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Throttle curve: cruise plateau around mid stick

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Old 05-16-2017, 04:02 AM
  #1
bem
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Default Throttle curve: cruise plateau around mid stick

Hi,
I read earlier this winter an article by Malcolm Harris about throttle curve for electric motors.
I can not remember where I found it on internet but I copied the text and the pictures in the article and pasted it into a Word document that I printed and read.

I reread it again some days ago and at the end of the article is is written this that I have thought about and might try:

There is more that can be done which I will save for another time, as, by tweaking the curve some more its possible to create a cruise plateau around mid stick to make it easier to find the best cruise throttle setting for horizontal manoeuvres and level flight.

I created a PDF of the article and attach here if You should like to read the article. I hope Malcolm do not mind.

I got more curious about this cruise plateau around mid stick.
Anyone using that? If yes how many clicks at mid throttle stick do You use with same cruise power?

/Bo
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Throttle_setup_electric_motors.pdf  

Last edited by bem; 05-16-2017 at 06:56 AM.
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Old 05-16-2017, 05:35 AM
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I do. I will take pictures of the radio when I get a chance after work.
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Old 05-16-2017, 06:03 AM
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Hi Bem,
You just published Malcolm's Email address at the bottom of the PDF - hope he does not mind !!

Brian
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Old 05-16-2017, 06:33 AM
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JerMilosek
 
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Bo,

On my Jeti DS16 I programmed audible alarms triggered off the throttle stick at a specific detent position; this ensures my "cruise" is always the same from the transmitter and eliminates the need for a plateau. I do the same for my DX9 Spektrum by making the "cruise" detent larger, more noticeable feel, by using a jeweler's file. After doing this I adjust the throttle curve to get the speed.

There's a couple more threads on throttle curves here in the RCU Electric Pattern Aircraft forum dated last year. Check for Jim Oddino who has written extensively on it for his DS16.

Another thread that might interest you contains info using the DX9 written by Scott Covey, aka Pattern_is_Fun, see:
https://www.rcgroups.com/forums/show...-Thread/page44

BTW, should I call you Bo or Bem?

Regards, J e r
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Old 05-16-2017, 06:53 AM
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Quote:
Originally Posted by serious power View Post
Hi Bem,
You just published Malcolm's Email address at the bottom of the PDF - hope he does not mind !!

Brian
Hi,
I will remove that, sorry.
The mailaddress was in the original article that was published somewhere on the internet (I just can not find it again).

/Bo

Last edited by bem; 05-16-2017 at 07:10 AM.
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Old 05-16-2017, 07:08 AM
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Hi J e r,
When I was out flying yesterday I was thinking about assigning a sound to throttle mid stick position. That might be possible to do on my Futaba 14MZ.
I will probably test and see if I like that.
My first name is Bo but my username bem here at RCU will be fine to use also.

/Bo
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Old 05-19-2017, 11:07 PM
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Hi,
I have now assinged a beep to mid stick position on my Futaba 14MZ.
In Linkage menu, Sound, I selected "BEEP" as sound and then J3 (throttle). As "On pos." for the sound to beep I selected:
Alternate: NORM
Mode: Linear
Type: Box

"On" (green) band is +6% to -6%
"Off" (red) band is the rest upper anb lower part of the bar.

Now when I have trottle stick exactly in middle or one dent up or down from the mid position the sound do one beep when stick enter the green band (+- 6% = mid stick position and one dent up/down).

The not so good thing is that, at least in Futaba 14MZ, You can not move the stick up/down too quick because then the sound do not beep. You have to move the stick rather slow up and down to enter the green "on" band where the beep activates at mid stick.
I did not want the sound to repeat, so it just beep one time when I enter the mid stick position (green) band.

I think this might be as good as I can get it on a Futaba 14MZ.

I have not changed my throttle curve yet for any "plateau" in the curve. I have to think lttle more if I want to change that.
I might change but not right now. I need to see if the sound beep to mid throttle is enough for me.

/Bo
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Last edited by bem; 05-20-2017 at 03:00 AM.
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Old 05-20-2017, 07:25 AM
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The problem. as I see it, is that your mid-stick position will vary, as you compensate for wind conditions. I set mine up for a mild plateau around mid-stick. It acts exponential on either side of the plateau.
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Old 05-20-2017, 10:22 PM
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big_G,
You are right about wind conditions is a factor that has influence on this mid stick scenario.
I was out flying about 10 flights yesterday flying the P-17 Schedule and tested my beep at mid stick position. It worked rather good.
It was windy yesterday at the airfield and I noticed the problem of course that in head-wind I had to add little more throttle then mid-stick.
In the wind condition yesterday I added 2 clicks up from mid stick position to get reasonable speed in the head wind.

The biggest drawback was that there was not always a beep at mid stick if the stick was moved to quick up or down, and I knew that already since I discovered that when setting up this mid stick beep in the Sound menu in my Futaba 14MZ. I'm not sure it is suppose to be that way or if it is some bug. I will have to live with that since I can not do anything about it.

I think the throttle mid stick position beep can be good to have so You know where the mid position is, where it is about 50% thrust (about 70 % RPM) if using the throttle exponential curve in Fig 4 in the PDF attachment in my first post in this thread.
On a calm day You could use the mid stick postion as cruise speed and on windy conditions You have to adjust throttle as needed in flight of course.
I think I will continue to use my present setup with the beep at mid stick position, I migh add just a little exp value so I have slightly more then Rate +40% (maybe +45) at mid stick in the Throttle setup in my 14MZ (see image below where this is changed). But I will test in calm winds to set this to a value I prefer (it was too windy yesterday).

/Bo
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Last edited by bem; 05-21-2017 at 12:21 AM.
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Old 05-22-2017, 10:12 PM
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Hi,
I have flown two more days with the mid stick beep now and although it is helpful it is a pitty that on Futaba 14MZ if You do not move the throttle stick slow enough it will be no beep at mid stick (band, +-6% in my case).
It would be interesting to hear if anyone that use a sound for mid stick position can move the stick up/down at whatewer speed and there will be a sound when stick enter the mid stick band, and please tell what radio You use.

/Bo
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Old 05-22-2017, 10:21 PM
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JR XG 11 beeps OK with rapid throttle movement.
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Old 05-23-2017, 01:49 AM
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No problem with Taranis X9E
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Old 05-23-2017, 10:49 PM
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Hi,
I asked about the Futaba throttle mid stick sound played over at Radio Manufacturer Direct Support, Futaba Radios Direct support forum, here at RCU and goit this answer:

Quote:
Originally Posted by Bax View Post
There's nothing wrong with your transmitter. You have a small area that must be detected for the sound to play. What happens when you move quickly through the box is that you do such a quick 'off-on-off' sequence that the sound player cannot respond in time. The player gets an 'off' command before it can fully execute the 'on' command. The 18MZ is no different, and the 18SZ does not have that capability.
Bill Baxter, Manager Hobby Services/Futaba Service/North America
3002 N. Apollo Dr. Ste. 1 Champaign, IL 61822 USA
Service Phone: 217 398-0007
Email: hobbyservices@hobbico.com
I made a suggestion to him:

Quote:
Originally Posted by bem View Post
Hi,
Thanks Bax for the answer.
On some other transmitters it works even if throttle stick is moved fast, for example on JR XG11 and Taranis X9G (and it probably work on some other transmitters also).

I may add that it is same type of problem on Futaba 14MZ if you have for example a 3 pos. switch and has assigned a sound to each position. Sometimes the sound is "missed" if for example if You move the switch from pos. 1 to pos. 2 and the sound is played and You move to pos. 3 while the sound for pos.2 has not finished there will be no sound played for pos. 3. On the other hand it is good that if one move the switch from lets say pos 3. back to pos. 1 or vice versa the sound for pos. 2 is not played as the swtich goes over pos. 2 - but this only works if the switch from end positions are fast enough so player has not started to play the sound for pos. 2.
I suppose I have to be gentle on the throttle stick to get greater chanse the mid stick position sound will play.
Maybe You could ask Futaba to add to future wishlist for some of their high end transmitters to be able to get a sound played regardless how fast the throttle stick is moved up/down, if You think this enhancement (as I see it) could be valuable to others also?

regards,
Bo
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Old 05-23-2017, 10:54 PM
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J e r,

Does Your Jeti DS16 and Spektrum DX9 transmitters play sound at mid stick position regardless how fast the stick is moved up/down?

/Bo
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Old 05-24-2017, 06:30 AM
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Bo,

My Jeti DS16 ALWAYS responds no matter how fast/slow I pass thru the "cruise" setting. I must say it took some work getting the points set and I use 2 logical switches, one for increasing throttle and another for decreasing.

My DX9 does not have the ability but then I never pursued it thoroughly, I just deepened the ratchet to get a feel for the "cruise" position. Scott Covey uses throttle position to change his rudder D/R & Expo, check the forum
https://www.rcgroups.com/forums/show...-Thread/page41 and look for posts 605 & 608.

Apologies for the late reply, yesterday was the best flying day of the year so far and I spent the day at the field.


J e r
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Old 05-24-2017, 01:22 PM
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J e r ,
Thanks for the answer.
I have also been busy flying lately since the weather here is superb, rather windy some days but sunshine mostly. Today in the afternoon it was super good weather with clear blue skies, some winds and comfortable temperature. Will fly tomorrow and next day also.

/Bo
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