Problem with tail, wouldnt turn.crash..

[nathkrul]

Hi Guys, Thanks for all your kind words in the other post.

I was out with the mini titan tonight although have been out 2 more times since last post, and definatly getting better however....

I removed the training gear which made the heli a lot more stable, hovered her a bit everything spot on landed a couple of times great, till.... I put her about 13-15 feet up nose forward to get a bit speed up, when I got to the end of the run and tried to turn her by pulling the nose up and banking her to the left the tail refused to turn, so I brought her back to me backwards sort of.

When I had her above me and gave some rudder input it was very jerky and wouldnt hold in the direction I tried pointing it (as we'll call her now) landed it and checked it out seemed ok.

Hovered it again seemed fine rudder was ok, back up again kept it close just incase and then the tail decided to flick around, anyhow I've ordered the parts lol

My gyro is a g401b and tail servo hsg-5084mg (needs a new case now)

Now I originally tested the heli using a turntable with heli strapped to it and HH worked great when I applied force it pushed back (lol sound a bit pornographic this) has anyone any idea as to what could be wrong.

Thanks
Colin

[nathkrul]

Hi, just a few extra notes, the tail was set up by adjusting servo up and down tail boom to get slider in centre, then I set up the limits on the gyro to make sure there was no binding.
I then put heli onto turntable started her up corrected the tail in rate mode so it held straight, then stopped heli and flicked HH switch on DX7 transmitter 3 times so gyro would remember centre, rotated heli CC and CW tail held fine, finally pushed against tail from both sides and tail pushed back to counteract.
Everything seemed ok till I got some speed up as above post.

Thanks
Colin

[Holst]

What is your gain set to?

Are you getting enough movement of the pitch slider?

[J-S-Q]

I then put heli onto turntable started her up corrected the tail in rate mode so it held straight

When you say "Corrected the tail" what do you mean exactly? Are you adding trim or sub trim on the transmitter? If you are doing it that way, that can create problems when you are in heading hold mode. Most people these days don't really bother with rate mode and personally I'd just set it up in heading hold only although others may disagree.

Having said that, this sounds more like a mechanical setup issue anyway.

[nathkrul]

Hi guys, Holst, with the g401b gyro when using a digital servo you have to have the gain set to 0 unless anyone else knows differently.

J-S-Q I adjusted the sub trim in the menu of the DX7 for rudder in rate mode whilst on the turntable till the tail was solid, then stopped the heli and reprogrammed the gyro by flipping the rate/HH switch (it blinked twice to tell me it was set) so it knew where the centre was.

Thing is it was ok a few days ago then it just began to act strange yesterday. As it flew in the direction I pointed it, it did flick the tail once to the left then at the end of the run as I turned it it gave a quick kick then nothing till I brought it back dwn on the ground.
I spun her up, hovered and the tail seemed ok it moved left and right ok, but when I took her up for a hover and sent her forward it just spun around to the left where I lost control ( didnt want to hurt me m8 ) and had to dump her into the ground full carbon tail boom, servo tail blades and main shaft including blades broken.
Forgot to add I did change the throtle profile in the dx7 0 85 85 85 85, could it be that?

But on a good note just found out I am going to be a Grandad

Colin

[J-S-Q]

Well certainly after adjusting subtrim, you should rebind the rx -have you done that? Anyway, if the gyro is fundamentally working but is having intermittent loss of control then it shouldn't have anything to do with the point I was making about trim but you can have problems if the gyro initialises before the reciever and then registers the sub trim as an unintended rudder command.

Do you mean the nose kicking to the left or the tail?

Am I right in thinking that the 401b is basically a clone of the Futaba GY401?

Hoist was referring to the gain setting in your transmitter -what is that set to?

[J-S-Q]

If your headspeed is too low then you can have trouble with the tail not holding so it might be worth bumping up the throttle curve just because it's very easy and quick to do.

[nathkrul]

Hi, the tail was kicking to the left, yes the g401b is supposed to be a clone of the gy401.
I have the switch set to HH 75% which initializes the gyro and rate to 30% which puts it into Rate mode.

I am awaiting a tacho so I'll find out what the head speed is.

Thanks
Colin

[Holst]

What heli is it and what transmitter?

You might be able to increase the gyro gain which will make it hold better but I think a higher headspeed will probably be the best thing to try (unless your already running it at 100%)

[nathkrul]

Hi Holst, its a thunder tiger mini titan e325 with se upgrades and transmitter is a Spektrum DX7.

Thanks
Colin

[J-S-Q]

Well the fact that the tail is kicking to the left and not the right would probably rule out a few mechanical issues such as slipping belts/gears. One possibility would be some kind of glitching -it's worth double checking all of your electrical connections. Is everything very smooth with the mechanics of the tail rotor? Is the gyro mounted in a relatively vibration free area, using a soft gyro pad? Is it too close to the ESC or motor? Certainly the higher headspeed and experimenting with the gain are worth a go in any case.

[nathkrul]

Thanks m8, When the parts turn up today I will certainly give all you have said a try and I'll report back here with the results, fingers crossed.

Colin

[nathkrul]

Hi, so today I rebuilt the heli.

While checking the mesh on the motor pinion I noticed it was slack, hopefully this was the cause of my problems the other day.

Now I did find a more serious fault in the gyro g401b, I could'nt steady the tail at all plus the reaction time of the tail in rate mode was slow, I took it apart and noticed that the dip switch for setting servo direction and digital or normal had came off the board, whether this had happened during the crash I dont know.
I have a reflow kit for surface mount components, and the switch is now working ok.

So thats one to watch out for.

Colin

[J-S-Q]

I would of thought that a faulty gyro would be the number one suspect for the tail problem then -pinion mesh should have nothing to do with it. If the pinion mesh is too tight, you'd lose a bit of power and if it's too loose you risk stripping the main gear, but there's no reason why it ought to cause the tail to kick out like that.

[nathkrul]

Sorry J-S-Q what I should have said is, the brass pinion on the motor shaft was not tight, somehow it had worked itself loose, probably explains the tail kick as the pinion bit onto the shaft every now and then, surely it would cause the tail to kick to the left? (I think)

Colin