted by derk (Post 18545327)
anyone else notice the perimeter thrust directing plates?...

That's a strange one.

Looks like they are free floating to me and get sucked up by the prop to help make the airstream more efficient.

#8 TheNiceGuy Jun 20, 2011 04:51 AM

OK, so here's a basic drawing of what I have in mind. All sizes are arbitrary, with the exception of the 8040 prop I hope to use on a bluwonder 3s setup I hope to use. Blue dash lines are control surfaces. Center "fuselage" is 5mm depron. 3mm FG rod ball-cage.
Not sure where, how big, and what shape to make the control surfaces exactly. Also, CoG as low as possible? The strength of this will be its hover, so forward flight doesn't need to be that great if it will make it squirley.
Ideas?

http://i22.photobucket.com/albums/b3...o/IMG_1420.jpg

#9 Brandano Jun 20, 2011 09:16 AM

Actually, if your control surfaces are near the bottom you will get better control with a high CoG. it does not "hang" from the prop, always remember that. It's not like if it was suspended on a wire, because the prop tilts with the airframe.

#10 swami Jun 20, 2011 04:53 PM

Looks like someone already tried an RC-version.
Uさんの球形飛行体 (2 min 18 sec)


Doesn't look to be so simple.

Epp would be a good idea i think.


Dirk.

#11 derk Jun 20, 2011 11:21 PM

here is an earlier video of it flying outdoors with some acrobatics and other demonstrations:
TRDI hoverbot test video - 球形飛行体 (1 min 27 sec)

i still believe the perimeter flaps to be active somehow, they seem to react to control input rather than actual airflow, at a very low speed, some are up and some are at a 45 to the motor shaft. perhaps its supposed to act like the bell mouth on a ducted fan, but being able to cancel out lift in the area of desired direction.

#12 Gary Mortimer Jun 21, 2011 04:24 AM

I have been playing with a Pogo inspired one, and once I have that nailed I will try a ball.

VTOL (7 min 52 sec)


Bit dull this vid, I have never prop hung anything. Have another motor putting it on and will try again.

#13 Gary Mortimer Jun 21, 2011 04:43 AM

I think its just something like the simple VTOL in this chaps build logs surrounded by a ball enclosure

http://www.rcexperimental.com/season-1.html

The outer tabs probably deflect a little air to help counter act torque. They look fixed to me.

#14 RCvertt Jun 21, 2011 10:30 PM

Quote:

Originally Posted by Gary Mortimer (Post 18555849)
I think its just something like the simple VTOL in this chaps build logs surrounded by a ball enclosure

http://www.rcexperimental.com/season-1.html

The outer tabs probably deflect a little air to help counter act torque. They look fixed to me.

That kid has some cool ideas. Looks like yours is progressing nicely also.

Looking at that white version rolling on the grass I think we need to start a patition to get RC bowling as an olympic sport. With curling, synchronized swimming and trampolining in there I think we have a chance.

#15 Gary Mortimer Jun 23, 2011 02:23 PM

Playing some more, getting my head around it and really need some exercise

Tailsitter, Pogo (2 min 33 sec)


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