NHP Rear servo mount

[marktigere1]

Hi Guys

Last night I set about installing the NHP control rod and servo onto my Shuttle. (Futaba 9404, CSM HL200)

To cut a long story short, I can only obtain 95% servo movement in one direction and 130% in the other before binding. Tail pitch slider is in the correct position at neutral, arm at 90 degrees etc etc.

I've never used a tail mounted servo before and just wanted to ask if this is likely to cause the CSM any problems and should I make the other direction 95% as well?

Or is this fine as a setup before test flight?

Cheers for any advice.

Mark

[Bender]

Hi Mark, the 200 is it heading hold only?, if so I would set the tail up mechanically with the rudder plugged straight in to the rx first.
set the pushrod more or less paralell with the boom, servo horn 90, you know the rest, get it set like this, then plug in the gyro and dont use any trim or sub-trim, untill you get it close mechanicaly on the bench
edit p.s., if this is yer first hh gyro, be aware that they behave quite strangely when on the bench, they dont centre and any input given will probably see the tail moving to the stop and staying there

[marktigere1]

Thanks for the reply Bender

Yes I should have said that the servo was plugged directly into the Rx not the HL200.

The figures above relate to end point adjustment. I don't have any Trim or Sub trim dialled in so I am guessing that 95% to 100% would be a good starting point? If I have 100% to 100% the servo binds in one direction even though the neutral point is correct mechanically.

Cheers

Mark

[Bender]

the servo arm is 90 as well?, all I can think is its some weird geometry, does the control rod look fairly parallel to the boom when looked at from the side AND from above,? I kow you have to juggle things to miss the boom supports
apart from mix's in the tx I cant think what else would do it :?

[kiwipilot]

To quote Fritzthecat, who posted this on another forum;

Not returning to center is just a characteristic of HH mode on the ground. In flight it will work fine. The servo arm does not return to center on the ground because when you moved the rudder stick, you told the HH gyro you wanted to rotate at a certain speed for a certain time. Since the heli is just sitting there on the bench, the gyro knows the tail hasn't moved and continues to try to swing the tail around by deflecting the rudder. If you give jus a tiny rudder input to say swing the nose right the servo arm will stay deflected. Now rotate the entire heli nose right and eventually the servo arm will return to center - when the HH gyro is satisfied the heli turned as far as the rudder stick commanded.


Hope this helps explain it a little

[marktigere1]

Thanks for the replies chaps.

The problem seems to lie with the Shuttle tail pitch slider.

If you move the servo so that the slider moves towards the gearbox you only get 95% movement from the servo. The other direction gives you 130%.

I cannot see any way of mechanically changing this so I will now plug in the HL200 and adjust during test flights.

Many thanks

Mark

[Dedcalm]

Remember that to hold the heli a certain amount of pitch would be required on the tail and as such this might explain why you have more movement 1 way than the other....

I have always tried to work out the amount of pitch used in non HH mode and set the link so that with the servo at centre the pitch would be about right... back in the days before I went HH this was required to trim out the heli.

Rob

[marktigere1]

Hi Rob

My thoughts exactly regarding the pitch slider so I'm not going to worry too much until I fly the bird.

I plugged in the HL200 last night and checked it was happy. All seems well. Strange little beasts these HH gyros.

Thanks for the braiding. I have finished installing the electronics and hope to post some pictures of my efforts soon. Looking good. I did run out of heat shrink but managed to obtain some more.

Cheers

Mark

[Dedcalm]

Glad you like the braiding, seems very popular (on ebay). I used to fly a non HH then decided that I would give the HH a go. Used a CSM 400 for a year or so and then when I got the Raptor I bought myself a Futaba GY401 which IMHO is far better. The CSM would drift whereas the Futaba is rock solid.

Rob

[G-DAVE]

The CSM would drift whereas the Futaba is rock solid.

I've been saying this for years - now the truth is out.
Dave

[antsis]

I use both the CSM400 and the SL560 on each of my R60's. Haven't had any drift problems with either one. I'm planning to get a GY401 for the raven this weekend, so will be able to make a comparision.

[Bender]

nt

[G-DAVE]

nt

Meaning
Dave :? :?

[Bender]

nt

Meaning
Dave :? :?

nt=no text......I posted something here offering a gyro to a good home
the gyro is now gone so I removed the message

[G-DAVE]

nt

Meaning
Dave :? :?

nt=no text......I posted something here offering a gyro to a good home
the gyro is now gone so I removed the message

Thanks Bender - I was just curious !
Dave