Almost ready, but channels reversed?

[Cralis]

I don't want to fly yet, but was spinning my new T-Rex 450 up so that it got light on the skids.

What I notice is that as soon as it starts getting light, it wants to raise the nose, so the tail fin goes down and touches the ground. If I put forward stick, it wants to do it even more. So, do I just reverse that channel?

The gyro SEEMS to be trying to hold the heading. But maybe not, as it's on a surfase that the skids are holding quite well, so now swivelling yet. However, when I put left or right rudder, she turns in the opposite direction.

Do I reverse the channel on the radio, or on the gyro?

[moyesboy]

First the channels and directions
Throttle - you go that sorted.

The heli is sitting the the tail pointing toward you and the nose away from you.

Elevator - when you push the stick forwad the front edge of the swashplate should go down and the back should go up. The ball in the middle of the swash should not move up and down at all if the ccpm setup is right in the tx.

Aileron - when you push the stick to the right the right side of the of the swash should go down and the left up.
Similarly it should move up and down at all.

Rudder.
Left rudder should make the nose of the heli move left, the tail move right.
Yuo need to look at the tail rotor and from the way it rotates and the angle of the blades to figure out which way it is going to push the tail. My heli is different.
somone might chip in and say that when the servo pulls the rod which direction of rudder that is.

You can plug the rudder servo direct into the rx and confirm correct direction on the tx. (even spin the heli up with no main blades and see the rudder respond to the stick with the hlei on a slidy surface (you can take the grippy rubber skid stops off if you have them).
Note which way the servo/pushrod moves for left and right rudder.

Now reconnect the gyro and initialise it in heading hold.
Turn the heli pointing the nose left. The gyro should apply right rudder trying to correct it, and it will soon apply full rudder. Check that it is moving the servo the same way as it went when you applied right rudder. If it moves the opposite way then reverse the gyro.

when you come to fly the heli, if it seems the tail servo is just not powerful enough to keep the heli straight the usual problem is that you don't have enough rotor rpm. If it is lifting by applying a lot of pitch with low rpm then the torque is more and the tail rotor isn't fast enough to hold it.
Check you have at least 1800 rpm - preferably 2200 to 2400 rpm (2400 max with wood blades).

Also it is very important that you power up and initialise the gyro in HH mode and then do not move the heli or the rudder stick but takeoff from exactly the same position. If you move the heli then it isn't pointng the way the gyro wants it to. When you lift off it will rotate to point the way it was when the gyro was initialised.
If you switch out of HH into rate, and back to HH then the gyro gets a new heading the way it is now pointing. So most of us flick out of HH and back in before takeoff
(Saturday I had my raptor spin round on takoff unexpectedly which was a bit of a shock (must have move the rudder stick while it wason the ground) - but wow it spun fast and stopped dead, which is what the csm560 is supposed to be best at).

[Smoothound]

You need to be flying the nose not the tail for starters so just to be sure, when you say it goes the wrong way do you mean when you move the stick left the tail goes right or the tail goes left? Left rudder should give nose left tail right.


Sounds like you need to reverse the elevator servo for a start, forward stick should be raising the tail.

[Cralis]

Elevator - when you push the stick forwad the front edge of the swashplate should go down and the back should go up. The ball in the middle of the swash should not move up and down at all if the ccpm setup is right in the tx.

Doesn't seem right.

When I push the right stick forward, here's the movement:

Servo with the rod on the left (Looking from the back) goes up a bit.
Servo on the right goes down the same amount.
Servo at the back goes all the way down.

Resulting in:

Servo going down, and a bit to the right.

Aileron - when you push the stick to the right the right side of the of the swash should go down and the left up.
Similarly it should move up and down at all.

Right stick moved to the left:

Front 2 servos go down.
Rear servo goes up slightly.

Resulting in swash plate going down at the front, and up at the back.

That doesn't seem right.... Does it?

I will be going to a club to get it checked out, guys. But I am trying to figure out as much as possible before that, and have it in a nearly sensable state.

[marktigere1]

On your TX, what settings do you have for a CCPM swash plate?

On the Futaba FF7 you have 5 (or 6) and you need to make sure you have the 120 degree one. I'm not familiar with the Hitec one.

You also need to make sure that the movement percentages are correct.

On Futaba negative values reverse the servo direction to allow the swash plate to move in the correct direction. It could be as simple as that.

Mark

[moyesboy]

Setting up 120 degree swash.

The 120 degree ccpm mix works using channels 1,2,and 6 (on futaba and hitec – JR is different)
1 and 6 are the front two servos (probably)
2 is the rear servo.

Setup your tx in heli mode and choose 120 degree ccpm (use your tx instructions).

Now with the front two servo plugged into 1 and 6 and the rear servo plugged into 2.

Move the throttle/collective up – swash should go up with all servos moving the same amount.
If the swash tips then either one servo is not moving (you didn’t select 120 ccpm on tx correctly, or you are not using the correct 3 channels) or one or more servos move the wrong way- reverse the channel 1,2,or 6 so that they all go the same way.

(it sounds like you already got this far and the collective is working right)

Now apply right aileron, be careful not to move the elevator.
Only the two front servos should move. If the wrong two servos move, change the plugs so the two front servos move (probably 1 and 6 are the two front ones).
If only one servo moves, or three servos move then you didn’t choose the right 120 degree ccpm settings in the tx.

Now do the aileron again and check which way the swash tilts. Right aileron drops the right side and raises the left side.
If it goes the wrong way then swap the plugs for the two front servos.

Now check the elevator. Push the stick forward should make the front of the swash go down and the rear go up. The front two servos should both move the same way.

If this goes the wrong way then you need to change the swash settings by perhaps putting a negative number in the swash menu for the elevator (not reversing the individual channels because that will muck up the collective pitch).

There are many different swash setups on different helis and with 120 degree ccpm the setup can have two servos at the front, or be the other way round with them at the back, or even with two on one side and one on the other so you need to pick the correct swash setting for your heli following the tx instructions. Above applies to the trex450SE which has equal length swash balls and two servos at the front and one at the back.

who will buy my book on this?

[Cralis]

OK, watched finless again, and watched his CCPM video. Noticed the swash was not close to what he was doing.

Checked the servo connections... all on correct channels.

Then reversed my roll and pitch servos, and hey presto!

Now we're getting this.
Note: Nose pointing away from me.

Push right stick forward:
All servos go up.
Swash raises.
Blades go positive pitch.

Push right stick back:
Exact opposite. Not as much, but that's my pitch curve? It's 40, 45, 50, 75, 100.

Right stick (throttle) up:
Front servos all go down.
Rear servo goes up.
Swash goes tilts forward.

Does that now seem like CCPM is setup correctly?

[Cralis]

On your TX, what settings do you have for a CCPM swash plate?

On the Futaba FF7 you have 5 (or 6) and you need to make sure you have the 120 degree one. I'm not familiar with the Hitec one.

You also need to make sure that the movement percentages are correct.

On Futaba negative values reverse the servo direction to allow the swash plate to move in the correct direction. It could be as simple as that.

Mark

If I select SWASH on my Tx, I am able to change a value for channels 1,2 and 6. I can set a value from -100% to +100%. Currently, they are all +50%.

120 degree is setup for the swash in the setting menu. So that seems right.

[marktigere1]

Check the values.

I would suspect you might need negative on the Aileron if its going the wrong way (which ever chanel that is.)

Mark

[moyesboy]

I remember nowin the hitec swash you can set -100to +100 for 1,2, and 6 in the swash.
These numbers do not refer to the individual channels but refer to 1 as aileron, 2 as elevator and 6 as collective.

For a start use the default settings here, or the same figure set negative to make the swash go the right way if it was reversed.
You might want to increase 6 up to 80% to get +/- 10 degrees of collective, but make sure you still end up with all the servos moving and no binding when the ctyclic (elev and aileron) stick goes to the corners.

Your post is unclear about whciuh stick nmuddling left and right sticks.
On the left stick is throttle up and down and rudder right and left.
On the right stick is airleron right and left and elevator forward and back.
(therw are other ways (modes) but I strongly suggest you use this mode which is the most popular by far).

One of the sticks is dong the collective propertly - shoudl be the left stick and that is where the swash moves up and down without tilting.

The right stick should tilt the swash forward and backward.

[Cralis]

100% now, I think.

Changed the reversing and I think it's right now.

Again, tail towards me:

Throttle up:
Swash raises. All servos move UP.

Aileron left:
Left servo UP. (??)
Right servo down.
Back servo - no movement.

Pitch forward:
Front 2 servos down.
Rear servo UP.
Swash tilts forward.

Does that seem OK now?

[Cralis]

Damn, according to you guys, it seems my aileron is doing the wrong thing... Opposite... I can't reverse them though, because that will screw my pitch and throttle...

[Cralis]

Alas, changed the swash from +50 to -50 for certain channels, did some more reversing, and all seems 100% now!

[marktigere1]

Yep

Its the old negative swash values to reverse servo direction problem again.

Just to check

Left Aileron = Swash tilts left
Right Aileron = Swash tilts right
Forward Elevator = Swash tilts forward
Back Elevator = Swash tilts back
Throttle up = Swash moves up but stays level.
Throttle down = Swash moves down but stays level.

Heli pointing away from you.

Hope all is okay.

Again, please get someone with experience to check again and to test fly it for your own safety sake.

Don't even attempt to get it off the ground yet!!

Cheers

Mark

[Cralis]

No intention of getting off the ground yet. Awaiting training gear anyway.