Raptor 30

[busybody flyer]

Good morning all. Does anybody know why the tail of my Raptor 30 V2 creeps from left to right (end on view). I am using a GY401.
As a novice I am at a loss to understand why this is happening and the guys at my club don't have any suggestions. When you are trying to learn to hover it is a bit off puting when having to correct the rudder every 4-5 seconds and sometimes I inadvertently increase the throttle when correcting the rudder.

[terryk2000]

I would say that the tail pitch isnt set correctly...check out this site
Tail Pitch

[0h5h1t]

check the mechanical setup of the tail, make sure tail pitch arm is at 90deg to the output shaft when tail has settled in heading hold mode, do this by adjusting the rod length not with trims on the radio and make sure you initialise the gyro in HH mode. if unsure check out the video's here,

Raptor Technique

[waveydavey]

You have answered it yourself GY401. Notorious for creeping. I have had 2 on different machines and both suffered with this annoying problem, others will say that they hold like a rock as long as you follow the setup correctly but I never managed it at all despite going through all of this frustratingly for months. A new member just thought that this was what you had to do with a heli until we advised him differently. I replaced mine with a SL720 from CSM, no mechanical changes and only went through a basic setut, same servo and it changed the way the heli handled completely. Held like a rock, never let go, never has.

[del19_82]

Check that the Gyro Pad is in good condition. I had this issue with my 401 on a Raptor 30 and when I looked at the gyro pad it was disintigrating, when I changed it the drift went away. I have been told by a friend that 99% of the time a nose left drift is due to vibrations which a failing gyro pad can cause!

Hope this helps

[trillian]

I have several GY401s and I used one on a Raptor 30 as well.

The mechanical setup needs to be correct; linkage should move freely, zero pitch at the servo centre, as close to full travel as possible in both directions without any binding. The gyro should be mounted on a proper gyro pad and not strapped too tightly in addition. Gain set high enough (raise it till you get wagging then back it down a bit). Using a fast enough tail servo (I have S9254s on most of mine with an Align DS650 on one heli).

None of my 401s creep so IMHO it is not normal for this to happen.

[mark954]

My 401 does the same on my Titan but I also have a slight wobble too, but the nose always slowly drifts right. I have tried changing the mechanical set up to include some blade pitch as set in rate mode and switched back to HH once set. I have tried it with zero pitch and nothing stops the drift. When it was new the gyro was solid, its survived 2 crashes and I'm thinking this could be an issue.

I'm going to replace it with a Align GP750, works like a charm on the Pro.

[trillian]

My 401 does the same on my Titan but I also have a slight wobble too, but the nose always slowly drifts right. I have tried changing the mechanical set up to include some blade pitch as set in rate mode and switched back to HH once set. I have tried it with zero pitch and nothing stops the drift. When it was new the gyro was solid, its survived 2 crashes and I'm thinking this could be an issue.

I'm going to replace it with a Align GP750, works like a charm on the Pro.

Hmmm, if it did work well before then it could be something inside shifted in one of the crashes. There is a mod people have been doing on the 401 clones applying some padding to the circuit board inside.

I always setup my 401s this way;
1. mount as close to the main rotorshaft as possible (on the Raptor I put them on the flat spot behind the swash) because the sensor is looking for a twisting action.

2. I get the approximate servo centre and set the mechanical linkage to where the tailrotor is at zero pitch and linkage and arms at close to 90 degrees so the geometry will be close to the same in both directions. On the Raptor the link guides on the boom need to be moved around to find the placement that allows the smoothest movement of the linkage for the full travel of the tailrotor. The ball link is usually set about 13mm or so on the servo arm from the centre of the servo shaft.

3. Turn on the radio (at this point leaving the gain setting at defaults which on the DX7 is usually 50% in gyro mode or 100 ATV). By moving the rudder stick to the full travel in each direction see if it is reaching the full travel or trying to go too far and adjust the travel on the gyro until you just touch the ends of travel on the pitch slider in both directions. On the Raptor this will mean adjusting the ball link until the slider can travel both directions as far as possible and watch for any binding or stiffness etc.

That's pretty much it with the 401. You don't have to make it any more complicated than that. But I have spent considerable time getting the linkage to move smoothly and the Raptor is not the smoothest even at it's best (but it's certainly good enough to do the job).

I think mine generally run at around 72 to 85 % gain but it varies depending on the heli. I think the only time I have needed to use any delay is on a Trex 450 when there was a bit of bounce when stopping from a piro. I have used the 401 on a Raptor 30, Raptor 50, Hirobo evo 50, Ely.Q Vision Ultimate, 450SE V1 and GL450 and so far never had a problem (touch wood).

[waveydavey]

None of my 401s creep so IMHO it is not normal for this to happen.

Again they work for some and not others, don't know why, maybe the same reason as the rear bearings rust for some and not for others. Ask Smoothound and you'll get the same answer as mine. If it was the mechanical setup etc,etc why would changing for a different gyro altogether correct the problem.

It was certainly normal in my case on 2 different machines and 2 different gyro/servo combinations, I am or were particularly anal about things not being right and followed every conceivable advice I could find without success. This included others more knowledgeable than myself including Wayne and Duncan Osbourn having a go. Maybe on a nitro they are particularly susceptible to vibration this causing the drift, but they didn't work for me, I consider them only marginally better than an Assan GA401 which I have on my sons 450, a complete pile of #### IMHO

[trillian]

Again they work for some and not others, don't know why, maybe the same reason as the rear bearings rust for some and not for others. Ask Smoothound and you'll get the same answer as mine. If it was the mechanical setup etc,etc why would changing for a different gyro altogether correct the problem.

It was certainly normal in my case on 2 different machines and 2 different gyro/servo combinations, I am or were particularly anal about things not being right and followed every conceivable advice I could find without success. This included others more knowledgeable than myself including Wayne and Duncan Osbourn having a go. Maybe on a nitro they are particularly susceptible to vibration this causing the drift, but they didn't work for me, I consider them only marginally better than an Assan GA401 which I have on my sons 450, a complete pile of #### IMHO

Weeeeel, who knows. I have 5 of them currently in use and another one on a vintage heli that has not flown yet.

My experience is that the only difficulties have been on the 450s as everything seems to require being totally fine-tuned on the mechanical side whereas the bigger helis are much easier to get working without a lot of fiddling.
I am being totally honest when I say that none of mine drift.

In truth there are many many variables that can affect the tail performance so beyond the basic gyro and mechanical stuff it's hard to say. But either you got 2 bad ones or something else was an issue. A different gyro might work with the same mechanical setup because it works differently and can compensate for some factor the previous gyro couldn't. CSM gyros work totally different from the Futabas and the GY601 for example works quite differently from the 401.

I'm not an expert but obviously I must be doing something right. Either that or I just got lucky and have the five GY401's that work really well