ssphoenix
Heliman
Location: Phoenix
| 4 points CCPMCreg,
I am going to take a crack at your last questions. Although I do not know exactly the reason behind why Vario opted for 4 Point CCPM, I know why I would. I too, have been flying 3 points CCMP in my old Furies and I suppose half CCPM on my milli. I’ve got my first experience and the first thing I did, cut the frames and tried to set it up for 3 points because the weight I though. To make the story short I gave up and decided to try the 4 points. Here is what I found:
The amount of weight adding an extra servo will not get you near the amount of benefits you get by implementing 4 Points CCPM.
1. You will get greater precision in control. Think about, now you have 4 points of transmitting control to the head rather then 3. Perhaps not as good of an analogy but 800 pixels on your monitor is better then 640. You get a clear picture condensing more pixel in the same amount of area. Same on the swash plate, you put more points, you get a better control to the rotor-head. I suppose to a certain extend. Someone was asking if anyone is doing 4D. Perhaps there is correlation to 4D and 6 or 7 or even 9 points CCPM. 
2. 4 Points CCPM will get you greater travel at the extremities. Again think about the swash-plate, draw a triangle. The corner of a 4 point CCPM will be longer therefore further out, therefore larger travel to the swashplate. I already mention in my last post. I am at %50 swash plate setup on my 9ZHP and I am getting 20 degrees of pitch with 100% servo ATV. A furie would be at %65 to get 20. I understand the geometry is different, the sizes of the swashplates might be differerent, therefore these number don't mean much but as an example and if you didn't miss your geometry classes, it is safe to say larger swashplate will give you larger travel (depends also on the inner ball links)
3. Now believe it or not with this range of travel, your servos will work better, last longer, and will draw less power from your battery which I do not have the ability to calculate but no doubt in my mind will offset the extra servo you now have.
4. No question your servos will work better because now you have 4 doing the job for 3.
5. Perhaps the most important of all and I’ve actually came to witness, is redundancy. I flew hard 3D with 3 servos in this configuration because I lost the screw on one of the servo arm. I did notice a bit of a slag in controls but nothing out of the ordinary. I found the screw missing on my next preflight check. I'll take %50 chance to save my helicopter any day.
I’ve already mentioned again in my last post. Perhaps the only down side of the 4 point CCPM is the cumbersome setup. You always need to change at least 2 controls rods. For example, if the helicopter drifts to the right, the proper way to adjust the swashplate is to unscrew the right servo rod, lets say one turn, and screw in the left side servo the same amount. Perhaps someone else care to fill in as to why.
Hope this helps. |
