Trex450L

[alan49]

Hi

This is my first time fully setting up my heli,
I got myself a Trex450L with a gpro unit I went through the step by step setup which was pretty straight forward.
But I'm not confident in my radio settings my radio is a DX9 I was wondering would anybody have a the settings they could give me as a good starting point..

thanks Alan

[Grumpy]

If you set up your DX9 an a new model using the helicopter template then there isnt too much that needs changing. I assume the swash type is correct (otherwise you wouldn't have been able to set up the GPro). So you probably just need to set throttle and pitch curves.

Throttle and pitch curves depend to some extent on personal preference and level of experience and what you want the heli to do ('scale' flight or aerobatics/3D).. can you can fill in these blanks?


If you like i could upload an 'spm' file from my transmitter than you can upload into yours but if my settings would suit your purposes I cant say.

[alan49]

I have set up the throttle and pitch curves as advised in the manual.
As for flying style it’s basic to say the least it’s been a few years since I’ve flown a helicopter. This is my first time fully setting up a heli I’ve done what it says in the manual but it doesn’t say much about radio settings like expo, gain and gyro setup in the radio that is my biggest concern.

Alan

[coolice]

Hey Alan.

With the Gpro setup as you've experienced is quite easy with their step by step guide to follow. Something the old 3GX wasn't known for.

Without referring to the manual, what pitch range/curves and throttle curves have you set?

On the subject of gyro gain, for cyclic leave it at the defaults for the time being.
With the tail gyro set 65% via your TX ATV values for now as once you're happy that the model is flying you can always experiment by adding a few more percent until you see some tail wag and then back it done a few points to be at the optimal.
Same logic applies to the cyclic gains to, as once you have confidence in the model you can start to experiment a little to fine tune it some more.

Exponential is very much personal preference, I always set my machines to varying levels depending on flight mode;

Normal mode: 65/70% dual rate and 20% expo
Idle ups and T-hold; 100 dual rate and 36 ~ 40% expo

This gives me a nice feel in normal mode to land and take off with, but allows a fast response in idle ups but with a nice soft, easily corrective area around centre stick.
To some this can make the model feel dead around centre stick, but it'll give you a good starting point.

One consideration is your BEC with the Gpro as it is a power hungry unit, so depending on your ESC's BEC output it might be worth looking at a separate BEC to avoid future problems.
I know you're not planning on anything too spirited just yet, but I'd rather say it now than hear you've had problems.

Ian Contessa

[alan49]

I have only set up the normal flight mode NO need for the other 2 for a will yet.

Throttle curve 0,40,65,85,100 my pitch curve is the same.
my pitch angle is from 0 to +11 degrees. 65% is about +5 degree.

Alan

[Grumpy]

Personally i'd advise not to use a 'normal mode' throttle curve. I always set electric helis up with 'idle up' in all flight modes (but each mode with different RPM). Using normal mode teaches you the bad habit of pulling down the cyclic to stop the motor. You are much better to get into the habit of stopping the motor with throttle hold. Also it's only a matter of time as your skills progress that you try to fly inverted and forget that you are in normal mode with disastrous consequences. Add to that that normal mode curve doesnt play well with an ESC in governor mode.

If you want a gentle low RPM flight mode then simply set a low throttle % in your first flight mode... easy.

Normal mode is basically just a carry over from i.c. power helis and makes no sense on electric, providing your ESC has soft start, which they all do these days. I've genuinly lost count of the number of crashes I've seen caused by normal mode.

My advice (take it or leave it) would be to set your 'easy' flight mode as follows:

• Throttle: 70% flat line (preferably with ESC in governor mode)
• Pitch curve: 0-50-100%

You also need to program Throttle Hold with a matching pitch curve and flat line 0% throttle curve.

I've tried softer pitch curves and personally didnt really get on with them but if you did want something 'softer' for upright flight only something like 33-66-100% would work

[coolice]

I have only set up the normal flight mode NO need for the other 2 for a will yet.

Throttle curve 0,40,65,85,100 my pitch curve is the same.
my pitch angle is from 0 to +11 degrees. 65% is about +5 degree.

Alan

Evening Alan.

Ah cool, that's ok if you're not planning on needing idle up just yet leave it alone until you need it.

For the throttle curve, as above to some degree, I'd suggest a curve within your transmitter of; 0 , 70, 70, 70, 70. As you can see here you can still kill the motor power with the throttle/collective stick at the bottom, but when you are actually flying your throttle output will not change. We are in essence trying to replicate what a govenor will do, without the full benefit of a govenor in this case.
With a near constant rotor rpm, we will use the collective only to go up or down, thus we limit any disturbance to the airframe. With varying throttle percentages problems can ensue due to soem ESC's not having a very smooth throttle range, so if we fix it we remove this.

Your ESC I'm sure has a govenor mode, but sadly the Align ESC isn't known to have a great govenor and it can give more problems than it's worth so we try to do similar with our throttle curves.

Normal mode is good, it's been around for years and works well for us. No real need to discard it as again it comes back to conditioning of your brain to know what mode your in at all times. Also I feel it gives us another way to kill the motor/engine power if need be, as anything can happen in panic mode.

Pitch curve, 0 degree's is good at the bottom for true begineers, but even then as a tutor you instill the very basic instruction not to chop the throttle in any panic situation. Hence the 0 degrees, so if the student does chop the power, he/she doesn't slam the model into the floor with negative pitch. Which I am sure you remember from years gone by.
Myself, I would advise adding a little negative, maybe -2 degree's and remember not to panic, but slowly lower the collective to bring the model down. My reason for this is simple, it will give us a bit more of a linear pitch curve with some added ability to bring the model down should it rise higher than desired. Also you're not an absolute begineer so this helps in my decison here and you'll never need to go into the negative value, but the overall stick feel will be much better I think.

Do you plan on moving onto some 3D or basic aerobatics in time?
My reasoning behind this question, is to maybe get you learning the zero centre stick collective setup now, than have to adjust yourself to it later on. There is a downsdie to this and that is the collective can seem a bit more sensitive, as you're now cramming 0 ~ 11 degree's in half the sticks movement, rather than the full throw.
But if you'd like to stick to a more F3C style collective setup then that is ok and you can tailor the below to suit the expanded stick range accordingly.
If you go either route, we can, as with a traditional 0 ~ hover pitch ~ full pitch setup, tame things slightly with our collective pitch curves. I will give you an example I use.

My machines run +-13 degree's, with zero at mid stick, so left alone the collective pitch increases proportionally along a line angled at 45 degree's from full negative to full positive. Your transmitter has intermediate collective pitch curve points at the 1/4 & 3/4 stick positions that we can use to soften the area where it will be beneficial to do so, this being the hovering zone either side of the mid stick position.
So for your proposed setup perhaps of;

-2 ~ 0 ~ +11 (0% ~ 50% ~ 100%)

I would set it as;

-2(0%) ~ 0(50%) ~ 68%(@3/4 stick) ~ 100%

Notice the 3rd 3/4 stick poisiton point is now a bit lower than the usual 75%, this is in effect adding exponential to our pitch curve by flattening it slightly where you're going to be spending a lot of time, hovering in this case. Thus you can make subtle collective pitch changes, which translate to softer inputs to the blade grips. But if you need to, full collective stick still yields the full 11 degree's.
It may sound a bit daunting but it isn't and we are basically putting an S curve into the pitch range.
I have attached two images of my pitch curves which show the bow I am introducing with the 1/4 and 3/4 collective pitch points, which is worth you using I feel. The ability is there within your transmitter to do this, so we may as well use it.

Any questions fire away mate.

Ian Contessa

[alan49]

Thanks a lot for your help I understand what your are saying and at the minute my fly in will be back to basics (hovering around) and then progressing into a bit of sports flying.

I am going to take your advice and put in the following settings

throttle curve 0,70,70,70,70
pitch curve -2(0%), 0(50%), 7.5(75%), 11(100%)

Alan

[coolice]

Thanks a lot for your help I understand what your are saying and at the minute my fly in will be back to basics (hovering around) and then progressing into a bit of sports flying.

I am going to take your advice and put in the following settings

throttle curve 0,70,70,70,70
pitch curve -2(0%), 0(50%), 7.5(75%), 11(100%)

Alan

Evening Alan.

No problem at all, you're most welcome.

Great, I feel you will not have any problems with this route. I have setup a great many models for all ranges of experience and have not had any negative responses to the way I do things. I am quite old school having been flying helicopters for over 37 years, but I do try to incorporate old and new techniques to provide the best possible feel.

Please do keep me posted and if you get any questions before or after flight, give me a shout.

Ian Contessa