Japanes Ball Drone. - Page 8 - RC Groups
 Aug 23, 2011, 06:05 PM Gaftopher What are your thoughts on why the lower and upper control surfaces are at angle of less than 90 degrees to each other? Maybe you commented and I missed it.
Aug 23, 2011, 07:02 PM
Registered User

Clocking the control surfaces:

Gary,

I've not address that one yet, so here's what I've observed. If you look at a circle you'll measure 360 degrees, if you divide 360 degrees by 4 you get 90 degrees. Okay now you can set the lower set of vanes at 90 degrees, opposite each other, next divide 360 degrees by 8 and you get 45 degrees. What does that tell us? That tells us that the sphere needs to be comprised of 8 sub-panels. Those sub-panel are made of styrene plastic and maybe carbon fibers. I'll call them ribs. The spoilers mount on the ribs also and we have 8 spoilers present on the craft. That is important too, since the more spoilers mounted the better the control, up to a point. That is, 8 spoilers are better than 6 spoilers. I guess 4 spoilers would work to some degree, but you get the idea.

Okay we now know that the sphere is made up of 8 circular ribs, set 45 degrees apart. Now you want to mount the lower set of vanes at 90 degree from each other and the upper set of vanes at 90 degree from each other but not on the same ribs or should I say plain, just mount the upper set of vanes 45 degree to the right or left of the lower set of vanes. Why do this? My guess is to keep the vanes in clean undisturbed propeller wash and make the craft VERY strong. The patent application stressed this on several occasions. The vanes transmit stresses across the sphere, by using all 8 ribs to mount the vanes these stresses are spread over a larger area. This makes understanding the controls of the great interest to me, it is a bit of work to decipher how they function from looking at the one video that shows them moving very fast. I've watched that one about 30 or 40 times in stop frame and I'm not sure what to think. I can say that the top and lower vanes control yaw in hover, and that the upper and lower vanes can all move in a format that look like elevons plus one more axis. Well let me say they can all move with respect to what we might call roll, pitch, and yaw control, I can't sort it out any better that that right now. Maybe some other readers could look it over and fill in the blanks.

I hope that helped,

Kelly
 Aug 24, 2011, 09:51 AM Expat Ya, thats in line with what I was saying a few pages back. Additionaly, perhaps the 45 degree CS offset allows more stability with air hitting the craft sideways at odd angles, weather in a turn or from a cross wind. I'm also curious about the control mixing. Initialy I thought maybe rudder/elevator top, and a kind of dual V-Tail elevons on the 4 bottom CS set. And maybe a special corkscrew mix for fast spins. I'm guessing these guysa are using something liek a 3-axis KKK board? BTW, that bottom set of spoilers look like a simple thrust vector shroud. Do the top spoilers lock out at 90 degrees (level with prop / 90 degrees down)? I can read a bit of Japanese, but something like a patent application is too deep for me and I'd need to get someone to give me a hand.
Aug 24, 2011, 01:30 PM
Registered User

Spoiler details:

Nice Guy,

I’m not sure I understand your question about the spoilers, so I’ll guess by giving a detailed description of how the spoiler react to the relative wind associated with the airflow entering the side of the propeller.

The spoilers are free floating. If you watch the videos you see the pilot picking up the craft and the spoilers dangle in various positions, some hang downward and others upward due to gravity and the angle that he happen to be holding the craft.

One other way to look at the matter is to explain they can swing not only downward, horizontal and upward within the sphere. They are captured by the outer edges of the spoilers. These outer edges of the spoilers strike the 8 ribs I mention in my last posting.

Keep in mind that if the sphere is resting on a table or floor with the motor turned off, all 8 of the spoilers will droop downward approximately 90 degrees. As you slowly add power the spoiler will gradually rise to the horizontal position. Now assume that you have used sufficient power to draw all 8 spoilers horizontal.

If you now pick up the craft in you hand holding it perfectly vertical then move it to the left you will notice that the spoilers on the left remain horizontal but the spoilers on the right side droop downward at a rate that is proportional to the rate you are move your hand/sphere to the left.

Now if you stop the motion of your hand/sphere all 8 spoilers will be drawn into the horizontal position waiting for your next movement. In flight the craft rotates around it CG, but for our illustration this help me describe what to expect when trying to describe the spoilers reactions. In any case whether it is held in your hand, or hovering and tilting about it’s center of gravity the relative airflow into the propeller disk will be disturbed.

Keep in mind these important facts (below) when dealing with these spoilers.

These facts apply to non-ducted, non-shrouded propeller as used on this sphere.

The airflow into the propeller disk enters from the front and the sides of the propeller. Or you could say air is drawn into the plain of rotation of the propeller as well as from in front of the propeller. Air enters both perpendicular and parallel to the plain of rotation of the propeller.

What we are interested in right how is the air that is flowing into the side of the propeller or plain of rotation. Or you could say the air that flows into the disk parallel to the rotation of the propeller. This is very important!

Most folks only think about the air entering the propeller from in front of the propellers plain of rotation not the side flow. The airflow coming into the side of the propeller is of little interest normally so it is natural to overlooks it value, but for the spoilers it is Critical!

This airflow into the side of the propeller is easily disturbed. When you move the craft held in your hand as mentioned above, the airflow on the left side continued to flow smoothly into the plain of rotation of the propeller thus it held the left hand spoiler horizontal. Now the airflow on the right side of the propeller plain of rotation is disturbed by the air entering from the left. This is an unbalanced in-rush of air. The air that was flowing into the propeller on the right is now disturbed, and directed downward into the propeller wash. At this point the spoiler on the right will no longer have the support from the side flow air and it will droop downward.

Other examples; if the craft was in a hover and you cut the power suddenly the craft will decend rapidly, the relative wind will be from the bottom of the craft, then all 8 spoilers would rise upward 90 degrees. Each spoiler responds to the local condition of the relative wind at any give moment of time. Or if you gas the throttle the craft will rise rapidly, the relatiive wind will be coming from above the craft and all 8 of the spoilers will droop downward 90 degrees. Or if you command a tilt to the right and it starts to translate (move) to the right, the left hand spoilers will droop, but the right hand spoilers will remain horizontal. This is completely automatic and happens very rapidly too.

One other thought to keep in your mind. All 8 spoilers will be held horizontal ONLY during hover or when motionless up against a wall. Any sideways motion (tilting) of the craft will droop the spoilers on the side opposite the inflow of the relative wind.

The spoiler placement is critical. If they are position too close the plain of rotation of the propeller they will not be droop fast enough to respond to very slight tilting of the craft. It they are placed too far away from the plain of rotation the spoilers will not be drawn into the horizontal position. This is the tricky part of setting up these spoilers. If you changed the pitch of the propeller, it most likely would also affect their performance and of course changing the diameter of the propeller would change their performance. It looks like you’d have to construct your craft, get it flying, then shape and distance the spoilers accordingly, then start moving the CG aft.
Last edited by corocopter; Aug 24, 2011 at 06:15 PM.
 Aug 24, 2011, 05:54 PM Quad Questions Team member amazing amount of design in this craft, all i can say is wow
 Sep 02, 2011, 12:45 PM DIY Mania from Taiwan Just found this thread,and really learned a lot from you guys. especially COROCOPTER...... the drone attracted my attention 2 monthes ago and decided to make one based only on the video & couple pictures,frankly,it's a guess work... it took me 10 days to complte the model one,good flying but the toy was too heavy and overheated of the motors were discovered, so I'm working on my model two and of course put the ideas learned from this thread to it. video of the model one...."somebody pls help if vid didn't work" http://http://www.youtube.com/watch?v=gbMwWg-V8gs Best regards to you all Sam
Sep 02, 2011, 01:22 PM
Gaftopher
Excellent job much better than mine well done

 PICT0178 (0 min 30 sec)
Sep 02, 2011, 06:50 PM
Registered User

Propeller Spoilers in Acton:

I made a simple test setup to show how the spoilers work. I used a sheet of plain paper and some tape to construct the spoiler.

Once the spoiler is drawn into the horizontal position it tends to hold that position until the power is substantially reduced.

 Japanese Ball Drone Propeller Spoilers (1 min 26 sec)
Last edited by corocopter; Sep 02, 2011 at 06:57 PM.
Sep 02, 2011, 06:56 PM
Registered User

Nice work Samwei

Samwei,

That's a nice sphere you built. It seems to be very stable. Can you please give us some details on your gyros and how you configured the control system vanes.

I'm looking forward to seeing your new version.

I'm happy to hear that some of my comments were useful to you.

Kelly
Sep 04, 2011, 08:02 AM
DIY Mania from Taiwan
Quote:
 Originally Posted by Gary Mortimer Excellent job much better than mine well done http://www.youtube.com/watch?v=gbMwWg-V8gs
many thanks for the help
my ball drone is still far away from the Japaness one.
really like the music you put in your version 2 video,it made me feel like to dance...
Sam
Sep 04, 2011, 09:48 AM
DIY Mania from Taiwan
Quote:
 Originally Posted by corocopter Samwei, That's a nice sphere you built. It seems to be very stable. Can you please give us some details on your gyros and how you configured the control system vanes. I'm looking forward to seeing your new version. I'm happy to hear that some of my comments were useful to you. Kelly
Hello Kelly
I hope my Taiwaness English did not drive you crazy.....
3 gyros were installed in the ball
a cheap headlock gyro to deal with YAW
two Piezo gyros handling elevator and aileron seperately.
I started to build the ball by a homemade counter rotating motors
8 thin CF sheets to form the ball drone at 45 degree
I attached four 4mm CF rods on the upper 3/1 between motor & "ribs" to hod the motors in the upper center.
and attached another four 4mm CF rods on the lower 3/1 between bottom of the fuse and lower part "ribs"(sames "ribs" as upper part)
then set lower set of 5mm Depron 4 vanes at 90 degree from each other
under four 4mm CF rods
two 6 gram servos installed in 2 vanes that connected other 2 vanes by CF sheets glued for elevator & aileron functions.
a 5mm Depron "skirt" is glued outside the lower part control surfaces.
I then attached two 4mm CF rods between upper CF rods & equater for the upper contorl surfaces,of course on other "ribs"
I mounted the upper set of 5mm Depron 4 vanes at 45 degree to the lower
set of vanes and installed four 6 gram servos on the four vanes for YAW control.
a BEC is used.
the CG is located at 10mm below the center.
finally the ball is surrounded by a CF sheet on the equator for durability.
the upper contorl surfaces work indepently as well as the lower one.
the ball is quite strong during the testing period.
the stability is OK but I just hate to use the "skirt" because it create drag
during flight.
I tried to get rid of it one time but the stability became an issue,maybe the
"spoilers" is the key for it.
best regards
Sam
 Sep 04, 2011, 05:24 PM Registered User Sam, Your English is excellent, I completely understand your explanation. The spoilers may help. It would be interesting to see what happens if you just add the spoilers to that ship. I have a couple of ideas that maybe of some help, gives these some thought and let me know what you think. You could reverse the control configuration of your current craft so that it is a canard. Move the elevator, and rudder to the upper surfaces/vanes and use just two servos. Setup the yaw control on the lower surfaces/vanes, but you only need two servo and two moving vanes for yaw control. I make these suggestions for these reasons. 1. You mentioned that removing the skirt upset the stability. 2. Moving the Yaw control to the lower surfaces will help to hold the center of pressure constant. Defecting a control surface has some affect on the CP. The less the defection the more stable the CP. Using only two vanes instead of 4 may help. I don't think yaw is the major problem. It appears to be more a pitch and roll problem. 3.The skirt appears to be a form of wing area as well as the internal wing area of the vanes/ladder area. Removing the skirt material reduces the wing area. 4. Maybe reversing the controls, making it a canard and using two less servos will lighten it and improve stability and performance. These would be simple modes you could perform to the existing craft. 5. Having the rudder and elevator closer to the propeller(s) improves there power (functions). You'll need to reduce the rates on the gyro perhaps? Then, if these suggestions help, I'd try adding spoilers. One other thought. A single large prop is more efficient that the two smaller props and one large prop may work better with the spoiler. These are just guesses on my part, maybe some of them may help? What do you think? Kelly
Sep 05, 2011, 02:08 AM
DIY Mania from Taiwan
the ball drone added some more fun to my retirement life.
here's another vid I shooted this AM w/o "skirt"
it swings on bottom side,or shall i say pitch & roll sides???
I can easily post vid locally but not in RCG.....
pls help to post this one again
 PICT0314 (0 min 37 sec)

best regards to all of you
Sam
Sep 05, 2011, 02:42 AM
DIY Mania from Taiwan
Quote:
 Originally Posted by corocopter Sam, Your English is excellent, I completely understand your explanation. The spoilers may help. It would be interesting to see what happens if you just add the spoilers to that ship. I have a couple of ideas that maybe of some help, gives these some thought and let me know what you think. You could reverse the control configuration of your current craft so that it is a canard. Move the elevator, and rudder to the upper surfaces/vanes and use just two servos. Setup the yaw control on the lower surfaces/vanes, but you only need two servo and two moving vanes for yaw control. I make these suggestions for these reasons. 1. You mentioned that removing the skirt upset the stability. 2. Moving the Yaw control to the lower surfaces will help to hold the center of pressure constant. Defecting a control surface has some affect on the CP. The less the defection the more stable the CP. Using only two vanes instead of 4 may help. I don't think yaw is the major problem. It appears to be more a pitch and roll problem. 3.The skirt appears to be a form of wing area as well as the internal wing area of the vanes/ladder area. Removing the skirt material reduces the wing area. 4. Maybe reversing the controls, making it a canard and using two less servos will lighten it and improve stability and performance. These would be simple modes you could perform to the existing craft. 5. Having the rudder and elevator closer to the propeller(s) improves there power (functions). You'll need to reduce the rates on the gyro perhaps? Then, if these suggestions help, I'd try adding spoilers. One other thought. A single large prop is more efficient that the two smaller props and one large prop may work better with the spoiler. These are just guesses on my part, maybe some of them may help? What do you think? Kelly
Kelly
many thanks for the great comments
let me catch your paces again...
1.move elevator/rudder to upper control surfaces with 2 servos
2.move YAW to lower control surfaces but only with 2 servos & 2 vanes
3.no skirt but spoilers may help
4.reduce some rate on gyros.especially upper control surfaces gyros.
I'm willing to do the tests to see what benifits the ball and come back to you again.
one question: do i needed to mix upper & lower control surfaers?
BTW:could not speak well but i can read Japaness,any secific topic you need my hands?
best regards
Sam
 Sep 05, 2011, 04:35 AM DIY Mania from Taiwan hi guys FYI I just put a new thread in the foamie(scratchbuilt) column that under AIRCRAFT-ELECTRIC-AIRPLANES it's about my newly scratchbuilt flying swan just incase you guys interested. regards Sam