In answer to this type of question:
a: What do all those switches and things do anyway?
b:Whats the deal with all those settings - the curves and expo and so on?
I hafta say that my transmitter is *still* a little intimidating. There is clearly just so darn much it can do and I'm supposed to be in charge
of setting it up correctly for *me* - as if I had a clue!
I'm trying to write things that will help *you* - so now I'm thinking: "what would have helped me?"
The first *really basic* question might be - how do I fly the machine? I already understood what the sticks were for and what they did, but
you might not know, so:
There are 4 orientations of the heli that you have control over:
move to the right or left
move to the front or rear
move up or down
point the nose to the right or left
The "cyclic" stick, typically the right stick, controls the first 2 and the control relationship is pretty natural: move the stick to the right, the heli
wants to go to the right, move to left, heli to left, move away from you, heli away from you, move towards you, heli towards you. (assuming the heli is oriented
"tail in", meaning with it's tail pointing towards you.)
The left stick uses right/left to control where the nose points: move the stick to the right, the nose turns towards the right, and vice versa to the left.
And finally, the resting position of this stick is all the way towards you, or "down", and this corresponds to 0 throttle, and maximum negative pitch on the blades.
As you move the stick up, or away from you, both the throttle and the pitch increase. Typically takeoff will occur a little ways past mid-stick.
I'd encourage you, if you need more info about how the sticks operate the machine, look online. I've found plenty of folks willing to talk about this, and even
a few videos demonstrating. Also, Real Flight has a nice learning tutorial, for instance.
Beyond the sticks, there are a few settings that you (may) need to fiddle with that will alter the course of your life, the rest you can wait on
until you become more proficient and curious.
These are what I consider to be the "important" aspects of your transmitter:
the "normal" pitch and throttle curves (almost certainly will need to be tweaked)
the "up" dual rate settings (almost certainly will need to be tweaked)
the reverse settings (this is only an issue if you're building your machine)
the swash type setting (this is only an issue if you're building your machine)
And here are my assumptions:
that the default settings for all the rest are reasonable, meaning that all pitch and throttle curves default to 0..100%, that the default for
the dual rates is 0% expo and 100% (EPA, EPA = End Point Adjustment) travel, that the various "mixing" functions will default to "off", that the gyro will default to "off", the swash mixing will
default to "off".
Futaba has a pretty good glossary - google "futaba glossary" to see what all of these crazy acronyms mean - not that you'll understand after you read the
definition, but it's a start.
So here are my recommendations for approaching the 4 items in my list above:
The reverse settings are about whether the servos travel in the correct direction relative to the stick - this is the only place you can tweak that.
For instance, if you move the collective up, you expect the swash to move up and you expect the engine speed to increase. These are configured in this
area of your transmitter.
The swash type setting - I'd expect most transmitters to come defaulted to the simplest swash setting, but it's unlikely that your heli uses
that setting, so you'll need to wade through the manual to try to figure out which is the correct swash setting for your machine.
I have a lot to say about the curves below, but for now, I'll assume that you're a rank novice like me and you need all the help you can get.
So read below and do it that way.
About the dual rate - well, face reality - you're so far away from even thinking about more than hover - just setup the normal dual rate to
maximize the benefit for your current flight needs and be done with it. Read below.
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Dont think or expect that you'll be able to set things so the machine will fly itself - the whole point of this is that you learn to fly!
The best you can hope for, I think, is that you'll be able to learn the skills more rapidly because fear wont be such a big part of your
experience as you learn to fly.
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The transmitter is really a pretty darn sophisticated piece of equipment - dont forget that folks have been doing RC for years, and that
transmitter manufacturers have been listening to users for years - you have a lot of catching up to do.
There are several classes of things that the transmitter does for you:
- servo management
-
This is a really big category. One aspect of servo management is providing a way to help you not destroy the servos by making sure you never push
them beyond their limits - the EPA (= End Point Adjustment) setting above allow you to tell your transmitter to never try to push the servo beyond x% of it's capability.
But it also, especially relative to the swash setup, can do a tremendous amount of work for you - namely, converting your left, right,
forward and backwards stick into the appropriate commands to the servo that push and pull on one side of the rotor mast. A non-trivial operation.
And another area: where the transmitter converts from stick/function to (potentially multiple) servo commands. For instance, the up collective is actually
2 distinct commands - up throttle and up pitch, and pitch (in modern ccpm) will likely translate into up all 3 rotor servos. It also gives you a way
to contol some pretty basic relationships - like the fact that up stick *might* not (for some reason) translate into up throttle for the heli. The
transmitter has a way to deal with this.
- sensitivity management
- You'll deal with this in the dual rate and the curves. This is all about *you* having control over how the helicopter responds to X control input.
When you move the collective ever-so-slightly up, is the heli going to zoom straight up for 200'? or is it going to go up 6 inches? This is the type of
sensitivity I'm talking about. Also - when you try to master the (not-so-easy) hover, your tendency is going to be to move the stick X amount, but likely
that amount will be *waaaayyy* more than the default setup of the heli needs. You can change this in the transmitter. You can make the transmitter so that
the machine behaves a lot more like the way you think it ought to.
For now I'm going to leave talk about the transmitter at this level. There is much more, but for now, you're just starting, this is plenty.
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So - back to the 4 items I listed above as things that you probably need to deal with right away:
the "normal" pitch and throttle curves
the "up" dual rate settings
the reverse settings
the swash type setting
So here's the detail:
the "normal" pitch and throttle curves (flight modes)
It's not "normal" vs. "abnormal", it's "normal" vs. "idle up". What the heck does "idle up" mean you ask? Well, apparently it's about when
you'd be wanting the motor to be running at or near max pretty much all of the time, as in "3D" flight - upside down in particular. So this switch
will allow you to do things (in the "normal" mode) like take off, land and hover, simple forward flight, and in "idle up", to have a great time
doing your acrobatics and 3D (but you couldn't land if you wanted to). If you're like me, the whole notion of 3D is so far out of the realm of
the possible right now - well, just forget
it!
I emphazise "normal" - meaning, dont even fiddle around w/ Idle up right now.
But for the normal curves, they can help you or they can hurt you (your pocket book for sure), and I feel pretty confident suggesting that if you dont
fiddle with them, you'll be buying replacement parts pretty soon.
These curves relate exclusively to the "collective" stick - on my transmitter it's the one on the left that doesn't center vertically - it always stays
where you leave it. This stick controls both throttle and pitch. The thing is, unless you change the curves, you have the potential to ask the machine for
100% full throttle and 100% full up pitch on all blades - the little thing will be zooming straight up in a *big* hurry, I promise. My idea is to
change the curves on these 2 settings so that the heli will maybee eventually get all the way to 5 or 6' in the air - at full stick. This feels safe
to me - something I have a chance at handling. When I then feel confident, I can increase the curves to new dangerous levels.
So the gist of my recommendation here has 2 parts:
1:Figure out which pitch/throttle you like to arrive at liftoff at, and 2:then *cap* the 2 curves at this level or slightly higher.
If you look through the research I did for myself about the throttle/pitch curves, you'll see the inverse relation between the 2 settings. I picked
the 1750 rpm setting as the ones I liked the most, and used them as the basis for my setup. You see that they are a *far* cry from anything linear.
They are both clearly capped and just over the liftoff throttle & pitch. This worked out great for me - I discovered in one battery that I could
pretty much shove the collective stick all the way to the top and the heli was just 6" in the air - this made me feel really good (meaning safe!)!
And it wasn't too long before I started bumping these values up as I gained confidence in using the collective stick.
the "up" dual rate settings (D/R)
It's "up" vs "down", just the direction the switch is pointing. It really doesnt matter, just however works for you. But, similar to the flight
modes, just pick one and fiddle with that - it'll be a little while before you need to fiddle with the other of this switch.
The dual rate (D/R) is something that's totally internal to the transmitter. It's one of those great features that will help you be better with
your heli. Dual Rate (at least on my transmitter) allows me to control the throw of the function and to set the "expo" (exponential softening) of
the servo response. So, just to be clear, for my Futaba transmitter the D/R switch actually controls the Dual Rate *and* the Expo - it might be
different on your transmitter.
The "throw of the function" or "Dual Rate" - I guess I hafta say it like this (i.e. function), because right-stick - to 3 o'clock, in most ccpm heli's moves *2* servos, not one,
and nose down will move all 3 of the servos. If it were a 1-1 relationship between stick and servo, you could reasonably talk about the "throw of the servo" here.
Anyway, back to the "throw of the function". For aileron (tip left-right), elevator (tip nose up-down), and rudder (turn nose right-left), these functions, you
can set the effective throw. And it might be nice, especially if you're a rank novice, to just say: "I really dont want the cyclic to move the servos
more than 70% of what they're capable of - this is *plenty* of movement for me". You can make that decision here.
Note: folks will *correctly* point out that it's possible to have *too much* dual rate setup. So dont go thinking that just because 75% or so
is good that 50% would be better. The specific problem is that it's possible to reduce the throw of the function so much that the heli simply
wont be able to correct itself, even when you give it full stick, and the result will be a crash. So if 75% helps, but you'd like a little more help, you might think of increasing
the D/R in increments of 5% - so, first go to 70%, and if that isnt enough, then 65%, and so on. And try these changes for a whole battery - give
yourself the chance to understand the full effect of the new setting.
Additionally, by default, there is a more-or-less linear relationship between the stick and the function. The "expo" (exponential) setting allows you to
"soften" the feel of the controls. If you leave the expo at 0, then at full stick, you get 100% of however the function is defined, and at 50% of stick,
you get 50% of however it is defined, but if you ask for a -20% expo (futaba), then at 100% of stick you still (always) get 100% of function, but at 50% of stick, you
now get 20% *less* of function, so not 50%, you get more like 40% of function. This is a really nice softening of the controls that allows you to grow
into your heli. Apparently it's pretty common for newbies to want to use more stick than the default setup, and expo will help you out in this regard -
you can always reduce it over time as you gain experience.
Here is a picture I found online that pretty clearly depicts various expo settings and how they relate to the non-expo linear response:
 (this is copied from http://www.modelaircraft.org/mag/FAQ/answers/faq-q27.htm
which I felt was helpful in the expo area, but *not* in the Dual Rate discussion.)
the reverse settings
You'll need to fiddle with these if you install a new servo or might need to be rebuilding (after a big crash) or building (you brave person).
There are quite a few sites that talk about this, but basically its about making the servos (or functions) move in the correct direction. So when you
use the elevator stick make a nose up (i.e., pull the stick down, towards you), you expect the swash to tilt towards the rear of the heli. If it's not
doing what you'd expect, then changing (reversing) the direction of travel is one thing to experiment with to try to fix this. Another is to look into
the SWASH values. One or possibly both of these will probably help you with this setup issue.
the swash type setting
Is something you'll need to set pretty early on. This is about the type of swash system you have on your heli. Most likely it's a CCPM, either
the 90 deg. type or the 120 deg type. You can recognize these types of swash setups by thinking about what is the relationship between one particular
servo and the swash. Actualy, the more I think about it, the less likely I am to be able to really reasonably characterize this.
For the point I'm trying to make now, the important detail is that you need to set this once and then you're done with it.
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