Author Topic: Elevators Servos Moving At Different Speed Video  (Read 530 times)

Offline TomLaird

  • Masters Class Poster
  • ****
  • Posts: 368
  • Flying Class: None
  • Other Status: None
Elevators Servos Moving At Different Speed Video
« on: 10, April 2018, 01:42:47 PM »
Hi,
I normally rely on my angle meter to set and check my throws, but on this occasion I also checked using the pointer method. Although the overall deflection is the same, as you can see in the video the rate of deflection is different. I mentioned this at the Skelbrooke comp and it was suggested I try using the servo speed adjustment feature in my transmitter. I did this and the servos are now moving at the same rate. For ailerons I guess you either need very long pointers or check before you install them into the wing.

https://youtu.be/ueo5Bu7D27U

br
Tom

Offline Mike Wood

  • GBRCAA Member
  • FAI Class Poster
  • *****
  • Posts: 1,285
  • F3A Precision Aerobatics
  • Flying Class: FAI Pilot (P)
  • Other Status: FAI Pilot (P)
Re: Elevators Servos Moving At Different Speed Video
« Reply #1 on: 10, April 2018, 06:44:36 PM »
Hi Tom

I was wondering if you were using a mix to get the two servo operating or ailevator function?

Mike

Offline SAB

  • Clubman Class Poster
  • *
  • Posts: 28
  • Flying Class: Advanced Pilot
  • Other Status: Advanced Pilot
Re: Elevators Servos Moving At Different Speed Video
« Reply #2 on: 10, April 2018, 07:45:33 PM »
Tom,


Could it be a function of Expo ? - more specifically a combination of expo & subtrim. Could prove this by doing the same test with no expo. 


Steve

Online Mark Allen

  • GBRCAA Member
  • Intermediate Class Poster
  • *****
  • Posts: 55
  • Flying Class: Intermediate Pilot
  • Other Status: None
Re: Elevators Servos Moving At Different Speed Video
« Reply #3 on: 10, April 2018, 08:33:57 PM »
Hi Tom, I had something similar last year when I conducted the same test. Proved to be sub trim causing the effect for me. An easy theory to check and dismiss.


Good to meet you at the weekend  :)
« Last Edit: 11, April 2018, 09:40:27 AM by Mark Allen »

Offline TomLaird

  • Masters Class Poster
  • ****
  • Posts: 368
  • Flying Class: None
  • Other Status: None
Re: Elevators Servos Moving At Different Speed Video
« Reply #4 on: 10, April 2018, 08:54:59 PM »
Tom,
Could it be a function of Expo ? - more specifically a combination of expo & subtrim. Could prove this by doing the same test with no expo. 
Steve

Sore point Steve :)  I removed the expo when I tried it out and it was after the 2nd round at Skelbrooke when I discovered I had not put it back in.

cheers

Tom

Offline TomLaird

  • Masters Class Poster
  • ****
  • Posts: 368
  • Flying Class: None
  • Other Status: None
Re: Elevators Servos Moving At Different Speed Video
« Reply #5 on: 10, April 2018, 09:01:03 PM »
Hi Tom
I was wondering if you were using a mix to get the two servo operating or ailevator function?
Mike

Hi Mike,
I have them going into different ports in the receiver, Elevator and Gear so no mixing. The radio is a JR XG8.
cheers
Tom

Offline Alan Wild

  • FAI Class Poster
  • *****
  • Posts: 651
Re: Elevators Servos Moving At Different Speed Video
« Reply #6 on: 10, April 2018, 09:27:06 PM »
Or again, could it be the DMSS system?
I've noticed that both my aileron and elevator movements have become a lot more "stepped" (non progressive, jerky)through the range of movement, than with the previous DSM2 system---that's with throws and expos the same on the same models.
I saw that Dave Wilshere (keen JR seller/user!) noted that he'd increased the amounts of expo used,for DMSS. on some model that I can't recall off hand.
With me, I've stopped using the JR DMSS Rx, and I have to say that the ridiculously cheap Chinese (Orange?) DMSS Rx is smoother, though still less so than any of my various-brand DSM2 receivers.

Offline SAB

  • Clubman Class Poster
  • *
  • Posts: 28
  • Flying Class: Advanced Pilot
  • Other Status: Advanced Pilot
Re: Elevators Servos Moving At Different Speed Video
« Reply #7 on: 11, April 2018, 12:32:36 PM »
DMSS won't cause this.


I use DMSS (XG11) in my Wind S Pro - elevators move in sync.


What I will say about DMSS vs DSM2 is it's much more responsive to the extent that on another plane in the club (Krill spark) with everything unchanged other than the Rx from DSM2 (JR12X) to DMSS (JR 28X) the servo speed was noticeably faster, and not by a small margin either. Saw the same surface speed difference when comparing my plane (DMSS XG11) to 2 planes running DSM2 (DSX9 & 12X) all with the same servo's (JR8401's) and nominally the same Mechanical & Electronic set-up.


Tom, obvious question - are the two elevator servo's the same ? - if they are is the mechanical set-up identical, same for the Electronic set up. How much sub trim do you have ?
Also, I see you set ailerons to Flaperon rather than Normal & "mating" to another channel - using flaps ?


Steve

Offline Mike Wood

  • GBRCAA Member
  • FAI Class Poster
  • *****
  • Posts: 1,285
  • F3A Precision Aerobatics
  • Flying Class: FAI Pilot (P)
  • Other Status: FAI Pilot (P)
Re: Elevators Servos Moving At Different Speed Video
« Reply #8 on: 11, April 2018, 09:57:34 PM »
Hi Tom

If you have a JetiBox, or access to one, you can use it to test the speed of your servos between
points that you define.

Mike

Offline Stuart Mellor

  • GBRCAA Member
  • FAI Class Poster
  • *****
  • Posts: 1,185
  • Flying Class: None
  • Other Status: None
Re: Elevators Servos Moving At Different Speed Video
« Reply #9 on: 12, April 2018, 08:08:16 PM »

Tom -assume you have swapped plugs in the receiver - to check if its a servo or transmitter problem? If the same problem occurs on the 'opposite' servo - its a servo problem. If the problem transfers to the other servo - its a transmitter problem.


Another check is to plug both servos into a y lead. If they move at different rates -you've got mis-matching servos.

Offline TomLaird

  • Masters Class Poster
  • ****
  • Posts: 368
  • Flying Class: None
  • Other Status: None
Re: Elevators Servos Moving At Different Speed Video
« Reply #10 on: 13, April 2018, 05:14:53 PM »
Hi guys,
Thank you to everyone who has replied. Although I fixed the issue by adjusting the servo speed, the replies here have given me other things to look at and consider.
best regards,
Tom