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Upgrading to 2.4GHz

Old 09-25-2008, 02:03 AM
  #1  
meesier42
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Default Upgrading to 2.4GHz

I have a couple of questions, that I am sure have been asked before, but I can't find what I am looking for in the search function

I am getting into 3D flying and will be upgrading all of my existing planes along with it. so I have lots of question

First- what would I use 7 channels for. and what each of the channel assignments would be. I guess if I don't use a Y harness for individual aerlion servos, I can see 5 channel, and with retractable gear 6, but what does #7 control

Second- Are there any real differences in the Spektrum systems vs the Futaba Systems. the Futaba systems seem a little more expensive, but not by much.

Third- from what I can tell the DX6i and the DX7 appear to have all the same functionality, except the DX7 can store more models, I have a feeling that it will be unlikely that I will be flying more than 10 models, so that function doesn't seem worth $100+. Is there some functionality that isn't obvious that I don't know about.

thanks
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Old 09-25-2008, 08:36 AM
  #2  
groundrushesup
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Originally Posted by meesier42 View Post
I have a couple of questions, that I am sure have been asked before, but I can't find what I am looking for in the search function

I am getting into 3D flying and will be upgrading all of my existing planes along with it. so I have lots of question

First- what would I use 7 channels for. and what each of the channel assignments would be. I guess if I don't use a Y harness for individual aerlion servos, I can see 5 channel, and with retractable gear 6, but what does #7 control

Second- Are there any real differences in the Spektrum systems vs the Futaba Systems. the Futaba systems seem a little more expensive, but not by much.

Third- from what I can tell the DX6i and the DX7 appear to have all the same functionality, except the DX7 can store more models, I have a feeling that it will be unlikely that I will be flying more than 10 models, so that function doesn't seem worth $100+. Is there some functionality that isn't obvious that I don't know about.

thanks
7th channel is what you make of it, my friend. Most folks like the option to have a 7th channel if necessary, gives you some wiggle room especially if you have larger glow aircraft with special functionality (smoke, etc). And the DX7 is made just for that: the flexibility to fly both electric and glow from the same Tx. If you don't ever plan to fly large glow planes or complex Helis, and as you said you don't foresee a need for the 20 model memory, go with the DX6i. In fact I think the DX6i was made specifically for folks in your situation.

Almost all of my planes use Spektrum AR6100's, which are 6-channel Rx's... but I like the idea that if I wanted a big ol' stunt glow plane, I could use the same Tx I use on my 10oz. scratchbuilds.

As for the Futaba gear, I'm no help... my shop is a Spektrum shop.

cheers,
GRU
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Old 09-25-2008, 02:52 PM
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rcers
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7 channel systems give more opportunity for mixing. I have used that for flap mixes - nose steering, parachute drops etc.

The biggest difference (that matters) between Futaba and Spektrum is the cost of receivers. The systems are about the same price, but the receivers are about double for the Futaba line. That adds up quickly!

You will need a system with Expo on the rudder - so make sure yours has that (especially if you pick Futaba).

The DX6i and DX7 are both excellent systems. The DX7 is more flexible with one more channel (you may not need that) and 5 programmable mixes. Granted I have never used more than 3 on any single model.

The DX7 has a better look and feel in my opinion and feel is important - so play around with them at the local hobby shop before you buy.

Mike
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Old 09-25-2008, 05:07 PM
  #4  
Liquidity
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7th channel can be used for lots of things. I use mine for mixing flaps and ailerons for a crow feature. Flaps go down, ailerons go up

So I have: rudder, elevator, Aileron 1, Aileron 2, Flap 1, Flap 2, Throttle
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Old 09-25-2008, 11:35 PM
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meesier42
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ok well, I am starting to get an idea of what the 7th channel can be used for, but now someone needs to explain to me how you control 7 servos with only 4 analog inputs (X-Y on 2 sticks)

Or is it that you can control 7 servos/actuators by mixing the outputs of the 4 channels, or do anything more than 4 outputs just become on/off
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Old 09-25-2008, 11:57 PM
  #6  
Old Fart
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You create mixes. You "plug in" (2) aileron servos to the RX - but it's still controlled by the right stick. On larger gas/glow planes, (2) servos for the elevator is common - you either need a reversing Y harness, or again, plug them into separate channels and program the radio to have one servo "follow" the other.

On my current build (World Models P-47D), I have separate servos for ailerons (once you go to individual servos for ailerons you'll get spoiled, you'll never be happy with "Y'd" ailerons again ), (2) servos for flaps (Y'd), (2) servos for retracts (Y'd), plus servos for elevator, throttle and rudder.

That's (9) servos (6 in just the wing) all controlled from a Futaba 9C. Flaps and retracts are controlled by separate switches on the TX.
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Old 10-14-2008, 04:24 PM
  #7  
AEAJR
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How many Channels?

I don't see any real benefit for having less than six channels, as the cost
difference is small and the benefits of 6 or more channels is high. Even
if you are flying a 3 channel airplane, today, next year you may be
adding spoilers or flaps or going to a full house plane in the future, so
get a radio that can handle that can handle this so you aren't going back
to the radio market right away.
>
> Here is a typical channel breakdown, how many and what they
> are used to control. These apply to electrics, glow, gas and gliders.
>
> Rudder - 1
> Elevator - 1 or 2
> Ailerons - 1 or 2
> Spoilers - 1 or 2
> Flaps - 1 or 2
> tow release - 1
> landing gear - 1
> Motor - 1
>
> That makes 4, 5, 6, up to 12 channels depending on what kind of plane you
> have and how you set it up. So how many do you need?
>
> In my opinion, most sport flyers will be well served for a long time with
a 6 channel entry to mid level sport computer radio. If you are a more
serious pattern, scale or sailplane pilot or contest flyer, you probably want a minimum of 7 channels > and support for a 4 servo wing.

Last edited by AEAJR; 10-29-2008 at 01:22 PM.
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Old 10-18-2008, 09:59 PM
  #8  
Gohmer
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I believe that only Spektrum has the Model Match feature. Very important to me! I usually fly several different airplanes every time I go to the club and I don't always remember to change my TX.
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Old 10-18-2008, 10:05 PM
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Twmaster
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One thing to keep in mind.

Going to 2.4 GHz only changes one thing. That one thing is how the signals get to your plane.

Otherwise a 7 channel radio will be and do pretty much the same things and functions wether on 72MHz or 2.4GHz
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Old 10-29-2008, 01:24 PM
  #10  
AEAJR
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Cool

Originally Posted by humeiling999 View Post
2.4G is great ,how about the synthesized receiver?
Synthesized receiver?

Are you refering to the fact that there is no need for channel control? I guess you could think of that as a synthesized receiver. Yes, that is great!
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