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Offset? what is it, how do you use it?

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Old 07-23-2007, 05:21 PM
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Capt Jim
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Default Offset? what is it, how do you use it?

Can anyone explain in simple layman terms exactly what offset is...what it does...where and how do you use it? I am flying a Spektrum DX7 system, which I love, on about ten different airplanes,...however, I cannot figure out how to get a high and low idle setup on a switch, (or switches), along with a throttle kill.
I had that on my old Futaba 9C, and I miss it terribly since I cant figure out how to duplicate it on the Spektrum DX-7 system.

I find the radio manuals to be sadly uninformative. They omit sorely needed explanations in favor of an economy of words. They seem to assume that the user is an engineer and already knows all about how these things work.
Oh...if only they would skip using all the current manual formats and just give us a recipe book with clearly written steps to achieve the setup we are trying for.
Thanks for the help with this.
Jim
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Old 07-24-2007, 02:49 AM
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Default RE: Offset? what is it, how do you use it?

G'day Jim,
Go here scroll down, a have a look at the DX7 page, http://www.rcaerobats.net/
All answers here, but, you must have your throttle set up so that it will in fact cut the engine when using the throttle trim, if it won't, then no mix will work.
Also set throttle recovery to "ON".
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Old 07-24-2007, 03:06 AM
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enakidos
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Default RE: Offset? what is it, how do you use it?

May be this can help. Here is quotation from DX6 manual.

"The purpose of the mixing offset feature is to redefine the neutral position of the slave channel to be mixed.
Any desired position may be selected for the offset reference point. To set the offset position, Place the master
channel’s stick to the desired position and press either the INCREASE or DECREASE keys."

Anyway observe DX6 manual, it was created with more advanced explanations.

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Old 07-28-2007, 04:53 PM
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Default RE: Offset? what is it, how do you use it?

Jim,
I did a little experimenting with using a throttle to throttle mix to act as a true throttle kill switch for transmitters that don't have throttle kill.
I found setting the offset to about 15% was a good point, then set the rate for when the stick is up to a value of 0%, after that with the mix active and the throttle stick full down, then adjust the down stick rate (watch the carb barrel (did I say to have the plane turned on on the bench?) with Futaba, adjusting the rate to around + 50% worked for me, with JR it may be a minus number, anyway you will be able to visually adjust it to fully close the barrel when the mix is activated. the important item here is that the 15% offset and zero value when the stick is above 15% is that there is absolutely no effect if you accidentally hit the throttle kill on a high speed pass, it only works when the throttle stick is at or below 15% .
I myself use the popular throttle to throttle mix with 0% offset and depending on brand plu or minus 100% rates, this gives a good throttle lock function for electric planes to avoid unexpected start ups, but is used for an IC engine can result in unwanted dead sticks.
You can use the same recipe here for an idle down funtion, set exactly the same as for the kill but just use a different down stick value to give yuo a lower idle than normal.
I hope this works for you,
Pete
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