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Old Mar 22, 2012, 01:16 AM
Cranky old fart
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Germantown, WI.
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Quote:
Originally Posted by N8LBV View Post
Also the "death spiral" you are refering to.. I'm pretty sure is only common to coaxial helicopters also frequently called TBE (toilet bowl effect).
Thanks,

Steve
It isn't unique to coax helis and has nothing to do with TBE. Your CB180D shares many properties with coax helis: a long vertical CoG, a 45 offset flybar, limited movement authority and self-stabilization. What occurs with this type of heli in a fast turn is it's need to bank exceeds it's ability. When it reaches this point, it will start to slough air from under the rotor blades, losing lift; which usually results in a crash.
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Old Mar 22, 2012, 04:10 AM
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You did check the flybar? It should move very freely with no binding. move it left to right as well and see if there is a lot of play and if it binds when pushed left or right (holding blades still). This was likely my issue when my heli did the exact same thing.
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Old Mar 22, 2012, 08:35 AM
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Quote:
Originally Posted by Balr14 View Post
It isn't unique to coax helis and has nothing to do with TBE. Your CB180D shares many properties with coax helis: a long vertical CoG, a 45 offset flybar, limited movement authority and self-stabilization. What occurs with this type of heli in a fast turn is it's need to bank exceeds it's ability. When it reaches this point, it will start to slough air from under the rotor blades, losing lift; which usually results in a crash.
100% correct, this was the cause of his crash, (and a bunch of mine). Thanks
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Old Mar 22, 2012, 06:40 PM
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United States, MI, Ann Arbor Charter Township
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Thanks both of you for the clarification (not TBE) and it being something different.
Sounds like I have a helicopter that can't handle simple maneuvers (fast turns) and that sucks!
This was to be my first non-coaxial to really start learning to fly on that I thought would be able to move around outside a bit in and break away from the incredible slowness and lack
of authority I get with the coaxial.
Sounds like I didn't pick a very good heli for what I was trying to accomplish.
I wanted to be able to turn at will without being afraid of losing it every time.
It certainly wasn't a cheaper very inexpensive helicopter and it had a lot of really good reviews.
Guess I really got suckered or I'm just new enough at the hobby that I really do need the TREX or something MUCH better if I expect to actually keep control of the thing.
And yes it did happen in a very easy but fast turn that I'm ever so used to doing in the simulator.
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Old Mar 22, 2012, 06:43 PM
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@shahram72 I did check for binding on the flybar and found no problems there very free moving.. was slightly stiff when brand new but never binding.
It's much smoother now (the flybar) after two flights and crashes.
And a lot of hover/indoor testing.
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Old Mar 22, 2012, 10:17 PM
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There's lessons for all beginner here:

1. Remember, the criteria for a "good" heli from most beginners is something that they can fly easily without crashing. Ask experienced pilots and do it before you buy! Ignore reviews on sellers websites!

2. Just because a heli is relatively cheap, doesn't mean it's a good value. If it's only 10 - 20% more difficult to fly than your previous heli, you may not be getting much value for your money. The best values are those that provide the broadest performance range because they will teach you the most.

3. Helis that look cool with lots of metal components are usually lower quality than crappy looking, all plastic models. Soft aluminum is cheap, plastic molds cost a lot more.

4. Pay attention to head design, tail drive system, motor type, weight and a other technical details. They will teach you a lot without spending a dime. If you don't know about something, ask!

5. Durability, reliability and parts availability should be your primary considerations. Your learning curve will take forever if you are always waiting for parts.



As for your CB180D, it has numerous design flaws that made Walkera discontinue it fairly quickly:

The motors are uneven quality and will burn out quickly.

The tail drive system generates too much heat and friction, causing it to draw excess amps, which reduce power available to the main motor. This contributes to the weak movement authority.

The 45 offset flybar's purpose is to damp movement, which it does very well, too well. It works fine in the nano sized models, but the design doesn't scale up well.

Walkera addressed most of the flaws (motors and tail drive) when it replaced the CB180D with the CB180Z. The rest of the flaws (flybar and gyro) were addressed when Walkera replaced the CB180Z with the D200D01 (Exceed Classima 300).

You can make some improvements to you CB180Z by shortening the flybar, or removing some weight and by repalcing the tail drive system with a direct drive unit.
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Old Mar 23, 2012, 02:46 AM
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Thanks 14, yeah a bad decision on buying that one.
The parts bills are already adding up 1 week later.
I also have an ESKY beltCP V2 which I was keeping put away and wanted to learn on
a small FP machine first.. this is not turning out to be the learning step I was looking for.
It's a learning step nonetheless but not a flying learning step unfortunately.
Good information, thank you.
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Old Mar 23, 2012, 10:02 AM
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You would have better luck and a much broader learning experience with a Blade 120SR. The Walkera V200D01 would also be a better choice than your current model, however it does not have the durability or parts availability of the 120SR.
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Old Mar 23, 2012, 06:09 PM
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Also My TX (2402) does not have a dual rate switch.
The manual for the helicopter and the TX make no mention of dual rate.
People on the forums have suggested that turning "AUX" on/off on the remote
enables (50% cyclic rate) and turns it off (back to 100%) responsiveness.
The manual makes no mention of what the "AUX" setting on the Walkera TX does.
People on the forums have suggested that you need a 2436 RX to support the aux/dualrate.
I have a 2426.
All of my testing turning on/off "aux" on the TX while powered up and turning off/rebooting TX and RX did not result in any change in cyclic travel whether aux was on or off.
Aside from all that, I'm not worried about dual rate but I did make sure I wasn't stuck in
some 50% or limited mode.. I have good cyclic movement.
120SR noted. (Thank You).
I'm not worried about good looks decals metal or paint. and those were not a factor on my purchase decision.
Just saw all the reviews about how wonderful & stable & crash resistent the thing was.
Another factor was it was one of the very few in stock at XHeli where I was already buying parts to fix up another helicopter
and in a hurry ( I waited 3 months for stock to get better) it never did I made the jump and bought this.
I wanted something that wasn't coaxial and I rushed it obviously too much.
It was an expensive date. and a sour taste of Walkera.. I won't be buying another Walkera product any time soon.
And this forum thread may encourge others to steer away as well if they search for and happen to find it.
For $150 +$44 for replacement parts) US I expected a little more quality than this.
Motors that burn up quickly under normal operations? no excuse for that 5hit seriously.
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Old Mar 24, 2012, 11:03 AM
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The blade 120 is crash resistant but flys like a sloppy dog next to the Walkera. Your going to have the same limitations with the 45' fly bar and the RTF TX is, Well........ They serve the purpose of making the transition from co-ax to single rotor easy. CB 180D is walkera's entry Helli to 180 - 200 size. Tail motors, well.... had to replace tail motors in every Helli I own. Tail motors in the MSR and 120 have failed more often then the Walkera. There is good and bad with all brands. To me the 120 is a kite when there is any air movement, but odds are if I smack it into the drive way I can pick it up and fly it again. The 180 holds its own in a 5 mph wind but If I ditch it something is going to break. As the size and or capability of the heli goes up so does the cost of a crash
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Old Mar 24, 2012, 12:20 PM
Cranky old fart
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Germantown, WI.
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The 120SR has a 45 offset head, not 45 offset flybar. It's properties are entirely different, it has much more movement authority and will not death dive. Any time you increase movement authority, you decrease stability, which contributes to your "sloppy dog" analogy.

If you are burning out tail motors, you spend way too much time just hovering. That's the hardest thing for a tail motor to do.

Walkera discontinued the CB180D two years ago, while Blade still makes the 120SR and it still sells very well.
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Old Mar 24, 2012, 12:44 PM
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i think we are starting a Chevy/Ford thing.
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Old Mar 24, 2012, 01:57 PM
Cranky old fart
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Germantown, WI.
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I have a number of Walkera and Blade helis and generally they were not meant to serve the same market. The issues I described with the CB180D are well known and documented, including the "death dive". There were even a number of websites that sold fixes and upgrades during the time this model was more popular. I believe RTF-Heli still sells some of those upgrades. On the other hand, there are no major issues with the 120SR. It flies exactly as it's design would dictate it should fly. If it's not what you expected, you didn't do your homework. 45 head helis simply do not stabilize like 45 flybar helis. If you expect any other heli to fly like a CB180D, you are going to be disappointed. It's very tame and easy to control.

OP has already reached the point where he is experiencing performance issues (death dive), so it's time to move on. It's impossible for the 120SR to suffer from this condition.
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Old Mar 24, 2012, 05:02 PM
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True, I didn't do my homework at the time of purchase and at that time I didn't realize I needed to.
I had thought then that I'd done enough and that the purchase would fly very well
outdoors in zero wind.
Shame on me for not realizing that It really would not. and has many shortcomings.
I'm learning, and sad as it is I'm so tempted to rebuild and mod the thing until it works better before I'll just give up & buy something better just so I can 'learn' in the process while griping & complaining the whole way.

I think my friend is correct when he says to stick to the simulator and get a TRex-600 get some help with it at first,
that I'll be happy be able to fly it and anything else will nickel and dime you to death and be constantly down and waiting for parts & repairs.
He watches me on the sim and says "you'll be fine on a Trex" I'm not so sure of that :-)

The 60 ft. transmitter to RX range (problem) on this is the icing on the cake.
I'm pretty sure I'm done with Walkera and this level of quality and obvious lack of engineering/testing or even caring abilities. I do wonder why after 2+ years of (well known & documented) problems WHY are these still being sold as new and not at any kind of deep discount?
I've been working with both inexpensive and expensive 2.4GHz digital spread spectrum
equipment and know this subject VERY well.
A low power TX (4mW) and good RX typically get +very+ well over 1000FT of range outdoors.
The 60-75 FT cutoff I'm seeing was a complete surprise in an area where I have done my homework for over 15 years and work professionally in this type of wireless equipment.
Something's seriously wrong with this radio system.
Very sorry for not doing my homework I knew better but was anxious
to get off of the coaxial and experience something outside a little more
Like I have been doing on the sims.

I'm still very much enjoying the challenge and appreciate all of your help! As well as all of the information available on forums like this one.

Steve
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Old Mar 24, 2012, 05:58 PM
Crash and learn
United States, PA
Joined Dec 2011
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Range, as you well know, is determined by the signal to noise ratio. You also can guess that the motors and electronics are all ones and zeros, and by default generate a lot of noise.

They should only sell one helicopter - the best one, and drop all others from the market.
---

Maybe the Russians have a new woodpecker.
http://www.google.com/imgres?imgurl=...QEwAg&dur=1435
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