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Old Mar 21, 2012, 03:45 PM
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My First FP Helicopter Walkera CB180D Crashing badly

Hello,
Just got my Walkera CB180D and have crashed it badly twice.

I'm fairly new at this however I have spent much time to become very good & comfortable with
The coaxial that I started with which is an Esky Hunter.
I'm able to fly that very nicely indoors in all directions/modes its capable of including the hardest which
was nose in.

I've also been spending a lot of time on simulators and can fly all the FP and CP helicopters on those pretty well
as well as some basic 3D.

I've spent a lot of time on the CB180 indoors hovering and making gentle flying around the room.

Now I've taken it outdoors (in no wind) to try and have some real fun twice now and have crashed it both attempts breaking off both main
blades and the tail blade.

It seems that it flys great for awhile I got around 5 minutes out of it this morning in zero wind before it went
out of control going very fast on it's side I couldn't recover it and I let off the power just before smacking the ground.
During that 5 minutes I got some really nice flying lots of turns forward flight climbed up high and brought it back down
I did notice it seeming to lose signal only about 75 feet away and 20 feet off the ground, this is very disappointing
The motor cut for a fraction of a second and I got it back under control.

The out of control event happened suddenly when I had it closer in.

What's most frustrating is that in any type of crash I've ever had before I knew exactly what I did and was able to learn from it.
In both crashes I've had so far 'it just happened' I can't place it on what I did wrong.
I'm sure I must have done something wrong but it's subtle and not making sense to me yet.

I'm doing alright in the simulators so I thought I would be alright at this suposedly "almost as easy as a coaxial" helicopter as keeps being
said about this helicopter.

Is this normal for this helicopter? Is the thing normally that easy to fall into some mode where it instantly goes out of control
and not possible to recover it no matter what you do on the sticks and throttle?

Are there any good reads out here about this? I've been reading and watching lots of videos and forum articles but have not really been able to find any good articles on "out of control situations" or recovering from out of control situations and/or
how you actually get into these situations where the helicopter is flying on it's side and you can't pull it out.
It hovers fine 'almost hands off' like it should, just seems that I can't do any real flying getting it moving.


Thanks for any info or links or just telling me this helicopter sucks and I'm pushing the controls too far or whatever.
I thought this helicopter would fly at least something like they do on the sim.
I've never had it just go wild like this in the sim and it's not the tail rotor or a spinning problem.
The most unstable manuever I've worked on the sim is a nose up descent and steering the rudder to keep it straight as it goes down
on an angle and trying to do this (dropping it) a bit fast.

Friends are all saying "just get a TREX700 you'll be a lot hapier and it flies so much better..
Um.. I'm sure it does. :-)

Thanks!

Steve
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Old Mar 21, 2012, 04:00 PM
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It sounds like a stall. Give a little throttle when you turn into a banked turn and that should solve it. Just my guess.
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Old Mar 21, 2012, 06:09 PM
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Ok sounds like good advice, I've not heard of this though on these little guys :-)
Are stalls common or usual on these helicopters?
And once it stalls can you normally just throttle up and stick it to get out of the stall?
Or is it too late and do I somehow have to learn how to avoid (deadly) stalls in the first place?
I thought blade stalls were more of a high speed bigger helicopter issue but maybe not?
Thanks for the advice!
Steve
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Old Mar 21, 2012, 06:34 PM
Crash and learn
United States, PA
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If it was cold, then the battery won't last as long outside in the cold.

Maybe 5 minutes was too long and the helicopter gave up.
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Old Mar 21, 2012, 06:41 PM
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There is something called the death spiral, it happened to me a couple times when I was learning to fly my Big Lama, which is a coaxial, but I'm not sure if it was that or a binding flybar from a poorly designed metal kit. You don't have one of those cheap metal kits on your heli, do you? I was not able to come out of it one time and it went sideways fast and hit the ground hard.
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Old Mar 21, 2012, 08:19 PM
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Thanks for trying to help, but nope it's not a battery issue there was plenty of battery reserve, I've tested it and am very familiar with the life of the battery and what charge level I was at.
Nope no kits, it's a stock Walkera CB-180D

Thanks

Steve
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Old Mar 21, 2012, 09:48 PM
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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
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Old Mar 21, 2012, 11:19 PM
Crash and learn
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Sounds like it is time to pay attention to the tail motor. Feel if it is getting warm or hot. You should know this already.
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Old Mar 21, 2012, 11:27 PM
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on your reciever you have a pot labled extent. this controls the limit of travel on your servos. It comes turned down out of the box. turn it up till you get the max movement on your servos. with it turned down it is very easy to loose control as you yaw back and forth. Also move the counter balance throw out to the next hole. This will allow more aggressive movement. Don't know about your loss of range issue could be tx battery low. For a fixed pitch the 180d is fun to fly. Much more fun then my 120sr. Its a very good back yard/small lot flyer which you just cant do with a 700
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Old Mar 21, 2012, 11:29 PM
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Oh ya don't forget to make small adj to the sense pot. this will allow you to adj the heading hold on the gyro to control the tail motor.
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Old Mar 21, 2012, 11:31 PM
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Yep, tail rotor appears to be working fine the motor runs very hot but is known to do that on these helicopters.
It even has a heat sink on it for this reason.
There was no loss of tail rotor power before or during my out of control situation as I would have noticed it spinning if the tail rotor had quit or lost partial power.
The helicopter was not in any kind of a rudder spin. But seemingly suddenly was at a steep angle going very fast and heading toward the ground. running full power to try to gain altitude and yanking on the cyclic to try and create downward thrust and gain altitude either didn't respond due to not having enough authority to pull it back over/upright in this atitude & speed or it wasn't quick enough to respond and provide the desired effect before hitting the ground.. I also lost some recovery time (1/2-3/4 second) at the decision point to pull back power versus continuing to try and pull out of the mess.
It gets into this situation so fast that I so far have not been able to tell what action
puts it into this mess.. I recognize the mess just fine and it's pretty hopeless but I have no idea what move it putting it in this position.
It ist normal to tip the thing over by applying too much cyclic but then not have enough authority to flip it back?? Gosh I hope not! :-)
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Old Mar 21, 2012, 11:35 PM
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one more that i forgot. If you have the WK-2402 or 3 if the aux control is turned on it will act like a dual rate switch at 50%. make sure its turn off when out side. There is a walkera 180 thread.
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Old Mar 21, 2012, 11:38 PM
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I think when I get replacement parts I'll try and fly it over thick grass so that it can handle a crash a little better and have someone video the helicopter for me so this can be better analyzed.
I'm having a bit of a problem finding anyone else on the web describing
Losing control of these in quite the same way.
I might be able to dscribe it as what it feels like to fly without a flybar manually..
I've done this before. and I've done it a lot with my coaxial for fun.
It will fly ok but when it gets moving and you try to turn or go backward the thing
just dumps on it's side way out of control or dumps backward and heads horizontal at a high speed.
My flybar *seems ok* and moves very freely and doesn't seem to get bound up when I force it around harshly (in my hand *wearing safety glasses) while the blades are spinning.
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Old Mar 21, 2012, 11:47 PM
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I'll investigate the dual rate comment (not even sure what that is but I'm about to find out).. and this *IS* a2402. thanks for the tip!
Gyro seems to do a great job although I think I'm sorta comfortable even if the thing didn't have a gyro and having to work the rudder manually.. at least on the sim I'm used to this :-)

I was eventually going to work to setting the extent all the way up (only on my second flight) since I got it. I'm already on the middle hole on the counter balance arm (did very well on this setting indoors) and I am planning on moving it to the outermost position + maxing out the extent pot once I got comfortable I could fly it outside with NO wind.
Todays crash was an upsetting surprise especially since I was flying it so well for a bit of time before I lost it.
Thanks!
Steve
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Old Mar 21, 2012, 11:48 PM
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Sounds like the death dive. Ive power dived several (a lot) times into the dirt just like you discribed but usualy i was caught by the wind and just pushed into the ground. Check to make sure your getting the full throw on your servos. Makes it harder to hover with out constant input but will give you alot more foward speed and control in the wind
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