Wattflyer RC Network: RC Universe :: RCU Magazine :: RCU Forums :: RCU Classifieds :: RCU User Reviews :: RCU YouTube
Home Who's Online Calendar Today's Posts RealTime Post Spy Mark Forums Read
Go Back   WattFlyer RC Electric Flight Forums - Discuss radio control eflight > Electric R/C Airplanes > Beginners
Register Members List Wattflyer Extras Articles Search Today's Posts Mark Forums Read Social Groups

Beginners New to e-power flying? Get the low down in here from experienced e-power RC pilots!

Thank you for your support (hide ads)
Reply
 
Thread Tools Display Modes
Old 09-09-2018, 12:06 PM   #1
RONALDO_UK
Member
 
Join Date: Jun 2011
Posts: 148
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default Linear servos:

Hi - is it possible to adjust linear servos (in a Parkzone micro Cub)? - I've got much more throw in one direction than the other.

Any advice will be appreciated.

Regards.
RONALDO_UK is offline  
  Reply With Quote
Old 09-09-2018, 02:23 PM   #2
giflyrc
Gravity is Attractive
 
Join Date: Aug 2005
Location: ALLIANCE, OHIO
Posts: 180
Thanked 9 Times in 8 Posts
Club: ALLIANCE BALSA BEES
iTrader: (2)
Friends: (0)
Default

If all servos are affected the same way; the problem is most likely in the transmitter

If not then try cleaning the linear servo

I had a new Kraft tx that had to be readjusted to center the pulse and then travel became equal in both directions

Roger aka GIFLYRC

Independently Poor
giflyrc is offline  
  Reply With Quote
Old 09-09-2018, 03:38 PM   #3
Turbojoe
Mountain Models Minion
 
Turbojoe's Avatar
 
Join Date: Aug 2005
Location: Mesa, Arizona
Posts: 1,104
Thanked 48 Times in 47 Posts
iTrader: (1)
Friends: (12)
Default

A few questions:

Is this a brand new plane or did you just find this problem after flying it for a while?

Are you using the little PNP transmitter or a better unit with programmability?

Are you sure your TX trims are centered?

Post a few GOOD pictures of the offending servo. Especially of the nut on the end of the threaded transit shaft. Those nuts have a habit of coming loose and even falling off. The transit shaft bearings fail regularly as well. The servos get really sloppy when any of that happens.

Anytime you are even looking at the servos then get out a Q-tip and some rubbing alcohol and clean off the carbon strip. Deoxit is best but the Q-tip and alcohol works in a pinch.

When I had all my micro helis I saved dozens of linear servos just by cleaning and a little Loctite on those blasted little shaft nuts.

Joe

The nonsensical ravings of a lunatic mind.....
Turbojoe is offline  
  Reply With Quote
Old 09-09-2018, 10:25 PM   #4
RONALDO_UK
Member
 
Join Date: Jun 2011
Posts: 148
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

Hi again -
Thanks for the fast responses and advice, much of which is useful regardless of my present problem. My photos are not good enough quality at the moment. This plane is 7 years old (the first I bought) and I'm using a Spektrum DX8 tx. I was flying it quite well a week ago. The rudder works fine in both directions, it's the elevator that is the problem. I had to use maximum trim to try and centre the control surface (which wasn't enough). I also relocated the control wire further up the horn to give more movement but it's now back in stock position (which I think is the lowest hole). Essentially it seems when the control surface is in its neutral position the servo mechanism has insufficient rail length to the left (up elevator) but of course more than enough to the right (down elevator). I'm beginning to think it may be as simple as adjusting the wire linkage to centre the elevator if possible, rather than using trim/subtrim. I'll give it a go but I've never had to change it in the past. And the blindingly obvious occurred to me - if you could adjust the servo itself it would presumably move the control surface anyway!

Regards.

PS Luckily I now have a lot more planes but this one has always been fun to fly on fairly calm days.
RONALDO_UK is offline  
  Reply With Quote
Old 09-09-2018, 11:40 PM   #5
Turbojoe
Mountain Models Minion
 
Turbojoe's Avatar
 
Join Date: Aug 2005
Location: Mesa, Arizona
Posts: 1,104
Thanked 48 Times in 47 Posts
iTrader: (1)
Friends: (12)
Default

OK. DX8 that's good. Make sure to double check the servo travel and rates. Make sure the numbers are even in both directions.

I'm sure you've already tried this but verify please. When the trim in the TX is centered is the servo centered? If the TX and servo are centered then either your elevator pushrod got bent or there is a mechanical issue (loose parts) in the servo. Take a close look at the elevator hinges too. Make sure one side isn't torn from the H Stab.

Joe

The nonsensical ravings of a lunatic mind.....
Turbojoe is offline  
  Reply With Quote
Old 09-10-2018, 07:53 AM   #6
RONALDO_UK
Member
 
Join Date: Jun 2011
Posts: 148
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

Hi Joe -

Thanks for that. No - when the trim is centred the servo is not centred. But I think you're right about the pushrod (and the thin plastic horn may also be fatigued) - the hinge itself looks fine. The Z-bend on the horn is a short wire heat-shrunk onto the main length of the pushrod so it may be worthwhile re-making this and also replacing the horn.

Thanks again for your advice.
RONALDO_UK is offline  
  Reply With Quote
Old 09-10-2018, 12:56 PM   #7
RONALDO_UK
Member
 
Join Date: Jun 2011
Posts: 148
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

Hi Joe -

I had a bit of luck without resorting to microsurgery! The Z-bend section of the control wire was a little loose inside the heatshrink and I was able to wriggle it out. I centralised the tx trim and subtrim, and the elevator control surface - then reinserted the Z-bend section and sealed it in position. I think I've now got enough up (and down) movement for full control - it doesn't need much.

Thanks for pointing me in the right direction.

Regards.
RONALDO_UK is offline  
  Reply With Quote
Old 09-10-2018, 05:15 PM   #8
Turbojoe
Mountain Models Minion
 
Turbojoe's Avatar
 
Join Date: Aug 2005
Location: Mesa, Arizona
Posts: 1,104
Thanked 48 Times in 47 Posts
iTrader: (1)
Friends: (12)
Default

It's good to hear that you may have found a solution. That non centering servo is still a bit concerning though.


Joe

The nonsensical ravings of a lunatic mind.....
Turbojoe is offline  
  Reply With Quote
Old 09-11-2018, 01:54 AM   #9
ron_van_sommeren
homo ludens modelisticus
 
ron_van_sommeren's Avatar
 
Join Date: Jul 2005
Location: near Nijmegen, Netherlands
Posts: 953
Thanked 180 Times in 159 Posts
Club: www.rmvc-cumulus.nl
iTrader: (0)
Friends: (0)
Default

Originally Posted by RONALDO_UK View Post
... The rudder works fine in both directions, it's the elevator that is the problem. ...
Swap rudder and elevator connectors on your receiver.

Problem still on same servo: servo, control wire or horn problem. Are the horns perpendicular to servo respectively control surface?
Problem on other servo: transmitter problem.

Vriendelijke groeten Ron
Without a watt-meter you are in the dark, until something starts to glow
e-flight calculators watt-meters diy motor tips Cumulus MFC
ron_van_sommeren is offline  
  Reply With Quote
Old 09-11-2018, 05:19 AM   #10
Turbojoe
Mountain Models Minion
 
Turbojoe's Avatar
 
Join Date: Aug 2005
Location: Mesa, Arizona
Posts: 1,104
Thanked 48 Times in 47 Posts
iTrader: (1)
Friends: (12)
Default

I was going to suggest the connector swap but (and I'm probably wrong here) isn't this one of the older birds that has the servos mounted on the board?

Joe

The nonsensical ravings of a lunatic mind.....
Turbojoe is offline  
  Reply With Quote
Old 09-11-2018, 09:50 AM   #11
RONALDO_UK
Member
 
Join Date: Jun 2011
Posts: 148
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

Hi Joe/ Ron -

I'm inclined to think the Cub is more or less back to stock set-up. Yes, it is onboard servos. They more or less centre - certainly there's room for maximum movement in both directions. Hopefully I'm attaching photos to show the state of affairs.

I didn't even think to swap controls on the tx altho' the problem obviously lay with the elevator adjustment (in hindsight!). Thanks again for all your advice.

Regards.


Attached Images
File Type: jpg CUB_MICRO_08.jpg (726.8 KB, 59 views)
File Type: jpg CUB_MICRO_09.jpg (647.2 KB, 56 views)
RONALDO_UK is offline  
  Reply With Quote
Old 09-11-2018, 01:15 PM   #12
Turbojoe
Mountain Models Minion
 
Turbojoe's Avatar
 
Join Date: Aug 2005
Location: Mesa, Arizona
Posts: 1,104
Thanked 48 Times in 47 Posts
iTrader: (1)
Friends: (12)
Default

Awesome! The pictures help a lot. If you still need more elevator then move the linkage UP towards the elevator for more effective surface travel. Try going one hole at a time until you get what works for you. All six of my UMX's had what I considered weak control surface response. I moved the linkage on all of them then added expo and dual rates in the TX to suit my flying style.

Joe

The nonsensical ravings of a lunatic mind.....
Turbojoe is offline  
  Reply With Quote
Old 09-11-2018, 08:45 PM   #13
RONALDO_UK
Member
 
Join Date: Jun 2011
Posts: 148
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

Hi Joe -

You wouldn't say awesome if you saw the front end which I deliberately omitted - it's a bit snub-nosed from various calamities! It was the first plane I bought 7 years ago on some impulse I've now forgotten and got me into the hobby late in life. It's a wonder I stuck with it as there were a few early crashes as I learned. The stock motor had a very small diameter shaft (about 1mm), prone to breaking - and it would normally break off and embed in the prop. Being Parkzone, spares were expensive for something so trivial - about $15 for shaft and prop plus a week's wait. It's now got a Mustang motor which has a thicker and more durable shaft. Later I joined a local club, prompted by a guy on this site who's also a member and an ace flyer. Luckily, the Cub's a lot easier for me now and flew as well as ever a week or so ago - probably even better now? I doubt I'll need to make any changes - I presume you have to twist the horn a little to remove the Z-bend? - at least I did. At 1oz it's a very delicate plane!

Thanks for your help and advice - happy flying!

Regards, Ron.
RONALDO_UK is offline  
  Reply With Quote
Old 09-12-2018, 06:04 AM   #14
Turbojoe
Mountain Models Minion
 
Turbojoe's Avatar
 
Join Date: Aug 2005
Location: Mesa, Arizona
Posts: 1,104
Thanked 48 Times in 47 Posts
iTrader: (1)
Friends: (12)
Default

Hey, things get a few bumps and bruises over time. That just means you're using and enjoying it. Those basic birds are a lot of fun. My (almost) son in law saw all my planes a few years back and wanted to get one. I took him over to the LHS and had him buy the RTF HobbyZone Champ. I did the maiden and was absolutely amazed at how well something that tiny and light could be so much fun. He destroyed it but I got my fun. Best part was three days later my daughter came to her senses and dumped that idiot.

Oh yeah, I did like you and was able to just twist the control horn enough to move the link and not do any damage on all of my UMX's.

Let us know how the next flight goes.

Joe

The nonsensical ravings of a lunatic mind.....
Turbojoe is offline  
  Reply With Quote
Old 09-15-2018, 12:39 AM   #15
Wildflyer
Past President of PSSF
 
Wildflyer's Avatar
 
Join Date: Sep 2009
Location: Lacey WA, 1 mile E of Mushroom Corner
Posts: 1,860
Thanked 181 Times in 176 Posts
Club: Puget Sound Silent Flyers -PSSF & Thurston County Miniature Aircraft Association - TCMAA
iTrader: (3)
Friends: (8)
Default

My flying buddy told me he found out that some of the tiny linear servos are made to travel further in one direction than the other. Just a non linear feed back pot.

They may be made for aileron usage in certain planes. It took him a while of searching to find this info, I could ask him where he found it if you like.


He too thought something was wrong with the servos.

Dave R, KI7MTA Proud PGR rider.
When you have flying skills like mine,
You become a master at repair.
Wildflyer is online now  
  Reply With Quote
Old 09-15-2018, 10:57 AM   #16
RONALDO_UK
Member
 
Join Date: Jun 2011
Posts: 148
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

Hi -

Thanks but don't worry - the servo perhaps doesn't exactly centre but is near enough to allow maximum movement in both directions. I think the problem was more related to trim, subtrim and postion of the linkage on the horn.

Thanks again.

Regards.
RONALDO_UK is offline  
  Reply With Quote
Old 09-15-2018, 11:04 AM   #17
RONALDO_UK
Member
 
Join Date: Jun 2011
Posts: 148
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

Hi Joe -

I flew the Cub the other day and I'm pleased to say it behaved itself and all is well.

I've got a Champ too. It's excellent for a beginner but I've found it less challenging than the Cub but very relaxing. It's my second - with the first one I was flying but took my eye off the ball for a second then couldn't locate it again! I think it was heading towards London Gatwick Airport which is a couple of miles from our site - just hope it didn't interfere with any commercial flights!

Regards.
RONALDO_UK is offline  
  Reply With Quote
Old 09-15-2018, 03:03 PM   #18
Turbojoe
Mountain Models Minion
 
Turbojoe's Avatar
 
Join Date: Aug 2005
Location: Mesa, Arizona
Posts: 1,104
Thanked 48 Times in 47 Posts
iTrader: (1)
Friends: (12)
Default

Glad to hear you got it all sorted and having fun with it again.

Joe

The nonsensical ravings of a lunatic mind.....
Turbojoe is offline  
  Reply With Quote
Reply

  WattFlyer RC Electric Flight Forums - Discuss radio control eflight > Electric R/C Airplanes > Beginners


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Let's talk about servos - Whatever is on your mind AEAJR Beginners 287 07-29-2017 11:11 PM
Everything You Wanted To Know About Electric Powered Flight AEAJR Beginners 165 06-28-2017 04:22 PM
Hitec BRUSHLESS servos now in stock! ServoCity New Product Announcements 0 07-09-2014 03:26 PM
ESC Linear BEC Current Rating??? kyleservicetech Power Systems 11 09-06-2011 05:19 AM
Walkera 5g6 brushless, carbon fiber frame, linear servos Mirek001 Micro Sized Electric Helicopters 0 02-20-2011 01:30 AM


All times are GMT +1. The time now is 03:56 AM.


Powered by: vBulletin
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright 2005 WattfFlyer.com
RCU Eflight HQ

Charities we support Select: Yorkie Rescue  ::  Crohn's & Colitis Foundation



Page generated in 0.18903 seconds with 59 queries