Jul 03, 2011, 09:50 AM
Gary Mortimer's Avatar
I think they do that so they don't touch at full deflection.
Last edited by Gary Mortimer; Jul 04, 2011 at 09:52 AM.
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Jul 04, 2011, 09:15 AM
Ah, OK, that makes sense.
What sort of gyros are required for basic flight?
Jul 04, 2011, 10:02 AM
Gary Mortimer's Avatar
Well I think if you were good enough on the sticks you could get away with none, but I'm certainly not!

The rudder might be a good start gyro wise. If you are doing it like the Japanese one with eight servos then probably one on rud elev and ail.

Good find with the other airframe. I looked and looked for a plan as it had to have been done before.
Jul 05, 2011, 02:44 AM
I'm thinking 8 servos, 5 chanels. Bottom four surfaces linked together into 2 chanels as elevons. Top four on 2 chanels as r/e.
No idea about gyro placement as I've never used them. Are we talking rate gyros?
What do you think?
Jul 13, 2011, 12:24 PM
8 9g servos + arms = 96g
motor+ESC+8040 = 60g
3s lipo=?
5mm depron control surfaces+skirt=?

I have 2 GY48Vs coming, they are 20g a piece.
Here is the motor:
I'll have to calculate the thrust and see if it can lift the ball!

I'm trying to keep the weight down!
EDIT: As a side, HK has these new cheapy ($10) MEMS gyros, GA-250, that are very small and light. Look a bit difficult, but would be great for this project.

I'm still wondering about gyro placement. 4 gyros, 2 for the four elevon surfaces, and 1 for the rudder and 1 for the elevator? Following this model, I'll need to get 4 servo Y-cables?
Last edited by TheNiceGuy; Jul 14, 2011 at 12:16 AM.
Jul 15, 2011, 02:37 AM
I have enough 3mm fiberglass rods to make a small 120cm circumference ball, or split some 5mm rods to make a larger 220cm ball. Smaller will be lighter, and with gyros harder to control doesn't matter? Does it matter with a VTOL like this as its not really using surfaces for lift?

I have been marooned on this thread! Noooo...!
KHAAAAAAN! (0 min 30 sec)
Jul 15, 2011, 05:00 AM
Gary Mortimer's Avatar
You have, my sons are staying with me and am busy, but I watch with interest.

Lighter = best

Looking at the Japanese one it looks like each surface moves independantly.
Jul 15, 2011, 02:51 PM
I did a few more rough calculations and a 40cm diameter/120cm circumfrence ball made from 3mm FG rods with all mechanics and electronics (minus gyros) will be about 350g minus 3s lipo (+70g/90g for 800/1000mah). The prop/motor/voltage I linked has a max thrust of 600g, so this means it will float? I'm sure there are much better materials (heli motor/prop, CF rods, etc.), but this is what I have on hand. I have all the stuff to make it right now except the gyros. I don't think something this small will be flyable without gyros. I got a feeling it will be really squirly.
Jul 18, 2011, 12:47 AM
Registered User
Jul 18, 2011, 03:10 PM
Bit more info here:
Mainly good video of surface movement, and it has 3 gyros, 16 "spoilers".
Jul 18, 2011, 04:24 PM
Gary Mortimer's Avatar
Fantastic info Nice Guy

This image

Is very interesting.
Jul 18, 2011, 05:12 PM
Ya, I was wondering about that as well. The other movements would fit a R/E/Elevon mix. Perhaps this is a special spiral mix for spin?
The lower 4 surfaces appear smaller than the top 4, which would be more in line with with a "tail surfaces" kind of setup?
Jul 19, 2011, 04:58 AM
Gary Mortimer's Avatar
No I think thats for display, but I do think one set of surfaces is handling Roll and Pitch perhaps the top set and the bottom are looking after yaw.

Of course they take on almost different meanings when vertical.

Are those outside vanes allowed to move with any purpose??
Jul 19, 2011, 09:51 AM
I'm sure I could see in the video the top "elevators" and bottom "elevons" moving in unison to, for example, move it forward (not sure of the terminology - is that negative pitch?). I'm guessing this would allow superior maneuverability compared to something like the VTOL linked earlier. A typical VTOL I'm guessing, for example, if you say wanted to reverse direction on a dime, there would be a huge 'wag' while the tail and prop got in synce, and probably some undesirable effects like a drop in altitude. But with tandem controls, the reversal would be much tighter.
The advantage of a VTOL I'm guessing would be more power efficiency and "airplane" characteristics at higher speeds, but this ball isn't shooting for that, although I'm sure it could be programed and layed out for forward flight if someone really wanted to, although that's not the purpose of this design.
I'd love to start trying it out, but believe it or not am having trouble finding 3mm FG rods long enough. I need at least 120cm lengths. HK sells CF rods max 75cm, and I'm not sure if they would shatter when bent and under impact. I'm going to have to split some 5mm FG garden rods, which work well in testing, but give off all kinds of tiny glass splinters which I HATE. I may coat the rods in electrical tape (more weight, as a 120cm circumference ball (thats pretty small, like 40cm diameter) needs about 600cm total rods for everything in my planned airship).
The design I have in mind will be very tough and able to bounce and absorb shock better than teh original if it all works out.
I have an idea to make a larger one, using these 5mm garden rods, and mount an FPV GoPro on teh bottom. I could modify the bottom to fit it with a pan/tilt, and this would be great for impact, and safer to use than a quadcopter.

For mixing, I'm thinking 4 channels, rudder/elevator/and all 4 bottom surfaces linked as elevons. These elevons will mirror each other. I still don't know enough about gyros to figure that out. 3 gyros?
How about 1 on top elevator, 1 on top rudder, and slave the bottom elevons to teh top rudder and elevator? The 3rd gyro could be used to stop roll/rotation and put on either R/E?

I'm imagining the rim of flaps as passive, and help to correct some bad habit.
Last edited by TheNiceGuy; Jul 19, 2011 at 10:07 AM.

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