spektrum dx7 programming questions

[Zachary B]

Got a 2.4gig radio for christmas and i am trying to program 2 fixed wing straight forward configurations with flaps.Looking for help with typical programming specifications for programming dual rate , exponential, elevator to flap, aileron to rudder, subtrim etc... Im not really sure i need all of these.
There doesn't appear to be any real starting point in the set up guide.
I understand that specifications will change for each airplane, but i am just looking for a starting point...

[cgroves]

Got a 2.4gig radio for christmas and i am trying to program 2 fixed wing straight forward configurations with flaps.Looking for help with typical programming specifications for programming dual rate , exponential, elevator to flap, aileron to rudder, subtrim etc... Im not really sure i need all of these.
There doesn't appear to be any real starting point in the set up guide.
I understand that specifications will change for each airplane, but i am just looking for a starting point...
Of course the best approach would be to make a time and come to the field with an instructor at your local club and they can confirm everything is reasonably setup. Which part of town are you in?
I am assuming we are talking about a standard fixed wing semi-aerobatic airplane with ailerons, flaps, rudder, elevator and motor? I would only use three of those settings for that type of airplane and leave the rest disabled:

Dual Rates: most airplanes come with recommended throws for high and low rates to allow aerobatics (high rate) but keep the plane under control for landing (low rate). I would start with the mfg recommendations if they exist. Once I am comfortable with a plane I rarely use this function and prefer to use expo.

Expo: Used to make the stick less sensitive in the center (or vise versa in some cases) and is what I use instead of dual rates since it makes for one less switch to worry about. It means I can make small, smooth corrections near the center of the sticks but still have full throw available it I move the sticks all the way to the stops.

Subtrim: Ideally your plane should fly straight and level at cruising speed with the main trims centered and the sticks centered. Subtrims could be considered permanent "hidden" trims. You use them when you can't quite get the mechanical links to perfectly center. They should be only used a little bit and they are not a substitute for proper mechanical setup. I have a rule that if I need more than 20 points (Futaba) of subtrim I pull it apart and fix the mechanical linkage. 20 points on the nearest hole of a servo arm is usually equivalent to about a 1/2 twist on a clevis or ball link.

Hope this helps, if you have any other questions or this isn't clear, go ahead and ask.

[Dave Rees]

Zachary,

As Corey said, the airplane manual should give you a starting point for D/R's expo etc. If you are looking for advice on how specifically to program your radio then I might be able to help. I was fortunate enough to win a DX7 at an event last summer and have been using the radio a bit. The programming is a little bit different than my trusty 9C but, I'm slowly figuring it out. So, if you have a specific question, let me know and I'll help out if I can.

Cheers,
Dave

[Zachary B]

Alright,
Thanks guys i'll give these a try.
Zac

[Zachary B]

Thank you, I am with ORCC and fly at the Drummond field. I plan on having somone take a look at the set up before flying anything. The first plane I am trying to set up is a RTF trainer where I have repalced the receiver and am changing the radio, i don't remember any set up criteria being provided, the second is ARF that I am putting together, which may have some radio set up instruction further back in directions, I will check. Both are straight forward wing type, elevator, rudder, aileron and flaps with separate channels. The radio guide indicates the same type of explanation you guys have provided, but simply says for dual rate 0 to 125% and for exponential -100 to + 100% not sure at this point what even a reaonsable starting point is given these wide ranges. Then there are a number other mixes possible aileron to rudder mix rates, elevator to flap mix rates etc... on the radio not sure if these should be inhibited or not. Any help you can provide would be great. I will keep reading the materials maybe I missed it.

[cgroves]

Nice avatar, that looks like the ramp at OAS (or someplace else with just as much FOD:p).

[Tyler2]

Hi Zach,

Your RTF trainer is the P-51...Correct? If so these are the expo and D/R that I used for it in my Spektrum:

Aileron High rate: Exp = +30%
D/R = 125%
Aileron Low Rate: Exp = +30%
D/R = 100%
Elevator High: Exp = +30%
D/R = 100%
Elevator Low: Exp = +25%
D/R = 125%
Rudder High: Exp = none
D/R = 100%
Rudder Low: Exp = none
D/R = 125%

I'm not quite sure why the Elevator and Rudder high rate is a smaller % than the low but thats how I flew it. You might want to do the opposite.

Make sure that all the exponentials are in POSITIVE. It is opposite to Futaba radios.

Hope this helps

Tyler

[Zachary B]

Thanks for the information thats what i was looking for. Talk to you later,
Zac