DA-50 Throttle Response

[Bartman]

Hi guys,

I've got a DA-50 that starts up and runs great but the throttle response is not very linear in the lower half of the throttle range. I can pull the stick back to about half and then below that it'll just drop off towards idle without much response between half and idle.

Is that normal?

 

[Jetpainter]

A lot depends on your linkage and arm geometry. When the throttle butterfly is half open it doesn't necessarily mean half power. I like to make the linkage as linear as I can, then tune the throttle curve in the radio to make it feel right.

 

[Bartman]

ok, i'll have to take a look at maybe incorporating a throttle curve. i guess i could give DA a call also and ask them about it, i've heard they're very helpful!

 

[bigblueswope]

Post a video of the servo arm moving. That will help us help you @Bartman.



BJ Swope

 

[combat chicken]

@Bartman Bart, I have a DL50 with very much the same issue. I had to program a curb in the throttle to get good linear response. Of course now I'm now having to change servos because the standard hitec 645 took a dump and started to dance all over the place. Just could not hold up to the vibration. Going to a digital 5645 which should hold up to the vibration better and being digital can, as I understand it, handle a programmed curb better.
Good Luck and what bird are you putting the DA in?
Bart

 

[Terryscustom]

Set it so that just below half open on the carb arm is at 50% of the servo travel. Then adjust your min and max travel on your transmitter. Use the shortest arm on the servo as possible to get at or above 100% of travel in both directions on your transmitter.

That's the K.I.S.S. method to get a pretty linear throttle. If your engine is actually running good and tuned well I'd see where you are in relation to what I described.

 

[Bartman]

what i normally do is close the throttle all of the way and then set the low end of the throttle position (with trim all the way down) to that but I also make sure at mid servo travel i'm about at mid throttle position in the carburetor. i check for binding, make sure i'm not over pushing the throttle arm with too much servo travel on the high end and then have at it.

I'll take a look at it tonight to see how well matched up mid servo position is to mid throttle position and adjust it from there. naturally i'll have to make time to fly it again after i check it!

@combat chicken;, the engine's in a PAU Pitts Challenger

 

[Terryscustom]

what i normally do is close the throttle all of the way and then set the low end of the throttle position (with trim all the way down) to that but I also make sure at mid servo travel i'm about at mid throttle position in the carburetor. i check for binding, make sure i'm not over pushing the throttle arm with too much servo travel on the high end and then have at it.

Start just below middle for better results. Use an inline amp meter to check for your max and min throws from there. Start with your transmitter set to 50/50 for throws so you know you don't over extend it by accident while setting it up. You should end up with roughly the same travel above and below center when you are done.

Lots of guy's use a curve to help fix a muffed up throttle linkage but then if that curve does not line up in the right spot you have really crappy throttle response.

Let us know how you come out.

 

[Bartman]

ok, will do, thanks for the help everyone!

 

[Robotech]

Look for slop anywhere in the system. Links, carb arm, servo arm, etc. I have seen some so bad that the first few clicks of throttle were just taking out slack.