My First Trex now built but several questions....

[Vic.P]

I have a silly question though, is there an explicit idle up switch on the DSX9? Or is this achieved through the flight mode switch a 3 position switch on the right hand side?



Cheers,


Gaz

Hi Gaz,
Yep, the 3 way flight mode switch top right is your idle up switch and will go through normal (switch away from you), idle 1 (switch centre) and idle 2 (switch torwards you).
It's not possible to disable the flight modes so set them up for each flight phase including HOLD (left top back switch) as per instructions. You'll find it's not that easy to accidentaly switch the flight mode switch or the hold switch while flying and if either switch is towards you when you switch on the transmitter you will get an alarm until you switch them back.
It may be worth dialing in some exponential on the flight modes to soften centre stick sensitivity while you get a feel for the heli. Somewhere around 15% to 20% would be a good start point.

[Gazzer1uk]

Hi all,

Vic you would be proud of me, did what you suggested, and all now works the right way, Low stick is 43% pitch curve -2 deg, 50% pitch curve is 0 deg, and 10% pitch curve is 82%. By going to 0 and 100% the pitch change is massive. I've set expo on it to to smoothen and it looks to me like mid stick should get the baby to hover!!!

Now I tried to set the idle up to be exactly the same but something is awry as when I go to pos 1 I get more pitch movement, despite there being the same curve. I have gone through all settings and can't see why. If I go to idle up 2 from 1, no change.... curious?? Any thoughts?

I also have the Align governor and have set it switched on via the gear channel, in the off position its 100% and for a headspeed of about 1750 the instructions say set to 70% which in my case is -70%. Is that correct or do I have the switch set back to front??

Sorry for all the questions guys but really appreciate the help, this is so far the best set up heli I have ever done!!!

Gaz

[Lad]

Not sure why ‘IU’ should be different from ‘Normal’ if you are using the same curves ~ I’d check again to make sure you are comparing like with like.

On the governor ~ if you look in the servo monitor screen on the radio you can see the radio output for all channels (including the Gear Channel). One end of the travel = 100% the other end = 100% with 0% in the middle. You need to set it up so when the governor is off you have 100% (the left side of the channel) and when it’s on 70% (on the right side of the channel).

Something like this;

Off ---------------------On

100%-------0%------70%

Does this make sense?

[Vic.P]

Hi all,

Vic you would be proud of me, did what you suggested, and all now works the right way, Low stick is 43% pitch curve -2 deg, 50% pitch curve is 0 deg, and 10% pitch curve is 82%. By going to 0 and 100% the pitch change is massive. I've set expo on it to to smoothen and it looks to me like mid stick should get the baby to hover!!!

Now I tried to set the idle up to be exactly the same but something is awry as when I go to pos 1 I get more pitch movement, despite there being the same curve. I have gone through all settings and can't see why. If I go to idle up 2 from 1, no change.... curious?? Any thoughts?

I also have the Align governor and have set it switched on via the gear channel, in the off position its 100% and for a headspeed of about 1750 the instructions say set to 70% which in my case is -70%. Is that correct or do I have the switch set back to front??

Sorry for all the questions guys but really appreciate the help, this is so far the best set up heli I have ever done!!!

Gaz

Ok, sounds like you may have gone slightly awry with the normal curve settings.
For the normal curve you should have - 2 degrees bottom stick, + 4 to + 5 degrees mid stick and + 9 degrees top stick. Having zero degrees mid stick on the normal curve will give you plenty of revs but no lift. Zero degrees mid stick should only be used on the idle 1, idle 2 and HOLD curves. Having first set up the idle and hold curves using the zero mid stick as a starting point you can then move on to the normal curve.

For the two idle curves it should be - 9 degrees bottom, 0 degrees mid, and + 9 degrees top although many 3Ders use more pitch up to + and - 12 to 13 degrees. For HOLD use a similar pitch range to the idle curves with perhaps a bit extra positive pitch to help with autorotations.

Below are my curves for the Trex 600E (starting at top for normal, idle 1, idle 2 and hold) to give you a guide as to the difference between flight phases. The important values in the set up are the pitch guage readings so do not copy these values percentage values on screen will vary depending on the heli swash set up and pitch degrees.

Hope this helps

[Gazzer1uk]

Lee,

Thanks that makes sense, will have a look see tomorrow now, I think I have it half right!

Vick,

I misunderstood previous but understand what your saying now, and thanks for taking the effort to do the pics.

When I have re done this I will re check the Idle up, went through everything and could not see any disparity.....

Also my left slide lever alters the pitch, I tried disabling the switch which I thought was Aux 3 but need to try other channels now...... it would be oh so me to accidentally shove that lever high and wonder why it wont land!!!!

Really appreciate the help your giving me guys,

Cheers,

Gaz

[Vic.P]

Also my left slide lever alters the pitch, I tried disabling the switch which I thought was Aux 3 but need to try other channels now...... it would be oh so me to accidentally shove that lever high and wonder why it wont land!!!!


Gaz

Don't worry about the slider, it's only active in the normal flight mode and will not affect the idle and hold modes.
It's quite handy if you're flying in normal and hovering but should become part of the start up routine of checking your switch positions before turning on.

[Gazzer1uk]

Lee, Vic,

Real progress tonight!!! Gyro set up, pitch curve done, governor done, realised where I was going wrong in flight mode pitch setting duh!!!! Thanks for your help!

Have one concern now, not sure if the rudder is binding. Every "so" often I get a deeper humm noise, the led's drop down to orange and red and then it eases off. I am sure it's the rudder servo, stirring sticks its fine no binding and seems free enough. Any thoughts at all?

Cheers,

Gaz

[Vic.P]

Lee, Vic,

Real progress tonight!!! Gyro set up, pitch curve done, governor done, realised where I was going wrong in flight mode pitch setting duh!!!! Thanks for your help!

Have one concern now, not sure if the rudder is binding. Every "so" often I get a deeper humm noise, the led's drop down to orange and red and then it eases off. I am sure it's the rudder servo, stirring sticks its fine no binding and seems free enough. Any thoughts at all?

Cheers,

Gaz

What servo are you using on the tail and what Rx pack are you using? A lot of tail servos are designed to run on 4.8v only so check that and the voltage supply to the tail. Also check the servo type set up on the gyro, ie standard or digital options and frame rate.
If they are ok then check the tail at full throws for stall and then try the tail linkage disconnected at the servo to make sure it's nice and smooth.

[Gazzer1uk]

Hi Vic,

Servo is jr 8900g and 770 gyro so matched, 7.4 volt 2 s lipo through an align 2 in 1 regulator, wonder if that is the issue, I need a step down??

Cheers,

Gaz

[Vic.P]

Hi Vic,

Servo is jr 8900g and 770 gyro so matched, 7.4 volt 2 s lipo through an align 2 in 1 regulator, wonder if that is the issue, I need a step down??

Cheers,

Gaz

Yep, looks like you need a step down regulator, the 2 in 1 gives 5.8v so it's over voltage on the JR servo although your cyclic servos should be fine. Most step downs give 5.1v which would be ok with the JR 8900g..... very fast servo at 4.8v too......nice

[Lad]

Gaz,

Time for an update...! Does it fly?

Lee.

[Gazzer1uk]

Hi Lee,

I fitted the regulator step down and it has cured the stalling and humming sound along with the voltage drop, the servos also seem a little quieter.

I had a busy work week and junior was back to university so have had no time since fitting the step down, so nothing more done I am afraid.

However, I have the header tank to fit, then check all the fasteners for tightness etc, and I think I can safely go and start up for the first time, so this weekend I am hopeful to get a tank of juice through her and might get a quick hover!!!!!!

Will post details and maybe a pic soon, but really grateful for interest and help, and we should see baby airborne soon!!!

Cheers,

Gaz

[Gazzer1uk]

Just a quick update and view solicit.....

mate of mine reckons it is best not to put the step down from the regulator to the RX but between gyro and RX. The wiring diagram shows both..... the reasoning is that the voltage drop under load might just cause brown out, which would cause spectacular results probably!!!

Not a big effort for me to unbraid and change, but an effort, so I think it is worth doing, but the cyclic servos are also JR digital....... should I put a step down on these individually or just think the over voltage mainly affects the gyro servo and not unduly worry?

Cheers,

Gaz

[Vic.P]

Just a quick update and view solicit.....

mate of mine reckons it is best not to put the step down from the regulator to the RX but between gyro and RX. The wiring diagram shows both..... the reasoning is that the voltage drop under load might just cause brown out, which would cause spectacular results probably!!!

Not a big effort for me to unbraid and change, but an effort, so I think it is worth doing, but the cyclic servos are also JR digital....... should I put a step down on these individually or just think the over voltage mainly affects the gyro servo and not unduly worry?

Cheers,

Gaz

First, yep, the stepdown should go between the servo and gyro, the gyro is fine working above 4.8v so it dosen't need stepping down itself.
It depends on the clyclic servo type but generaly they should be fine running up to 6v for maximum speed.
Your servos should have technical specifications written on the box or instructions showing speed and torque at different voltages like these for the JR DS8717 Ultra Speed Cyclic Servo:

Speed: .09 sec/60° @ 4.8V, .07 sec/60° @ 6V
Torque: 160 oz-in @ 4.8V; 196 oz-in @ 6V

Whereas your 8900g tail servo will show only:

Speed: 0.05 sec/60 degrees
Torque: 3.5Kg
Operating voltage: 3.8V to 4.8V

Hope this helps

[Gazzer1uk]

Gents,

Very quick update, did some quick changes on the set up, added a Quick UK header tank, filled with fuel, went to back garden, started quite quickly ( I have a really big back garden!) got it idling OK, spooled up to light on feet all looking good..... but, bit of vibration, no real worries though.......

There is a patch of flatter lawn so I went down there, spooled up again, all looking good bit of drift, slight trim change bit more throttle and very light on the feet and then.......

Kapow

Not entirely sure the sequence of events but.......

I suddenly got a fast piroutte at kind of the same time the tail rotor caught the uneven part of the ground and I slammed it shut and the motor cut......

Bummer

Damage is fortunately limited to the tail rotors both written off, all else seems in order.

Now when I went to drain the fuel, I couldn't and there seems an inordinate amount of "suck" needed to get it out the main tank, all OK from the header..... will do that tomorrow.

So not sure if the fuel problem caused a drop in revs and the rotors hit the ground, or the piroutte was causes by a yet undiagnosed problem and I hit the ground, or if I caught the ground smashed the tail rotors and then pirouetted!!!

All did seem nicely controlled and going the right way with the sticks until then.

I am sure these are carbon tail blades in natural finish, but stuggling to find these, lots of white ones, am I being thick again?

Any other thoughts on the short run up, do chip in for me!!!

Cheers,

Gaz