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Good beginner computer radio reference manual?

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Old 07-11-2006, 09:12 AM
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TerryE
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Default Good beginner computer radio reference manual?

OK;

I just upgraded from an old Futaba FG series to a 9C Super. I love the radio, but am only getting about 20% of the use out of it since there is a lot it will do that I don't know what it means. I fly both aircraft and helicopters with it.

The manual is ok, it tells you how to do a lot, but not necessarily why you would want to.

Does anyone know of a book / site that will guide a newbie cptr radio operator through the "why's" - I don't want to post a bunch of stuff - I will research it myself, but I need a reliable place to get started.

Questions like (and I know these may be simple for most of you, but I am just learning):

Why Dual rates, when would I use them, and how?
Why Exponential, when would I use them, and how?
What mixing should I do, and why?
What is a 5-point curve, and why would I care?


Sorry - I am just a bit overwhelmed.

Thanks
Terry
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Old 07-11-2006, 09:54 AM
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Default RE: Good beginner computer radio reference manual?

Ann Marie Cross wrote a book on the 9C published by Traplet

But don't fret about asking questions here.

Dual Rates allow you to have full throw of the servo with one switch position and a lesser total throw with a second switch position. This has the effect of desensitizing the control across the entire range of stick travel. If you have an airplane that you like to throw around but the elevators and ailerons are a bit sensitive during landing or just bombin around you could set high rate to 100 percent and low rate at 70 and flip to low rate to land. On the 9c you can assign each axis to a different switch or you could have all three control surfaces tied to one switch, its very flexable.

Expo reduces throw around center while giving you full control at the extremes. Its the best of both high and low rates, a nice soft center for hovering but full control at the extremes of the stick throw incase you get in trouble. You can combine them with dual rates to customize the feel of a helicopter or airplane for different situations.

What mixing depends on the type of aircraft/heli and what you want to accomplish but an example in an airplane is you could have 2 aileron servos, one on each aileron instead of a y harness plug them into different reciever channels. Then mixing would be activated that would let you use them as flaps with the side slider and ailerons with the aileron stick, or just simple mixing so they both work as ailerons plugged into different channels. A helicopter example would be when you give cyclic input you set up a mix from elevator to throttle and aileron to throttle to compensate for the increased drag that control inputs create to help keep your rotor speed constant.

5 point mixing is just being able to adjust the mixing over 5 separate points of stick travel for collective pitch and throttle on a helicopter. Cheap radios have 3 point mixing so it gives you a finer level of control.

http://www.futaba-rc.com has lots of good FAQs for the 9c and like I said, the AMCross book is excellent.

But if you have questions fire away
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Old 07-11-2006, 10:04 AM
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Default RE: Good beginner computer radio reference manual?

Wow - thanks for the info - I feel like I just hit the jackpot

I understand dual rates, and the concept of exp (now, thanks).

For my first "forray" into expo what settings would you recommend (for aircraft first, I don't want to try it with my Jet Ranger until I REALLY know what I am doing).

Do you set the position that the expo kicks in (eg: low rates until half stick, then go high), or is it a gradual pre-programmed thing?

Thanks
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Old 07-12-2006, 02:28 PM
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Default RE: Good beginner computer radio reference manual?

Expo works over the entire stick range, you can set either side of a dual rate switch to be a percentage of expo, if you dont want dual rates just leave them at 100 and you can have just different expo amounts, the 9c is very flexable, and at first so flexable as to be overwhelming.

Expo works like this, and assume all stick movements are from center to one extreme.

0 expo if you move the stick 25 percent you will get 25 percent servo movement, 50 percent stick 50 percent servo motion and so on.

Now lets say you dial in -25 percent expo. 25 percent stick gets 15 percent servo motion, 50 percent stick gives you 40 percent servo motion but 100 percent stick gives you 100 percent servo motion. This is what makes them preferable to dual rate, you get the soft center but full throw if you get in a bind w/o switch flipping.

If you go in to the *D/R:EXP (dual rate:expo) screen and pick a channel you can see a graph of the stick motion vs servo motion. If you put an exaggerated amount of expo you will see the graph flatten out around center, if you move the stick back and forth you will see a line moving across that graph, that shows the stick position and the graph line shows where the servo will be for that stick position, if you go positive expo you will make the surface more sensitive around center. You will also see the effects of moving the dual rate on the graph in real time as you make the changes (this is why I love the 9c)

Not to confuse you farther but to answer your how much question you should also know this. When you are taking a linear stick movement and translating it to a round servo wheel you actually get positive expo by default. About 20 percent negative expo will make the surface movement linear, any more than that and it does get softer. All my helicopters are set up with 22 percent negative on both cyclic controls and on the tail rotor. I don't use dual rates and I set the same amount to both sides of the switch so if something gets bumped I don't get any surprises. You can tie any and all of the dual rates/expo to any switch, in the rare cases I use dual rates (like my Funtana) I have all 3 assigned to the same switch, I'm not into unneeded switch flipping.

In the case of a 3d plane you might have high rate 100 percent elevator throw with 50 percent expo for flopping around and low rate elevator, 60 percent with 25 percent expo for take off and landing. Same with the ailerons.

The nice thing about the 9c is you can copy the model to another memory location, experement, see what you like and dont and incorporate the changes into the main models program, just make sure you know what program you are running when you take off!

Jet Ranger?? My fav! What model?

Disclaimer For all the calculus students out there the numbers I have used are mostly for example and clarity before you bust out the slide rule and correct my numbers
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Old 07-12-2006, 03:20 PM
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Default RE: Good beginner computer radio reference manual?

It is a 60 size Kavan - an old one, but it is a great flier.

Thanks for all of the fantastic info - I think I am starting to get it!

Terry
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Old 07-13-2006, 10:58 AM
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Default RE: Good beginner computer radio reference manual?

Oh dear a Kavan Jet Ranger.........woo hoo.

I'm working on my own.

See my gallery.
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Old 07-13-2006, 11:12 AM
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Default RE: Good beginner computer radio reference manual?

Yep, that's it

I was gonna say that it doesn't look like they have ever changed the box, then I read it was a NIB kit from 1975 [X(]
Has it really been that long.... I got mine in 1986, which would make it.... OH MY [X(][X(]

Wonder if I could sell it on the "antique" forum for a premium

Naw... I enjoy flying it too much
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Old 07-13-2006, 11:20 AM
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Default RE: Good beginner computer radio reference manual?

What gets me is you can fly these planes without mixes, expo and reduced throws. If you can do rolls and loops and knife edge with heli's and airplanes without expo and mixes, then you should keep doing it. No slight intended. You are better than the normal flyer. I know I can't fly my plane without expo or reduced rates. I could not get it to fly straight without mixes. YOU are definately a better pilot than me!

As I said, no slight intended!
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Old 07-13-2006, 11:25 AM
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Default RE: Good beginner computer radio reference manual?

But...but...but...

then what all about the fancy features I just paid for [X(]

I can do most of the stuff (except a decent 8 point roll [:'(]) with an airplane, but I am not comfortable with any aerobatics at all with the heli. That's one reason I got the cptr radio - to try and "tame" the beast.

I wanna be able to do aerobats with a heli, and I figure the fancy stuff on the radio has to help.... I hope
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Old 07-13-2006, 01:11 PM
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Default RE: Good beginner computer radio reference manual?

Save the aerobats for a different heli.

Though the Kavan Jet Ranger was the first r/c helicopter flown inverted in competition, Ernie Huber did it.

Its quite the antique, the NIB kits go for over 1000 dollars on ebay. I was lucky to get mine from someone that had it in their attic for several years and knew I would really appreciate it. If its in good shape 4 to 8 hundred on ebay wouldn't be out of the question.
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Old 07-13-2006, 02:52 PM
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Default RE: Good beginner computer radio reference manual?

I have a Hirobo shuttle I was gonna try the areobatics on, as well as a Shogun 400 (electric) clone.

I also have a tiny little indoor heli that is supposed to be 3D capable (http://www.ltair.com/products/model/Helicopter.htm)

No way am I gonna risk the 'ranger doing aerobatics [X(]
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