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Old Sep 21, 2011, 09:43 AM
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Spoilers

Sam,

Thank you for the mixer and gyro info.

If you open the movie to "full screen" and watch closely you will see the spoiler go downward very briefly and then pull back up to horizontal (level).

They are working exactly as I described to create a resistance to a roll, or pitch motion. You could say, they work like "shock absorbers" on your car. They assist the gyros in resisting a tilting motion.

You're sphere appears to be smaller in diameter and your spoilers are longer, thus they will not function correctly. You have too much in-flow of air. I'd try the button idea first. It is extremely important to get the spoiler to drop, you will see a change in the flight characteristics.

I attached clips from a different video showing the spoilers at work.

Let me know if you need further clarification.

Thanks again for the info.

Kelly
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Old Sep 21, 2011, 10:43 AM
DIY Mania from Taiwan
Taiwan
Joined Aug 2011
1,962 Posts
Kelly:
you are more than just welcome.
my sphere size is same as Japaness one,42mm in diameters,I l'll lower
down the motor position tomorow,and keep on trying.
Have a nice day
Sam
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Old Sep 21, 2011, 11:05 AM
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Quote:
Originally Posted by samwei1950 View Post
l'll lower down the motor position tomorow,and keep on trying.

Sam,

That is an Excellent Idea.

That's the spirit, keep working at getting those spoilers to work. When you take the Taiwan Ball 1 to the games, you'll want to be able to show and explain the spoilers. That is Blue Ribbon technology completely unseen and new. That is what Always Wins!

Of course we have to give credit to the original inventor.

Regards,

Kelly
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Old Sep 21, 2011, 07:48 PM
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Question:

Quote:
Originally Posted by samwei1950 View Post
Kelly:
pls take a close look at this vid,the spoiler tips keep a bit downward against prop tips all the time,why downward.........

http://www.youtube.com/watch?v=fqYV9aUjSf0
Sam,

I'm not sure I understand your question.

Did I answer this question yet with the photos etc., if not please rephrase the question and I'll try again?

Kelly
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Old Sep 22, 2011, 12:50 AM
DIY Mania from Taiwan
Taiwan
Joined Aug 2011
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Quote:
Originally Posted by corocopter View Post
Sam,

I'm not sure I understand your question.

Did I answer this question yet with the photos etc., if not please rephrase the question and I'll try again?

Kelly
Kelly:
I just know you'll bring up this topic.
you did not answer my question, maybe it's hard for me to express.
I was wondering why my spoilers' tips that facing prop keep a little upward
"tilt upward "when hovering while the Japaness spoilers' tip keep a "little tilt downward"when in hovering mode.
I just thought this could be one of he clues.
best regards.
Sam
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Old Sep 22, 2011, 09:43 AM
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In-flow of propeller air:

Good morning Sam,

I understand your question now, I had it backward, but the answer are really the same. I need to make a sketch and give you a detailed answer, this will take about 1 hour, but the short and simple answer is: Your spoilers are too long (close) to the propeller.

If you trim off 10 mm it may be sufficient, if not then cut off 5mm more, until they fly horizontal. You could add the button weights first, to see the affect and learn what to expect. Either way that is the major problem that prevents the spoilers from dropping downward.

If you move the motor downward you must move the spoilers too, that way you gain distance between the spoiler tips and the propeller.

More details later today....

Kelly
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Old Sep 22, 2011, 09:54 AM
Expat
Japan
Joined Apr 2010
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I think those flaps lockout at 90 degrees, each direction. Perhaps a stop mechanism built in the hinge.
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Old Sep 22, 2011, 11:34 AM
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Quote:
Originally Posted by TheNiceGuy View Post
I think those flaps lockout at 90 degrees, each direction. Perhaps a stop mechanism built in the hinge.
Yes, that is correct.
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Old Sep 22, 2011, 12:31 PM
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Spoiler Trimming:

Sam,

Would you please watch the video posted below of the propeller smoke. While you're watching this video please observe how the smoke enters the propeller horizontally from the right-hand side, as the smoke approaches the propeller tip the smoke rises upward creating what looks like a miniature wave. The smoke is drawn upward and then down through the propeller, it is this wave of high-energy air that your spoiler is surfing on. Your spoiler is being lifted upward in this crest of the wave area.

Propeller Smoke. (0 min 25 sec)


I have attached three sketches please look at sketch A.

In this sketch I have tried to illustrate the horizontal inflow of air into the propeller from the right-hand side, please note the rising wave of air on the top side of the propeller. Please realize that the rising air has tremendous energy and the ability to draw your spoiler into this inflow. The trick here is to have your spoiler the correct length so that the air flowing into the propeller horizontally is used to float the spoiler horizontal. When your spoiler is too long it enters the high-energy air in the crest of the wave, thus lifting the spoiler upward and locking it into this position.

Please reference sketch B.

In sketch B on the left hand side, the spoiler is too long and reaches over into the high-energy crest of the wave area, thus supporting the spoiler at an upward angle. This amount of lift is excessive; the spoiler will never be released from this high-energy area to deploy downwards. The spoiler is captured here and will never function correctly to dampen the pitch and roll oscillations.

In sketch B on the right-hand side, you can see a shorter spoiler is now floating, or just barely floating on the horizontal inflow air. It's extremely important for you to visualize the fact that the spoiler is barely supported on this horizontal inflow of air that is slightly below the lower surface of the propeller. This is the secret of the operation of the spoilers. The slightest disturbance of this horizontal air will allow the spoiler to drop downwards very rapidly, thus a slight tilting of the craft to the left, in this case, would destroy this horizontal inflow of air and allow the spoiler to be dropped downward.

Please reference sketch C.

In sketch C. the sphere is tilted slightly to the left, the airflow (relative wind) is entering the propeller from the left and above.

On the left-hand side, the airflow is entering at a horizontal angle with sufficient energy to support the spoiler since it is flying on the relative wind. The crest of wave pattern is no longer present here, it has been disturbed by the motion of the sphere flying to the left. Once again, the air entering the left hand spoiler is sufficiently horizontal to support the spoilers on the left

On the right-hand side of sketch C. you will see that the airflow is coming from the left side and above the sphere. This airflow will not have this crest of wave pattern either, the airflow will flow directly downward and to the left into the propeller and also passed the edge of the propeller and strike the upper surface of the spoiler deflecting it downwards, thus creating drag on the right-hand side of the sphere which will tend to pull the sphere to the right.

It is the creation of a uniform airflow in hover that has a crest of wave feature and the horizontal airflow just below this crest of wave feature that supports all eight spoilers uniformly, the slightest motion to the left, right, forward, or backwards will disturbed this uniform crest of wave pattern. One side of the sphere will maintain this crest of wave at very low tilting angles, but as the craft is tilted over to steeper angles i.e. horizontal flight the airflow will disturbed the crust of wave and all the spoilers will assume a position that corresponds to the local relative wind. The spoilers on the top of the sphere will be locked back in the downward position, the spoilers on the bottom part of the sphere will fly along at an angle that corresponds to the local relative wind.

Sam, you have a couple of options you can try to put weights on your spoilers to make them heavy so that they drop down into the horizontal airflow just below the crest of wave, or more appropriately, trim them off in length so that they do not extend into this crest of wave, high energy, up lifting airflow.

One other idea is to lower the propeller, and the spoilers together, this will move the spoilers further away from the tips of the propeller since the spoilers are attached to the outer edge of the sphere, and as you drop downwards the sphere’s diameter increases, thus increasing the distance between the tip of the spoiler and the tip of the propeller.

My suggestion would be to add the weights (buttons), first to see what happens, if that doesn't work then I would suggest trimming off approximately 10 mm from the tips of the spoilers.

I am going to make the suggestion that trimming the spoilers is going to be an “Inversely proportional to the square of the Distance ” relationship, IE if you double the distance between the tip of the propeller and the tip of the spoiler you get one fourth the lift. So trim slowly, if you trim 10 mm the first time, you would want to trim 5 mm or less the second time. This sort of affect is also present in forces like gravity.

Adjusting the spoilers is going to be much like tuning a glow engine needle valve. Very slight changes will make a huge difference in the performance of your sphere. I suspect you will have to make several sets of spoilers before you get it just right, but once they are configured correctly the craft should feel much more solid to the controls.

Please let me know if I described everything clearly in this posting, I'm happy to take as much time and postings as necessary to clarify how the spoilers work and are tuned.

Regards,

Kelly
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Old Sep 23, 2011, 01:46 AM
DIY Mania from Taiwan
Taiwan
Joined Aug 2011
1,962 Posts
[QUOTE=corocopter;19390667]Sam,

Would you please watch the video posted below of the propeller smoke. While you're watching this video please observe how the smoke enters the propeller horizontally from the right-hand side, as the smoke approaches the propeller tip the smoke rises upward creating what looks like a miniature wave. The smoke is drawn upward and then down through the propeller, it is this wave of high-energy air that your spoiler is surfing on. Your spoiler is being lifted upward in this crest of the wave area.

Propeller Smoke. (0 min 25 sec)


Kelly:
thank you so much for the detailed descriptions of the captioned subject,this is the best explainations on the Japaness ball spoilers function you've ever posted,what a great learnings....
I've tried buttons,but seems not easy to glue,so I prepared mini metal washes
instead,meanwhile I'll try to trim the spoilers shorter as to avoid the hi-energy
crest of the wave area later on.
to update the status of my sphere:
I have installed a new motor which is 1200kv with 9x6 prop,so no more heat problem created,my sphere performs pretty much like a helicopter now,I'm flying the ball around my house,crossed the doors,even the window, but I'm looking for outdoor test,unfortunately it's windy season now in Taiwan,so keep on waiting......
thanks again for the valuable infos,another very educational posting.
have a nice day
Sam
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Old Sep 23, 2011, 10:07 AM
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Coanda effect:

Hello Sam,

I"m happy to hear my description yesterday was helpful. I should also mention that these spoilers are a form of a "Boundary Layer Effect" devices, specifically they employ the Coanda effect on the upper surfaces of the spoilers to Pull the spoilers Up into the horizontal air flow.

Take a look at this site and please watch the video. I would suggest reading the material too. http://www.laesieworks.com/ifo/how/C...effect-P1.html

Additionally, do a Goggle search on "Coanda effect" it is rather interesting and applicable to some of the aerodynamic features of the spoilers.

The Coanda effect lifts the spoilers up, if your spoilers are too long or raised up too close under the propeller, the combination of the "Crest of Wave" (which is a term I made up to simplify the discussion) and the Coanda effect will hold the spoilers up in the horizontal position at all times. Both effects work together.

The relative wind pushes the spoilers down. It is the balancing of all of these forces (tuning) that makes the spoilers work like a dampening device. The spoilers are "contained within" (surrounded by) the relative wind and follow the direction of the relative wind, but they are also affected by the boundary layer airflow over the top surfaces of the spoiler (Coanda effect).

Please keep in mind that I have over simplified this discussion to try to keep the language barrier low, and hopefully the understanding high.


Kelly
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Last edited by corocopter; Sep 23, 2011 at 06:37 PM.
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Old Sep 23, 2011, 06:45 PM
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Rant be done:

Sam,

Okay, you can relax now, I'm done ranting about the physics of the spoilers for awhile.

In the mean time can you please tell me the make and model of your new motor and propeller, and the total flying weight of the craft, along with the capacity of your battery?

Many thanks.

Kelly
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Old Sep 23, 2011, 07:54 PM
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Quote:
Okay, you can relax now, I'm done ranting about the physics of the spoilers for awhile
Why .. it has been very interesting and educational ... thanks for sharing all this info ... been watching this thread ,,but just don't have time to understand it all and participate but love the ideas floating around here Keep em coming
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Old Sep 23, 2011, 08:39 PM
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Hello Chap,

Thank you for the kind words. I've seen your work here on RCGs, I'm impressed with many of your projects. You have a sharp mind.

Okay since you are interested, here's a bit more on the Coanda effect, take a look here,

http://rides.webshots.com/album/162470801whJBFy

I made this device 7 years ago to study the affects of a spinning disk and propeller combination. I used smoke trails and a strobe light to study what happens when the disk was raise or lowered with respect to the propeller. This device was spun with an electric drill mounted to a table in the vertical axis (up-right).

This study was conducted to get a better understanding of the physics involved with the Turboplane, a very strange Austrian VTOL craft from the early 1980's.

It was these experiments that allowed me to recognize how the Japanese spoilers work.

I've been holding off on show this information since the Turboplane is rather complex and difficult to describe. The Japanese\Taiwan Ball has been a challenges too.

My first objective is for Sam to win a Gold Metal / Blue Ribbon at his RC games and to help anyone else I can understand this fantastic sphere device, before I cloud the issue by showing my versions of the the Turboplane and how it relates to the Japaneses spoiler devices. I'll add this information in the coming days.

If you look here, you can see my version and the original Turboplane.

http://community.webshots.com/user/poppyparrot


Thank you for your feedback, that is very encouraging and it is nice to know that others are enjoying this discussion.

Regards,

Kelly
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