Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Radio Equipment => Topic started by: Cabin Boy on October 25, 2020, 12:38:09 pm

Title: Spektrum DX6i - mixing
Post by: Cabin Boy on October 25, 2020, 12:38:09 pm
I have a boat using two motors (with two ESCs) - both controlled with the LH forward/reverse stick. Rudder servo is on the RH stick (horizontal).
At speed the boat is very sensitive to rudder movement. To avoid the risk of overturning the boat at speed I want to proportionally reduce the available throw of the rudder as the throttle is increased. At low speeds, however, I want to retain full rudder travel for manoeuverability. Is this possible with the DX6i, I can't see that the mix feature of the DX6i would do this.
Can anyone help?
Does anyone manufacture a separate mixer that would do the job?

Title: Re: Spektrum DX6i - mixing
Post by: clockworks on October 25, 2020, 05:15:52 pm
Might be easier to do it a different way:


Reduce the rudder throw to make it less sensitive at speed - do this mechanically with the linkage, or by reducing the "endpoint" on the rudder channel.


Put the second motor on a separate channel, and use a mix to "slave" it off the main throttle channel.
Use a couple of mixes to add "outside" motor to each rudder direction to assist turning at low speed.
This is what I do with my Futaba radio.


Another way may be to use a "curve" for the rudder channel, so that it moves a lot less at smaller inputs (stick travel), more at bigger inputs. It'll be less sensitive, but still have full throw if you move the stick right over.




It might be possible to use "dual rates" to reduce rudder sensitivity above a certain throttle position, but I don't think you can make it truly proportional with your radio.
I think you'd need a really fancy computer radio to do that.
Title: Re: Spektrum DX6i - mixing
Post by: spearfish99 on October 25, 2020, 10:04:36 pm



Another way may be to use a "curve" for the rudder channel, so that it moves a lot less at smaller inputs (stick travel), more at bigger inputs. It'll be less sensitive, but still have full throw if you move the stick right over.






      Known to aeromodellers as expo.


https://www.bing.com/videos/search?q=spektrum+dx6i+expo&docid=608041672955924407&mid=483AE10CAA6915534E3C483AE10CAA6915534E3C&view=detail&FORM=VIRE


Title: Re: Spektrum DX6i - mixing
Post by: morley bill 1 on October 27, 2020, 03:05:52 pm
Hi i use tank steering for twin screw you are already useing two esc its good for low speed steering all thats required are two mk1 thumbs  Bill..
Title: Re: Spektrum DX6i - mixing
Post by: clockworks on October 27, 2020, 03:33:09 pm
Hi i use tank steering for twin screw you are already useing two esc its good for low speed steering all thats required are two mk1 thumbs  Bill..


Tank steering is fine for a slow-ish boat like a tug, but might get a bit hairy on a fast pleasure boat
Title: Re: Spektrum DX6i - mixing
Post by: Cabin Boy on October 29, 2020, 10:43:11 am
I have used tank steering on a tug. Agree with clockworks that it would be hairy on a fast pleasure boat - in this case its Aerokits Sea Commander.