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Old Feb 24, 2015, 11:02 AM
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Hey guys. I converted my brushless main f49 with a v912 pcb to use my stock v2 turnigy 9x. I only get about half the servo throw as the stock tx. Is it required that I flash the er9x firmware to get regular servo throw or is some setting with the stock turnigy 9x to get full servo throw with the v912/3 pcb?
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Old Feb 24, 2015, 11:34 AM
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I saw a few posts here about 450 FP helis. If you want a 45 degree latent balance bar, you have to change the head, but if you want FBL, you don't need to change a single thing except the pitch and throttle curves in your transmitter. Set your pitch to a flat positive pitch and lower your head speed with the throttle curve. BOOM! Done.

The fact that a helicopter is capable of changing the pitch of the blades has absolutely nothing to do with the way it flies except on the vertical axis where it gets more responsive, especially if you go negative. So what makes the difference?

1) High head speed typical on a CP.
2) The FBL controller.
3) Onboard stabilization software in the FBL controller.
4) The 45 degree latent balance bar (if so equipped).

You can control all of these things on any 450 build if you so desire. You don't need to change anything except your transmitter setup, and pick your FBL system carefully. I hate to recommend anything from Walkera these days, but the all-in-one RX from the V450D03 is an incredibly simple and stable RX, FBL controller, and 6G stabilization system all in one for a beginner who does not want to learn to program a KBAR (3G) or who wants the self-stabilizing contained in the Walkera unit. Just plug in your servos, set the TX as you see fit, and fly.

-Florida Heli-
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Old Feb 24, 2015, 12:31 PM
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FH - I'm building a 450 FP and plan on using the CC3D, any thoughts on this flight controller?
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Old Feb 24, 2015, 01:21 PM
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Are you are planning to use that with a FBL controller like a KBAR, or use CC3D as a FBL controller?

I read that CC3D isn't supposed to be used with a 45 degree balance bar, which makes perfect sense from the physics involved. The 45 degree balance bar would be fighting with the FBL controller constantly. FBL controllers work based on instant reactions, not damped reactions caused by the interference of a latent balance bar.

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Old Feb 24, 2015, 05:40 PM
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FH - the 450 FP is flybarless and I plan on using the CC3D as the FBL controller.
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Old Feb 24, 2015, 06:43 PM
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Just curious. Why not use a KBAR instead?

KBAR

Member jetplaneflyer put up a YouTube video of his 700 hovering hands off with a KBAR in it. That's good enough for me.

Compass 7HV hovering 'hands-off' (0 min 16 sec)


Also a TREX 500 hands off hover. The dude just drops his hands while hovering, LOL.

helidayz skytech on the trex 500 kbar hands free hover rc helicopter (1 min 9 sec)


I spent two days browsing the forums for CopterControl, and it isn't something I will be trying. I applaud those who are trying it, but I'm going to stick with the proven KBAR.

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Old Feb 24, 2015, 07:21 PM
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The CC3D has a 3axis gyro plus a 3axis accelerometer. I figure this would make it more stable and easier to fly. I will definitely keep the KBAR in mind if the CC3D doesn't work out. Thanks FH.
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Old Feb 24, 2015, 08:15 PM
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Quote:
Originally Posted by vincent713 View Post
The CC3D has a 3axis gyro plus a 3axis accelerometer. I figure this would make it more stable and easier to fly.
That's what I used to think, and I was incorrect. My latest blog entry explains more.

A true FBL controller does not use accelerometers. A true FBL controller only needs two gyros to do its job - one for pitch and one for roll. Those two gyros compensate for the constant twitches needed on the AIL and ELE channels to replace the pitch and roll damping that a flybar would provide. It's an electronic flybar. A flybar doesn't have any accelerometers. It's a paddle bar spinning in a plane, and physical feedback from it goes back into the head. Lateral motions, which is what the left-right and forward-backward accelerometers would sense, mean nothing to a flybar. Pitch and roll most definitely mean something to a flybar, and gyros sense pitch and roll, not accelerometers.

So how do we get a heli to self-stabilize with only two gyros on pitch and roll? An FBL controller can be made to simply counteract the little twitches needed to keep pitch and roll under control and not interfere otherwise, or it can be used to keep everything rock solid and self-stabilizing. Think of a tail gyro. A tail gyro can be used to damp tail movement or it can be used to keep the heli pointed one direction rock solid steady. An FBL controller has two gyros. They just work on pitch and roll, not on yaw. Make sense? If I want absolute level rock solid roll, I would use the roll gyro in the FBL controller feeding back to the AIL channel to immediately counteract any roll and keep the heli absolutely vertical. I don't need an accelerometer for that.

Add the tail gyro to the pitch and roll gyros, and now we have a 3G system.

Now we add three accelerometers to the three gyros to get a 6G system. The 6G system is completely useless without software to control it. Something has to talk to and coordinate the three accelerometers and the three gyros and the four servos. This is more stabilization software than 3G has. Given that we can keep a heli rock solid stable with a 3G system, what do the three accelerometers add? They add a tiny bit of lateral stability (forward-backward and left-right) that I do appreciate sometimes. If a puff of wind hits me from the side while I hover, the accelerometer on that axis will sense it and temporarily (very temporarily) twitch the heli into the wind to resist it. That lasts about 1/4 second. After that, it's up to the pilot. It is possible to get a stronger and longer lasting response than that, but the heli starts to get really sluggish as you fight with the accelerometers and the delay in getting them to be overridden by you becomes noticeable. Usually that level of stability would be reserved for a position hold button so it can be turned on or off. Using just a little bit of resistance (not much) to movement of the accelerometers helps a lot more in tiny little micros than it does in larger helis since the tiny micros get blown around like feathers and larger helis do not.

I hope this makes sense. Maybe I need to expand and/or clarify my blog entry. There is so much faulty information about 3G and 6G and FBL and software stabilization techniques floating around the Internet that it's just sad. I always try to take it right down to the nuts and bolts of what the hardware and the software are actually doing. That makes it easier to separate what's really accurate. We have multiple components in any system, so we can't just say, "It's 3G" or "It's 6G" and mean anything other than a count of the physical parts. When dealing with manufacturers, they too often use the term 6G to refer to a heavily stabilized flight controller. Well, I can use a heavily stabilized 3G controller and get the exact same response, only without the resistance to physical movement from things like a puff of wind. If I get hit by a puff of wind, I react to it. No big deal really, except in a micro that's getting blown around like a feather so bad that I can't control it.

I think what we all want is a stable heli. The two videos I posted show two 3G helicopters hovering hands off. We can't ask for much more than that. 6G properly implemented can add a little more flight assistance to a tiny micro, but on larger helis I just don't see it as that big a deal.

With this said, if the CC3D isn't really very seriously optimized for use as a FBL controller, as is a KBAR, it's not going to work as well regardless of whether it has accelerometers or not. From what I have read, the CC3D isn't anywhere near the level where it needs to be for use as a FBL controller.

-Florida Heli-
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