View Full Version : DX7 swash expo
I've tried one in my 450SE. In my case, flipping it on/off is required full CCPM setup not only because of reduced pitch range (when it's on) but swash got moved (from perfect level at center stick) a tiny bit as well.
I see no difference in flight, maybe heli is a bit tame when this expo option is on.
What do you think about this function?
Has someone test it / use it?
BarracudaHockey
12-19-2007, 12:00 PM
Its not made to "soften response" like expo on a control axis does.
A round servo wheel has natural negative expo (since we are talking jr here) making it move more at the center of travel than at the extremes. The swash plate expo strives to make control throw linear at top and bottom stick as well as center.
Its not made to "soften response" like expo on a control axis does.
I know what it is suppose to do.
Question is: do you use it and if you do how do you feel your flying?
Does it makes any difference for you?
The only difference I can see when testing on the bench. Say you give +6 elevator and then go from -11 to 11 collective. If this function is ON then swash stays more or less with the same angle through collective range.
And if this option is OFF then swash reduces its angle a very tiny bit at the collective extremes.
And I can not tell if I feel any differences when I'm flying.
Gino CP
12-19-2007, 08:34 PM
If you can't tell the difference then either setting is fine for you. It's one of those things that are put there for technical reasons.
Pinecone
12-19-2007, 09:23 PM
Only thing is, the servo is not outputing to a linear input. The swash balls move in an arc also. As do the washout arms, mixers, and grip balls.
Danal Estes
12-19-2007, 09:27 PM
It is difficult to tell in flight, as your left thumb is sort of programmed to put in whatever pitch it takes to get the heli to do something...
Having said that, I usually turn it on prior to mechanical setup of the heli. Don't really know why; just sounds like the right thing to do.
When I crashed my 450 I had a chance to start all over again. This time I've turned swash expo OFF. And I like it better, cyclic is more quick (not much but any tiny bit counts).
And I find out that if ANY amount of sub-trim is used then switching this function On/Off will throw out perfectly leveled swash (not only pitch range). So if later you don't like it or like it and you are using sub-trim then more likely you have to start your CCPM setup from step one.