My First FP Helicopter Walkera CB180D Crashing badly - Page 7 - RC Groups
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May 04, 2012, 03:47 PM
Cranky old fart
Balr14's Avatar


....and effective!
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May 05, 2012, 11:34 AM
Registered User
Hey B-14 sorry to keep asking so many questions..
But do you think I'd get any improvement at all from installing
a 90 degree head part instead of the stock 45?
Are the electronics specific around the 45 degree head design where
they would fight me with a non stock 90 degree flyweight arrangement?
I'm pretty sure the flybarweight/angle/clyclic interraction is purely mechanical
and should have nothing to do with the RX electronics.
But I also think it's one of those "not so simple" things.. as a 90 degree flybar
is a totally different design.. and I may actually need paddleqweights (not just weights)
and proper mechanical mixing for the rest of the design (not just a $12 part).

I'm sure I'm not the first to have been tempted to try that $12 replacement
part from another heli but I'm having a hard time finding any posts where someone actually tried it out.

I'm nothing special yet, but I do have about 15-20 flight hours on the 450 CP
Now without crashing.. :-) !!
I mention this because I expect the CB180 to be much harder to fly if it were
modified to a 90 degree head design.. and I'd love to continue practicing on it
If it can be done inexpensively.
I will be getting a smaller CP bird to beat and practice on soon.
The 450 is a little big for my hourly practice needs :-)

I tried idle-up for the first time yesterday, and *almost* lost it.
The ESKY Idle-up and pitch program makes NO sense to me..
Seems very dangerous and stupid by design.. I don't get it.
I posted about that over here:

Seemed to go all over for a bit and at the same time seemed about 5X more sensitive
that I was used to on the controls.
Fortunately I adapted fast enough to save it.
Then coming *OUT* of idle-up it shot up about 30 Feet.. I handled that OK but
It was stressful because I'm not used to flying it that far up in the air as I have
been doing pretty much all near the ground and close up practice.
May 05, 2012, 11:37 AM
Registered User
Any of my next helicopters are not likely to be RTF packages..
I'm doing this carefully from now on.
My next purchase will be a DX6i TX and a reciever.
Then I will rebuild my other BeltCP V2 that needs a few parts.
I need the other CP V2 flyable for when I lose my only one I have now :-)

Then I'll get/make a smaller practice bird that I can also fly with the DX6i.
I'll keep one of the Belt CP V2's stock so long as it keeps working.
May 05, 2012, 12:00 PM
Cranky old fart
Balr14's Avatar
The DH9116 uses control mixing because both aileron and elevator have to move for either function, due to the 120 swashplate. If you are going to replace the entire head, swashplate and all, the electronics won't work. If you are going use the existing swashplate and just replace the mainshaft and head, I don't see a problem. Maybe you will have to reposition the anti-rotation bracket; hard to say.

By the way, is just hold ALT and type 2 4 8 on the number pad, if you are tired of typing degrees.
May 05, 2012, 12:07 PM
Registered User
Thanks! 248 is easy for me to remember it's one of our area codes here. :-) ◘
May 05, 2012, 12:08 PM
Registered User
That's really hard to do from my phone. ;-)
Sometimes I'll copy & paste it to get the job done.
May 05, 2012, 12:10 PM
Cranky old fart
Balr14's Avatar
There's no way I'd even try that on my cell phone. I consider it a major accomplishment if I can see the keys good enough to enter a phone number.
May 06, 2012, 08:11 PM
Registered User
I pretty much 'retired' the CB180D to be a 'showpiece' and slow flyer.
It's great for slow flight in little or no wind.
And I still have a lot of slow flight modes to master, backwards flight turns
slow low angle funnels/tornadoes etc. things like that but tempered WAY
down to slow speeds and angles..
Slow pirouettes (without the heli losing it's place in the air at all) in light wind
where I really have to work it to keep it from moving out of its spot.

So there is still a LOT I can do with it practicewise despite whatever I've been doing on the CP for 20 hours without crashing :-)

Flew it just fine in 5Mph wind today I just can't take those fast turns which is a
bummer but oh well.

When I'm good (or have some money) I'll get me a small CP heli to play with and maybe that Mqx!

I'll DEFINTELY build a FP heli from scratch eventually that will be awesome fun..
Might start out simple using someone's 4in1 RX and base the design on something that the 4in1 normally flys with.

Fixed up the CB180b really nice and put LED markers and strobe on it.
It's an impressive 'scale' slow flyer now and It never crashes if I dont try to
Hotrod it.

I can nose-in fly it very nice now so it puts on a very nice show with those lights!
Going from that CP back to this thing it's seems so incredibly easy to fly now.
Comapred to when I first started this thread.
May 06, 2012, 08:21 PM
Registered User
I'm continuing to work myself to better understand your explanation of the 45 flybar.
I get the concept of the 90 out of phase responce caused by gyroscopic precession..
but not the thing about the action not happing until the blade comes back around a second time after the force is applied quite yet.
It will hit me like bricks when I take some more time to understand it.
I also like to hold the helicopter and picture in slow or frozen time what's happening wit hthe swash, blades flybar & mixing.. that's fun as well..
I show people how the swash works all the time and what it does on the blades and how it happens..
They're usually no as interested as I am :-)
May 06, 2012, 11:26 PM
Cranky old fart
Balr14's Avatar
I believe the "next cycle" refers to the next 90, not the next rotation. So, a 45 will be felt at 135 (90 + 45). It's a small distinction, but it might help you. Now to take this a step further, think of the helis with 45 offset heads, like the MSR, 120SR, Quark and the ill designed 9958. With a 45 offset head, the head missed the signal from the swashplate, the flybar gets it at 90 and the head gets it at 135. So, the flybar gets the signal, to influence head movement and the head gets the original signal while the flybar is responding. By mixing the two together (Bell-Hiller linkage), you get a very smooth and quick movement, with lots of smoothing to improve stability, with no loss of movement authority. Since the flybar influences movement, you want it to have paddles. It would be pretty useless without them.

The 9958 I mentioned was a copy that uses a 45 offset head and a flybar with weights, not paddles. You will see lots of complaints about how it handles. Dumbasses had no clue how what they were copying worked.

One more thing you find interesting, since you seem to enjoy this stuff, is the pendulum effect. All of these self-stabilizing FP helis have extras linkage to support their 45 offset (head or flybar), have overall light weight and the battery located below the mainshaft. The makes for a long and low vertical CoG. This is essentially a pendulum or plumb-bob, and makes the heli want to remain upright. As I've mentioned before, this is part of the cause of your coax death dive (the pendulum and the 45 flybar inhibits movement authority, so it does not have the ability to bank as much as is needed.

Anyway, the pointed I wanted to make is you often hear complaints about the pendulum effect on the helis with a 45 head (MSR or 120SR), when stopping or changing directions. But, you don't hear this mentioned as often on those with a 45 flybar. Remember, the 45 flybar is used to damp movement, so it acts like shock absorber. The 45 does not damp movement, nothing to damp those stops.

Now I'm sure if you relate all of these interesting facts to your friends their eyes will gloss over and they will fake a heart attack or burst appendix to get away from you.
May 06, 2012, 11:43 PM
Registered User
Thanks fun stuff, I'm going to go process that over the next week or so and
And maybe try some stuff.
I'll keep you updated on my understanding level and associated fun.
Thanks for helping out so much all this time!

Oh, and here's a peek after last night's rebuild.

I put about 2 hours on it today outside.
It looks really cool out there at night!

Walkera CB180D Night Flyer (0 min 52 sec)
May 14, 2012, 01:09 AM
Registered User
I'm just back to say it's truly a piece of crap!
Not good for much other than hovering indoors.
It really truly won't handle any type of fast forward or fast turn or 3 mph of wind without going
out of control with no way to steer or power it out of death.
My Belt CP V2 is MUCH harder to fly but I've not crashed in over a month of flying it and
15+ hours of flight time.
I give up on this thing!! When it's gone it's gone, I won't be spending any more money on parts for it.
May 18, 2012, 11:34 AM
Registered User
I'm going to take some time this weekend to study the 45 stuff.
I still do not have the clear understanding I'm looking for and I know you are describing it so
well that I should be completely getting it.
It will eventually click as I keep looking into it with VERY much interest indeed.
I still don't understand the difference between a 45 head and a 45 flybar helicopter.

Every one (except CP) I've had on my table have weights and not paddles.
Don't paddles also normally 'fly' and change pitch from controls as well?
They're certainly linked on the CP, I've read a bit about moving the paddles and this has some kind of effect of moving the blade pitch with less servo power required, but I'll come back to that 'old fasioned' noise later.
As much as I absolutely LOVE computers and assembly language in terns of flybarless
systems I'm a little irritated that computers can stablize the machines better/faster than we can ;-)
But then again.. so can a dumb passive looking chunk of scrap called a 'flybar'.

CPX V2 is on the way, trying to talk a buddy into getting an MQX (so I can fly it of course) but I think I need to give him my coaxial first and let him bash that up a bit more.
May 18, 2012, 12:25 PM
Cranky old fart
Balr14's Avatar
Unless you have a MSR, 120SR or Quark, you aren't going to find a 45 offset head heli. The linkage on the MSR and 120SR is simple but very subtle. You really have to understand the concept to see it. All of the guys I know here at RCG, who originally learned about offset heads and flybars and using out-of-phase conditions, learned by studying and playing with the SRB Quark head. That was the first successful use of such a feature, on a commercial scale. Nothing beats "hands on" experience.

You are right, the paddles "influence" head movement. I used to tell beginners to set the paddles of their HBFP at about 30, while they were learning to hover. This would "influence" the head to lift easier and come back down softer. It also made it more difficult for the head to tilt, which aided stability. Flybars are easier to move than the rotor head and the flybar design and linkage absorbs more vibration and movement irregularities. That saves a lot of wear and tear on the servos.

But, with 45 offset flybars, they are behind the head in gyroscopic precession, so they influence head movement by damping it. Think of having a Siamese twin who is a little slow. You are walking down the street and want to turn right, but he's slow and wants to go straight, so you settle for turning 45. Now if he was making the decisions (has paddles), you'd never turn where you wanted to go.
May 26, 2012, 01:45 AM
Registered User
And now we have these goofy things as well:

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