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Old Jul 04, 2012, 02:10 PM
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Control, channels, mixing and servo query - absolute beginner!

Hello there, I'm completely new to the RC flying scene and I have been throwing caution to the wind in order to have a bit of fun with a first-time project.

Here is my query, my model is a bi-plane (think Sopwith Camel) to have an elevator, a rudder and four ailerons. My initial plan was to have one channel for yaw control via the rudder, one channel for elevator control and two channels for the aileron sets (left and right). Each of these channels using one respective servo. (It may be possible to initially just use the elevator and rudder for flight making this question redundant but I will aim to have aileron control at the end of the day). So, getting to the point, how do I configure the controls to allow for the ailerons to all move in the same direction when the elevator is used AND get them to move in opposite directions for cornering/rolling?

I've heard the term mixing floating around but I'm not sure what this involves; would it be the case that I could mix the pitch control of both the elevator and the ailerons onto a single channel?

Also, how could the aileron servos be configured such that one channel can be used for 'left and right', as it were, it seems that needing to use a channel for each side seems a bit complex - can servo wires be connected such that multiple channels' signals can affect the same servo?

I'm not sure I've explained myself as succinctly as possible, but rather than toying around with servo connections and rendering tens of pounds worth of equipment unusable, I thought I'd seek some advice.

Regards,

Asa.
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Old Jul 04, 2012, 03:22 PM
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I don't know just what you are trying to do. Maybe for some type of wildly aerobatic model you might use some of the mixes you are asking about but for a Sopwith Camel type of biplane I can't see it.

For general sport flying I don't even use mixes, I want to fly the plane not my computer transmitter.

It is common to use one channel for elev and rudder and two for aileron. You would use a 6 channel receiver (RX), plug a "Y" lead into the ail channel and your two right ail servos into the Y. Do the same thing for the left ail servos plugging them into the AUX1 channel. Your TX would be set to Dual Ail wing type, or maybe Flaperon.
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Old Jul 04, 2012, 04:45 PM
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Quote:
Hello there, I'm completely new to the RC flying scene and I have been throwing caution to the wind in order to have a bit of fun with a first-time project.
It would be more fun if you learn how to fly an RC plane before trying to build your own and do all the fancy mixing and such. Just trust me on this. You could even just build a simple 3-channel trainer to learn on.

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My initial plan was to have one channel for yaw control via the rudder, one channel for elevator control and two channels for the aileron sets (left and right). Each of these channels using one respective servo.
The ailerons will be controlled by one transmitter channel. Using two aileron servos means you either need to use a Y-lead or flaperon mixing, where one servo is in the receiver's aileron spot and one is in the flap socket.

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(It may be possible to initially just use the elevator and rudder for flight making this question redundant but I will aim to have aileron control at the end of the day).
Yes, as long as you have some decent dihedral in the wings.

Quote:
So, getting to the point, how do I configure the controls to allow for the ailerons to all move in the same direction when the elevator is used AND get them to move in opposite directions for cornering/rolling?
This would be a combination of flaperon mixing and a secondary elevator-to-flap mix. However, this type of setup is extremely unnecessary and is much more likely to cause difficult control. It's sometimes known as "snap flaps" and is occasionally used with fast racers to change the overall camber of a wing (via flaps) which increases the wing's lift and allows faster, sharper cornering. For 99% of planes, it is REALLY not needed. You can experiment once you're proficient at flying, but you don't want strange things happening while learning.

Quote:
Also, how could the aileron servos be configured such that one channel can be used for 'left and right', as it were, it seems that needing to use a channel for each side seems a bit complex - can servo wires be connected such that multiple channels' signals can affect the same servo?
It's not so much "left" and "right". One transmitter channel will control as many servo outputs (receiver) as your radio will allow. I explained flaperons earlier. If you want you can connect servos via a Y-lead, but then you have no individual control of the two servos. You cannot plug one servo into multiple channels, though. The effect must be achieved through transmitter mixing.

The big question is which radio you have, or which one you're planning to buy. Some are capable of damn near anything, and some are totally dunderheaded with no mixing whatsoever. Multiplex's EVO series (German manufacturer) is really incredible in its flexibility, for example, whereas most Asian-styled stuff (JR, Spektrum, Futaba etc.) is a little more rigid but still incredibly capable at the higher end. For what it's worth, most decent radios will include flaperon mixing. Many also allow a couple "free" mixes with user-assignable channels.
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Old Jul 04, 2012, 06:11 PM
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Thank you for the quick responses, it seems I should be able to fly the plane just on the rudder, elevator and simple aileron control using three channels.

To simplify my original point, how has the modeller here configured his TX and servos to allow for the range of control shown and how many channels would this require?


http://www.youtube.com/watch?v=P9Qc0jmgASA


Regards,

Asa.
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Old Jul 04, 2012, 06:27 PM
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Originally Posted by Asatorae View Post
I'm not sure I've explained myself as succinctly as possible, but rather than toying around with servo connections and rendering tens of pounds worth of equipment unusable, I thought I'd seek some advice.

Regards,

Asa.
If you are really looking for advice to keep from wasting tens of pounds then forget all of that control mixing garbage and self built biplanes and buy an airplane that is purposely designed to help a beginner learn to fly. Then find an experienced RC flyer to help you.

Quote:
Originally Posted by Asatorae
To simplify my original point, how has the modeller here configured his TX and servos to allow for the range of control shown and how many channels would this require?
Before trying to emulate that monstrosity, you might look for a video that shows it can actually fly, and more importantly, that it is even controllable.

Larry
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Old Jul 04, 2012, 06:36 PM
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You need at least 4-channels for throttle, rudder, elevator and ailerons. For the setup in that video you will need either a 5 or 6-channel receiver and a transmitter with flapperon programming or programmable mixes. However the plane in that video isn't for someone who has never flown before.

I agree with the others you should build a 3-channel trainer first (throttle, rudder and elevator), or better yet get one that's already built like the hobbyzone champ or super cub. You will have a much better chance of success, not to mention fun (crashing a plane you just put a lot of time into building isn't fun). There are plans in the foamies (scratchbuilt) section for trainers that you can build such as the blu-baby or ezfly. You can also buy these in kit form with some of the work done for you (EzFly and Blu-baby). I also would suggest building it out of EPP as it's very tough and easy to fix. If you build it make sure to plan out your build, take your time and get it right. If you do a sloppy job on building it won't fly well (something a beginner really needs for their first plane).

You should also read the six keys to success for new pilots, it covers the most common mistakes beginners make. You may also want to look into buying a simulator and seeking out a local club or an experienced rc pilot to help you learn how to fly.
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Old Jul 04, 2012, 06:46 PM
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While I think that some of the answers to your questions were a bit harsh, I think the advice is solid. Flying your self built bipe should be left for the day when you can honestly handle a trainer type aircraft. A good solid 3 channel plane like the Hobbyzone Super Cub will get you in the air and give you some practical experience with orientation while flying. I have been flying my 3 channel airplanes now for about 3 months and recently graduated to 4 channel. My first flight on the 4 channel went well, my second, not so much. I ended up crashing and finding my plane about a mile from where I thought it went down. Up until then, I had only crashed one of my planes once, and that was on it's maiden flight. A good simulator would help immensely too. In this hobby, it is essential to take baby steps and not jump into advanced aircraft too quickly. That is, unless you don't mind destroying your plane.
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Old Jul 04, 2012, 06:59 PM
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The plane in the video has 2 aileron servos on the bottom wing, the top 2 are linked with a rod to the bottom pair.

What I saw was basically a standard setup. However the ailerons were set to work as Flaperons and Spoilerons, which is less common and not needed to fly a plane. That is when the ailerons all go down, Flaperon, and all go up, Spoileron. That is not a mix so much as a function of the wing type selected in the TX. I could be wrong but I don't believe a DX6i TX could do both spoilerons and flaperons but I can do it with my DX8. It would take a 6 channel RX to set those functions up.

1) Throttle
2) Ail (right wing)
3) Ele
4) Rud
5) Gear (not used)
6) AUX (Left aileron)
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Old Jul 05, 2012, 04:37 AM
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Thank you for the replies, I think I'll stick to a simple three channel set up to start with.

It is not my intention to fly my model myself as I refuse to plough several weeks/months work into the ground the moment it gets (or doesn't, as the case may be) in the air.

For me the fun/challenge was always going to be in the construction of the vehicle and the relevant systems rather than flying it, that is someone else's realm.

Regards,

Asa.
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Old Jul 05, 2012, 12:33 PM
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To avoid confusion when talking to people at hobby shops or wherever you might buy parts or when asking for advise you should know that a "3 channel set up" would be:

1) Throttle
2) Ele.
3) Rud

Ailerons are not used with a 3 channel. If you want a plane with ailerons it would be a 4 channel setup. Unless of course it is an un-powered sailplane
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Old Jul 05, 2012, 01:45 PM
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Originally Posted by 600Bob View Post
To avoid confusion when talking to people at hobby shops or wherever you might buy parts or when asking for advise you should know that a "3 channel set up" would be:

1) Throttle
2) Ele.
3) Rud

Ailerons are not used with a 3 channel. If you want a plane with ailerons it would be a 4 channel setup. Unless of course it is an un-powered sailplane

Not necessarily. A huge number of three-channel planes have throttle, elevator, and aileron control and simply do away with the rudder.
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Old Jul 05, 2012, 01:48 PM
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Originally Posted by Asatorae View Post
For me the fun/challenge was always going to be in the construction of the vehicle and the relevant systems rather than flying it, that is someone else's realm.
If that's the case you should build whatever kind of plane interests you. I think it would be helpful to know how to fly, but that's certainly not necessary. I lived with two aerospace engineers in college, and they were designing airplanes and testing aspects of flight performance without any real flight experience.

If you do want to learn how to fly, the traditional 3 or 4 channel trainer is the best way to go. Even so, there's no rule against building more than one plane!
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Old Jul 05, 2012, 02:12 PM
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Originally Posted by Asatorae View Post
I've heard the term mixing floating around but I'm not sure what this involves; would it be the case that I could mix the pitch control of both the elevator and the ailerons onto a single channel?

Also, how could the aileron servos be configured such that one channel can be used for 'left and right', as it were, it seems that needing to use a channel for each side seems a bit complex - can servo wires be connected such that multiple channels' signals can affect the same servo?
Check out the ER9X project if you want to learn more about mixing. The actual goal of the project is to replace the firmware in a particular type of radio, but they have a related project called eepe (links are on the same page) that includes a very handy radio simulator utility. Download eepe, read the ER9X manual, and watch some of the instruction videos on youtube. It's quite easy to create some very sophisticated mixing setups.

The ER9X mixing is more flexible than what is available on most radios. There are no built-in mixes that group several individual mixes together. That can sometimes make it more tedious, but I think it better illustrates what is happening "behind the scenes". So, even if you have no interest in the various 9X projects or radios, I suggest you check out eepe as a resource for learning and experimentation.
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Old Jul 05, 2012, 02:32 PM
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Originally Posted by C₄H₁₀ View Post
Not necessarily. A huge number of three-channel planes have throttle, elevator, and aileron control and simply do away with the rudder.
Since the OP hasn't flown I was thinking of trainer type planes, how many beginner planes are designed that way? The 3 channel rudderless planes I have seen are a PZ P-51 and a very large F-86, not really what I was thinking of at the time
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Old Jul 05, 2012, 08:11 PM
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I lived with two aerospace engineers in college, and they were designing airplanes and testing aspects of flight performance without any real flight experience.
I'm still amused by that no matter how many times I see it. Real pilots can look at an airplane and know if it will fly or not, but aerospace engineers run equations on computers and play with billion dollar wind tunnels for five years and come up with a plane so tail heavy even Chuck Yeager can't fly it. Amazes me every time.

My advice is to learn to fly, and more importantly, learn to own an aircraft, before you try to design one... trust me, with literally thousands of airplane designs out there, you aren't going to come up with anything original at your current skill level, and you might design a beautiful plane that handles the stresses of flight just fine, but if the wing breaks on the car ride to the field, the owner of aircraft is not going to be happy with you.

When you have some flying experience then you will understand how to build an airplane properly so that it not only flies well, but is a joy to own. Many of the designs coming out of China right now show that they don't understand that at all.
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