Tail Authority

[JoshNZ]

Has anyone ever experienced losing tail authority with a blade 500 3D? I was doing some weird flips today I don't know if they have a name but from fast forward flight, pulling up while reducing pitch, punching negative collective and pushing around a back loop inverted like that, if you get that.

I did a few in a row ok, the last one I did was weird it pretty much spun a couple of times, somehow ended upright and with no airspeed. I was certain the belt had slipped and shed all it's teeth but it is fine, and I can't make it slip with my hands. So the only thing I can think is a gyro brain fart or the tail somehow lost effectiveness. Both seem unlikely

[Gladius]

I've had the same thing happen on my TRex 500 while pulling a similar move. Inverted, tail first flight with a quick flip to upright really pushes the limits of your control. You exceeded the capabilities of your heli. Congratulations!

To fix, I would start by checking for any binding in your tail. Check for vibes - they will make it harder for your gyro to do its job. How is your tail servo? Does it have any slop? It may be time to upgrade it.

[JoshNZ]

I haven't touched anything since it came out of the box a few months ago, tracks perfectly, and no vibration. I have taken the control link out a notch on the servo horn, because it wasn't able to throw the pitch change slider the whole way along the tail shaft with where it was factory set. I can wiggle the tail blades and the slider shifts maybe ~1mm or 2/32" back and forth on the shaft, but that slop is in the slider and bell crank (i.e. the tail control rod/servo horn doesn't move) so a new servo would not resolve this anyway. I'm pretty pleased with the servo and gyro, for a $300 helicopter or whatever it was.

I have had a little bit of trouble getting it locked solid. For me it is ok I'm not a very advanced pilot but if I held a still hover for 30 seconds or so, it will have drifted a little by then. But any higher on the gain and it will wag during certain flight conditions.

Before I took the rod out a hole on the servo horn it didn't have enough pitch to stop the heli spinning in a full pitch climb out from a hover. So it seems likely I could have exceeded the tails capability when it weather cocked out from tail first flight with heaps of pitch on?

[SumOFparts]

Are you using plastic tail blades????????????

[JoshNZ]

Yeah stock plastic tail blades. Does it make a big difference?

I got CF's with my 600N and I replaced them once I think after clipping the concrete, after doing it again I never went back to them I stuck with plastic just because CF's are so unforgiving, during autos or just landing in long grass etc. Too much money to run at 9,000RPM only half an inch from the concrete lol

[JoshNZ]

It actually drifts worse than I thought I just hovered it in the basement for a few minutes, over 30 seconds with no tail input the heli yaws the better part of 90 degrees. Yawing to the left, so requiring slight right input to hold it steady.

Why does this happen? I have the horn at 90 degrees at neutral stick, no trim, servo limit on the gyro is set to max and it throws the slider the full travel of the tail shaft.

Anything else I can check?

[Gladius]

CF blades will help your tail hold better than plastic, since they are stiffer. As for the chipping, can you take off and land from grass? Or, you can add spacers between the rear skids and the frame to raise the tail a bit.

Are you using a GY210 gyro? That's not the greatest gyro in the world. Try a Spartan Quark and see if that helps.

[Relisys190]

Originally Posted by Gladius

Are you using a GY210 gyro? That's not the greatest gyro in the world. Try a Spartan Quark and see if that helps.

Spartan quark. best stand alone tail gyro ever!

They can be found for CHEAP now too. a huge improvment over the stock gyro. good luck!

[JoshNZ]

Originally Posted by Gladius

CF blades will help your tail hold better than plastic, since they are stiffer. As for the chipping, can you take off and land from grass? Or, you can add spacers between the rear skids and the frame to raise the tail a bit.

Are you using a GY210 gyro? That's not the greatest gyro in the world. Try a Spartan Quark and see if that helps.

Spacers is a good idea I saw someone post a pic of a 500 with the tail raised it looked pretty neat. And much more functional. Maybe i'll do that and switch to CFs.

I can land and take off from grass but I like autos too, they're always easier to the pavement with a 500 anyway. 500 isn't that big a knuckle of grass is a pretty big upset for its footprint compared to the 600 I've found.

I may give the quark ago, thanks for the advice. I may upgrade all together. This was supposed to be a filler model until I get settled down somewhere so can get a bigger one built .

[SumOFparts]

I actually had good luck with that G210 gyro that came on the blades - what was a problem was the plastic blades on the 4503D/450x's - in any kind of wind it was a real struggle....

On trex 600 - plastic blades turned out to be the way to go - with 95mm and the high tail ratio they have no problems...

On the 450's and 500's been using the ultra stiff plastic variations - ie KBdd -
only problem there is they break fairly easily and without warning.....especially if you sand the root down to fit in a grip.....


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[JoshNZ]

lol never heard of sanding a blade root thinner. I think the 210 holds pretty well too, at least when you're beating the pitch max and min it holds pretty straight, just that slight bit of drift that is a nuisance but it's not enough to notice any time other than hovering.

[JoshNZ]

Where do you mechanically set your tail when the gyro is calling for neutral, in rate mode centre stick or HH after just powering on?

Centre of the tail shaft? Zero pitch? Or holding straight in a hover?

[SumOFparts]

You want it as trim free in a hover as you can get it....

I dont get too anal about it - I get it close - then use tx trims to fine tune...

The slider wont be even on the shaft at hover neutral.....

- its the same rubbish with getting the swash absolutely square to shaft -
when its in steady hover state - tail kicks heli little out of square that the swash has to counter....
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[JoshNZ]

So you adjust your rod length until you're hovering in rate mode with as little stick input as possible, then adjust servo travel to stop it binding at the one end it's closer to, then run it in HH mode from then on? Is it worth trimming in rate mode as well?

I tried that last night and it does hold much steadier, still wafts around a bit but for all the drifting one way it does it drifts the other way as much so after a minute or so it's still bang on. Discrepancies of a cheap gyro I guess. I might be able to go up on the gain a little now maybe that will help but I'll have to get it outside to try that.

[Gladius]

Originally Posted by JoshNZ

lol never heard of sanding a blade root thinner. I think the 210 holds pretty well too, at least when you're beating the pitch max and min it holds pretty straight, just that slight bit of drift that is a nuisance but it's not enough to notice any time other than hovering.

I had a set of Edge tail blades that needed to be sanded in order to fit. I only sanded it until they fit, and even then, they were really tight. I was never comfortable with that set of blades.

[JoshNZ]

Just never hover it looking straight down the tail rotor plane lol

[Gladius]

I try not to do that on general principle!

[JoshNZ]

This is what the heli has been doing, it does it on the bench too.
Anyone seen this before?

Twitches with slight inputs, and when you move the stick from centre to one side it blips in the opposite direction for a moment before it rotates the right way.
Does it with the cyclic servos plugged into the gyro too...