SitNFly

My Feedback: (54)

Hello again, Danny,

I just set up the throttle on my AW Edge with Brison 3.2. Throttle ATV is at 100% both ways and throttle trim step is at 100%. Anyway, I get just about zero travel when the analog throttle trim lever is moved from low to high. Servo barely moves at all. This is with a brand new JR 537 servo. Normal throttle travel is fine, the servo strokes back and forth, fully opening and closing the throttle. Just no movement with the trim lever. No mixes set up with throttle. Help and thanks!

dsnyder

Have you changed the throttle curve any? Does this happen in a clean model memory?

SitNFly

My Feedback: (54)

Throttle curve wasn't touched. I'll try a clean model tonight and see if the problem still exists. Thanks.

Carroll-RCU

My Feedback: (43)

I had the same problem with my new 9303. The analog throttle trim wouldn't function until I lowered the ATV to 65% on low throttle. Then it started to function.
Carroll

SitNFly

My Feedback: (54)

Did you just live with it or was Horizon able to make it right? That's not a good bug if there is no fix for it, especially with a brand new transmitter....

LenAlessi

My Feedback: (1)

Just a thought.... Make sure the throttle stick is in the low position when you work the trim lever. I believe the trim only functions at low throttle - it does not add-to or subtract-from travel when the throttle stick is in the high position.

Len

Carroll-RCU

My Feedback: (43)

I just live with it. It doesn't matter as long as the the throttle works and you can pull the trim back and kill the engine.
My Futaba 9C isn't set at 100% atv either. Some say that you should have the low and high throttle setting at 100%, but I haven't been able to do that on any plane due to linkage and servo arm length not to mention the throttle arm on the engine.
Maybe someone will have an answer to this.
Carroll

sonicboom

Another problem with this dammm throttle set up. When i set the throttle cut, I flick the swithch and the servo moves in the same direction no matter if the radio trim is programmed for -ve or +ve.

On other models it doesnt activate at all.

There is certainly a bug in the system.. Im using the first version of the PCM9 that cam out.

SitNFly

My Feedback: (54)

I went out to the garage last night and fiddled with the system. First thing was to try Danny's advice and create a clean model. Same problem, no throttle trim when throttle low and high travel is at default setting of 100%. So I tried Carroll-RCU's idea. I moved the throttle pushrod out on the throttle servo arm so that I would be forced to reduce the throttle servo travel. Sure enough, when I got down to about 60% or less, the throttle trim lever started to work. Still doesn't have much throw, when compared to my other radios, but at least now I think I can set the idle with the trim lever.

Len, the trim doesn't work no matter where the throttle stick is, if the servo travel is set at 100%. Or actually, if it's set anywhere above about 60%. It's too bad, because having to do this goes against the goal of using as much servo travel as possible for best resolution. It'll be interesting to see if it's a widespread problem. I'd be willing to send the transmitter in for service, since it bothers me to have to work around a bug. Maybe a service bulletin will be issued if enough owners are affected. Thanks for the tip, Carroll, at least now I can use my new transmitter.

dsnyder

I have not seen or heard of this being a problem to date. If you have the travel adjust set up to 150 or so, the throttle trim movement is reduced, or if you have a program mix, say a throttle to throttle mix active without knowing it, it could cause this type of issue. But at 100% travel adjust with no mixing I have not seen this. Does the servo montor indicate the same thing, and where is the servo position on the monitor when this is happening?

SitNFly

My Feedback: (54)

Danny,
I did as you suggested by resetting a clean model last night, then turning on my plane without touching anything else. One elevator servo was fubar because I hadn't set dual servos up and the throttle servo was running in the wrong direction because I didn't reverse it. Like I said, I didn't adjust anything, but I still had no throttle trim travel. It just wiggles a spline or two when the trim lever is operated. I also tried replacing the throttle servo with one of the digitals that came with the radio. Same problem. Seems like Carroll-RCU and I have the same issue. What should I look for on the servo monitor?

Carroll-RCU

My Feedback: (43)

Danny, Could you possibly get a 9303, receiver, and a servo, and plug the servo into the throttle
ch. in the receiver and see if you have the same problem that we have.
Carroll

LenAlessi

My Feedback: (1)

Just went out in the shop fired up the 9303 and plugged 3 different servos into the throttle channel of a 770 RX (servos were 241, 517, 8611). With travel set to 100% in both directions the trim works just fine. It works fine all the way up to 115% travel. Once low-end travel is set to higher that 115%, the trim lever becomes increasing less effective in the down direction, and if set to 150%, the trim lever no longer moves the throttle in the down direction.

I recommend doing what Danny said - look at the servo Monitor when moving the trim lever with the travel set to 100%. If the Monitor shows movement, then I suspect that the servo travel limit has been reached and the trim lever cannot move it any further. If this is the case, try plugging in a different servo(s), perhaps a different model of servo, and test it again.

BTW, the trim only works when the throttle stick is below 1/2 throttle.

Len

Carroll-RCU

My Feedback: (43)

Len, I'm using the JR 811 digital for throttle. I have no mixes, the throttle curve is INH.
At 100% set for low and high throttle, the trim tab is centered, the monitor shows the low throttle to be at the end of the bar. Now, I can increase the throttle with the tab, but cannot lower the throttle unless I adjust the atv below 60 at low throttle. Also the 811 maxes out at 75% atv at high throttle. At 100%, you have to lower the throttle stick several clicks before the servo starts to move.
Maybe the 9303 doesn't like the JR 811! I give up!
Carroll

LenAlessi

My Feedback: (1)

Carroll,

What you are seeing doesn't sound right to me. At 100% ATV, the monitor should not be showing the channel being all the way at the end of it's travel. There should be some travel left to allow the trim lever to work.

BTW, I forgot to mention that I was in ACRO mode - not Heli or Sailplane.

At this point I will defer to Danny and the techs at Horizon. It would be good if someone who is experiencing this issue sent their TX in. Then the techs can look at it and figure out what is going on.

Len

Roquewj

My Feedback: (4)

I checked it with several servos (811, 810G, 4131, 605).

In heli mode, the trim doesn't work when you put the ATV over 120 %.

In Acro mode, the trim works but the throw diminishes as you move to more %. At 147% it moves just a little. At 150%, it doesn't move.

I might be wrong, of course, but believe this is some sort of protection to avoid damaging the servo.

Carroll-RCU

My Feedback: (43)

Maybe I've been setting my throttle up wrong. Last night I went out to the shop and reset the high throttle at 75% and at low throttle to 40% with the trim tab pulled all the way down, at 40% the carb butterfly is completly closed so when the trim tab is centered, the butterfly is opened up for Idle. With this setup, the monitor bar maxes out to the left at high throttle and about 25% from the end on the right at low throttle withe the trim centered.
I tried different servo arm lengths so as to keep the range as close to 100% as possible.
I have good travel and with this setup, I can kill the engine with the trim tab.
Danny, can you educate me on what I'm doing wrong?
Carroll

dsnyder

I have checked 2 9303's here and I also fly with the 9303 with many models and have never experienced this. The servo position should not be maxed out on the montor at 100% throw. It it is, there is a mix or something else causing it to move that far. At 100% travel adjust, with the trim in the center and the throttle stick at idle, the throttle position should be at the first full slash mark, and with the throttle trim all the way down it should move a little over half the distance between that mark and the full throw line. If this is not the case, look through your program mixes and ensure that there are no throttle to throttle mixes, or anything mixed to the throttle. Also be sure not to center your servos so that it is binding at low throttle.

Carroll-RCU

My Feedback: (43)

Well I went through all my program mixes last night and all are INH. There are no throttle mixes and the throttle curve is also INH. My throttle trim is at 100%. I hate to send a new radio in but I will if you think it's necssary.
I will go over all the programs one more time tonight to make sure I didn't miss something.
If all the other 9303 radio's aren't exhibiting the same probelm as mine, then I must be doing something wrong in the programming.
Thanks,
Carroll

SitNFly

My Feedback: (54)

After reading Len's post, I went out to the garage last night to tinker. I hooked up a battery and new JR 537 servo to a JR 649 receiver. The throttle trim worked fine, even with servo travel set at 100% both ways. What the...? So I took the same servo and plugged it into the throttle channel in my plane. I did not hook up the throttle linkage. Again, the trim worked great with travel set to 100% both ways. So now I was thinking something was wrong with my throttle linkage. I reconnected my existing throttle servo with linkage, set travel to 100% both ways, and ran the throttle all the way closed. This put a bow in the pushrod and mechanically bound the servo. Under these conditions, the trim lever did not move the servo.

It seems if you have the servo travel far enough off to bind the throttle servo at the low end, then the trim lever has no effect. This was the condition when I first set up the plane. All I noticed was the trim didn't work and posted the question to Danny. As soon as I adjusted the travel to take the bind off the servo, the trim lever once again became effective. This may be Carroll-RCU's problem, too. Don't know if this exists on other radios or maybe I just never noticed it. Anyway, I learned something and am happy (even a blind squirrel finds a nut now and then ).

One problem with the web is that it allows a guy to jump to conclusions a little too easily. Sorry if I misled anybody; I'm just glad I got it figured out. Thanks to Danny, Len, and Carroll for all the input.


Mitch Rein

Carroll-RCU

My Feedback: (43)

I think I'll disconnect my servo arm tonight and try that at 100% and see what happens>
Maybe that's been my problem also.
Thanks for the feedback Mitch
Carroll

dsnyder

Glad you were able to find the problem!

Carroll-RCU

My Feedback: (43)

Problem found! First I removed the servo arm and reset the Throttle ATV to 100% on both high and low throttle and the problem still existed
I then went to the program mix1 and it showed thro-thro. I scrolled down to the thr-stk and clicked on that which was in the INH mode. I switched it to the 0 position and then the trim tab started working properly. I reinstalled the servo arm and now at 100% on both high and low throttle the trim tab functions properly. I could not find anything in the book on this (but I could have missed it). Apparently the INH position prevents the trim tab from functioning.
Carroll

dsnyder

If you had a throttle to throttle mix in mix one or two in particular, the values are automatically 100% each way which will add to the throw causing excessive throw. Glad you were able to find the problem as well!

Tailwind 76

Hi All
I have just purchased a JR PCM 9X 2 and would like to allocate the throttle trim to a separate switch as I am using this to shut my turbine down can this be done on this set.

I have a Futaba FF9 that I have this system working on.

Thanks

John.