[NSRCA-discussion] JR DSM glitch - trouble-shooting.

Bill Glaze billglaze at bellsouth.net
Wed May 6 10:14:33 AKDT 2009


The loose covering Don describes below, reminds me of a WW 2 P-51 problem.  At high speed, several aircraft had wings peel off.  Not a good thing.  Finally, it was tracked down to the fact that the 50 Cal. ammunition doors were swelling outward, and the increased camber increased the lift enough (suddenly) that the wings would separate.  Strengthened the doors--end of problem.
Bill
  ----- Original Message ----- 
  From: tocdon at netscape.net 
  To: nsrca-discussion at lists.nsrca.org 
  Sent: Tuesday, May 05, 2009 10:20 PM
  Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.


  Jon, Colin,

  I'll pass on something that may or may not be related.  The NMP Li Ion battery packs come with a "JR" type connector but it's a slightly different design for the pins.  There is play especially if you use it inside a Futaba female connector.  That is what my dad used on his Smart Light Switch design.  

  So any case, here's the story.  I was flying and something did not feel right.  It felt like it went in to momentary hold, like during the bottom of loop with 4 point roll (when the servos are loaded quite high).  I bring it down immediately and check the data logger which records  zero holds logged.  However, I notice something out of ordinary.  The data logger shows no packet losses, no fades, zero holds.  That seems odd since it always has some minor packet losses during a flight log.  Everything seems normal.  I take the switch out and notice that when I wiggle all the wires its ok,  but when I get to the connector from the battery to the switch I see the smart light flash briefly (showing it goes under 5.4 volts).  Now with no servos on this is odd.  So what I find, after wiggling the connector (almost impossible to reproduce but I do it finally) inside the yellow clip-on connector-holder thing (the thing where the connectors clip inside and will not separate even when pulled hard) the light goes out and stays out.  The yellow clip thing allows for some wiggle of the pins ba ck and forth while the connectors are inside the clip.   I find that its at best its at a high resistence, and at worst it has intermittant connections.  That explains why the rx voltage was dropping during the loop with 4 point roll.  I subsituted a very small tightly tied tie-wrap in place of the yellow removable clip and the problem was solved.  So I thought I would pass this on. I have heard of at least one plane lost from the black slip-on clips pulling loose (the one where you slide one wire on one slot and the other wire in the other slot to keep the connector from loosening).  However , I have never heard or experienced problems with the yellow clips.

  On the topic of trimming, here is another one of interest.  I'm flying tonight, the plane is trimmed perfectly, then half  way through the flight the trim below quarter throttle goes way out, like the wing is about to separate.  Real bad. Lots of up elevator and opposite aileron required to land.  Just get it on the ground.  Felt like it lost an aileron, elevator side, or both.  I land, and after checking everything carefully I notice a small section of trim covering on the top of the wing- maybe 6 inches in length is loose.  It did not tear off but in the frontal exposure to wind would lift up like a miniature parachute.  After carefully taping that down I fly again.  Same exact thing happens.  This Magic VF3 PHX really isn't happening.  I land and guess what, another, smaller section comes loose (just a little bit at the front edge of the trim covering), but closer to the tip.  I tape that down (boy I wish I had an Iron with me.).  Any case, I fly again and third time is the charm  Everything flies well.  If such a small piece of covering could effect the trim that much, it makes me wonder how much any drag differential would cause the common pattern pilot headaches in trimming.  Note this- a small amount of drag differential on one wing tip has the same effect as an out-of rudder trim, except it's non-linear with speed (drag).  Reminds me of the story that George Asteris had of a landing gear retract that was dragging (hanging down on one side).  Upright it would hang down slightly causing drag, inverted it would go back into the wheel well and the drag would go away.

  One final bit of wisdom.  Plane rolls faster left than right.  I go to ATV to adjust control throws.  It does not make sense.  I have to add a bunch of ATV in to get it close.  I double check flight trim, guess what, that is it.   I do the clevis thing, get the trim beeps into the center transmitter trim, and fly.  Its perfect, and no ATV required at all.  Plane rolls so much better now.  I'm now a 1 or two beep kind of guy. 

  Lots of food for thought.  Well, I'm off to iron that covering back down... tight.


  Don


  -----Ori ginal Message-----
  From: colin chariandy <cchariandy at yahoo.ca>
  To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
  Sent: Sat, 2 May 2009 5:54 pm
  Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.


        I am using a Hyde ARA70, centarl hobbies nose ring. It seems loose enough.

        The aileron servos are 9252s...I tested them on the bench and could find nothing wrong.

        I'm going to take the readings again with the shorter arms.

        --- On Sat, 5/2/09, Jon Lowe <jonlowe at aol.com> wrote:


          From: Jon Lowe <jonlowe at aol.com>
          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.
          To: nsrca-discussion at lists.nsrca.org
          Received: Saturday, May 2, 2009, 1:48 PM


          What mount are you using?  Hyde?  Budd? If Hyde, which model?   How tight is your nose ring?  Too tight can transfer a lot of vibration.  Should be a loose fit on the front of the engine.

          I've done some testing with a Hanger 9 current meter, and your engine off draw is about right.  I see around .9 to 1=2 0amp at idle, and 1.6 to 2 amps at full throttle, using a Hyde mount with a YS 1.70.  This, of course, is on the ground.  How airloads dampen the oscillations, I have no idea.

          Have you checked your aileron servos for dead spots around neutral?  Are your servo gears getting sloppy?  They can start oscillating with the engine running, and really kick up the amps.  Put a servo tester on them with a slow sweep and see if there is any hesitation in movement of the servo thruout its travel.  I've had a single aileron servo draw 1.5 amps by itself if it started self oscillating due to a worn pot.

          I'd get rid of the long arms.  Are you at about 130% or more ATV at high rates?  If not, do that first to get more travel.


          Jon Lowe


          -----Original Message-----
          From: colin chariandy <cchariandy at yahoo.ca>
          To: nsrca-discussion at lists.nsrca.org; glmiller3 at suddenlink.net; Ed Alt <ed_alt at hotmail.com>
          Sent: Sat, 2 May 2009 11:16 am
          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.














          I know most are probabl
          y fed up of this but I've got some info that may help others...


           


          After changing the regulator, battery and throttle servo I checked the regulator load as follows:


           


          Bench - 160mA.


          Feild, Engine off, windy day - 160-200mA


          Engine idle - 1.6A!!


          Mid power (roughest) - 2.0A!!!!


           


          I tried to isolate the high draw by holding each control. When I held the two ailerons it dropped to 680mA from 2.0A.


           


          This year, in an attempt to speed up my snaps I changed to dubro super long servo arms.


           


          I'll need to improve the settings on the engine to smooth it out a bit and/or go back to the shorter arms.


           


          With this set-up I would have to consume 300-400mAhrs per flight. I typically fly 4-5 flights....that's too close to the limit for a 2000mAhr pack and could easily have cost me the plane if I wasnt checking between flights. For what ever the reason the rx shut down on the ground....I am very grateful


           


          Anyone using long arms with big 4Cs, ensure that you arent taking too much out of your packs.


           


          Now...any advice on how to smooth out the mid range on the 170? Top end is amazing, idle is reliable...what should I change?


           


          Colin.

          --- On Tue, 4/28/09, Ed Alt <ed_alt at ho
          tmail.com> wr ote:




          From: Ed Alt <ed_alt at hotmail.com>
          Subject: RE: [NSRCA-discussion] JR DSM glitch - trouble-shooting.
          To: cchariandy at yahoo.ca, nsrca-discussion at lists.nsrca.org, glmiller3 at suddenlink.net
          Received: Tuesday, April 28, 2009, 11:15 AM





          Handle the problem as you see fit, I've done my best to give you advice that has always served me well.  Good luck!
           
          Ed
           


          ------------------------------------------------------------

          Date: Tue, 28 Apr 2009 05:19:28 -0700
          From: cchariandy at yahoo.ca
          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.
          To: nsrca-discussion at lists.nsrca.org; glmiller3 at suddenlink.net; ed_alt at hotmail.com











          Additionally, if the average for flight was 0.16A then we would only consume 21mAhr in a typical 8min flight. Not the case, it' s more like 150mAhr.


           


          Colin

          --- On Tue, 4/28/09, colin chariandy <cchariandy at yahoo.ca> wrote:




          From: colin chariandy <cchariandy at yahoo.ca>
          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.
          To: "General pattern discussion" <nsrca-discussion at lists.nsrca.org>, glmiller3 at suddenlink.net, "Ed Alt" <ed_alt at hotmail.com>
          Received: Tuesday, April 28, 2009, 8:12 AM













          Binding in the neutral position????


           


          Everything is free, I can't find any mechanical problems.

          --- On Tue, 4/28/09, Ed Alt <ed_alt at hotmail.com>=2
          0wrote:




          From: Ed Alt <ed_alt at hotmail.com>
          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.
          To: "colin chariandy" <cchariandy at yahoo.ca>, "General pattern discussion" <nsrca-discussion at lists.nsrca.org>, glmiller3 at suddenlink.net
          Received: Tuesday, April 28, 2009, 12:28 AM







          The idle current of 0.16A is about as high as your avwerage current for model in flight should be.  Something is binding.




          ----- Original Message -----


          From: colin chariandy


          To: General pattern discussion ; glmiller3 at suddenlink.net ; Ed Alt


          Sent: Tuesday, April 28, 2009 12:04 AM


          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.














          Just tried the same using the regulator from my back-up (same except not switched) and a new throttle servo.


           


          Throttle servo amps increased to 0.35A max.


           


          Although the package was labelled 6.0V the output is 5.7V and min output was 5.5V.


           


          After a minute of servo wagging it was hotter than the original.

          --- On Mon, 4/27/09, colin chariandy <cchariandy at yahoo.ca> wrote:




          From: colin chariandy <cchariandy at yahoo.ca>
          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.
          To: "General pattern discussion" <nsrca-discussion at lists.nsrca.org>, glmiller3 at suddenlink.net, "Ed Alt" <ed_alt at hotmail.com>
          Received: Monday, April 27,
          2009, 9:22 PM













          Ok, although this is a 1 year old airplane with 150 flights I checked the current draw after the regulator with all servos energized and the engine off.


           


          I used a "watts up" meter that logs peaks (but I'm not sure what the sampling fequency is).


           


          Idle current - 0.16A.


          Throttle servo movement max - 0.25A (doesnt seem like a problem but it's a little more noisy than a new one).


          All other servos - 0.22-0.24 A max.


          Moving all servos together rapidly - 1.72A max.


          Regulator output min - 5.82V


           


          I did this (moved all the servos rapidly for 1 min) and checked the little heat sink at the end of the regulator chip...quite warm, almost hot.


           


          I may try this again with the engine running and compare the results.


           
          =0 A

          Colin.

          --- On Mon, 4/27/09, Ed Alt <ed_alt at hotmail.com> wrote:




          From: Ed Alt <ed_alt at hotmail.com>
          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.
          To: "General pattern discussion" <nsrca-discussion at lists.nsrca.org>, "colin chariandy " <cchariandy at yahoo.ca>, glmiller3 at suddenlink.net
          Received: Monday, April 27, 2009, 6:24 PM



          This is easy to resolve.  Nothing high tech is needed.  One by one, move your controls and carefully watch to see if it looks l
          ike the any of them are straining at the end of their maximum travel.  Check the throttle in particular.  I have seen digital servo cases melt from having the throw set up further than the linkage will allow.  If that's not it, disconnect the linkages at servo and work the control surface by hand.  If it does not move very freely, fix it.  If you don't find the problem there, work the servos around in a 10 minute mock flight on the ground, except exaggerate the movements considerably since there will be no air load and engine vibration to add to the loa d.  Listen to each servo.  If it sounds like it's having a problem, remove it and check it out on the bench.  If there's nothing obviously wrong by the sound of things, then feel the servo cases  to see
            if any of them are getting warm, or even try smelling them for that characteristic smell that hot electronics tend to have.  If there is a regulator that got so hot as to discolor it, and there is nothing at all wrong with the linkages or control surfaces, then this ought to find the culprit.

          Ed
          ----- Original Message ----- From: "David Cotton " <davercotton at hotmail.com>
          To: "colin chariandy " <cchariandy at yahoo.ca>; <nsrca-discussion at lists.nsrca.org>; <glmiller3 at suddenlink.net>
          Sent: Monday, April 27, 2009 6:09 PM
          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.


          You will need a very good meter
          to read the current, because a fully loaded digital setup takes the current in short spikes and most meters do not have a good enough frequency response. I have tried using a very good quality HP meter with over 20k frequency response and concluded it's not accurate, but it does give you a ball park numb er and will indicate if you have a serious problem. I have monitored my receiver voltage using a FDR data recorder and using two nimh batteries pack in parallel see at least one volt drop spikes at the receiver when the servos are heavily loaded.  I run 2 20amp  schottky diode connected packs in parallel for safety. You can be sure that these spikes are  5amps  or more. I placed a Castel reg in the circuit and it drops the spikes to a few
          hundred millivolts

          The average current draw is around 250 mA for 2 masters sequences.

          Hope this helps. Incidentally the regulator does not get hot.
          Sent via BlackBerry by AT&T

          -----Original Message-----
          From: colin chariandy <cchariandy at yahoo.ca>

          Date: Mon, 27 Apr 2009 20:40:21
          To: <nsrca-discussion at lists.nsrca.org>; <glmiller3 at suddenlink.net>
          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.


          Yes.

          I can't find by physical inspection any "wacked out servos" or other issues that might cause increased current load on the regulator.
            So....I'm trying to find the typical (or average) current that should be seen at any moment (inst
          ant) on a meter in-line with the regulator. Then I'll run my set-up and compare. If I'm in the ball park (less than 1A based on a couple of inputs so far) then the problem is not related to "wacked out" servos, binding etc.

          Colin

          --- On Mon, 4/27/09, Ed Alt <ed_alt at hotmail.com> wrote:

          From: Ed Alt <ed_alt at hotmail.com>
          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.
          To: nsrca-discussion at lists.nsrca.org, glmiller3 at suddenlink.net
          Received: Monday, April 27, 2009, 3:25 PM


          Average current is not the same as instantaneous current, unless the only current being drawn was just for that single instant in time. Anyway, I will repeat, with an added quailifer, for the sake of understanding for where to look to help you solve the problem:

          If you are using a JACCIO, Tech-Aero, or whatever regulator in a pattern setup, even with a YS CDI on a shared output, and if you find that you need a heat sink, then:


          Something Else Is Wrong. Check your setup for binding linkages, stiff hinges, whacked out servos, whatever.

          Seriously, check your setup, OK? Just trying to help here.

          Regards
          Ed


          ----------------
          Date: Mon, 27 Apr 2009 10:32:54 -0700
          From: cchariandy at yahoo.ca
          To: nsrca-discussion at lists.nsrca.org; glmiller3 at suddenlink.net
          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.



          Actually, if you consumed 200mAhr in 0.25hrs, then your average (instantaneous) current was 800mA.0D

          Colin.

          --- On Mon, 4/27/09, glmiller3 at suddenlink.net <glmiller3 at suddenlink.net> wrote:

          From: glmiller3 at suddenlink.net <glmiller3 at suddenlink.net>
          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.
          To: "General pattern discussion" <nsrca-discussion at lists.nsrca.org>
          Cc: "colin chariandy" <cchariandy at yahoo.ca>
          Received: Monday, April 27, 2009, 12:34 PM


          Colin,

          I'm running a different ignition system, but total consumption radio and ignition) for an entire 15 minute flight is about 200 mah..200 X4 = 800 milliamps for an hour==2 00.8 amps per hour So the
          instantaneous current shouldn't be much.

          G

          ---- colin chariandy <cchariandy at yahoo.ca <http://ca.mc313.mail.yahoo.com/mc/compose?to=cchariandy@yahoo.ca> > wrote:

          =============
          Does anyone know what the current consumption should be at idle/run-up for a typical YS170/Hyde/all digital servos installation?

          I'll stick a Watt's Up meter in there to see how much I'm pulling after the regulator.

          Jim, what's the current limit for continuous operation and spike/inrush for your regulator?

          Colin.

          --- On Sun, 4/26/09, James Oddino <joddino at socal.rr.com <http://ca.mc313.mail.yahoo.com/mc/compose?to=joddino@socal.rr.com> > wrote:


          From: James Oddino <joddino at socal.rr.com <http://ca.mc313.mail.yahoo.com/mc/compose?to=joddino@socal.rr.com> >
          Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.
          To: cchariandy at yahoo.ca <htt p://ca.mc313.mail.yahoo.com/mc/compose?to=cchariandy@yahoo.
          ca> , "General discussion" <nsrca-discussion at lists.nsrca.org <http://ca.mc313.mail.yahoo.com/mc/compose?to=nsrca-discussion@lists.nsrc

          a.org> >
          Received: Sunday, April 26, 2009, 4:00 PM


          I don't believe a bad battery could cause the engine to rev up unless your battery failsafe isn't set properly. Make sure it is.


          The first thing I would look at is the possibility that the throttle servo is stalled at low speed. That could be pulling the battery/voltage regulator voltage down and it could recover after you started to throttle up and removed the heavy load.


          Finally I would run a one amp discharge test on the battery after it is fully charged to see if the battery is near its original capacity. The best way to
            do this is to plot the voltage vs. time taking readings every 5 to 10 minutes.


          Hope this helps. Let us know what you find.


          Jim





          On Apr 25, 2009, at 4:30 PM, cchariandy at yahoo.ca <http://ca.mc313.mail.yahoo.com/mc/compose?to=cchariandy@yahoo.ca>  wrote:







          I had a close call today=2 0with my R921 Rx in an Integral.

          I noticed on taxi out that the engine rev'd up and quickly back down without any command. At first I thought I must have bumped the stick by accident. Then just before take-off there was no responce from the throttle for a second or two then it was back. I thought the 170 may have loaded up a lit
          tle and didnt respond. It did that one more time before
            I aborted the flight. However, I could'nt reproduce the problem in the pits.

          Before powering down, I checked for holds or fades on the data logger - nil.

          Battery voltage droped from 8.2V to 7.8V and 7.6 under 1A load. When I re-charged it took 350mA and I was only on for 3-4 mins.

          Now...I did accidentally run the battery down to like 5V during winter but it did eventually recharge.

          I'm using a Jaccio perfect switch/6V regulator, Jaccio 2000mAHr (1 season



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