normal or not?

[AustinDave]

Hi all, just received my first heli a little walkera lama 2 (a palm sized co-axle). Have been having a blast with it, so much fun. One thing I have noticed though is that when I get it to a steady hover and try to let it sit there it wants to start doing circles. It keeps its heading(pointing the same direction) and if I let it keep going they get bigger. I can reel it in back to a steady hover but just wondering if this a normal characteristic of this type of heli and if not what adjustments do I need to make to correct. Thank you for any input or sujestions. newly addicted flyer Dave.

[arbilab]

Is that the dreaded 'toilet-bowl effect'? Not yawing, but making circles with the nose pointing pretty much the same way. Welcome to heliworld. It's like a daycare for machinery.

There's flybar straighness and balance. There's flybar link length. There's rotorset symmetry/tracking. There are also FAQ threads here dealing with all of those. The problems are generic to helis, you don't have to look only under your model.

If it holds heading, that's GOOD. The rest is mechanical. I know the manual gives you no clue to this. I've only had TBE when my flybar link slid off the ball onto the shaft. Easy eyeball fix.

Look at it real closely for anomalies in the integrity of bladeset and flybar. Therein lies most TBE. It's NOT electronic, the problem Walkeras seem to have most.

[AustinDave]

Thank you arbilab, have to laugh at the name you called what I decsribed but it does sum it up pretty well. TBE for short, figure I have alot of terms of that nature to learn now but look forward to them all. I checked the flybar and it has no bends. When I pull on the top blades to straighten them out it sits level as well. I will keep searching for the answer and thank you for your help and the warm welcome :) Happy flying, Dave

[jasmine2501]

The flybar might 'sit level' and still not be balanced. Measure it just to be sure - that is the usual cause of the toilet bowl. Also "wall effect" can cause it - flying in too small of a room.

[arbilab]

Ah yes, you'll find helis drawn toward solid objects, as though suicidally possessed. The wash accelerates encountering an obstruction. Higher velocity, lower pressure, toward which the craft moves. Thanks for nothing, Bernoulli. :censored:

Well wait. I better take that back. It's that principle that makes all flight possible.

But yeah, TBE is notorious, and almost always a flybar issue. It's a low-rate resonance of an imbalance aggravated by precession (as if that's any help). One possible thing, are your blades resistant to movement? That is, not rigid and not floppy. I don't know the bladeholder arrangement on your model. But on mine, too tight and they may fail to balance themselves centrifugally, too floppy and they can oscillate cyclically.

[Balr14]

I wouldn't spend an undue amount of time and effort on TBE. Fixing it won't improve your flying skills.

[AustinDave]

Thanks jasmine I will check the length to be sure.

arbilab, another nice sujestion. My blades are rather loose and free to flop when ever I pick up the heli. maybe a little tightening is in order.

Barl14, as stated in my original post I can reel it back in and have control, the TBE is just something of an anoyance and actualy kind of proud I can do that. In the long run though why fight something that can be fixed, seems to me that would make for a more enjoyable experience.

Best wishes to you all
Dave

[arbilab]

Yes, the "spec" is, loose enough to align themselves centrifugally, and tight enough to stay in position when the heli is tilted.

The heli will generate some movement on its own as it responds to its own turbulence, as Jas was referring to in a confined space. But that should be largely random, not predictably cyclic. A consistent pattern of uncommanded movement can and should be corrected.

This is the "stable platform" to which we all aspire. That is, the heli responds to what it's told, and doesn't independently employ its imagination in a cyclic manner. Yes, you can counter the 'imagination' part. Either with increased control diligence, or with diligent alignment of the airframe.

[Andrew McGregor]

Best way of avoiding that is to anticipate... learn to feed in your control inputs BEFORE the machine reacts. After all, it does it exactly the same way each time, so you can figure out what the input is to cancel that out. Eventually this becomes second nature, and you find yourself noticing that your sticks are moving without conscious involvement... and the heli is just doing what you're intending it to.

[arbilab]

Not seeing exactly what you see, hard to nail exactly what it is. But helis in general and coaxes in particular have a pendulum effect. That is, a control input from neutral will swing it one way and when the input is removed it's going to want to swing the other way.

In the worst case, if your control timing is exactly wrong, the heli will amplify that pendulum effect and quickly exceed your control range, slamming into the nearest obstacle.

Control inputs must be measured and deliberate, predictive rather than reactive. All heli pilots--including 'real' ones--tend to overcontrol until they learn not to.

[AustinDave]

Thanks all for the great information. I look forward to lots more practice enjoyment.
Dave

[Balr14]

Barl14, as stated in my original post I can reel it back in and have control, the TBE is just something of an anoyance and actualy kind of proud I can do that. In the long run though why fight something that can be fixed, seems to me that would make for a more enjoyable experience.


Nice theory, but let's see you find a way to adjust the flybar on that thing. TBE is caused by flybar being loose in the head on that heli. I'll bet you can wiggle it sideways. But you can't tighten it.

[heli_addict]

I've just learned to live with it on the CX. Once you get it steady, it will stay that way for a bit and slowly begin to exhibit that TBE again--it's not hard to cancel it out once you're used to it.

[AustinDave]

Hi heli addict, that is basicly what I am running into. Having a blast with this little one and plan on getting something a bit bigger soon. Not ready to move up past a coaxil just yet I dont think but would like something I can fly out doors on a calm day. As far as the TBE I have I dont think its a major thing now but being the noob that I am... well just wanted to make sure. I am sure more questions will arise for me in the future and I hope all can be answered as nicely as this(my first one). Thanks heli addict and all that have posted here to help, its very much appreceated. more than you know.

happy flying all
Dave