|
|
|||
|
|
First flap cut - Try
Hi all,
Just did a quick cut to see how the look in real. All good, i will do some modifications so they will fit better on servo Horn. sorry for the bad cellular pictures ![]() ![]() And here is a movement movie...
|
||
|
|||
|
|
|
|
|||
|
|
|
||
|
|||
|
|
|
|
Joined May 2010
302 Posts
|
Hello everyone
Your current configuration of flight controls will not function in the manner of the original Japanese sphere. Sam's version of the Japanese sphere indicated that canarderon's were required for adequate flight control, additionally the implementation of the spoilers greatly increased flight stability. If you go back and look at the two RC groups threads about the Japanese sphere that Sam started and review the various photographs posted of the original craft especially photographs of the original patent you will be able to get a reasonable idea of the appropriate size, shape and position of the flight controls. I will briefly review some of the criteria here and make a few suggestions that I hope are helpful. Before I continue I would just like to compliment your quality of work and the work of others, the 3-D renderings are spectacular, as well as the computer aided machine work. Looking at the 3-D rendering that shows the placement of your current flight controls I can see that the upper set of flight controls respectively referred to as canards are installed below the center gravity this is not the correct location, the canards must be placed above the center gravity. Additionally these control surfaces are somewhat undersized. The lower set of control surfaces which I will refer to as pitch and roll vanes are undersized. Also the craft is lacking the required skirt that wraps around the lower one third of the sphere. A quick review of how the Japanese sphere flight controls were configured maybe helpful to you. The upper set of canarderon's are positioned above the center gravity, the lower control pitch and roll vanes are positioned below the center gravity, both the upper and lower controls are approximately equal in control surface area and distance from the center gravity. The center gravity of the Japanese sphere and Sam's sphere is slightly below the Meridian of the sphere, approximately Œ to 1/2 inch. To implement a pitch change in the sphere to tip the sphere away from the pilot, the upper control surfaces i.e. the canarderon on the pitch axis would tilt towards the pilot and the lower pitch change control surfaces would tip away from the pilot. This articulated control surface interaction could be described as canarderon's. The same interaction would occur if you were to tilt the sphere left or right the upper and lower control surfaces work opposite of each other. The reason for this interaction of reverse control surface deflection is to overcome the very low moment of force of the control surfaces, i.e. the fact that the control surfaces are relatively small and very closely spaced to the center gravity. (Low control surface moments) Yaw control of the sphere can be implemented in two manners. The original Japanese sphere utilized eight servos this allowing all eight control vanes to be twisted in the same direction to implement a Yaw control, i.e. to command a turn on the vertical Yaw axis to the right all a control vanes would be tipped to the left, and conversely for a right turn. The second manner, as employed by Sam was to utilize six servos. This decision to limit the aircraft to 6 servos was primarily based upon the restriction of power availability from the electronic speed controller. In Sam's configuration the upper control surfaces, canards, did not interact or facilitate the Yaw control, they only function as canarderon's to facilitate pitch and roll motion. Only the lower control surfaces functions for Yaw control. It appears that both configurations, the Japanese sphere and Sam's work, although the configuration utilizing eight servos will give more precise control, and an increase in Yaw rate change. Implementation of the spoilers will allow the flight control stabilization computer to have its control rates set at a higher setting give a more precise flight control. The spoilers act as pitch and roll dampening devices. It appears that the spoilers are well worth the trouble to install as per Sam's numerous comments regarding their requirement; additionally the original designer would not have used the spoilers if they did not give substantial handling improvement. Most interesting is the fact that the original designer makes no mention of the spoilers in any documentation. Feedback from one RC group correspondent that attended one of his live demonstrations in Japan said not one word was mentioned about the spoilers. It appears that the original designer did not want to draw attention to this design feature. Please don't let my comments discourage you in any way your workmanship is spectacular, just a few tweaks here and there and you'll have a spectacular flying devices. Kelly
|
|
|
|
|
Japan
Joined Apr 2010
2,398 Posts
|
Lol, bit late for that. I assume you are ignorant, you are already copying. If you had looked through the video and photo archive you'd have seen that your current configuration in the video has already been tried - twice - by 2 different people. Chorocopter knows what he's talking about and you'd do well to listen to him. I get the impression that won't be happening.
You are correct this is your project and you and inbreed can do whatever your little heart wishes with it. Goodbye. |
|
|
|
|
|
|
|
We are not in it for sales or money. Its a hobby of which we are enjoying. Any information has been listened to.
I was not rude with my reply and so Im not sure why you seem offended. The original design holds a patient. And oh yeah lets copy it directly. As i said its a hobby. And two failed attempts doesn't mean we can't try. If the other cafts failed then there are problems there too. Maybe you should give your cent there too. ...Bye |
|
|
|
|
||
|
Joined May 2010
302 Posts
|
Quote:
I'm not sure if your address me here, or some other poster, but I agree with all of your comments here. I'm not offended in the least, I was just leading a hand, reflecting upon what Sam and I learned. Why not build every possible configuration and post the results; this the very best possible use of these forums. I'm looking forward to your test results. I agree the craft has a Japanese patent, but from what I could understand via translation software was that it was not covered under an international patent, but this is not my field of expertise, so building only a "one off" model for personal use is a very smart move! |
|
|
|
|
|
Joined Aug 2006
46 Posts
|
Thats a great project and concept you got there.
If you look around for a "single 26cc gas engine vtol" thread, you will see some of my ideas and tests. as its based on the same airflow vains concept, perhaps i can share a bit from my humble experience - first, your CAD drawing (solidworks, right?) are great. consider lowering the the motor plate so that the prop plane will be at the widest part of the sphere, this will enable you to select a larger prop thus increasing the static thrust. my latest microtricopter tests showed that placing the CoG ABOVE the prop plane will increase the platform's inherent stability, consider mounting the battery and all other heavy equipment at the upper part of the sphere. looking at your vains design, and seems that they are large enough to produce decent control authority, one should consider using only four vains with four servos and proper radio mixing to control the Pitch/Roll/Yaw axis. lowering the vain count will reduce the overall drag and will increase the static thrust. anyways, these are just few of my findings. will continue reading this thread, i really like the design and craftsmanship. Ravivos. |
|
|
|
|
||
|
Joined May 2010
302 Posts
|
Quote:
Excellent suggestions! ALL TRUE! Sito's craft is a special purpose craft with ground roll, and high speed horizontal flight capacity, not all required here. If the sphere is intended to hover only then these suggestion shine, configuring high speed flight performace maybe a challenge, as a certain amount of wing area is required. Sito used the Canard configuration successfully to this end. Your suggestions reduce weight, parts count, cost, and complexity. Additionally a larger prop increase thrust to weight ratio. All improvements. COG above the prop is the way to go, as well as a large slower turning prop, the only drawback is increased counter-motor torque from the larger prop mass, but that is offset by the additional thrust. Large edit for expanded ideas: Kelly |
|
|
| Thread Tools | |
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| Discussion Flying sphere | TheZero | Multirotor Talk | 13 | Dec 13, 2011 05:51 PM |
| Discussion Japan's Flying Sphere UAV | jbrundt | Electric Plane Talk | 1 | Nov 10, 2011 09:42 AM |
| Cool Japan Defense Ministry - Flying Sphere | martinic | Multirotor Talk | 1 | Oct 27, 2011 08:04 AM |
| Discussion Japan's Flying Sphere? | Excogitate | Electric Plane Talk | 4 | Oct 27, 2011 04:35 AM |