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Ron’s HeliProz South . Century Helicopter . MTA Hobbies

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Beginners Corner > Help me solve the problem
 
 
StevenT
Senior Heliman
Location: Dallas, GA USA

The last two times I tried to go inverted, my heli (Blade 400) dumps hard to the left and I was not able to recover either time. I would think that I was inputting right side roll accidentally, but on the sim I've never had an issue. Also, I was very high and not able to recover either time.

I don't believe that it is in the set up. What else could it be? Just as I went inverted I input full negative pitch, which I know is a problem and have corrected that, but it still doesn't explain why it dumps to the left (my left, helis right). Can a pitch control rod pop off and cause the right side roll with hard inputs? Has anyone else had a similar problem?

Thanks for any help.

Steven

Shhh, don't tell the wife.
06-05-2008 11:12 PM
 
 
nmrs
Senior Heliman
Location: Austin, TX

Do you have any right aileron trim when upright to counteract the tail rotor pushing the heli left in hover? When inverted this will compound the problem. Now this trim gets added to the tail rotor pushing the heli...

See this similar thread:

http://www.runryder.com/helicopter/t408072p1/
06-06-2008 12:31 AM
 
 
StevenT
Senior Heliman
Location: Dallas, GA USA

No right aileron trim or subtrim. Imagine dumping water from a bucket and you'll have some visualization of what happened to the heli when I inverted.


Steven

Shhh, don't tell the wife.
06-06-2008 12:35 AM
 
 
nmrs
Senior Heliman
Location: Austin, TX

Are you in idle up?

Do you have your throttle curves set up in a V (so you are getting increased throttle as you pull down on the stick)? i.e. make sure you have enough headspeed when inverted to keep you airborne.

Do you have equal pitch inverted and upright?

Do you have any mixes in your radio (negative pitch -> aileron for example)?

The fact that it happened twice in the exact same way makes me doubt that it is something mechanical that just happened to go wrong both times (like a rod popping off...).

Maybe unplug your motor or remove the pinion and watch what happens to the swash when you go from positive to negative pitch...
06-06-2008 12:45 AM
 
 
Fullpitch
Senior Heliman
Location: Deerfield Beach,Florida

You might need good stick control ,when I frist started invert I was
almost doing the same thing and it was me not controling my sticks properly.It was diffrent for me on the sim vs. the real thing,I could
fly the crap out of it on the sim and a bit of a strugle on a heli.
But I am doing good now scens I got a good feel for it now.
06-06-2008 01:29 AM
 
 
StevenT
Senior Heliman
Location: Dallas, GA USA

nmrs,

Yeah I was in Idle up. Again, I don't think it is in setup. I fairly confident that I know what I'm doing there.

Fullpitch,

Your prob right. But the first time, it was setup and prob dumb thumbs. My swash wasn't level in negative pitch. The second time I had HS-65mg's on cyclic and the swash is level all the way through pitch. How much different is the sim from the real thing? It's frustrating when I thought I gave myself enough height to recover, but in both cases the heli seemed to just tip over and loose all control.


Steven

Shhh, don't tell the wife.
06-06-2008 01:37 AM
 
 
speeddemon370
Veteran
Location: Spruce Grove, Alberta, Canada

I'm still perfecting the inverted hover myself but one major thing I noticed between the sim and real life is that the heli is really top heavy when inverted. In the sim you're roll rate is consistent no matter what the orientation but in real life that heli always tries to go skids down on it's own. I find you have to be alot quicker on the sticks to keep a solid hover inverted than upright. Other than that, I can't figure out what's makin you dive to the right other than some adverse ccpm interaction in neg pitch. Whenever I'm trying to check for such a thing I strap my heli to the workbench and spool it up. WITHOUT touching ANY cyclic go into idle up and go full pos and full neg collective. Don't hold it there for more than a second because it's alot of load to put on the motor and esc and it's gonna get really friggin hot really fast if you're not careful, but while you're doing this it's pretty apparent if there's any adverse interaction in the disc. You can spot it from a mile away.

with 2 ears and 1 mouth you should listen twice as much as you talk
06-06-2008 04:12 AM
HOMEPAGE  
 
 
Zman9545
Veteran
Location: The Golden STATE

Check your endpoints!

I personally don't think your dumb thumbing it. You would know yourself if it’s your own mistake. I know you repeatedly state that its not in your settings but something tells me that there is a high possibility that it is. Have you observed your swashplate lately as it travels its full range of motion up and down the shaft? I'm going out on the limb here and assume that you have an eCCPM heli because from what your describing, you might have your endpoints jacked up on one or more of your channels on your negative portion of travel effecting your cyclic controls to be uneven. Typically your endpoints should be identical on all the servos that are working in unison during cyclic inputs. This is critical on eCCPM systems because variations will effect how your swash functions.

Hope this helped


Trex600N Pro
Kinetic 50

-The ONLY way you fail is when you quit.-
06-06-2008 08:11 AM
 
 
dhollein
Key Veteran
Location: Tucson, AZ

Have you been successful with flying inverted on a simulator?
06-06-2008 08:39 AM
HOMEPAGE  
 
 
StevenT
Senior Heliman
Location: Dallas, GA USA

Zman,

Are you asking if the swash is level all the way through the pitch range? If you are, the answer is yes. I don't profess to know it all and I am still learning, but I do believe that it was set up properly.

Dhollin,

No problems at all on the sim.

Shhh, don't tell the wife.
06-06-2008 09:52 AM
 
 
Zman9545
Veteran
Location: The Golden STATE

In that case, the only other possibility that I could think of is either one of your servo is going out or has a strip gear and or maybe your servo arm is slipping on the servo itself under load. Disconnect your linkages and put a little resistance on each of your cyclic servos to determine if this is the case. If not, I don’t know what to tell ya. I seriously think your problem lies in your flight controls or the equipment that’s running it because if it’s a sudden jolt then I could see this approach being more logical than what I suggested earlier. Otherwise, it’s basically a process of elimination.


Trex600N Pro
Kinetic 50

-The ONLY way you fail is when you quit.-
06-06-2008 10:13 AM
 
 
SkyWarp
Senior Heliman
Location: Planet Earth

Quote 
Can a pitch control rod pop off and cause the right side roll with hard inputs?

Anything can happen.


Century Swift-
I was born at night, but I wasn't born last night.
06-09-2008 05:41 AM
 
 
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Beginners Corner > Help me solve the problem
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