760x tail movement

[mb-1953]

There were no problems with the 3gx, gpro or 815 servos either.???

[devilfish]

( sorry for my English )

Im using this heli for F3C for about a week now.
The tail works, it dont let go in any of the manouvers, so far..
BUT I also think its a strange design.
In order to make the tail feel to what im used to, I hade to tweak my FBL gyro alot.
To get the tail to stop crisp on both direction I need a ton of "stop gain" in one way, and almost none in the other direction (yes im familiar with the mechanical setup of a tail, I always set them up in rate mode when I can, and when I cant, use pitch gauge etc ).

Also "needed" to tune the PID, add P gain, and D gain.
And play alot with stuff like "acceleration gain", to get as even left/right preformance as I could , and yet its not as good as other tail setups im used to tune.
I can definitely feel a bit of "mushiness" in one directions vs the other.

Im with Atomic on this one. I think the design is not optimal, yes it works, but it take some unnecessary work to tune it.

Another note to Align.
If you offer a kit for both F3C and 3D, please offer other dampers then the hard plastic ones, these are usesless for F3C, and also include a non-slant landing gear. I know these items can be bought as optional parts, but for someone that dont know its way around F3C, and would like to start out. The pastic DFC dampers that comes with the kits, will make the heli a pita to tune for a good competitive hover setup.

BUT with other dampers installed, I love the 760x, the F3C pitch arms give super geometry, and it sits nice in a hover even in windy conditions..

//Anders

[Smoggie]

Originally Posted by Atomic Skull

I suspect they just want to clear out the existing stock before they issue a fix.

I think it's more likely that they are still in the denial phase. Either the message isn't getting got back to 'Align HQ' or they are choosing to turn a deaf ear to it... After all what do customers know compared to their own 'experts'

All that's needed to fix it is three slightly longer 'dog-bone' links (cost of these is insignificant). These links could just be thrown in with the tail kit complete with a leaflet telling the builder to change the originals out for the new ones. It would not effect the sales of existing stock at all.

There isn't a manufacturer out there who hasn't had a few teething troubles with a new heli from time to time. What's important and what sets the good ones apart is how they deal with those troubles when they arise. Talking down to their customers, not even discussing the technical merits of the argument but simply stating words to the effect 'we are experts, we know best' isn't the way to go IMHO.

[Coolice]

Hey guys.

Without looking too far into this, can't the tail offset differential be reduced by doing the old "grip flip" trick?
If the stock setup is leading edge pitch control, change it to trailing edge or vice-versa.

This trick used to work wonders in situations like it appears I've read. Indeed my 450L required the tail grips flipping to equal out the travel movement.

Ian Contessa

[mb-1953]

I installed longer dogbones, tail is ok now.

[devilfish]

Originally Posted by Coolice

Hey guys.

Without looking too far into this, can't the tail offset differential be reduced by doing the old "grip flip" trick?
If the stock setup is leading edge pitch control, change it to trailing edge or vice-versa.

This trick used to work wonders in situations like it appears I've read. Indeed my 450L required the tail grips flipping to equal out the travel movement.

Ian Contessa

I hade also all kinds of ides. But after some fligths I dident have any problems with the tail as it is. So I keept it stock.

[Coolice]

Originally Posted by mb-1953

I installed longer dogbones, tail is ok now.

Hey buddy.

Yeah that is the other fix for it, but if need be I'm sure the stock links can be used by grip flipping.

Originally Posted by devilfish

I hade also all kinds of ides. But after some fligths I dident have any problems with the tail as it is. So I keept it stock.

Hey buddy.

Ah cool, that's good to know.

I don't have this machine myself, I was just browsing last night and came across the link complaining about the tail offset so thought I'd post the idea of flipping the grips as it hadn't been mentioned.

Ian

[Smoggie]

Originally Posted by Coolice

Hey buddy.

Yeah that is the other fix for it, but if need be I'm sure the stock links can be used by grip flipping.

I'm pretty sure that the grip flip wouldst work on the 700 tri blade tail. The problem is that the pitch is off in the centre position and if you flipped the grips it would be still off but in the opposite direction.. In fact it might be worse because at least as-it-is in the centre position the offset counters torque (albeit far too much).

[Coolice]

Originally Posted by Grumpy_Old_Man

I'm pretty sure that the grip flip wouldst work on the 700 tri blade tail. The problem is that the pitch is off in the centre position and if you flipped the grips it would be still off but in the opposite direction.. In fact it might be worse because at least as-it-is in the centre position the offset counters torque (albeit far too much).

Hey buddy.

See I'm not sure sure it would make matters worse, if anything it should be better, as you need to do more changes than just rotating the grips which offsets the now different neutral position.
Looking at the photos on my PC the only thing that might still be a problem is the overall travel range balance, but again changing the blade grip arms neutral position with the flip may help balance this out.

In flipping the grips you'd still have to provide the 3'ish degrees of tail offset, but with the tail blades also needing rotating 180 degrees in the grips as rotation is still in the same direction, instead of the pitch arms being outwards slightly they would be inwards. Thus this counteracts the effects of the shorter dog bone links that get fixed by fitting longer ones in theory.
Of course if you then run the tail on the opposite side of the boom and in a different direction you'd be in the same boat. But you wouldn't be, as it stays on the same side.

The tail mechanism is still the same as other models, it just has 3x the control paths. The 450's suffer with this mainly still to my knowledge.
Also there appears to be no ill effects on the tail blades by running trailing edge control rather than leading edge. Unlike the rotor head that can change its characteristics.

I've not seen one up close to fully comment, but the logic is sound when keeping the same layout. It would be nice to actually try it, as there is only so much you can gleen from photos.

Ian

[Smoggie]

You could have a point there Ian!.. I dont have the 3 blade tail so cant test it out unfortunately.

[Coolice]

Originally Posted by Grumpy_Old_Man

You could have a point there Ian!.. I dont have the 3 blade tail so cant test it out unfortunately.

Me neither, I've not even seen one yet in the flesh yet :-(
But now I'm eager to know if it would help or not in this case, I'm not buying one to try though :-) lol

Ian

[Smoggie]

Originally Posted by Coolice

instead of the pitch arms being outwards slightly they would be inwards. Thus this counteracts the effects of the shorter dog bone links that get fixed by fitting longer ones in theory.

Actually i think the reverse would be true. As standard the grip arms are slightly inward with the tail blades against torque. If you flipped the grips then the arms would have to be outward, which would exacerbate the short link problem

[Coolice]

Originally Posted by Grumpy_Old_Man

Actually i think the reverse would be true. As standard the grip arms are slightly inward with the tail blades against torque. If you flipped the grips then the arms would have to be outward, which would exacerbate the short link problem

You may well be right, just studying some other photos and it looks like this trick won't work with this tail.

Shame, would have been a dirty yet simple trick.

Ian