John McClean 1 Posted June 23, 2021 Share Posted June 23, 2021 Hi. I'm trying to understand the Throttle Curve set-up on my T12K. It is in the Contents list as (Air / Glider / Multirotor) The plane is a four channel trainer, Seagull Models, Arising Star. I know I don't need a Throttle Curve for it but I want to know how the menu works. The menu shows Stick Position. Curve Rate Curve Point 5 100 (100) 4 75 75 3 50 50 2 25 25 1 0 (0) The Curve Point seems to alter the Tx Throttle Stick Position, I think. What does the Curve Rate do ? Why are there two adjustments ? Surely you could just adjust the RPM by using the Curve Point on the Stick position. Regards John McClean Quote Link to comment Share on other sites More sharing options...
Dickw Posted June 23, 2021 Share Posted June 23, 2021 (edited) I don't know anything about Futaba, but I notice that "Curve Point" (100) and (0) are the only ones with the (). On another brand you can alter the horizontal axis positions of points 4, 3 & 2 but 1 & 5 are fixed so perhaps that is similar with Futaba? i.e. Curve Rate is the vertical axis adjustment and Curve Point is the horizontal axis adjustment options? Dick Edited June 23, 2021 by Dickw Quote Link to comment Share on other sites More sharing options...
MattyB Posted June 23, 2021 Share Posted June 23, 2021 I'm not a Futaba user, but I strongly suspect Curve rate relates to the output of the channel (i.e. the Y axis) whilst Curve point is the stick position that will give you that rate (i.e. stick position, measured on the x-axis). To test just set up a curve that is esily recognisable (something like below should do it), plug in a servo to the throttle channel and watch how it behaves as you change each variable: Stick Position. Curve Rate Curve Point 5 0 (100) 4 50 75 3 100 50 2 50 25 1 0 (0) Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted June 23, 2021 Share Posted June 23, 2021 This function relates mostly to models with engines. Most throttles don’t give a linear response so it means that you can set lower rates at small throttle openings where there is more response and consequently give finer control over the whole range. Those amongst us who bang the throttle open for the duration of their flights and only close it for a glide approach can safely ignore this facility! Quote Link to comment Share on other sites More sharing options...
MattyB Posted June 23, 2021 Share Posted June 23, 2021 1 hour ago, Martin Harris - Moderator said: This function relates mostly to models with engines. Most throttles don’t give a linear response so it means that you can set lower rates at small throttle openings where there is more response and consequently give finer control over the whole range. The same is true of electric powertrains though - you rarely get a linear feeling response in terms of thrust:stick position. Well worth playing with to get the feel you want. Quote Link to comment Share on other sites More sharing options...
John McClean 1 Posted June 23, 2021 Author Share Posted June 23, 2021 Hi. Thanks for all the answers. I've found that Curve Rate is the 'Y' axis and Curve Point is the 'X' axis. (0) is the Tx stick minimum position and (100) the maximum, so they're not adjustable. By changing the Curve Point to something like this Stick Position. Curve Rate Curve Point 5 100 (100) 4 75 75 3 50 28 2 25 25 1 0 (0) The servo arm does a sudden large movement from one position to another. Y axis, Curve Rate l ------------- l / l / l l l l < Servo Arm l---l-------------- X axis, Curve Point l l l / l / l/ ----------------------------- By changing the Curve Rate to something like this (and putting the Curve Point back to original values) Stick Position. Curve Rate Curve Point 5 100 (100) 4 75 75 3 28 50 2 25 25 1 0 (0) l l / l / l / l-----------------/------- l / l _____________/ < Servo Arm position l / l/ So the servo arm stays still as the Throttle stick goes up. Perhaps these extremes are for 3D flying. ------------------------------------ For me, a little change at the low end of the Curve Rate gives me smoother control of the lower engine revs. l / l / l / l / l-----------/--------- l / l / l _____/ l / l/ Regards John Quote Link to comment Share on other sites More sharing options...
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