Iam fairly new to the sport and have just bought a Spectrum DX6I to replace my DX5E. Could someone please explain the following functions to me....when and why I might want to use them and roughly what the initial settings might be:

Travel adjust
Servo monitor
Wing tail mix
Dual rate combo
Travel adjustment
Sub trim
Programmable mixing & Trim include
Differential aileron mixing

For what I can offer :

DUAL RATE COMBO - you can allocate all the Ali, Elevator and rudder Dual rates to one single switch instead of each single switch on the TX (it allows you to turn them all on at once for when your planes setup, and you want to fly at high speed)

SUB TRIM - a "permanent" centering tool for your servo, it is adjusted in the programming when setting up (to ensure your servo arms are centered), and will also allow you to set as default any adjustment to a given servo should you require to remove any trim down the line - the one on your tx face should only be a setup tool, and should be centered once your sub trim is setup correctly

First I don't know why you would have gone from the 5 to the 6 rather then going to the Dx7 which is far better than other 2. Also each of these things you question are explained in your manual?

l

I went from the 5 to the 6 upon recommendation from several club members.

They are not explained in the manual. How to set them is explained but not why I would want or need to use them. I understand the servo reversing and throttle cutoff, pretty simple, even for me. Nor do they give any initial values to try.

Here's a thought....maybe because the DX6i is 1/2 the price of a DX7 or maybe he never will need more than 5-6 channels? If you don't plan to use 20 model memory or whatever it is or you don't have a need for the "7th" channel, the DX6i is just fine. EVERYONE but two people that I know that have radios greater than 6 channels is only using at most 5 channels and most still use a Y harness on the separate Ailerons. NONE of them have more than 5-10 models flying at any one point. The two people I've seen at the field using more than 6 channels is one guy flying a quad flap ultra stick and the other is a hard core helicopter pilot.

Though this is moving away from the original question even though I mainly fly a fully 3D capable nitro .50 heli, I can survive with my Dx6i, and still even place a governor on it IF I use my head re what one I will buy. IE - even a model with 5 separate servos, a gyro and a head speed governor can run on a 6ch system if thought out correctly. Sure you lose some adjustment function re being able to turn the governor on of of by the TX, but I am not, not do I ever intend to be Curtis Youngblood or Alan Szabo re my flying ability, so I just don't need that level of TX options.
Secondly, I could not justify the expense of a DX7 after coming to the understanding that a 6ch system would so all I "needed". Also, I personally have yet to see a prop plane at the local club that "needs" anything more than a 6ch system, I cannot see myself flying a prop plane with more requirement than a 6ch system, so a 6ch system is what I have!!

As far as "travel adjust" function goes, while I'm not 100% sure, but i think this sets the absolute maximum travel on a servo re available throw on a given control surface (someone please correct me if I'm wrong), where the dual rate adjusts the percentage of that 'standard' off your switches (yet how they are really any different is beyond me - as they really just do the same thing from what I can see)

Programable Mixing and Trim Include -

This allows you to mix any channel into any other channel. So some applications might be

1. To use two channels to drive two aileron servos. One servo would be in the Aileron channel and one would be in a spare channel - say flap. Then you mix aileron into flap (100% usually) and you then control both ailerons but from separate channels. This allows you to set up differential ailerons to minimise adverse yaw and other problems.

2. To use two servos to contol the two halves of the elevators - similar to above.

3. To compensate for a flat bottom wing's tendency to climb under increased power - mix the throttle into the elevator so that as the throttle increases, a small amount of down trim is added.

4. To mix aileron into rudder. This allows you to fly a plane that really does need coordinated turns (aileron and rudder and elevator all used in turns) without actually having to use the rudder stick. My Decathlon is a real handful without rudder in turns - it just wants to turn very large turns but with a bit of rudder mixed in it makes the plane much easier to fly and land. (This is cheating and I really should learn to use the rudder as well).

An example of "trim include: would be where you are using two channels for the elevator. If you adjust the trim on the elevator channel so there is - say - a small amount of UP trim then this is also applied to the other channel and both elevator channels match properly. If you use a mix which does not allow trim include, the trim would not affect the second channel.

Hope this helps a bit.

Mike

Mike:

Exactly the kind of info I was looking for. Thanks.

G'day My pleasure.

Travel adjust. This allows you to increase or decrease the maximum servo movement. Say you have a model and you have set it up with the supplied hardware and you simply cannot get enough rudder travel. This happened to me with a small electric glider. So I then used the travel adjust to get 150% of the normal movement and this was enough to fly the model.

Another example might be when setting up a throttle connection you find that the throttle is fully open but there is still some servo movement to go and the push rod is being bent. This is not good as the servo is stalled and drawing more current than necessary. So you use the travel adjust to decrease the servo throw to avoid the stall. If you find you have to use large amounts of travel adjust, it is generally best to try to correct the problem mechanically first and use the travel adjust for small adjustments.

Sub Trim. I find that when I build a model, put the servos in and set things up that the servos do not always end up a the Zero position ie, the horn may not quite be at right angles to the servo when the radio is set at the middle of its travel. You can then use the sub trim to zero the servo and then mechanically zero the elevator or aileron and then fine adjust with the sub trim.

Have fun. You are right. The books that come with radios rarely tell you examples of how to use the functions they provide.

I really like the features on the computer radios these days. Even the low cost ones like the DX6 and Hitec Optic 6 have some very nice features which make setting models up and flying them far easier than in the "good old days". But, don't rely on the features to fix problems with servo and pushrod adjustments. Get them as close to right as you can with mechanical adjustments and then use the electronics to fine adjust things.

Cheers

Mike in Oz

Guys, please don't try to talk people into the DX7 for nearly double the price of the DX6i... That's obviously my opinion but here's why: I fly a DX6i with over 1000 flights on it problem free. I've owned the radio since the day it was released on the shelves. I use my DX6i & AR7200 (yes 7ch RX as I use a dual a123 redundant power setup) to fly my 30% Edge 540T giant scale and it works PERFECTLY. This includes a channel for opti-kill too. So there really is no point buying a DX7 (unless you're a heli flier possibly). If you need more than 6 channels, you're also at the point in this hobby where you need more than 7 as well. Buy at least an 8 or 10 channel radio and save the 1/2 step-up. Not to mention, the DX8 is on for $400 which makes it extremely superior to the 7 in every way. To top it off the DX6i is new and has more advanced programming than the 7 as well.

Anyway just a piece of advice for those recommending radios!

Yeah, I gotta agree, in part at least. I have both radios and they both have their advantages and disadvantages. The DX6i is less expensive but has most of the capabilities of the DX7. The DX6i uses disposable batteries, but can use chargeable batteries, but not as a pack.

But to the OP, learning the basics if far more important than trying to use the advanced functions of that radio, if that is your intent.

CGr.

CG

My intent is to try and learn all the functions on my 6I and their applications so I can decide if any of them will help me in my flying. For example, the engine cutoff switch, which I did not have on the 5E, is really nice. I am sure the others are useful also or they wouldn't be there. I just have to figure out what they do.

Well, you know the saying about learning to walk before learning to fly.

When I was learning, I had a nice and new Airtronics RD6000 radio. I wanted to use all the neat stuff that this radio was capable of, but my instructor really insisted that I learn with a basic non-computer radio. This required me to get the mechanical linkage set up properly without all the fancy exponents, end point adjustments, and so on.

With that buddy box setup, that was the only option available to me.. however, once I solo'ed, I was free to do what I wanted. It didn't take long to learn that the basic functions, once set up properly, were really what I needed to know.

I am not trying to discourage you from using the bells and whistles, I just wish for you to realize that going basic before you try to push the limits of your transmitter is a really good idea. Besides, it is so much fun and a great learning aid to do the complete set up mechanically so everything works without the use of end points and so on.. and really rewarding.

Either way, enjoy your new DX6i !! I enjoy mine!!

CGr.

Expo and Dual Rates are odds on the only two functions (aside from sub trim for setup and centering of servos) that will help re learning to fly any basic aircraft (the kill switch is only mandatory if you get a nitro model) ..... I can recommend that you remember and "really understand" what K.I.S.S. means - the flying bit is difficult enough to begin without worrying about all that other junk. Don't over complicate things unless you have too.
I use a Dx6i on my nitro heli, and sure you have to use a few of the programmable settings that are available, but in all fairness, even on that monster, the only thing aside from the gyro gain that helped to make that bird easier to fly was the expo adjustment, the rest of the TX's functions are really almost wasted on that model, and trust me when I say that a .50 nitro heli is a hell of a lot more complicated and harder to fly than a basic 4ch trainer plank (I now have one, so can knowingly comment on that front)

One quick question for you.... how many hands do you really have? Really? I realized a long time ago that I didn't have enough hands to fly a helicopter...

But, I can imagine where expo IS important for that because it doesn't take much in reaction to make a drastic change in the attitude of that helicopter. Overcorrecting can and will ruin your whole day!

CGr.

Hmmmmmmm ....... let me see ...... one ...... errrr ......... two - YEP, two hands, and no magical 3rd appendage!

To answer the point re expo being important on a heli, YES ... IMO, expo is critical on the heli as the reactions to input without it are mind numbingly fast, to the point where they can be dangerous!
I almost lost mine on the maiden flight due to not having enough programmed in (that old video is on my youtube channel under the same user name, I was TRYING to be careful when I nearly put the nose into the deck form a low 'hover')

I'll still use some on the plane as well (65" trainer with a .61 2 stroke in it), as I found some surfaces more responsive than others at the factory recommended throws, so will just add a little expo to sedate those surfaces as required, as that way, I'll have maximum throw available as and when needed, yet have them feeling 'just right' for normal flight.