Trex 450 ccpm with X-378?

[sky-t]

Hi

i have the JR x-378 heli version and on bob's videos all setups are done on futaba's. i have not watched them yet...

Can anyone help me on setting it up with the x-378? or will i be able to read off the futaba configuration? I have a futaba gy240 gyro and hitec hs56hb tail servo, the rest is all cheap towerpro servos. will i at least be able to use the gy401 settings on the gy240

Any help please...



:?:

[Coolice]

Hey,

To a degree the Futaba setup will be similar, the only change from memory will be the eCCPM travel limits in the JR set which I think default to 60% travel and Futabas are different (dont know how much).
Other settings will be the same like making sure all servo's move in the right directions etc. and also that the servo's are at 90 degree's along with all arms/bell cranks parallel to one another when the throttle/collective stick is in the middle of it's travel.

The GY240 setup is also very similar, the difference being on the 240 you only have heading hold or rate mode, selectable via a dip switch on the gyro itself. All other settings during the setup phase are the same.

There are various articles on the net along with videos, using the resources available you should be able to get the model pretty close to flying off the building bench. But if you can get expert help after you have had a go I would do so, saves you money and aggrovations if it's not quite right.
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[sky-t]

That sounds good thanks Ian

Glad i can use the video for reference on my gy 240 setup, and i am going to fly it right off th "bench" (after tuning is complete via the videos) taking it slowly, and cutting the throttle stick immediately once it starts to lift off and is not controllable.

If i cannot get it trimemd out i'll seek expert help. From what i've read, if all is set up correctly it should go into a hover without problems just by gradually moving the throttle stick up? Or is there no such thing as a "hands off" hover on lift off?

I have started on the ccpm setup with the video and so far it is going well, just wish i had these video's before i started building it. Many things would've made the head more accurate from the start when looking at setting up the head.

Thank you

ST

[Coolice]

Hey,

No problem, your very welcome.

Yes the videos are of good use during your setup phase and the techniques shown will stay with you through your modelling career. As time goes by and you get more skilled you will find other ways to do things which suit you better, basically building on what you learn from people such as myself and others through these forums and such like.

On thing I will say is during your setup set the machine up with no more than -1 degree's of pitch while you are learning and also remember to be gentle on the stick. Feed commands in smooth an gently, if you get into trouble dont just dump the throttle quickly as the heli will fall fast if you gain to much height. Instead gradually bring the power down.
With a set of training under carriage fitted to the model you will not go much higher than a few inches and so gently lowering the throttle will land the model and you can start again. Eventually you will get higher and higher until you are in a steady hover in front of you.

Hands off can be acheived to a degree, but no heli sits still for long especially on take off as small corrective inputs are needed to take the heli up vertically. The level of the ground also effects your take off.

See how you get on, there is a lot of knowledge here available to you if you require any more help. Just ask us.
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[sky-t]

:shock:

[sky-t]

Thanks Coolice, i've watched the finless gyro video, it just doesn't tell me what i want to hear, i think my gyro is set up correctly. I just have not yet hovered to really test it.

If you can just tell me the following? the avcs, gain and reverse of the gyro is all on the gyro.

So does that mean i have to do exactly nothing on my radio,

except for maybe just adjusting rudder servo throw, sub-trim and mainly normal trim for rudder if needed?

Should i also then leave revo mixing at 0%, and gyro in off mode on the transmitter?

I have tested the rudder by spooling up, because i have not flown a heli yet, i am not sure how the gyro should behave( the different stages and
effects it goes through when spooling up, and what to look for.)

What i can say is:

That the rudder servo movement is slow when i change the sticks (i thinks that is normal), when i spooled up it looked to me to be functioning correctly, on 80% throttle on the ground, when i give right input, the nose goes left, and left input, the nose goes right at a comfortable pace.

Avcs mode is on and i'm at 75 % gain on the gyro.

When i take off, will the gyro want to keep the tail steady? and stop it from drifting left or right? will something unexpected happen? So if i say lift off and the heli (main head) drifts say left or right, at the same time the tail moves slightly left or right,

if i stay on the cyclic only to correct the right or left drifting of the (main head) to stay in hover, will the gyro automatically correct rudder so the tail is staionary? (Avcs on)

[sky-t]

I have also limited the travel on my rudder servo.

[Coolice]

If you can just tell me the following? the avcs, gain and reverse of the gyro is all on the gyro.

Yes, on the GY240 all adjustments to the gyro settings are performed on the gyro itself using the small pots and dip switches on the gyro's casing.

So does that mean i have to do exactly nothing on my radio, except for maybe just adjusting rudder servo throw, sub-trim and mainly normal trim for rudder if needed?

Yes and no, yes as in the gain is set on the gyro and no in that some things need to be changed in the Tx.
Tail servo throw is adjusted on the gyro, by turning the limit pot clockwise to increase the travel and anti-clockwise to decrease it. Always keep in mind that you do not want to lower this setting below 100% if possible and if you find you are having to go lower than 100% use a shorter servo arm.
Also remember to check the throw in both directions and adjust the limit pot on the gyro so as not to over drive the servo in any one direction.

Subtrim leave at 0, I always stay away from sub trim and prefer to try and match up a servo arm that is parallel to the servo case rather than use sub trim. Sometimes it cannot be helped but a little extra time can mean it is not needed.

Ideally you should also not use the Tx. rudder trim to trim the tail, once you are more proficient the best way to trim a tail is in normal rate mode (non heading locking) and adjust the tail pushrod until the tail holds straight. Then once this is done turn on heading lock and you will have a nicely setup tail. But as you are learning attempting to fly out of heading hold will be asking for trouble and so just leave it in heading hold to help you out for now.

Another point to remember is that the TX. travel limit or ATV value for the rudder channel changes the pirouette speed of the model and NOT the travel of the tail servo in either direction. The latter, as mentioned above is controlled by the limit pot on the GY240.

Should i also then leave revo mixing at 0%, and gyro in off mode on the transmitter?

Yes, with heading lock gyros do not use revo mixing as this upsets the heading lock feature. This is true of all heading lock gyro's.
The gyro page within your Tx. will be of no use for now on or off as the gyro does not have another connection back to the Rx. for gain control etc. Leave this as default in the Tx.

I have tested the rudder by spooling up, because i have not flown a heli yet, i am not sure how the gyro should behave( the different stages and effects it goes through when spooling up, and what to look for.)

What i can say is:

That the rudder servo movement is slow when i change the sticks (i thinks that is normal), when i spooled up it looked to me to be functioning correctly, on 80% throttle on the ground, when i give right input, the nose goes left, and left input, the nose goes right at a comfortable pace.

On spool up there is nothing really to look for from the gyro, some heading hold gyro's do hold in some rudder command until such time that flying rpm is reached and a new neutral is found. You may have noticed already that with the model turned on if its nose is turned left or right a command is given to the tail servo to counteract this and this command is held in until the model moves in the opposite direction.
If you haven't seen this give it a go, slowly swing the model to the left or right and watch the tail servo move along with the model. Basically the gyro will keep a command in until the tail moves back to its original position before it was blown off course, this is heading lock in a nut shell.
Avcs mode is on and i'm at 75 % gain on the gyro.
Good place to start, you can always reduce this amount if need be or go up in gyro gain if the tail does not wag through the gain being too high. It’s always best to start off with less and wind more in than have too much to start with, see the tail violently swinging left & right which will then scare you seeing it for the first time.
When i take off, will the gyro want to keep the tail steady? and stop it from drifting left or right? will something unexpected happen? So if i say lift off and the heli (main head) drifts say left or right, at the same time the tail moves slightly left or right, if i stay on the cyclic only to correct the right or left drifting of the (main head) to stay in hover, will the gyro automatically correct rudder so the tail is staionary? (Avcs on)

Yes, the gyro in heading lock mode will try to keep the tail pointing in the direction you pointed it in to start with. This assumes you have things going in the right direction to start with.
From your post I get the feeling you are looking at the heli in the wrong light to a degree, when controlling the direction in which the heli is pointing you should always look at the nose of the model, in this case the front of the canopy. If the nose swings left then the pilot needs to put in a right command to counteract it and vice-versa.
NEVER look at the tail of the model as this will mean you have set the heli up wrong if you "Fly The Tail" so to speak. The proper way is to look at the nose.
For a left tail command the nose must turn left and the tail rotor will travel to the right. With the tail rotor turning and the blades facing the right direction, the thrust the tail rotor generates must go to the left to swing the model left.
Look at the angle of the tail blades and their direction, try to visualise with the tail rotor turning in which direction the thrust of it will go for a given control input and alter the Transmitters rudder channel reversing if it is wrong.
A good trick when setting the gyro direction is to place your finger on the back of the tail rotor casing behind the tail rotor bell crank and operate the tail from left to right and feel the bell crank pinch your finger. One way you will feel it pinch you and the other direction it the arm will move away from your finger. Then choose a direction, say left and operate the stick to the left. If the tail pinches your finger or not it doesn't matter for now, just remember what it does do as this is needed for the next step.
Now, with your finger still on the back end lift the heli by its rotor head and turn the nose of the heli to the right, if the tail servo is going in the right direction then it should pinch your finger assuming a left tail command did so. If it does the opposite then the gyro needs reversing as it is sensing the swing of the model but correcting with a wrong command.
It sounds long winded but once you understand the principle of the above trick you will see how simple it is.
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[sky-t]

Coolice thank you for the detailed reply!, i'm going to take some time, taking it in and read through it one or two more times and post my result.

Thank you!

[Coolice]

No worries, your very welcome. Glad to help.

Have fun.
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